/* pngrtran.c - transforms the data in a row for PNG readers
*
- * Last changed in libpng 1.5.2 [March 31, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ * Last changed in libpng 1.5.14 [January 24, 2013]
+ * Copyright (c) 1998-2013 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
return;
}
- png_ptr->transformations |= PNG_BACKGROUND;
+ png_ptr->transformations |= PNG_COMPOSE | PNG_STRIP_ALPHA;
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
png_memcpy(&(png_ptr->background), background_color,
png_sizeof(png_color_16));
png_ptr->background_gamma = background_gamma;
png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
- png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0);
+ if (need_expand)
+ png_ptr->transformations |= PNG_BACKGROUND_EXPAND;
+ else
+ png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
}
# ifdef PNG_FLOATING_POINT_SUPPORTED
# endif /* FLOATING_POINT */
#endif /* READ_BACKGROUND */
-#ifdef PNG_READ_16_TO_8_SUPPORTED
-/* Strip 16 bit depth files to 8 bit depth */
+/* Scale 16-bit depth files to 8-bit depth. If both of these are set then the
+ * one that pngrtran does first (scale) happens. This is necessary to allow the
+ * TRANSFORM and API behavior to be somewhat consistent, and it's simpler.
+ */
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+void PNGAPI
+png_set_scale_16(png_structp png_ptr)
+{
+ png_debug(1, "in png_set_scale_16");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->transformations |= PNG_SCALE_16_TO_8;
+}
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+/* Chop 16-bit depth files to 8-bit depth */
void PNGAPI
png_set_strip_16(png_structp png_ptr)
{
return;
png_ptr->transformations |= PNG_16_TO_8;
- png_ptr->transformations &= ~PNG_EXPAND_16;
}
#endif
}
#endif
+#if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED)
+static png_fixed_point
+translate_gamma_flags(png_structp png_ptr, png_fixed_point output_gamma,
+ int is_screen)
+{
+ /* Check for flag values. The main reason for having the old Mac value as a
+ * flag is that it is pretty near impossible to work out what the correct
+ * value is from Apple documentation - a working Mac system is needed to
+ * discover the value!
+ */
+ if (output_gamma == PNG_DEFAULT_sRGB ||
+ output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB)
+ {
+ /* If there is no sRGB support this just sets the gamma to the standard
+ * sRGB value. (This is a side effect of using this function!)
+ */
+# ifdef PNG_READ_sRGB_SUPPORTED
+ png_ptr->flags |= PNG_FLAG_ASSUME_sRGB;
+# endif
+ if (is_screen)
+ output_gamma = PNG_GAMMA_sRGB;
+ else
+ output_gamma = PNG_GAMMA_sRGB_INVERSE;
+ }
+
+ else if (output_gamma == PNG_GAMMA_MAC_18 ||
+ output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18)
+ {
+ if (is_screen)
+ output_gamma = PNG_GAMMA_MAC_OLD;
+ else
+ output_gamma = PNG_GAMMA_MAC_INVERSE;
+ }
+
+ return output_gamma;
+}
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+static png_fixed_point
+convert_gamma_value(png_structp png_ptr, double output_gamma)
+{
+ /* The following silently ignores cases where fixed point (times 100,000)
+ * gamma values are passed to the floating point API. This is safe and it
+ * means the fixed point constants work just fine with the floating point
+ * API. The alternative would just lead to undetected errors and spurious
+ * bug reports. Negative values fail inside the _fixed API unless they
+ * correspond to the flag values.
+ */
+ if (output_gamma > 0 && output_gamma < 128)
+ output_gamma *= PNG_FP_1;
+
+ /* This preserves -1 and -2 exactly: */
+ output_gamma = floor(output_gamma + .5);
+
+ if (output_gamma > PNG_FP_MAX || output_gamma < PNG_FP_MIN)
+ png_fixed_error(png_ptr, "gamma value");
+
+ return (png_fixed_point)output_gamma;
+}
+# endif
+#endif /* READ_ALPHA_MODE || READ_GAMMA */
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+void PNGFAPI
+png_set_alpha_mode_fixed(png_structp png_ptr, int mode,
+ png_fixed_point output_gamma)
+{
+ int compose = 0;
+ png_fixed_point file_gamma;
+
+ png_debug(1, "in png_set_alpha_mode");
+
+ if (png_ptr == NULL)
+ return;
+
+ output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
+
+ /* Validate the value to ensure it is in a reasonable range. The value
+ * is expected to be 1 or greater, but this range test allows for some
+ * viewing correction values. The intent is to weed out users of this API
+ * who use the inverse of the gamma value accidentally! Since some of these
+ * values are reasonable this may have to be changed.
+ */
+ if (output_gamma < 70000 || output_gamma > 300000)
+ png_error(png_ptr, "output gamma out of expected range");
+
+ /* The default file gamma is the inverse of the output gamma; the output
+ * gamma may be changed below so get the file value first:
+ */
+ file_gamma = png_reciprocal(output_gamma);
+
+ /* There are really 8 possibilities here, composed of any combination
+ * of:
+ *
+ * premultiply the color channels
+ * do not encode non-opaque pixels
+ * encode the alpha as well as the color channels
+ *
+ * The differences disappear if the input/output ('screen') gamma is 1.0,
+ * because then the encoding is a no-op and there is only the choice of
+ * premultiplying the color channels or not.
+ *
+ * png_set_alpha_mode and png_set_background interact because both use
+ * png_compose to do the work. Calling both is only useful when
+ * png_set_alpha_mode is used to set the default mode - PNG_ALPHA_PNG - along
+ * with a default gamma value. Otherwise PNG_COMPOSE must not be set.
+ */
+ switch (mode)
+ {
+ case PNG_ALPHA_PNG: /* default: png standard */
+ /* No compose, but it may be set by png_set_background! */
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+ break;
+
+ case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */
+ compose = 1;
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+ /* The output is linear: */
+ output_gamma = PNG_FP_1;
+ break;
+
+ case PNG_ALPHA_OPTIMIZED: /* associated, non-opaque pixels linear */
+ compose = 1;
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags |= PNG_FLAG_OPTIMIZE_ALPHA;
+ /* output_gamma records the encoding of opaque pixels! */
+ break;
+
+ case PNG_ALPHA_BROKEN: /* associated, non-linear, alpha encoded */
+ compose = 1;
+ png_ptr->transformations |= PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+ break;
+
+ default:
+ png_error(png_ptr, "invalid alpha mode");
+ }
+
+ /* Only set the default gamma if the file gamma has not been set (this has
+ * the side effect that the gamma in a second call to png_set_alpha_mode will
+ * be ignored.)
+ */
+ if (png_ptr->gamma == 0)
+ png_ptr->gamma = file_gamma;
+
+ /* But always set the output gamma: */
+ png_ptr->screen_gamma = output_gamma;
+
+ /* Finally, if pre-multiplying, set the background fields to achieve the
+ * desired result.
+ */
+ if (compose)
+ {
+ /* And obtain alpha pre-multiplication by composing on black: */
+ png_memset(&png_ptr->background, 0, sizeof png_ptr->background);
+ png_ptr->background_gamma = png_ptr->gamma; /* just in case */
+ png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE;
+ png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
+
+ if (png_ptr->transformations & PNG_COMPOSE)
+ png_error(png_ptr,
+ "conflicting calls to set alpha mode and background");
+
+ png_ptr->transformations |= PNG_COMPOSE;
+ }
+
+ /* New API, make sure apps call the correct initializers: */
+ png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
+}
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_alpha_mode(png_structp png_ptr, int mode, double output_gamma)
+{
+ png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr,
+ output_gamma));
+}
+# endif
+#endif
+
#ifdef PNG_READ_QUANTIZE_SUPPORTED
-/* Dither file to 8 bit. Supply a palette, the current number
+/* Dither file to 8-bit. Supply a palette, the current number
* of elements in the palette, the maximum number of elements
* allowed, and a histogram if possible. If the current number
* of colors is greater then the maximum number, the palette will be
#endif /* PNG_READ_QUANTIZE_SUPPORTED */
#ifdef PNG_READ_GAMMA_SUPPORTED
-/* Transform the image from the file_gamma to the screen_gamma. We
- * only do transformations on images where the file_gamma and screen_gamma
- * are not close reciprocals, otherwise it slows things down slightly, and
- * also needlessly introduces small errors.
- *
- * We will turn off gamma transformation later if no semitransparent entries
- * are present in the tRNS array for palette images. We can't do it here
- * because we don't necessarily have the tRNS chunk yet.
- */
-static int /* PRIVATE */
-png_gamma_threshold(png_fixed_point scrn_gamma, png_fixed_point file_gamma)
-{
- /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma
- * correction as a difference of the overall transform from 1.0
- *
- * We want to compare the threshold with s*f - 1, if we get
- * overflow here it is because of wacky gamma values so we
- * turn on processing anyway.
- */
- png_fixed_point gtest;
- return !png_muldiv(>est, scrn_gamma, file_gamma, PNG_FP_1) ||
- png_gamma_significant(gtest);
-}
-
void PNGFAPI
png_set_gamma_fixed(png_structp png_ptr, png_fixed_point scrn_gamma,
png_fixed_point file_gamma)
if (png_ptr == NULL)
return;
- if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) ||
- (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
- png_gamma_threshold(scrn_gamma, file_gamma))
- png_ptr->transformations |= PNG_GAMMA;
+ /* New in libpng-1.5.4 - reserve particular negative values as flags. */
+ scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/);
+ file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/);
+
+#if PNG_LIBPNG_VER >= 10600
+ /* Checking the gamma values for being >0 was added in 1.5.4 along with the
+ * premultiplied alpha support; this actually hides an undocumented feature
+ * of the previous implementation which allowed gamma processing to be
+ * disabled in background handling. There is no evidence (so far) that this
+ * was being used; however, png_set_background itself accepted and must still
+ * accept '0' for the gamma value it takes, because it isn't always used.
+ *
+ * Since this is an API change (albeit a very minor one that removes an
+ * undocumented API feature) it will not be made until libpng-1.6.0.
+ */
+ if (file_gamma <= 0)
+ png_error(png_ptr, "invalid file gamma in png_set_gamma");
+
+ if (scrn_gamma <= 0)
+ png_error(png_ptr, "invalid screen gamma in png_set_gamma");
+#endif
+
+ /* Set the gamma values unconditionally - this overrides the value in the PNG
+ * file if a gAMA chunk was present. png_set_alpha_mode provides a
+ * different, easier, way to default the file gamma.
+ */
png_ptr->gamma = file_gamma;
png_ptr->screen_gamma = scrn_gamma;
}
void PNGAPI
png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
{
- png_set_gamma_fixed(png_ptr,
- png_fixed(png_ptr, scrn_gamma, "png_set_gamma screen gamma"),
- png_fixed(png_ptr, file_gamma, "png_set_gamma file gamma"));
+ png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma),
+ convert_gamma_value(png_ptr, file_gamma));
}
# endif /* FLOATING_POINT_SUPPORTED */
#endif /* READ_GAMMA */
#endif /* defined(PNG_READ_EXPAND_SUPPORTED) */
#ifdef PNG_READ_EXPAND_16_SUPPORTED
-/* Expand to 16 bit channels, expand the tRNS chunk too (because otherwise
+/* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise
* it may not work correctly.)
*/
void PNGAPI
return;
png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS);
- png_ptr->transformations &= ~PNG_16_TO_8;
-
png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
+
+ /* New API, make sure apps call the correct initializers: */
+ png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
}
#endif
switch(error_action)
{
- case 1:
+ case PNG_ERROR_ACTION_NONE:
png_ptr->transformations |= PNG_RGB_TO_GRAY;
break;
- case 2:
+ case PNG_ERROR_ACTION_WARN:
png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
break;
- case 3:
+ case PNG_ERROR_ACTION_ERROR:
png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
break;
}
#endif
{
- png_uint_16 red_int, green_int;
- if (red < 0 || green < 0)
+ if (red >= 0 && green >= 0 && red + green <= PNG_FP_1)
{
- red_int = 6968; /* .212671 * 32768 + .5 */
- green_int = 23434; /* .715160 * 32768 + .5 */
- }
+ png_uint_16 red_int, green_int;
- else if (red + green < 100000L)
- {
- red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L);
- green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L);
+ /* NOTE: this calculation does not round, but this behavior is retained
+ * for consistency, the inaccuracy is very small. The code here always
+ * overwrites the coefficients, regardless of whether they have been
+ * defaulted or set already.
+ */
+ red_int = (png_uint_16)(((png_uint_32)red*32768)/100000);
+ green_int = (png_uint_16)(((png_uint_32)green*32768)/100000);
+
+ png_ptr->rgb_to_gray_red_coeff = red_int;
+ png_ptr->rgb_to_gray_green_coeff = green_int;
+ png_ptr->rgb_to_gray_coefficients_set = 1;
}
else
{
- png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients");
- red_int = 6968;
- green_int = 23434;
+ if (red >= 0 && green >= 0)
+ png_warning(png_ptr,
+ "ignoring out of range rgb_to_gray coefficients");
+
+ /* Use the defaults, from the cHRM chunk if set, else the historical
+ * values which are close to the sRGB/HDTV/ITU-Rec 709 values. See
+ * png_do_rgb_to_gray for more discussion of the values. In this case
+ * the coefficients are not marked as 'set' and are not overwritten if
+ * something has already provided a default.
+ */
+ if (png_ptr->rgb_to_gray_red_coeff == 0 &&
+ png_ptr->rgb_to_gray_green_coeff == 0)
+ {
+ png_ptr->rgb_to_gray_red_coeff = 6968;
+ png_ptr->rgb_to_gray_green_coeff = 23434;
+ /* png_ptr->rgb_to_gray_blue_coeff = 2366; */
+ }
}
-
- png_ptr->rgb_to_gray_red_coeff = red_int;
- png_ptr->rgb_to_gray_green_coeff = green_int;
- png_ptr->rgb_to_gray_blue_coeff =
- (png_uint_16)(32768 - red_int - green_int);
}
}
}
#endif
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* In the case of gamma transformations only do transformations on images where
+ * the [file] gamma and screen_gamma are not close reciprocals, otherwise it
+ * slows things down slightly, and also needlessly introduces small errors.
+ */
+static int /* PRIVATE */
+png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma)
+{
+ /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma
+ * correction as a difference of the overall transform from 1.0
+ *
+ * We want to compare the threshold with s*f - 1, if we get
+ * overflow here it is because of wacky gamma values so we
+ * turn on processing anyway.
+ */
+ png_fixed_point gtest;
+ return !png_muldiv(>est, screen_gamma, file_gamma, PNG_FP_1) ||
+ png_gamma_significant(gtest);
+}
+#endif
+
/* Initialize everything needed for the read. This includes modifying
* the palette.
*/
-void /* PRIVATE */
-png_init_read_transformations(png_structp png_ptr)
+
+/*For the moment 'png_init_palette_transformations' and
+ * 'png_init_rgb_transformations' only do some flag canceling optimizations.
+ * The intent is that these two routines should have palette or rgb operations
+ * extracted from 'png_init_read_transformations'.
+ */
+static void /* PRIVATE */
+png_init_palette_transformations(png_structp png_ptr)
{
- png_debug(1, "in png_init_read_transformations");
+ /* Called to handle the (input) palette case. In png_do_read_transformations
+ * the first step is to expand the palette if requested, so this code must
+ * take care to only make changes that are invariant with respect to the
+ * palette expansion, or only do them if there is no expansion.
+ *
+ * STRIP_ALPHA has already been handled in the caller (by setting num_trans
+ * to 0.)
+ */
+ int input_has_alpha = 0;
+ int input_has_transparency = 0;
- {
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
- defined(PNG_READ_SHIFT_SUPPORTED) || \
- defined(PNG_READ_GAMMA_SUPPORTED)
- int color_type = png_ptr->color_type;
-#endif
+ if (png_ptr->num_trans > 0)
+ {
+ int i;
+
+ /* Ignore if all the entries are opaque (unlikely!) */
+ for (i=0; i<png_ptr->num_trans; ++i)
+ if (png_ptr->trans_alpha[i] == 255)
+ continue;
+ else if (png_ptr->trans_alpha[i] == 0)
+ input_has_transparency = 1;
+ else
+ input_has_alpha = 1;
+ }
+
+ /* If no alpha we can optimize. */
+ if (!input_has_alpha)
+ {
+ /* Any alpha means background and associative alpha processing is
+ * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA
+ * and ENCODE_ALPHA are irrelevant.
+ */
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
+ if (!input_has_transparency)
+ png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
+ }
#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+ /* png_set_background handling - deals with the complexity of whether the
+ * background color is in the file format or the screen format in the case
+ * where an 'expand' will happen.
+ */
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
- /* Detect gray background and attempt to enable optimization
- * for gray --> RGB case
- *
- * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
- * RGB_ALPHA (in which case need_expand is superfluous anyway), the
- * background color might actually be gray yet not be flagged as such.
- * This is not a problem for the current code, which uses
- * PNG_BACKGROUND_IS_GRAY only to decide when to do the
- * png_do_gray_to_rgb() transformation.
+ /* The following code cannot be entered in the alpha pre-multiplication case
+ * because PNG_BACKGROUND_EXPAND is cancelled below.
*/
if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
- !(color_type & PNG_COLOR_MASK_COLOR))
+ (png_ptr->transformations & PNG_EXPAND))
{
- png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
- }
+ {
+ png_ptr->background.red =
+ png_ptr->palette[png_ptr->background.index].red;
+ png_ptr->background.green =
+ png_ptr->palette[png_ptr->background.index].green;
+ png_ptr->background.blue =
+ png_ptr->palette[png_ptr->background.index].blue;
+
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+ if (png_ptr->transformations & PNG_INVERT_ALPHA)
+ {
+ if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+ {
+ /* Invert the alpha channel (in tRNS) unless the pixels are
+ * going to be expanded, in which case leave it for later
+ */
+ int i, istop = png_ptr->num_trans;
- else if ((png_ptr->transformations & PNG_BACKGROUND) &&
- !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
- (png_ptr->transformations & PNG_GRAY_TO_RGB) &&
- png_ptr->background.red == png_ptr->background.green &&
- png_ptr->background.red == png_ptr->background.blue)
+ for (i=0; i<istop; i++)
+ png_ptr->trans_alpha[i] = (png_byte)(255 -
+ png_ptr->trans_alpha[i]);
+ }
+ }
+#endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */
+ }
+ } /* background expand and (therefore) no alpha association. */
+#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
+}
+
+static void /* PRIVATE */
+png_init_rgb_transformations(png_structp png_ptr)
+{
+ /* Added to libpng-1.5.4: check the color type to determine whether there
+ * is any alpha or transparency in the image and simply cancel the
+ * background and alpha mode stuff if there isn't.
+ */
+ int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0;
+ int input_has_transparency = png_ptr->num_trans > 0;
+
+ /* If no alpha we can optimize. */
+ if (!input_has_alpha)
{
- png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
- png_ptr->background.gray = png_ptr->background.red;
+ /* Any alpha means background and associative alpha processing is
+ * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA
+ * and ENCODE_ALPHA are irrelevant.
+ */
+# ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+# endif
+
+ if (!input_has_transparency)
+ png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
}
-#endif
+#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+ /* png_set_background handling - deals with the complexity of whether the
+ * background color is in the file format or the screen format in the case
+ * where an 'expand' will happen.
+ */
+
+ /* The following code cannot be entered in the alpha pre-multiplication case
+ * because PNG_BACKGROUND_EXPAND is cancelled below.
+ */
if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
- (png_ptr->transformations & PNG_EXPAND))
+ (png_ptr->transformations & PNG_EXPAND) &&
+ !(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
+ /* i.e., GRAY or GRAY_ALPHA */
{
- if (!(color_type & PNG_COLOR_MASK_COLOR)) /* i.e., GRAY or GRAY_ALPHA */
{
/* Expand background and tRNS chunks */
+ int gray = png_ptr->background.gray;
+ int trans_gray = png_ptr->trans_color.gray;
+
switch (png_ptr->bit_depth)
{
case 1:
- png_ptr->background.gray *= (png_uint_16)0xff;
- png_ptr->background.red = png_ptr->background.green
- = png_ptr->background.blue = png_ptr->background.gray;
- if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
- {
- png_ptr->trans_color.gray *= (png_uint_16)0xff;
- png_ptr->trans_color.red = png_ptr->trans_color.green
- = png_ptr->trans_color.blue = png_ptr->trans_color.gray;
- }
+ gray *= 0xff;
+ trans_gray *= 0xff;
break;
case 2:
- png_ptr->background.gray *= (png_uint_16)0x55;
- png_ptr->background.red = png_ptr->background.green
- = png_ptr->background.blue = png_ptr->background.gray;
- if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
- {
- png_ptr->trans_color.gray *= (png_uint_16)0x55;
- png_ptr->trans_color.red = png_ptr->trans_color.green
- = png_ptr->trans_color.blue = png_ptr->trans_color.gray;
- }
+ gray *= 0x55;
+ trans_gray *= 0x55;
break;
case 4:
- png_ptr->background.gray *= (png_uint_16)0x11;
- png_ptr->background.red = png_ptr->background.green
- = png_ptr->background.blue = png_ptr->background.gray;
- if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
- {
- png_ptr->trans_color.gray *= (png_uint_16)0x11;
- png_ptr->trans_color.red = png_ptr->trans_color.green
- = png_ptr->trans_color.blue = png_ptr->trans_color.gray;
- }
+ gray *= 0x11;
+ trans_gray *= 0x11;
break;
default:
case 8:
+ /* FALL THROUGH (already 8 bits) */
case 16:
- png_ptr->background.red = png_ptr->background.green
- = png_ptr->background.blue = png_ptr->background.gray;
+ /* Already a full 16 bits */
break;
}
+
+ png_ptr->background.red = png_ptr->background.green =
+ png_ptr->background.blue = (png_uint_16)gray;
+
+ if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+ {
+ png_ptr->trans_color.red = png_ptr->trans_color.green =
+ png_ptr->trans_color.blue = (png_uint_16)trans_gray;
+ }
}
- else if (color_type == PNG_COLOR_TYPE_PALETTE)
- {
- png_ptr->background.red =
- png_ptr->palette[png_ptr->background.index].red;
- png_ptr->background.green =
- png_ptr->palette[png_ptr->background.index].green;
- png_ptr->background.blue =
- png_ptr->palette[png_ptr->background.index].blue;
+ } /* background expand and (therefore) no alpha association. */
+#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
+}
-#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
- if (png_ptr->transformations & PNG_INVERT_ALPHA)
- {
-#ifdef PNG_READ_EXPAND_SUPPORTED
- if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
-#endif
- {
- /* Invert the alpha channel (in tRNS) unless the pixels are
- * going to be expanded, in which case leave it for later
- */
- int i, istop;
- istop=(int)png_ptr->num_trans;
- for (i=0; i<istop; i++)
- png_ptr->trans_alpha[i] = (png_byte)(255 -
- png_ptr->trans_alpha[i]);
- }
- }
-#endif
+void /* PRIVATE */
+png_init_read_transformations(png_structp png_ptr)
+{
+ png_debug(1, "in png_init_read_transformations");
+ /* This internal function is called from png_read_start_row in pngrutil.c
+ * and it is called before the 'rowbytes' calculation is done, so the code
+ * in here can change or update the transformations flags.
+ *
+ * First do updates that do not depend on the details of the PNG image data
+ * being processed.
+ */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds
+ * png_set_alpha_mode and this is another source for a default file gamma so
+ * the test needs to be performed later - here. In addition prior to 1.5.4
+ * the tests were repeated for the PALETTE color type here - this is no
+ * longer necessary (and doesn't seem to have been necessary before.)
+ */
+ {
+ /* The following temporary indicates if overall gamma correction is
+ * required.
+ */
+ int gamma_correction = 0;
+
+ if (png_ptr->gamma != 0) /* has been set */
+ {
+ if (png_ptr->screen_gamma != 0) /* screen set too */
+ gamma_correction = png_gamma_threshold(png_ptr->gamma,
+ png_ptr->screen_gamma);
+
+ else
+ /* Assume the output matches the input; a long time default behavior
+ * of libpng, although the standard has nothing to say about this.
+ */
+ png_ptr->screen_gamma = png_reciprocal(png_ptr->gamma);
}
+
+ else if (png_ptr->screen_gamma != 0)
+ /* The converse - assume the file matches the screen, note that this
+ * perhaps undesireable default can (from 1.5.4) be changed by calling
+ * png_set_alpha_mode (even if the alpha handling mode isn't required
+ * or isn't changed from the default.)
+ */
+ png_ptr->gamma = png_reciprocal(png_ptr->screen_gamma);
+
+ else /* neither are set */
+ /* Just in case the following prevents any processing - file and screen
+ * are both assumed to be linear and there is no way to introduce a
+ * third gamma value other than png_set_background with 'UNIQUE', and,
+ * prior to 1.5.4
+ */
+ png_ptr->screen_gamma = png_ptr->gamma = PNG_FP_1;
+
+ /* Now turn the gamma transformation on or off as appropriate. Notice
+ * that PNG_GAMMA just refers to the file->screen correction. Alpha
+ * composition may independently cause gamma correction because it needs
+ * linear data (e.g. if the file has a gAMA chunk but the screen gamma
+ * hasn't been specified.) In any case this flag may get turned off in
+ * the code immediately below if the transform can be handled outside the
+ * row loop.
+ */
+ if (gamma_correction)
+ png_ptr->transformations |= PNG_GAMMA;
+
+ else
+ png_ptr->transformations &= ~PNG_GAMMA;
}
#endif
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
- png_ptr->background_1 = png_ptr->background;
+ /* Certain transformations have the effect of preventing other
+ * transformations that happen afterward in png_do_read_transformations,
+ * resolve the interdependencies here. From the code of
+ * png_do_read_transformations the order is:
+ *
+ * 1) PNG_EXPAND (including PNG_EXPAND_tRNS)
+ * 2) PNG_STRIP_ALPHA (if no compose)
+ * 3) PNG_RGB_TO_GRAY
+ * 4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY
+ * 5) PNG_COMPOSE
+ * 6) PNG_GAMMA
+ * 7) PNG_STRIP_ALPHA (if compose)
+ * 8) PNG_ENCODE_ALPHA
+ * 9) PNG_SCALE_16_TO_8
+ * 10) PNG_16_TO_8
+ * 11) PNG_QUANTIZE (converts to palette)
+ * 12) PNG_EXPAND_16
+ * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY
+ * 14) PNG_INVERT_MONO
+ * 15) PNG_SHIFT
+ * 16) PNG_PACK
+ * 17) PNG_BGR
+ * 18) PNG_PACKSWAP
+ * 19) PNG_FILLER (includes PNG_ADD_ALPHA)
+ * 20) PNG_INVERT_ALPHA
+ * 21) PNG_SWAP_ALPHA
+ * 22) PNG_SWAP_BYTES
+ * 23) PNG_USER_TRANSFORM [must be last]
+ */
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+ if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
+ !(png_ptr->transformations & PNG_COMPOSE))
+ {
+ /* Stripping the alpha channel happens immediately after the 'expand'
+ * transformations, before all other transformation, so it cancels out
+ * the alpha handling. It has the side effect negating the effect of
+ * PNG_EXPAND_tRNS too:
+ */
+ png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA |
+ PNG_EXPAND_tRNS);
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
+ /* Kill the tRNS chunk itself too. Prior to 1.5.4 this did not happen
+ * so transparency information would remain just so long as it wasn't
+ * expanded. This produces unexpected API changes if the set of things
+ * that do PNG_EXPAND_tRNS changes (perfectly possible given the
+ * documentation - which says ask for what you want, accept what you
+ * get.) This makes the behavior consistent from 1.5.4:
+ */
+ png_ptr->num_trans = 0;
+ }
+#endif /* STRIP_ALPHA supported, no COMPOSE */
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA
+ * settings will have no effect.
+ */
+ if (!png_gamma_significant(png_ptr->screen_gamma))
+ {
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+ }
#endif
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if ((color_type == PNG_COLOR_TYPE_PALETTE && png_ptr->num_trans != 0)
- && png_gamma_threshold(png_ptr->screen_gamma, png_ptr->gamma))
+#if defined(PNG_READ_EXPAND_SUPPORTED) && \
+ defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+ defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+ /* Detect gray background and attempt to enable optimization for
+ * gray --> RGB case.
+ *
+ * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
+ * RGB_ALPHA (in which case need_expand is superfluous anyway), the
+ * background color might actually be gray yet not be flagged as such.
+ * This is not a problem for the current code, which uses
+ * PNG_BACKGROUND_IS_GRAY only to decide when to do the
+ * png_do_gray_to_rgb() transformation.
+ *
+ * TODO: this code needs to be revised to avoid the complexity and
+ * interdependencies. The color type of the background should be recorded in
+ * png_set_background, along with the bit depth, then the code has a record
+ * of exactly what color space the background is currently in.
+ */
+ if (png_ptr->transformations & PNG_BACKGROUND_EXPAND)
+ {
+ /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if
+ * the file was grayscale the background value is gray.
+ */
+ if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
+ png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+ }
+
+ else if (png_ptr->transformations & PNG_COMPOSE)
{
- int i, k;
- k=0;
- for (i=0; i<png_ptr->num_trans; i++)
+ /* PNG_COMPOSE: png_set_background was called with need_expand false,
+ * so the color is in the color space of the output or png_set_alpha_mode
+ * was called and the color is black. Ignore RGB_TO_GRAY because that
+ * happens before GRAY_TO_RGB.
+ */
+ if (png_ptr->transformations & PNG_GRAY_TO_RGB)
{
- if (png_ptr->trans_alpha[i] != 0 && png_ptr->trans_alpha[i] != 0xff)
- k=1; /* Partial transparency is present */
+ if (png_ptr->background.red == png_ptr->background.green &&
+ png_ptr->background.red == png_ptr->background.blue)
+ {
+ png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+ png_ptr->background.gray = png_ptr->background.red;
+ }
}
- if (k == 0)
- png_ptr->transformations &= ~PNG_GAMMA;
}
+#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED (etc) */
+
+ /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations
+ * can be performed directly on the palette, and some (such as rgb to gray)
+ * can be optimized inside the palette. This is particularly true of the
+ * composite (background and alpha) stuff, which can be pretty much all done
+ * in the palette even if the result is expanded to RGB or gray afterward.
+ *
+ * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and
+ * earlier and the palette stuff is actually handled on the first row. This
+ * leads to the reported bug that the palette returned by png_get_PLTE is not
+ * updated.
+ */
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ png_init_palette_transformations(png_ptr);
- if ((png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY)) &&
- png_ptr->gamma != 0)
+ else
+ png_init_rgb_transformations(png_ptr);
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+ defined(PNG_READ_EXPAND_16_SUPPORTED)
+ if ((png_ptr->transformations & PNG_EXPAND_16) &&
+ (png_ptr->transformations & PNG_COMPOSE) &&
+ !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+ png_ptr->bit_depth != 16)
+ {
+ /* TODO: fix this. Because the expand_16 operation is after the compose
+ * handling the background color must be 8, not 16, bits deep, but the
+ * application will supply a 16-bit value so reduce it here.
+ *
+ * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at
+ * present, so that case is ok (until do_expand_16 is moved.)
+ *
+ * NOTE: this discards the low 16 bits of the user supplied background
+ * color, but until expand_16 works properly there is no choice!
+ */
+# define CHOP(x) (x)=((png_uint_16)(((png_uint_32)(x)*255+32895) >> 16))
+ CHOP(png_ptr->background.red);
+ CHOP(png_ptr->background.green);
+ CHOP(png_ptr->background.blue);
+ CHOP(png_ptr->background.gray);
+# undef CHOP
+ }
+#endif /* PNG_READ_BACKGROUND_SUPPORTED && PNG_READ_EXPAND_16_SUPPORTED */
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+ (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
+ defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
+ if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) &&
+ (png_ptr->transformations & PNG_COMPOSE) &&
+ !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+ png_ptr->bit_depth == 16)
+ {
+ /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
+ * component this will also happen after PNG_COMPOSE and so the background
+ * color must be pre-expanded here.
+ *
+ * TODO: fix this too.
+ */
+ png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257);
+ png_ptr->background.green =
+ (png_uint_16)(png_ptr->background.green * 257);
+ png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257);
+ png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257);
+ }
+#endif
+
+ /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the
+ * background support (see the comments in scripts/pnglibconf.dfa), this
+ * allows pre-multiplication of the alpha channel to be implemented as
+ * compositing on black. This is probably sub-optimal and has been done in
+ * 1.5.4 betas simply to enable external critique and testing (i.e. to
+ * implement the new API quickly, without lots of internal changes.)
+ */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+# ifdef PNG_READ_BACKGROUND_SUPPORTED
+ /* Includes ALPHA_MODE */
+ png_ptr->background_1 = png_ptr->background;
+# endif
+
+ /* This needs to change - in the palette image case a whole set of tables are
+ * built when it would be quicker to just calculate the correct value for
+ * each palette entry directly. Also, the test is too tricky - why check
+ * PNG_RGB_TO_GRAY if PNG_GAMMA is not set? The answer seems to be that
+ * PNG_GAMMA is cancelled even if the gamma is known? The test excludes the
+ * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction
+ * the gamma tables will not be built even if composition is required on a
+ * gamma encoded value.
+ *
+ * In 1.5.4 this is addressed below by an additional check on the individual
+ * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the
+ * tables.
+ */
+ if ((png_ptr->transformations & PNG_GAMMA)
+ || ((png_ptr->transformations & PNG_RGB_TO_GRAY)
+ && (png_gamma_significant(png_ptr->gamma) ||
+ png_gamma_significant(png_ptr->screen_gamma)))
+ || ((png_ptr->transformations & PNG_COMPOSE)
+ && (png_gamma_significant(png_ptr->gamma)
+ || png_gamma_significant(png_ptr->screen_gamma)
+# ifdef PNG_READ_BACKGROUND_SUPPORTED
+ || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE
+ && png_gamma_significant(png_ptr->background_gamma))
+# endif
+ )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA)
+ && png_gamma_significant(png_ptr->screen_gamma))
+ )
{
png_build_gamma_table(png_ptr, png_ptr->bit_depth);
#ifdef PNG_READ_BACKGROUND_SUPPORTED
- if (png_ptr->transformations & PNG_BACKGROUND)
+ if (png_ptr->transformations & PNG_COMPOSE)
{
- if (color_type == PNG_COLOR_TYPE_PALETTE)
+ /* Issue a warning about this combination: because RGB_TO_GRAY is
+ * optimized to do the gamma transform if present yet do_background has
+ * to do the same thing if both options are set a
+ * double-gamma-correction happens. This is true in all versions of
+ * libpng to date.
+ */
+ if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+ png_warning(png_ptr,
+ "libpng does not support gamma+background+rgb_to_gray");
+
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
- /* Could skip if no transparency */
+ /* We don't get to here unless there is a tRNS chunk with non-opaque
+ * entries - see the checking code at the start of this function.
+ */
png_color back, back_1;
png_colorp palette = png_ptr->palette;
int num_palette = png_ptr->num_palette;
}
if (png_gamma_significant(gs))
+ {
+ back.red = png_gamma_8bit_correct(png_ptr->background.red,
+ gs);
+ back.green = png_gamma_8bit_correct(png_ptr->background.green,
+ gs);
+ back.blue = png_gamma_8bit_correct(png_ptr->background.blue,
+ gs);
+ }
+
+ else
{
back.red = (png_byte)png_ptr->background.red;
back.green = (png_byte)png_ptr->background.green;
back.blue = (png_byte)png_ptr->background.blue;
}
+ if (png_gamma_significant(g))
+ {
+ back_1.red = png_gamma_8bit_correct(png_ptr->background.red,
+ g);
+ back_1.green = png_gamma_8bit_correct(
+ png_ptr->background.green, g);
+ back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue,
+ g);
+ }
+
else
{
- back.red = png_gamma_8bit_correct(png_ptr->background.red,
- gs);
- back.green = png_gamma_8bit_correct(png_ptr->background.green,
- gs);
- back.blue = png_gamma_8bit_correct(png_ptr->background.blue,
- gs);
+ back_1.red = (png_byte)png_ptr->background.red;
+ back_1.green = (png_byte)png_ptr->background.green;
+ back_1.blue = (png_byte)png_ptr->background.blue;
}
- back_1.red = png_gamma_8bit_correct(png_ptr->background.red, g);
- back_1.green = png_gamma_8bit_correct(png_ptr->background.green,
- g);
- back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue,
- g);
}
+
for (i = 0; i < num_palette; i++)
{
if (i < (int)png_ptr->num_trans &&
palette[i].blue = png_ptr->gamma_table[palette[i].blue];
}
}
- /* Prevent the transformations being done again, and make sure
- * that the now spurious alpha channel is stripped - the code
- * has just reduced background composition and gamma correction
- * to a simple alpha channel strip.
+
+ /* Prevent the transformations being done again.
+ *
+ * NOTE: this is highly dubious; it removes the transformations in
+ * place. This seems inconsistent with the general treatment of the
+ * transformations elsewhere.
*/
- png_ptr->transformations &= ~PNG_BACKGROUND;
- png_ptr->transformations &= ~PNG_GAMMA;
- png_ptr->transformations |= PNG_STRIP_ALPHA;
- }
+ png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA);
+ } /* color_type == PNG_COLOR_TYPE_PALETTE */
/* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
- else
- /* color_type != PNG_COLOR_TYPE_PALETTE */
+ else /* color_type != PNG_COLOR_TYPE_PALETTE */
{
- png_fixed_point g = PNG_FP_1;
- png_fixed_point gs = PNG_FP_1;
+ int gs_sig, g_sig;
+ png_fixed_point g = PNG_FP_1; /* Correction to linear */
+ png_fixed_point gs = PNG_FP_1; /* Correction to screen */
switch (png_ptr->background_gamma_type)
{
png_error(png_ptr, "invalid background gamma type");
}
- png_ptr->background_1.gray = png_gamma_correct(png_ptr,
- png_ptr->background.gray, g);
+ g_sig = png_gamma_significant(g);
+ gs_sig = png_gamma_significant(gs);
+
+ if (g_sig)
+ png_ptr->background_1.gray = png_gamma_correct(png_ptr,
+ png_ptr->background.gray, g);
- png_ptr->background.gray = png_gamma_correct(png_ptr,
- png_ptr->background.gray, gs);
+ if (gs_sig)
+ png_ptr->background.gray = png_gamma_correct(png_ptr,
+ png_ptr->background.gray, gs);
if ((png_ptr->background.red != png_ptr->background.green) ||
(png_ptr->background.red != png_ptr->background.blue) ||
(png_ptr->background.red != png_ptr->background.gray))
{
/* RGB or RGBA with color background */
- png_ptr->background_1.red = png_gamma_correct(png_ptr,
- png_ptr->background.red, g);
+ if (g_sig)
+ {
+ png_ptr->background_1.red = png_gamma_correct(png_ptr,
+ png_ptr->background.red, g);
- png_ptr->background_1.green = png_gamma_correct(png_ptr,
- png_ptr->background.green, g);
+ png_ptr->background_1.green = png_gamma_correct(png_ptr,
+ png_ptr->background.green, g);
- png_ptr->background_1.blue = png_gamma_correct(png_ptr,
- png_ptr->background.blue, g);
+ png_ptr->background_1.blue = png_gamma_correct(png_ptr,
+ png_ptr->background.blue, g);
+ }
- png_ptr->background.red = png_gamma_correct(png_ptr,
- png_ptr->background.red, gs);
+ if (gs_sig)
+ {
+ png_ptr->background.red = png_gamma_correct(png_ptr,
+ png_ptr->background.red, gs);
- png_ptr->background.green = png_gamma_correct(png_ptr,
- png_ptr->background.green, gs);
+ png_ptr->background.green = png_gamma_correct(png_ptr,
+ png_ptr->background.green, gs);
- png_ptr->background.blue = png_gamma_correct(png_ptr,
- png_ptr->background.blue, gs);
+ png_ptr->background.blue = png_gamma_correct(png_ptr,
+ png_ptr->background.blue, gs);
+ }
}
else
png_ptr->background.red = png_ptr->background.green
= png_ptr->background.blue = png_ptr->background.gray;
}
- }
- }
+
+ /* The background is now in screen gamma: */
+ png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN;
+ } /* color_type != PNG_COLOR_TYPE_PALETTE */
+ }/* png_ptr->transformations & PNG_BACKGROUND */
+
else
/* Transformation does not include PNG_BACKGROUND */
#endif /* PNG_READ_BACKGROUND_SUPPORTED */
- if (color_type == PNG_COLOR_TYPE_PALETTE)
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ /* RGB_TO_GRAY needs to have non-gamma-corrected values! */
+ && ((png_ptr->transformations & PNG_EXPAND) == 0 ||
+ (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
+#endif
+ )
{
png_colorp palette = png_ptr->palette;
int num_palette = png_ptr->num_palette;
int i;
+ /* NOTE: there are other transformations that should probably be in
+ * here too.
+ */
for (i = 0; i < num_palette; i++)
{
palette[i].red = png_ptr->gamma_table[palette[i].red];
/* Done the gamma correction. */
png_ptr->transformations &= ~PNG_GAMMA;
- }
+ } /* color_type == PALETTE && !PNG_BACKGROUND transformation */
}
#ifdef PNG_READ_BACKGROUND_SUPPORTED
else
#endif
#endif /* PNG_READ_GAMMA_SUPPORTED */
+
#ifdef PNG_READ_BACKGROUND_SUPPORTED
- /* No GAMMA transformation */
- if ((png_ptr->transformations & PNG_BACKGROUND) &&
- (color_type == PNG_COLOR_TYPE_PALETTE))
+ /* No GAMMA transformation (see the hanging else 4 lines above) */
+ if ((png_ptr->transformations & PNG_COMPOSE) &&
+ (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
{
int i;
int istop = (int)png_ptr->num_trans;
}
}
- /* Handled alpha, still need to strip the channel. */
- png_ptr->transformations &= ~PNG_BACKGROUND;
- png_ptr->transformations |= PNG_STRIP_ALPHA;
+ png_ptr->transformations &= ~PNG_COMPOSE;
}
#endif /* PNG_READ_BACKGROUND_SUPPORTED */
#ifdef PNG_READ_SHIFT_SUPPORTED
if ((png_ptr->transformations & PNG_SHIFT) &&
- (color_type == PNG_COLOR_TYPE_PALETTE))
+ !(png_ptr->transformations & PNG_EXPAND) &&
+ (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
{
- png_uint_16 i;
- png_uint_16 istop = png_ptr->num_palette;
- int sr = 8 - png_ptr->sig_bit.red;
- int sg = 8 - png_ptr->sig_bit.green;
- int sb = 8 - png_ptr->sig_bit.blue;
+ int i;
+ int istop = png_ptr->num_palette;
+ int shift = 8 - png_ptr->sig_bit.red;
- if (sr < 0 || sr > 8)
- sr = 0;
+ png_ptr->transformations &= ~PNG_SHIFT;
+
+ /* significant bits can be in the range 1 to 7 for a meaninful result, if
+ * the number of significant bits is 0 then no shift is done (this is an
+ * error condition which is silently ignored.)
+ */
+ if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
+ {
+ int component = png_ptr->palette[i].red;
- if (sg < 0 || sg > 8)
- sg = 0;
+ component >>= shift;
+ png_ptr->palette[i].red = (png_byte)component;
+ }
- if (sb < 0 || sb > 8)
- sb = 0;
+ shift = 8 - png_ptr->sig_bit.green;
+ if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
+ {
+ int component = png_ptr->palette[i].green;
- for (i = 0; i < istop; i++)
+ component >>= shift;
+ png_ptr->palette[i].green = (png_byte)component;
+ }
+
+ shift = 8 - png_ptr->sig_bit.blue;
+ if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
{
- png_ptr->palette[i].red >>= sr;
- png_ptr->palette[i].green >>= sg;
- png_ptr->palette[i].blue >>= sb;
+ int component = png_ptr->palette[i].blue;
+
+ component >>= shift;
+ png_ptr->palette[i].blue = (png_byte)component;
}
}
#endif /* PNG_READ_SHIFT_SUPPORTED */
- }
-#if !defined(PNG_READ_GAMMA_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) \
- && !defined(PNG_READ_BACKGROUND_SUPPORTED)
- if (png_ptr)
- return;
-#endif
}
/* Modify the info structure to reflect the transformations. The
{
if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
- if (png_ptr->num_trans &&
- (png_ptr->transformations & PNG_EXPAND_tRNS))
+ /* This check must match what actually happens in
+ * png_do_expand_palette; if it ever checks the tRNS chunk to see if
+ * it is all opaque we must do the same (at present it does not.)
+ */
+ if (png_ptr->num_trans > 0)
info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
else
}
#endif
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
- if (png_ptr->transformations & PNG_EXPAND_16 && info_ptr->bit_depth == 8 &&
- info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
- {
- info_ptr->bit_depth = 16;
- }
-#endif
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
- if (png_ptr->transformations & PNG_BACKGROUND)
- {
- info_ptr->color_type = (png_byte)(info_ptr->color_type &
- ~PNG_COLOR_MASK_ALPHA);
- info_ptr->num_trans = 0;
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+ /* The following is almost certainly wrong unless the background value is in
+ * the screen space!
+ */
+ if (png_ptr->transformations & PNG_COMPOSE)
info_ptr->background = png_ptr->background;
- }
#endif
#ifdef PNG_READ_GAMMA_SUPPORTED
- if (png_ptr->transformations & PNG_GAMMA)
- {
- info_ptr->gamma = png_ptr->gamma;
- }
+ /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4),
+ * however it seems that the code in png_init_read_transformations, which has
+ * been called before this from png_read_update_info->png_read_start_row
+ * sometimes does the gamma transform and cancels the flag.
+ */
+ info_ptr->gamma = png_ptr->gamma;
#endif
-#ifdef PNG_READ_16_TO_8_SUPPORTED
-#ifdef PNG_READ_16BIT_SUPPORTED
- if ((png_ptr->transformations & PNG_16_TO_8) && (info_ptr->bit_depth == 16))
- info_ptr->bit_depth = 8;
-#else
- /* Force chopping 16-bit input down to 8 */
if (info_ptr->bit_depth == 16)
{
- png_ptr->transformations |=PNG_16_TO_8;
- info_ptr->bit_depth = 8;
+# ifdef PNG_READ_16BIT_SUPPORTED
+# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+ if (png_ptr->transformations & PNG_SCALE_16_TO_8)
+ info_ptr->bit_depth = 8;
+# endif
+
+# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+ if (png_ptr->transformations & PNG_16_TO_8)
+ info_ptr->bit_depth = 8;
+# endif
+
+# else
+ /* No 16 bit support: force chopping 16-bit input down to 8, in this case
+ * the app program can chose if both APIs are available by setting the
+ * correct scaling to use.
+ */
+# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+ /* For compatibility with previous versions use the strip method by
+ * default. This code works because if PNG_SCALE_16_TO_8 is already
+ * set the code below will do that in preference to the chop.
+ */
+ png_ptr->transformations |= PNG_16_TO_8;
+ info_ptr->bit_depth = 8;
+# else
+
+# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+ png_ptr->transformations |= PNG_SCALE_16_TO_8;
+ info_ptr->bit_depth = 8;
+# else
+
+ CONFIGURATION ERROR: you must enable at least one 16 to 8 method
+# endif
+# endif
+#endif /* !READ_16BIT_SUPPORTED */
}
-#endif
-#endif
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
if (png_ptr->transformations & PNG_GRAY_TO_RGB)
- info_ptr->color_type |= PNG_COLOR_MASK_COLOR;
+ info_ptr->color_type = (png_byte)(info_ptr->color_type |
+ PNG_COLOR_MASK_COLOR);
#endif
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
if (png_ptr->transformations & PNG_RGB_TO_GRAY)
- info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR;
+ info_ptr->color_type = (png_byte)(info_ptr->color_type &
+ ~PNG_COLOR_MASK_COLOR);
#endif
#ifdef PNG_READ_QUANTIZE_SUPPORTED
}
#endif
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+ if (png_ptr->transformations & PNG_EXPAND_16 && info_ptr->bit_depth == 8 &&
+ info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+ {
+ info_ptr->bit_depth = 16;
+ }
+#endif
+
#ifdef PNG_READ_PACK_SUPPORTED
if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
info_ptr->bit_depth = 8;
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_STRIP_ALPHA)
- info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
+ {
+ info_ptr->color_type = (png_byte)(info_ptr->color_type &
+ ~PNG_COLOR_MASK_ALPHA);
+ info_ptr->num_trans = 0;
+ }
#endif
if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
+ /* Adding in 1.5.4: cache the above value in png_struct so that we can later
+ * check in png_rowbytes that the user buffer won't get overwritten. Note
+ * that the field is not always set - if png_read_update_info isn't called
+ * the application has to either not do any transforms or get the calculation
+ * right itself.
+ */
+ png_ptr->info_rowbytes = info_ptr->rowbytes;
+
#ifndef PNG_READ_EXPAND_SUPPORTED
if (png_ptr)
return;
* decide how it fits in with the other transformations here.
*/
void /* PRIVATE */
-png_do_read_transformations(png_structp png_ptr)
+png_do_read_transformations(png_structp png_ptr, png_row_infop row_info)
{
png_debug(1, "in png_do_read_transformations");
if (png_ptr->row_buf == NULL)
{
-#ifdef PNG_CONSOLE_IO_SUPPORTED
- char msg[50];
-
- png_snprintf2(msg, 50,
- "NULL row buffer for row %ld, pass %d", (long)png_ptr->row_number,
- png_ptr->pass);
- png_error(png_ptr, msg);
-#else
+ /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
+ * error is incredibly rare and incredibly easy to debug without this
+ * information.
+ */
png_error(png_ptr, "NULL row buffer");
-#endif
}
-#ifdef PNG_WARN_UNINITIALIZED_ROW
- if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
- /* Application has failed to call either png_read_start_image()
- * or png_read_update_info() after setting transforms that expand
- * pixels. This check added to libpng-1.2.19
+
+ /* The following is debugging; prior to 1.5.4 the code was never compiled in;
+ * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
+ * PNG_WARN_UNINITIALIZED_ROW removed. In 1.5 the new flag is set only for
+ * selected new APIs to ensure that there is no API change.
+ */
+ if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
+ !(png_ptr->flags & PNG_FLAG_ROW_INIT))
+ {
+ /* Application has failed to call either png_read_start_image() or
+ * png_read_update_info() after setting transforms that expand pixels.
+ * This check added to libpng-1.2.19 (but not enabled until 1.5.4).
*/
-#if (PNG_WARN_UNINITIALIZED_ROW==1)
png_error(png_ptr, "Uninitialized row");
-#else
- png_warning(png_ptr, "Uninitialized row");
-#endif
-#endif
+ }
#ifdef PNG_READ_EXPAND_SUPPORTED
if (png_ptr->transformations & PNG_EXPAND)
{
- if (png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE)
+ if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
{
- png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_expand_palette(row_info, png_ptr->row_buf + 1,
png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
}
{
if (png_ptr->num_trans &&
(png_ptr->transformations & PNG_EXPAND_tRNS))
- png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_expand(row_info, png_ptr->row_buf + 1,
&(png_ptr->trans_color));
else
- png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_expand(row_info, png_ptr->row_buf + 1,
NULL);
}
}
#endif
- /* Delay the 'expand 16' step until later for efficiency, so that the
- * intermediate steps work with 8 bit data.
- */
-
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
- (png_ptr->row_info.color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
- png_ptr->row_info.color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
- png_do_strip_channel(&(png_ptr->row_info), png_ptr->row_buf + 1,
- 0/*!at_start, because SWAP_ALPHA happens later*/);
+ !(png_ptr->transformations & PNG_COMPOSE) &&
+ (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+ row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+ png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+ 0 /* at_start == false, because SWAP_ALPHA happens later */);
#endif
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
if (png_ptr->transformations & PNG_RGB_TO_GRAY)
{
int rgb_error =
- png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info),
+ png_do_rgb_to_gray(png_ptr, row_info,
png_ptr->row_buf + 1);
if (rgb_error)
*/
if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
!(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
- png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
#endif
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
- if ((png_ptr->transformations & PNG_BACKGROUND) &&
- ((png_ptr->num_trans != 0) ||
- (png_ptr->color_type & PNG_COLOR_MASK_ALPHA)))
- png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1,
- &(png_ptr->trans_color), &(png_ptr->background)
-#ifdef PNG_READ_GAMMA_SUPPORTED
- , &(png_ptr->background_1),
- png_ptr->gamma_table, png_ptr->gamma_from_1,
- png_ptr->gamma_to_1, png_ptr->gamma_16_table,
- png_ptr->gamma_16_from_1, png_ptr->gamma_16_to_1,
- png_ptr->gamma_shift
-#endif
- );
+#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
+ (defined PNG_READ_ALPHA_MODE_SUPPORTED)
+ if (png_ptr->transformations & PNG_COMPOSE)
+ png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
#endif
#ifdef PNG_READ_GAMMA_SUPPORTED
if ((png_ptr->transformations & PNG_GAMMA) &&
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
- !((png_ptr->transformations & PNG_BACKGROUND) &&
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ /* Because RGB_TO_GRAY does the gamma transform. */
+ !(png_ptr->transformations & PNG_RGB_TO_GRAY) &&
+#endif
+#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
+ (defined PNG_READ_ALPHA_MODE_SUPPORTED)
+ /* Because PNG_COMPOSE does the gamma transform if there is something to
+ * do (if there is an alpha channel or transparency.)
+ */
+ !((png_ptr->transformations & PNG_COMPOSE) &&
((png_ptr->num_trans != 0) ||
(png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
#endif
+ /* Because png_init_read_transformations transforms the palette, unless
+ * RGB_TO_GRAY will do the transform.
+ */
(png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
- png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1,
- png_ptr->gamma_table, png_ptr->gamma_16_table,
- png_ptr->gamma_shift);
+ png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+ if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
+ (png_ptr->transformations & PNG_COMPOSE) &&
+ (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+ row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+ png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+ 0 /* at_start == false, because SWAP_ALPHA happens later */);
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ if ((png_ptr->transformations & PNG_ENCODE_ALPHA) &&
+ (row_info->color_type & PNG_COLOR_MASK_ALPHA))
+ png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+ if (png_ptr->transformations & PNG_SCALE_16_TO_8)
+ png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
#endif
-#ifdef PNG_READ_16_TO_8_SUPPORTED
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+ /* There is no harm in doing both of these because only one has any effect,
+ * by putting the 'scale' option first if the app asks for scale (either by
+ * calling the API or in a TRANSFORM flag) this is what happens.
+ */
if (png_ptr->transformations & PNG_16_TO_8)
- png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_chop(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_QUANTIZE_SUPPORTED
if (png_ptr->transformations & PNG_QUANTIZE)
{
- png_do_quantize(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_quantize(row_info, png_ptr->row_buf + 1,
png_ptr->palette_lookup, png_ptr->quantize_index);
- if (png_ptr->row_info.rowbytes == 0)
+ if (row_info->rowbytes == 0)
png_error(png_ptr, "png_do_quantize returned rowbytes=0");
}
#endif /* PNG_READ_QUANTIZE_SUPPORTED */
* better accuracy results faster!)
*/
if (png_ptr->transformations & PNG_EXPAND_16)
- png_do_expand_16(&png_ptr->row_info, png_ptr->row_buf + 1);
+ png_do_expand_16(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+ /* NOTE: moved here in 1.5.4 (from much later in this list.) */
+ if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+ (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
+ png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_INVERT_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_MONO)
- png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_invert(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_SHIFT_SUPPORTED
if (png_ptr->transformations & PNG_SHIFT)
- png_do_unshift(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_unshift(row_info, png_ptr->row_buf + 1,
&(png_ptr->shift));
#endif
#ifdef PNG_READ_PACK_SUPPORTED
if (png_ptr->transformations & PNG_PACK)
- png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_unpack(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
+ /* Added at libpng-1.5.10 */
+ if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
+ png_ptr->num_palette_max >= 0)
+ png_do_check_palette_indexes(png_ptr, row_info);
#endif
#ifdef PNG_READ_BGR_SUPPORTED
if (png_ptr->transformations & PNG_BGR)
- png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_bgr(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_PACKSWAP_SUPPORTED
if (png_ptr->transformations & PNG_PACKSWAP)
- png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
- /*NOTE: this must be in the wrong place - what happens if BGR is set too?
- * Need pngvalid to test this combo.
- */
- /* If gray -> RGB, do so now only if we did not do so above */
- if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
- (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
- png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_packswap(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_FILLER_SUPPORTED
if (png_ptr->transformations & PNG_FILLER)
- png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_read_filler(row_info, png_ptr->row_buf + 1,
(png_uint_32)png_ptr->filler, png_ptr->flags);
#endif
#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_ALPHA)
- png_do_read_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_ALPHA)
- png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_16BIT_SUPPORTED
#ifdef PNG_READ_SWAP_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_BYTES)
- png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_swap(row_info, png_ptr->row_buf + 1);
#endif
#endif
{
if (png_ptr->read_user_transform_fn != NULL)
(*(png_ptr->read_user_transform_fn)) /* User read transform function */
- (png_ptr, /* png_ptr */
- &(png_ptr->row_info), /* row_info: */
+ (png_ptr, /* png_ptr */
+ row_info, /* row_info: */
/* png_uint_32 width; width of row */
/* png_size_t rowbytes; number of bytes in row */
/* png_byte color_type; color type of pixels */
png_ptr->row_buf + 1); /* start of pixel data for row */
#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
if (png_ptr->user_transform_depth)
- png_ptr->row_info.bit_depth = png_ptr->user_transform_depth;
+ row_info->bit_depth = png_ptr->user_transform_depth;
if (png_ptr->user_transform_channels)
- png_ptr->row_info.channels = png_ptr->user_transform_channels;
+ row_info->channels = png_ptr->user_transform_channels;
#endif
- png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth *
- png_ptr->row_info.channels);
+ row_info->pixel_depth = (png_byte)(row_info->bit_depth *
+ row_info->channels);
- png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
- png_ptr->row_info.width);
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
}
#endif
-
}
#ifdef PNG_READ_PACK_SUPPORTED
png_do_unshift(png_row_infop row_info, png_bytep row,
png_const_color_8p sig_bits)
{
+ int color_type;
+
png_debug(1, "in png_do_unshift");
- if (
- row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+ /* The palette case has already been handled in the _init routine. */
+ color_type = row_info->color_type;
+
+ if (color_type != PNG_COLOR_TYPE_PALETTE)
{
int shift[4];
int channels = 0;
- int c;
- png_uint_16 value = 0;
- png_uint_32 row_width = row_info->width;
+ int bit_depth = row_info->bit_depth;
- if (row_info->color_type & PNG_COLOR_MASK_COLOR)
+ if (color_type & PNG_COLOR_MASK_COLOR)
{
- shift[channels++] = row_info->bit_depth - sig_bits->red;
- shift[channels++] = row_info->bit_depth - sig_bits->green;
- shift[channels++] = row_info->bit_depth - sig_bits->blue;
+ shift[channels++] = bit_depth - sig_bits->red;
+ shift[channels++] = bit_depth - sig_bits->green;
+ shift[channels++] = bit_depth - sig_bits->blue;
}
else
{
- shift[channels++] = row_info->bit_depth - sig_bits->gray;
+ shift[channels++] = bit_depth - sig_bits->gray;
}
- if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+ if (color_type & PNG_COLOR_MASK_ALPHA)
{
- shift[channels++] = row_info->bit_depth - sig_bits->alpha;
+ shift[channels++] = bit_depth - sig_bits->alpha;
}
- for (c = 0; c < channels; c++)
{
- if (shift[c] <= 0)
- shift[c] = 0;
+ int c, have_shift;
- else
- value = 1;
- }
+ for (c = have_shift = 0; c < channels; ++c)
+ {
+ /* A shift of more than the bit depth is an error condition but it
+ * gets ignored here.
+ */
+ if (shift[c] <= 0 || shift[c] >= bit_depth)
+ shift[c] = 0;
- if (!value)
- return;
+ else
+ have_shift = 1;
+ }
- switch (row_info->bit_depth)
+ if (!have_shift)
+ return;
+ }
+
+ switch (bit_depth)
{
default:
+ /* Must be 1bpp gray: should not be here! */
+ /* NOTREACHED */
break;
case 2:
+ /* Must be 2bpp gray */
+ /* assert(channels == 1 && shift[0] == 1) */
{
- png_bytep bp;
- png_size_t i;
- png_size_t istop = row_info->rowbytes;
+ png_bytep bp = row;
+ png_bytep bp_end = bp + row_info->rowbytes;
- for (bp = row, i = 0; i < istop; i++)
+ while (bp < bp_end)
{
- *bp >>= 1;
- *bp++ &= 0x55;
+ int b = (*bp >> 1) & 0x55;
+ *bp++ = (png_byte)b;
}
break;
}
case 4:
+ /* Must be 4bpp gray */
+ /* assert(channels == 1) */
{
png_bytep bp = row;
- png_size_t i;
- png_size_t istop = row_info->rowbytes;
- png_byte mask = (png_byte)((((int)0xf0 >> shift[0]) & (int)0xf0) |
- (png_byte)((int)0xf >> shift[0]));
+ png_bytep bp_end = bp + row_info->rowbytes;
+ int gray_shift = shift[0];
+ int mask = 0xf >> gray_shift;
+
+ mask |= mask << 4;
- for (i = 0; i < istop; i++)
+ while (bp < bp_end)
{
- *bp >>= shift[0];
- *bp++ &= mask;
+ int b = (*bp >> gray_shift) & mask;
+ *bp++ = (png_byte)b;
}
break;
}
case 8:
+ /* Single byte components, G, GA, RGB, RGBA */
{
png_bytep bp = row;
- png_uint_32 i;
- png_uint_32 istop = row_width * channels;
+ png_bytep bp_end = bp + row_info->rowbytes;
+ int channel = 0;
- for (i = 0; i < istop; i++)
+ while (bp < bp_end)
{
- *bp++ >>= shift[i%channels];
+ int b = *bp >> shift[channel];
+ if (++channel >= channels)
+ channel = 0;
+ *bp++ = (png_byte)b;
}
break;
}
#ifdef PNG_READ_16BIT_SUPPORTED
case 16:
+ /* Double byte components, G, GA, RGB, RGBA */
{
png_bytep bp = row;
- png_uint_32 i;
- png_uint_32 istop = channels * row_width;
+ png_bytep bp_end = bp + row_info->rowbytes;
+ int channel = 0;
+
+ while (bp < bp_end)
+ {
+ int value = (bp[0] << 8) + bp[1];
+
+ value >>= shift[channel];
+ if (++channel >= channels)
+ channel = 0;
+ *bp++ = (png_byte)(value >> 8);
+ *bp++ = (png_byte)(value & 0xff);
+ }
+ break;
+ }
+#endif
+ }
+ }
+}
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+/* Scale rows of bit depth 16 down to 8 accurately */
+void /* PRIVATE */
+png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_scale_16_to_8");
+
+ if (row_info->bit_depth == 16)
+ {
+ png_bytep sp = row; /* source */
+ png_bytep dp = row; /* destination */
+ png_bytep ep = sp + row_info->rowbytes; /* end+1 */
+
+ while (sp < ep)
+ {
+ /* The input is an array of 16 bit components, these must be scaled to
+ * 8 bits each. For a 16 bit value V the required value (from the PNG
+ * specification) is:
+ *
+ * (V * 255) / 65535
+ *
+ * This reduces to round(V / 257), or floor((V + 128.5)/257)
+ *
+ * Represent V as the two byte value vhi.vlo. Make a guess that the
+ * result is the top byte of V, vhi, then the correction to this value
+ * is:
+ *
+ * error = floor(((V-vhi.vhi) + 128.5) / 257)
+ * = floor(((vlo-vhi) + 128.5) / 257)
+ *
+ * This can be approximated using integer arithmetic (and a signed
+ * shift):
+ *
+ * error = (vlo-vhi+128) >> 8;
+ *
+ * The approximate differs from the exact answer only when (vlo-vhi) is
+ * 128; it then gives a correction of +1 when the exact correction is
+ * 0. This gives 128 errors. The exact answer (correct for all 16 bit
+ * input values) is:
+ *
+ * error = (vlo-vhi+128)*65535 >> 24;
+ *
+ * An alternative arithmetic calculation which also gives no errors is:
+ *
+ * (V * 255 + 32895) >> 16
+ */
- for (i = 0; i < istop; i++)
- {
- value = (png_uint_16)((*bp << 8) + *(bp + 1));
- value >>= shift[i%channels];
- *bp++ = (png_byte)(value >> 8);
- *bp++ = (png_byte)(value & 0xff);
- }
- break;
- }
-#endif
+ png_int_32 tmp = *sp++; /* must be signed! */
+ tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24;
+ *dp++ = (png_byte)tmp;
}
+
+ row_info->bit_depth = 8;
+ row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+ row_info->rowbytes = row_info->width * row_info->channels;
}
}
#endif
-#ifdef PNG_READ_16_TO_8_SUPPORTED
-/* Chop rows of bit depth 16 down to 8 */
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
void /* PRIVATE */
+/* Simply discard the low byte. This was the default behavior prior
+ * to libpng-1.5.4.
+ */
png_do_chop(png_row_infop row_info, png_bytep row)
{
png_debug(1, "in png_do_chop");
if (row_info->bit_depth == 16)
{
- png_bytep sp = row;
- png_bytep dp = row;
- png_uint_32 i;
- png_uint_32 istop = row_info->width * row_info->channels;
+ png_bytep sp = row; /* source */
+ png_bytep dp = row; /* destination */
+ png_bytep ep = sp + row_info->rowbytes; /* end+1 */
- for (i = 0; i<istop; i++, sp += 2, dp++)
+ while (sp < ep)
{
-#ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
- /* This does a more accurate scaling of the 16-bit color
- * value, rather than a simple low-byte truncation.
- *
- * What the ideal calculation should be:
- * *dp = (((((png_uint_32)(*sp) << 8) |
- * (png_uint_32)(*(sp + 1))) * 255 + 127)
- * / (png_uint_32)65535L;
- *
- * GRR: no, I think this is what it really should be:
- * *dp = (((((png_uint_32)(*sp) << 8) |
- * (png_uint_32)(*(sp + 1))) + 128L)
- * / (png_uint_32)257L;
- *
- * GRR: here's the exact calculation with shifts:
- * temp = (((png_uint_32)(*sp) << 8) |
- * (png_uint_32)(*(sp + 1))) + 128L;
- * *dp = (temp - (temp >> 8)) >> 8;
- *
- * Approximate calculation with shift/add instead of multiply/divide:
- * *dp = ((((png_uint_32)(*sp) << 8) |
- * (png_uint_32)((int)(*(sp + 1)) - *sp)) + 128) >> 8;
- *
- * What we actually do to avoid extra shifting and conversion:
- */
-
- *dp = *sp + ((((int)(*(sp + 1)) - *sp) > 128) ? 1 : 0);
-#else
- /* Simply discard the low order byte */
- *dp = *sp;
-#endif
+ *dp++ = *sp;
+ sp += 2; /* skip low byte */
}
+
row_info->bit_depth = 8;
row_info->pixel_depth = (png_byte)(8 * row_info->channels);
row_info->rowbytes = row_info->width * row_info->channels;
}
}
}
- row_info->channels += (png_byte)2;
+ row_info->channels = (png_byte)(row_info->channels + 2);
row_info->color_type |= PNG_COLOR_MASK_COLOR;
row_info->pixel_depth = (png_byte)(row_info->channels *
row_info->bit_depth);
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
/* Reduce RGB files to grayscale, with or without alpha
- * using the equation given in Poynton's ColorFAQ at
- * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008)
- * New link:
- * <http://www.poynton.com/notes/colour_and_gamma/>
+ * using the equation given in Poynton's ColorFAQ of 1998-01-04 at
+ * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008 but
+ * versions dated 1998 through November 2002 have been archived at
+ * http://web.archive.org/web/20000816232553/http://www.inforamp.net/
+ * ~poynton/notes/colour_and_gamma/ColorFAQ.txt )
* Charles Poynton poynton at poynton.com
*
* Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
*
- * We approximate this with
+ * which can be expressed with integers as
+ *
+ * Y = (6969 * R + 23434 * G + 2365 * B)/32768
+ *
+ * Poynton's current link (as of January 2003 through July 2011):
+ * <http://www.poynton.com/notes/colour_and_gamma/>
+ * has changed the numbers slightly:
*
- * Y = 0.21268 * R + 0.7151 * G + 0.07217 * B
+ * Y = 0.2126*R + 0.7152*G + 0.0722*B
*
* which can be expressed with integers as
*
- * Y = (6969 * R + 23434 * G + 2365 * B)/32768
+ * Y = (6966 * R + 23436 * G + 2366 * B)/32768
+ *
+ * Historically, however, libpng uses numbers derived from the ITU-R Rec 709
+ * end point chromaticities and the D65 white point. Depending on the
+ * precision used for the D65 white point this produces a variety of different
+ * numbers, however if the four decimal place value used in ITU-R Rec 709 is
+ * used (0.3127,0.3290) the Y calculation would be:
+ *
+ * Y = (6968 * R + 23435 * G + 2366 * B)/32768
+ *
+ * While this is correct the rounding results in an overflow for white, because
+ * the sum of the rounded coefficients is 32769, not 32768. Consequently
+ * libpng uses, instead, the closest non-overflowing approximation:
*
- * The calculation is to be done in a linear colorspace.
+ * Y = (6968 * R + 23434 * G + 2366 * B)/32768
*
- * Other integer coefficents can be used via png_set_rgb_to_gray().
+ * Starting with libpng-1.5.5, if the image being converted has a cHRM chunk
+ * (including an sRGB chunk) then the chromaticities are used to calculate the
+ * coefficients. See the chunk handling in pngrutil.c for more information.
+ *
+ * In all cases the calculation is to be done in a linear colorspace. If no
+ * gamma information is available to correct the encoding of the original RGB
+ * values this results in an implicit assumption that the original PNG RGB
+ * values were linear.
+ *
+ * Other integer coefficents can be used via png_set_rgb_to_gray(). Because
+ * the API takes just red and green coefficients the blue coefficient is
+ * calculated to make the sum 32768. This will result in different rounding
+ * to that used above.
*/
int /* PRIVATE */
png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
{
- png_uint_32 i;
-
- png_uint_32 row_width = row_info->width;
int rgb_error = 0;
png_debug(1, "in png_do_rgb_to_gray");
if (!(row_info->color_type & PNG_COLOR_MASK_PALETTE) &&
(row_info->color_type & PNG_COLOR_MASK_COLOR))
{
- png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
- png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
- png_uint_32 bc = png_ptr->rgb_to_gray_blue_coeff;
+ PNG_CONST png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
+ PNG_CONST png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
+ PNG_CONST png_uint_32 bc = 32768 - rc - gc;
+ PNG_CONST png_uint_32 row_width = row_info->width;
+ PNG_CONST int have_alpha =
+ (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0;
- if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+ if (row_info->bit_depth == 8)
{
- if (row_info->bit_depth == 8)
- {
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
- if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
+ /* Notice that gamma to/from 1 are not necessarily inverses (if
+ * there is an overall gamma correction). Prior to 1.5.5 this code
+ * checked the linearized values for equality; this doesn't match
+ * the documentation, the original values must be checked.
+ */
+ if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
+ {
+ png_bytep sp = row;
+ png_bytep dp = row;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
{
- png_bytep sp = row;
- png_bytep dp = row;
+ png_byte red = *(sp++);
+ png_byte green = *(sp++);
+ png_byte blue = *(sp++);
- for (i = 0; i < row_width; i++)
+ if (red != green || red != blue)
{
- png_byte red = png_ptr->gamma_to_1[*(sp++)];
- png_byte green = png_ptr->gamma_to_1[*(sp++)];
- png_byte blue = png_ptr->gamma_to_1[*(sp++)];
-
- if (red != green || red != blue)
- {
- rgb_error |= 1;
- *(dp++) = png_ptr->gamma_from_1[
- (rc*red + gc*green + bc*blue)>>15];
- }
+ red = png_ptr->gamma_to_1[red];
+ green = png_ptr->gamma_to_1[green];
+ blue = png_ptr->gamma_to_1[blue];
- else
- *(dp++) = *(sp - 1);
+ rgb_error |= 1;
+ *(dp++) = png_ptr->gamma_from_1[
+ (rc*red + gc*green + bc*blue + 16384)>>15];
}
- }
- else
-#endif
- {
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
- {
- png_byte red = *(sp++);
- png_byte green = *(sp++);
- png_byte blue = *(sp++);
- if (red != green || red != blue)
- {
- rgb_error |= 1;
- *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
- }
+ else
+ {
+ /* If there is no overall correction the table will not be
+ * set.
+ */
+ if (png_ptr->gamma_table != NULL)
+ red = png_ptr->gamma_table[red];
- else
- *(dp++) = *(sp - 1);
+ *(dp++) = red;
}
+
+ if (have_alpha)
+ *(dp++) = *(sp++);
}
}
-
- else /* RGB bit_depth == 16 */
+ else
+#endif
{
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
- if (png_ptr->gamma_16_to_1 != NULL &&
- png_ptr->gamma_16_from_1 != NULL)
- {
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
- {
- png_uint_16 red, green, blue, w;
-
- red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-
- if (red == green && red == blue)
- w = red;
-
- else
- {
- png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff)
- >> png_ptr->gamma_shift][red>>8];
- png_uint_16 green_1 =
- png_ptr->gamma_16_to_1[(green&0xff) >>
- png_ptr->gamma_shift][green>>8];
- png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff)
- >> png_ptr->gamma_shift][blue>>8];
- png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1
- + bc*blue_1)>>15);
- w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
- png_ptr->gamma_shift][gray16 >> 8];
- rgb_error |= 1;
- }
+ png_bytep sp = row;
+ png_bytep dp = row;
+ png_uint_32 i;
- *(dp++) = (png_byte)((w>>8) & 0xff);
- *(dp++) = (png_byte)(w & 0xff);
- }
- }
- else
-#endif
+ for (i = 0; i < row_width; i++)
{
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
- {
- png_uint_16 red, green, blue, gray16;
+ png_byte red = *(sp++);
+ png_byte green = *(sp++);
+ png_byte blue = *(sp++);
- red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+ if (red != green || red != blue)
+ {
+ rgb_error |= 1;
+ /* NOTE: this is the historical approach which simply
+ * truncates the results.
+ */
+ *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
+ }
- if (red != green || red != blue)
- rgb_error |= 1;
+ else
+ *(dp++) = red;
- gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
- *(dp++) = (png_byte)((gray16>>8) & 0xff);
- *(dp++) = (png_byte)(gray16 & 0xff);
- }
+ if (have_alpha)
+ *(dp++) = *(sp++);
}
}
}
- if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+
+ else /* RGB bit_depth == 16 */
{
- if (row_info->bit_depth == 8)
- {
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
- if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
+ if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL)
+ {
+ png_bytep sp = row;
+ png_bytep dp = row;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
{
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
- {
- png_byte red = png_ptr->gamma_to_1[*(sp++)];
- png_byte green = png_ptr->gamma_to_1[*(sp++)];
- png_byte blue = png_ptr->gamma_to_1[*(sp++)];
+ png_uint_16 red, green, blue, w;
- if (red != green || red != blue)
- rgb_error |= 1;
+ red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+ green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+ blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- *(dp++) = png_ptr->gamma_from_1
- [(rc*red + gc*green + bc*blue)>>15];
+ if (red == green && red == blue)
+ {
+ if (png_ptr->gamma_16_table != NULL)
+ w = png_ptr->gamma_16_table[(red&0xff)
+ >> png_ptr->gamma_shift][red>>8];
- *(dp++) = *(sp++); /* alpha */
+ else
+ w = red;
}
- }
- else
-#endif
- {
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
+
+ else
+ {
+ png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff)
+ >> png_ptr->gamma_shift][red>>8];
+ png_uint_16 green_1 =
+ png_ptr->gamma_16_to_1[(green&0xff) >>
+ png_ptr->gamma_shift][green>>8];
+ png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff)
+ >> png_ptr->gamma_shift][blue>>8];
+ png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1
+ + bc*blue_1 + 16384)>>15);
+ w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
+ png_ptr->gamma_shift][gray16 >> 8];
+ rgb_error |= 1;
+ }
+
+ *(dp++) = (png_byte)((w>>8) & 0xff);
+ *(dp++) = (png_byte)(w & 0xff);
+
+ if (have_alpha)
{
- png_byte red = *(sp++);
- png_byte green = *(sp++);
- png_byte blue = *(sp++);
- if (red != green || red != blue)
- rgb_error |= 1;
-
- *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
- *(dp++) = *(sp++); /* alpha */
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
}
}
}
- else /* RGBA bit_depth == 16 */
+ else
+#endif
{
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
- if (png_ptr->gamma_16_to_1 != NULL &&
- png_ptr->gamma_16_from_1 != NULL)
- {
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
- {
- png_uint_16 red, green, blue, w;
-
- red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-
- if (red == green && red == blue)
- w = red;
-
- else
- {
- png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) >>
- png_ptr->gamma_shift][red>>8];
-
- png_uint_16 green_1 =
- png_ptr->gamma_16_to_1[(green&0xff) >>
- png_ptr->gamma_shift][green>>8];
+ png_bytep sp = row;
+ png_bytep dp = row;
+ png_uint_32 i;
- png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) >>
- png_ptr->gamma_shift][blue>>8];
+ for (i = 0; i < row_width; i++)
+ {
+ png_uint_16 red, green, blue, gray16;
- png_uint_16 gray16 = (png_uint_16)((rc * red_1
- + gc * green_1 + bc * blue_1)>>15);
+ red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+ green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+ blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
- png_ptr->gamma_shift][gray16 >> 8];
+ if (red != green || red != blue)
+ rgb_error |= 1;
- rgb_error |= 1;
- }
+ /* From 1.5.5 in the 16 bit case do the accurate conversion even
+ * in the 'fast' case - this is because this is where the code
+ * ends up when handling linear 16 bit data.
+ */
+ gray16 = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
+ 15);
+ *(dp++) = (png_byte)((gray16>>8) & 0xff);
+ *(dp++) = (png_byte)(gray16 & 0xff);
- *(dp++) = (png_byte)((w>>8) & 0xff);
- *(dp++) = (png_byte)(w & 0xff);
- *(dp++) = *(sp++); /* alpha */
- *(dp++) = *(sp++);
- }
- }
- else
-#endif
- {
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
+ if (have_alpha)
{
- png_uint_16 red, green, blue, gray16;
- red = (png_uint_16)((*(sp)<<8) | *(sp + 1)); sp += 2;
- green = (png_uint_16)((*(sp)<<8) | *(sp + 1)); sp += 2;
- blue = (png_uint_16)((*(sp)<<8) | *(sp + 1)); sp += 2;
-
- if (red != green || red != blue)
- rgb_error |= 1;
-
- gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
- *(dp++) = (png_byte)((gray16>>8) & 0xff);
- *(dp++) = (png_byte)(gray16 & 0xff);
- *(dp++) = *(sp++); /* alpha */
+ *(dp++) = *(sp++);
*(dp++) = *(sp++);
}
}
}
}
- row_info->channels -= 2;
+
+ row_info->channels = (png_byte)(row_info->channels - 2);
row_info->color_type = (png_byte)(row_info->color_type &
~PNG_COLOR_MASK_COLOR);
row_info->pixel_depth = (png_byte)(row_info->channels *
return rgb_error;
}
#endif
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
/* Build a grayscale palette. Palette is assumed to be 1 << bit_depth
* large of png_color. This lets grayscale images be treated as
* paletted. Most useful for gamma correction and simplification
- * of code.
+ * of code. This API is not used internally.
*/
void PNGAPI
png_build_grayscale_palette(int bit_depth, png_colorp palette)
palette[i].blue = (png_byte)v;
}
}
+#endif
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
+ (defined PNG_READ_ALPHA_MODE_SUPPORTED)
/* Replace any alpha or transparency with the supplied background color.
* "background" is already in the screen gamma, while "background_1" is
* at a gamma of 1.0. Paletted files have already been taken care of.
*/
void /* PRIVATE */
-png_do_background(png_row_infop row_info, png_bytep row,
- png_const_color_16p trans_color, png_const_color_16p background
+png_do_compose(png_row_infop row_info, png_bytep row, png_structp png_ptr)
+{
#ifdef PNG_READ_GAMMA_SUPPORTED
- , png_const_color_16p background_1, png_const_bytep gamma_table,
- png_const_bytep gamma_from_1, png_const_bytep gamma_to_1,
- png_const_uint_16pp gamma_16, png_const_uint_16pp gamma_16_from_1,
- png_const_uint_16pp gamma_16_to_1, int gamma_shift
+ png_const_bytep gamma_table = png_ptr->gamma_table;
+ png_const_bytep gamma_from_1 = png_ptr->gamma_from_1;
+ png_const_bytep gamma_to_1 = png_ptr->gamma_to_1;
+ png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table;
+ png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1;
+ png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1;
+ int gamma_shift = png_ptr->gamma_shift;
#endif
- )
-{
- png_bytep sp, dp;
+
+ png_bytep sp;
png_uint_32 i;
png_uint_32 row_width = row_info->width;
+ int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0;
int shift;
- png_debug(1, "in png_do_background");
+ png_debug(1, "in png_do_compose");
- if (background != NULL &&
- (!(row_info->color_type & PNG_COLOR_MASK_ALPHA) ||
- (row_info->color_type != PNG_COLOR_TYPE_PALETTE && trans_color)))
{
switch (row_info->color_type)
{
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x01)
- == trans_color->gray)
+ == png_ptr->trans_color.gray)
{
*sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
- *sp |= (png_byte)(background->gray << shift);
+ *sp |= (png_byte)(png_ptr->background.gray << shift);
}
if (!shift)
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x03)
- == trans_color->gray)
+ == png_ptr->trans_color.gray)
{
*sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
- *sp |= (png_byte)(background->gray << shift);
+ *sp |= (png_byte)(png_ptr->background.gray << shift);
}
else
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x03)
- == trans_color->gray)
+ == png_ptr->trans_color.gray)
{
*sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
- *sp |= (png_byte)(background->gray << shift);
+ *sp |= (png_byte)(png_ptr->background.gray << shift);
}
if (!shift)
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x0f)
- == trans_color->gray)
+ == png_ptr->trans_color.gray)
{
*sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
- *sp |= (png_byte)(background->gray << shift);
+ *sp |= (png_byte)(png_ptr->background.gray << shift);
}
else
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x0f)
- == trans_color->gray)
+ == png_ptr->trans_color.gray)
{
*sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
- *sp |= (png_byte)(background->gray << shift);
+ *sp |= (png_byte)(png_ptr->background.gray << shift);
}
if (!shift)
sp = row;
for (i = 0; i < row_width; i++, sp++)
{
- if (*sp == trans_color->gray)
- *sp = (png_byte)background->gray;
+ if (*sp == png_ptr->trans_color.gray)
+ *sp = (png_byte)png_ptr->background.gray;
else
*sp = gamma_table[*sp];
sp = row;
for (i = 0; i < row_width; i++, sp++)
{
- if (*sp == trans_color->gray)
- *sp = (png_byte)background->gray;
+ if (*sp == png_ptr->trans_color.gray)
+ *sp = (png_byte)png_ptr->background.gray;
}
}
break;
v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
- if (v == trans_color->gray)
+ if (v == png_ptr->trans_color.gray)
{
/* Background is already in screen gamma */
- *sp = (png_byte)((background->gray >> 8) & 0xff);
- *(sp + 1) = (png_byte)(background->gray & 0xff);
+ *sp = (png_byte)((png_ptr->background.gray >> 8)
+ & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.gray
+ & 0xff);
}
else
v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
- if (v == trans_color->gray)
+ if (v == png_ptr->trans_color.gray)
{
- *sp = (png_byte)((background->gray >> 8) & 0xff);
- *(sp + 1) = (png_byte)(background->gray & 0xff);
+ *sp = (png_byte)((png_ptr->background.gray >> 8)
+ & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.gray
+ & 0xff);
}
}
}
sp = row;
for (i = 0; i < row_width; i++, sp += 3)
{
- if (*sp == trans_color->red &&
- *(sp + 1) == trans_color->green &&
- *(sp + 2) == trans_color->blue)
+ if (*sp == png_ptr->trans_color.red &&
+ *(sp + 1) == png_ptr->trans_color.green &&
+ *(sp + 2) == png_ptr->trans_color.blue)
{
- *sp = (png_byte)background->red;
- *(sp + 1) = (png_byte)background->green;
- *(sp + 2) = (png_byte)background->blue;
+ *sp = (png_byte)png_ptr->background.red;
+ *(sp + 1) = (png_byte)png_ptr->background.green;
+ *(sp + 2) = (png_byte)png_ptr->background.blue;
}
else
sp = row;
for (i = 0; i < row_width; i++, sp += 3)
{
- if (*sp == trans_color->red &&
- *(sp + 1) == trans_color->green &&
- *(sp + 2) == trans_color->blue)
+ if (*sp == png_ptr->trans_color.red &&
+ *(sp + 1) == png_ptr->trans_color.green &&
+ *(sp + 2) == png_ptr->trans_color.blue)
{
- *sp = (png_byte)background->red;
- *(sp + 1) = (png_byte)background->green;
- *(sp + 2) = (png_byte)background->blue;
+ *sp = (png_byte)png_ptr->background.red;
+ *(sp + 1) = (png_byte)png_ptr->background.green;
+ *(sp + 2) = (png_byte)png_ptr->background.blue;
}
}
}
png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+ *(sp + 5));
- if (r == trans_color->red && g == trans_color->green &&
- b == trans_color->blue)
+ if (r == png_ptr->trans_color.red &&
+ g == png_ptr->trans_color.green &&
+ b == png_ptr->trans_color.blue)
{
/* Background is already in screen gamma */
- *sp = (png_byte)((background->red >> 8) & 0xff);
- *(sp + 1) = (png_byte)(background->red & 0xff);
- *(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
- *(sp + 3) = (png_byte)(background->green & 0xff);
- *(sp + 4) = (png_byte)((background->blue >> 8) & 0xff);
- *(sp + 5) = (png_byte)(background->blue & 0xff);
+ *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+ *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+ & 0xff);
+ *(sp + 3) = (png_byte)(png_ptr->background.green
+ & 0xff);
+ *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+ & 0xff);
+ *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
}
else
png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+ *(sp + 5));
- if (r == trans_color->red && g == trans_color->green &&
- b == trans_color->blue)
+ if (r == png_ptr->trans_color.red &&
+ g == png_ptr->trans_color.green &&
+ b == png_ptr->trans_color.blue)
{
- *sp = (png_byte)((background->red >> 8) & 0xff);
- *(sp + 1) = (png_byte)(background->red & 0xff);
- *(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
- *(sp + 3) = (png_byte)(background->green & 0xff);
- *(sp + 4) = (png_byte)((background->blue >> 8) & 0xff);
- *(sp + 5) = (png_byte)(background->blue & 0xff);
+ *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+ *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+ & 0xff);
+ *(sp + 3) = (png_byte)(png_ptr->background.green
+ & 0xff);
+ *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+ & 0xff);
+ *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
}
}
}
gamma_table != NULL)
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 2, dp++)
+ for (i = 0; i < row_width; i++, sp += 2)
{
png_uint_16 a = *(sp + 1);
if (a == 0xff)
- *dp = gamma_table[*sp];
+ *sp = gamma_table[*sp];
else if (a == 0)
{
/* Background is already in screen gamma */
- *dp = (png_byte)background->gray;
+ *sp = (png_byte)png_ptr->background.gray;
}
else
png_byte v, w;
v = gamma_to_1[*sp];
- png_composite(w, v, a, background_1->gray);
- *dp = gamma_from_1[w];
+ png_composite(w, v, a, png_ptr->background_1.gray);
+ if (!optimize)
+ w = gamma_from_1[w];
+ *sp = w;
}
}
}
#endif
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 2, dp++)
+ for (i = 0; i < row_width; i++, sp += 2)
{
png_byte a = *(sp + 1);
- if (a == 0xff)
- *dp = *sp;
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
- else if (a == 0)
- *dp = (png_byte)background->gray;
-
- else
- png_composite(*dp, *sp, a, background_1->gray);
+ if (a == 0)
+ *sp = (png_byte)png_ptr->background.gray;
-#else
- *dp = (png_byte)background->gray;
-#endif
+ else if (a < 0xff)
+ png_composite(*sp, *sp, a, png_ptr->background.gray);
}
}
}
gamma_16_to_1 != NULL)
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 4, dp += 2)
+ for (i = 0; i < row_width; i++, sp += 4)
{
png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
+ *(sp + 3));
png_uint_16 v;
v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
- *dp = (png_byte)((v >> 8) & 0xff);
- *(dp + 1) = (png_byte)(v & 0xff);
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
}
-#ifdef PNG_READ_GAMMA_SUPPORTED
else if (a == 0)
-#else
- else
-#endif
{
/* Background is already in screen gamma */
- *dp = (png_byte)((background->gray >> 8) & 0xff);
- *(dp + 1) = (png_byte)(background->gray & 0xff);
+ *sp = (png_byte)((png_ptr->background.gray >> 8)
+ & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
}
-#ifdef PNG_READ_GAMMA_SUPPORTED
else
{
png_uint_16 g, v, w;
g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
- png_composite_16(v, g, a, background_1->gray);
- w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8];
- *dp = (png_byte)((w >> 8) & 0xff);
- *(dp + 1) = (png_byte)(w & 0xff);
+ png_composite_16(v, g, a, png_ptr->background_1.gray);
+ if (optimize)
+ w = v;
+ else
+ w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8];
+ *sp = (png_byte)((w >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(w & 0xff);
}
-#endif
}
}
else
#endif
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 4, dp += 2)
+ for (i = 0; i < row_width; i++, sp += 4)
{
png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
+ *(sp + 3));
- if (a == (png_uint_16)0xffff)
- png_memcpy(dp, sp, 2);
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
- else if (a == 0)
-#else
- else
-#endif
+ if (a == 0)
{
- *dp = (png_byte)((background->gray >> 8) & 0xff);
- *(dp + 1) = (png_byte)(background->gray & 0xff);
+ *sp = (png_byte)((png_ptr->background.gray >> 8)
+ & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
}
-#ifdef PNG_READ_GAMMA_SUPPORTED
- else
+ else if (a < 0xffff)
{
png_uint_16 g, v;
g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
- png_composite_16(v, g, a, background_1->gray);
- *dp = (png_byte)((v >> 8) & 0xff);
- *(dp + 1) = (png_byte)(v & 0xff);
+ png_composite_16(v, g, a, png_ptr->background.gray);
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
}
-#endif
}
}
}
gamma_table != NULL)
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 4, dp += 3)
+ for (i = 0; i < row_width; i++, sp += 4)
{
png_byte a = *(sp + 3);
if (a == 0xff)
{
- *dp = gamma_table[*sp];
- *(dp + 1) = gamma_table[*(sp + 1)];
- *(dp + 2) = gamma_table[*(sp + 2)];
+ *sp = gamma_table[*sp];
+ *(sp + 1) = gamma_table[*(sp + 1)];
+ *(sp + 2) = gamma_table[*(sp + 2)];
}
else if (a == 0)
{
/* Background is already in screen gamma */
- *dp = (png_byte)background->red;
- *(dp + 1) = (png_byte)background->green;
- *(dp + 2) = (png_byte)background->blue;
+ *sp = (png_byte)png_ptr->background.red;
+ *(sp + 1) = (png_byte)png_ptr->background.green;
+ *(sp + 2) = (png_byte)png_ptr->background.blue;
}
else
png_byte v, w;
v = gamma_to_1[*sp];
- png_composite(w, v, a, background_1->red);
- *dp = gamma_from_1[w];
+ png_composite(w, v, a, png_ptr->background_1.red);
+ if (!optimize) w = gamma_from_1[w];
+ *sp = w;
v = gamma_to_1[*(sp + 1)];
- png_composite(w, v, a, background_1->green);
- *(dp + 1) = gamma_from_1[w];
+ png_composite(w, v, a, png_ptr->background_1.green);
+ if (!optimize) w = gamma_from_1[w];
+ *(sp + 1) = w;
v = gamma_to_1[*(sp + 2)];
- png_composite(w, v, a, background_1->blue);
- *(dp + 2) = gamma_from_1[w];
+ png_composite(w, v, a, png_ptr->background_1.blue);
+ if (!optimize) w = gamma_from_1[w];
+ *(sp + 2) = w;
}
}
}
#endif
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 4, dp += 3)
+ for (i = 0; i < row_width; i++, sp += 4)
{
png_byte a = *(sp + 3);
- if (a == 0xff)
- {
- *dp = *sp;
- *(dp + 1) = *(sp + 1);
- *(dp + 2) = *(sp + 2);
- }
-
- else if (a == 0)
+ if (a == 0)
{
- *dp = (png_byte)background->red;
- *(dp + 1) = (png_byte)background->green;
- *(dp + 2) = (png_byte)background->blue;
+ *sp = (png_byte)png_ptr->background.red;
+ *(sp + 1) = (png_byte)png_ptr->background.green;
+ *(sp + 2) = (png_byte)png_ptr->background.blue;
}
- else
+ else if (a < 0xff)
{
- png_composite(*dp, *sp, a, background->red);
+ png_composite(*sp, *sp, a, png_ptr->background.red);
- png_composite(*(dp + 1), *(sp + 1), a,
- background->green);
+ png_composite(*(sp + 1), *(sp + 1), a,
+ png_ptr->background.green);
- png_composite(*(dp + 2), *(sp + 2), a,
- background->blue);
+ png_composite(*(sp + 2), *(sp + 2), a,
+ png_ptr->background.blue);
}
}
}
gamma_16_to_1 != NULL)
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 8, dp += 6)
+ for (i = 0; i < row_width; i++, sp += 8)
{
png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
<< 8) + (png_uint_16)(*(sp + 7)));
png_uint_16 v;
v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
- *dp = (png_byte)((v >> 8) & 0xff);
- *(dp + 1) = (png_byte)(v & 0xff);
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
- *(dp + 2) = (png_byte)((v >> 8) & 0xff);
- *(dp + 3) = (png_byte)(v & 0xff);
+ *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(v & 0xff);
v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
- *(dp + 4) = (png_byte)((v >> 8) & 0xff);
- *(dp + 5) = (png_byte)(v & 0xff);
+ *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(v & 0xff);
}
else if (a == 0)
{
/* Background is already in screen gamma */
- *dp = (png_byte)((background->red >> 8) & 0xff);
- *(dp + 1) = (png_byte)(background->red & 0xff);
- *(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
- *(dp + 3) = (png_byte)(background->green & 0xff);
- *(dp + 4) = (png_byte)((background->blue >> 8) & 0xff);
- *(dp + 5) = (png_byte)(background->blue & 0xff);
+ *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+ *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+ & 0xff);
+ *(sp + 3) = (png_byte)(png_ptr->background.green
+ & 0xff);
+ *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+ & 0xff);
+ *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
}
else
{
- png_uint_16 v, w, x;
+ png_uint_16 v, w;
v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
- png_composite_16(w, v, a, background_1->red);
-
- x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
- *dp = (png_byte)((x >> 8) & 0xff);
- *(dp + 1) = (png_byte)(x & 0xff);
+ png_composite_16(w, v, a, png_ptr->background_1.red);
+ if (!optimize)
+ w = gamma_16_from_1[((w&0xff) >> gamma_shift)]
+ [w >> 8];
+ *sp = (png_byte)((w >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(w & 0xff);
v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
- png_composite_16(w, v, a, background_1->green);
+ png_composite_16(w, v, a, png_ptr->background_1.green);
+ if (!optimize)
+ w = gamma_16_from_1[((w&0xff) >> gamma_shift)]
+ [w >> 8];
- x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
- *(dp + 2) = (png_byte)((x >> 8) & 0xff);
- *(dp + 3) = (png_byte)(x & 0xff);
+ *(sp + 2) = (png_byte)((w >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(w & 0xff);
v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
- png_composite_16(w, v, a, background_1->blue);
+ png_composite_16(w, v, a, png_ptr->background_1.blue);
+ if (!optimize)
+ w = gamma_16_from_1[((w&0xff) >> gamma_shift)]
+ [w >> 8];
- x = gamma_16_from_1[(w & 0xff) >> gamma_shift][w >> 8];
- *(dp + 4) = (png_byte)((x >> 8) & 0xff);
- *(dp + 5) = (png_byte)(x & 0xff);
+ *(sp + 4) = (png_byte)((w >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(w & 0xff);
}
}
}
#endif
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 8, dp += 6)
+ for (i = 0; i < row_width; i++, sp += 8)
{
png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
<< 8) + (png_uint_16)(*(sp + 7)));
- if (a == (png_uint_16)0xffff)
- {
- png_memcpy(dp, sp, 6);
- }
-
- else if (a == 0)
+ if (a == 0)
{
- *dp = (png_byte)((background->red >> 8) & 0xff);
- *(dp + 1) = (png_byte)(background->red & 0xff);
- *(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
- *(dp + 3) = (png_byte)(background->green & 0xff);
- *(dp + 4) = (png_byte)((background->blue >> 8) & 0xff);
- *(dp + 5) = (png_byte)(background->blue & 0xff);
+ *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+ *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+ & 0xff);
+ *(sp + 3) = (png_byte)(png_ptr->background.green
+ & 0xff);
+ *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+ & 0xff);
+ *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
}
- else
+ else if (a < 0xffff)
{
png_uint_16 v;
png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+ *(sp + 5));
- png_composite_16(v, r, a, background->red);
- *dp = (png_byte)((v >> 8) & 0xff);
- *(dp + 1) = (png_byte)(v & 0xff);
+ png_composite_16(v, r, a, png_ptr->background.red);
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
- png_composite_16(v, g, a, background->green);
- *(dp + 2) = (png_byte)((v >> 8) & 0xff);
- *(dp + 3) = (png_byte)(v & 0xff);
+ png_composite_16(v, g, a, png_ptr->background.green);
+ *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(v & 0xff);
- png_composite_16(v, b, a, background->blue);
- *(dp + 4) = (png_byte)((v >> 8) & 0xff);
- *(dp + 5) = (png_byte)(v & 0xff);
+ png_composite_16(v, b, a, png_ptr->background.blue);
+ *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(v & 0xff);
}
}
}
default:
break;
}
-
- if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
- {
- row_info->color_type = (png_byte)(row_info->color_type &
- ~PNG_COLOR_MASK_ALPHA);
- row_info->channels--;
- row_info->pixel_depth = (png_byte)(row_info->channels *
- row_info->bit_depth);
- row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
- }
}
}
-#endif
+#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_READ_ALPHA_MODE_SUPPORTED */
#ifdef PNG_READ_GAMMA_SUPPORTED
/* Gamma correct the image, avoiding the alpha channel. Make sure
* build_gamma_table().
*/
void /* PRIVATE */
-png_do_gamma(png_row_infop row_info, png_bytep row,
- png_const_bytep gamma_table, png_const_uint_16pp gamma_16_table,
- int gamma_shift)
+png_do_gamma(png_row_infop row_info, png_bytep row, png_structp png_ptr)
{
+ png_const_bytep gamma_table = png_ptr->gamma_table;
+ png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table;
+ int gamma_shift = png_ptr->gamma_shift;
+
png_bytep sp;
png_uint_32 i;
png_uint_32 row_width=row_info->width;
}
#endif
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+/* Encode the alpha channel to the output gamma (the input channel is always
+ * linear.) Called only with color types that have an alpha channel. Needs the
+ * from_1 tables.
+ */
+void /* PRIVATE */
+png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structp png_ptr)
+{
+ png_uint_32 row_width = row_info->width;
+
+ png_debug(1, "in png_do_encode_alpha");
+
+ if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ PNG_CONST png_bytep table = png_ptr->gamma_from_1;
+
+ if (table != NULL)
+ {
+ PNG_CONST int step =
+ (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2;
+
+ /* The alpha channel is the last component: */
+ row += step - 1;
+
+ for (; row_width > 0; --row_width, row += step)
+ *row = table[*row];
+
+ return;
+ }
+ }
+
+ else if (row_info->bit_depth == 16)
+ {
+ PNG_CONST png_uint_16pp table = png_ptr->gamma_16_from_1;
+ PNG_CONST int gamma_shift = png_ptr->gamma_shift;
+
+ if (table != NULL)
+ {
+ PNG_CONST int step =
+ (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4;
+
+ /* The alpha channel is the last component: */
+ row += step - 2;
+
+ for (; row_width > 0; --row_width, row += step)
+ {
+ png_uint_16 v;
+
+ v = table[*(row + 1) >> gamma_shift][*row];
+ *row = (png_byte)((v >> 8) & 0xff);
+ *(row + 1) = (png_byte)(v & 0xff);
+ }
+
+ return;
+ }
+ }
+ }
+
+ /* Only get to here if called with a weird row_info; no harm has been done,
+ * so just issue a warning.
+ */
+ png_warning(png_ptr, "png_do_encode_alpha: unexpected call");
+}
+#endif
+
#ifdef PNG_READ_EXPAND_SUPPORTED
/* Expands a palette row to an RGB or RGBA row depending
* upon whether you supply trans and num_trans.
if (row_info->bit_depth == 8)
{
{
- if (trans_alpha != NULL)
+ if (num_trans > 0)
{
sp = row + (png_size_t)row_width - 1;
dp = row + (png_size_t)(row_width << 2) - 1;
*/
void /* PRIVATE */
png_do_expand(png_row_infop row_info, png_bytep row,
- png_const_color_16p trans_value)
+ png_const_color_16p trans_color)
{
int shift, value;
png_bytep sp, dp;
{
if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
{
- png_uint_16 gray = (png_uint_16)(trans_value ? trans_value->gray : 0);
+ png_uint_16 gray = (png_uint_16)(trans_color ? trans_color->gray : 0);
if (row_info->bit_depth < 8)
{
row_info->rowbytes = row_width;
}
- if (trans_value != NULL)
+ if (trans_color != NULL)
{
if (row_info->bit_depth == 8)
{
- gray = gray & 0xff;
+ /* NOTE: prior to libpng 1.5.14 this cleared out the top bits of
+ * 'gray', however if those are set it is an error.
+ */
sp = row + (png_size_t)row_width - 1;
dp = row + (png_size_t)(row_width << 1) - 1;
row_width);
}
}
- else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_value)
+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_color)
{
if (row_info->bit_depth == 8)
{
- png_byte red = (png_byte)(trans_value->red & 0xff);
- png_byte green = (png_byte)(trans_value->green & 0xff);
- png_byte blue = (png_byte)(trans_value->blue & 0xff);
+ png_byte red = (png_byte)(trans_color->red & 0xff);
+ png_byte green = (png_byte)(trans_color->green & 0xff);
+ png_byte blue = (png_byte)(trans_color->blue & 0xff);
sp = row + (png_size_t)row_info->rowbytes - 1;
dp = row + (png_size_t)(row_width << 2) - 1;
for (i = 0; i < row_width; i++)
}
else if (row_info->bit_depth == 16)
{
- png_byte red_high = (png_byte)((trans_value->red >> 8) & 0xff);
- png_byte green_high = (png_byte)((trans_value->green >> 8) & 0xff);
- png_byte blue_high = (png_byte)((trans_value->blue >> 8) & 0xff);
- png_byte red_low = (png_byte)(trans_value->red & 0xff);
- png_byte green_low = (png_byte)(trans_value->green & 0xff);
- png_byte blue_low = (png_byte)(trans_value->blue & 0xff);
+ png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
+ png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
+ png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
+ png_byte red_low = (png_byte)(trans_color->red & 0xff);
+ png_byte green_low = (png_byte)(trans_color->green & 0xff);
+ png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
sp = row + row_info->rowbytes - 1;
dp = row + (png_size_t)(row_width << 3) - 1;
for (i = 0; i < row_width; i++)
#endif
#ifdef PNG_READ_EXPAND_16_SUPPORTED
-/* If the bit depth is 8 and the colour type is not a palette type expand the
+/* If the bit depth is 8 and the color type is not a palette type expand the
* whole row to 16 bits. Has no effect otherwise.
*/
void /* PRIVATE */
}
}
#endif /* PNG_READ_QUANTIZE_SUPPORTED */
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
#ifdef PNG_MNG_FEATURES_SUPPORTED
/* Undoes intrapixel differencing */
png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
- png_uint_32 red = (png_uint_32)((s0 + s1 + 65536L) & 0xffffL);
- png_uint_32 blue = (png_uint_32)((s2 + s1 + 65536L) & 0xffffL);
+ png_uint_32 red = (s0 + s1 + 65536) & 0xffff;
+ png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
*(rp ) = (png_byte)((red >> 8) & 0xff);
*(rp + 1) = (png_byte)(red & 0xff);
*(rp + 4) = (png_byte)((blue >> 8) & 0xff);
projects / reactos.git / blobdiff