+++ /dev/null
-
-/* pngwutil.c - utilities to write a PNG file
- *
- * Last changed in libpng 1.6.32 [August 24, 2017]
- * Copyright (c) 1998-2002,2004,2006-2017 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.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-#include "pngpriv.h"
-
-#ifdef PNG_WRITE_SUPPORTED
-
-#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
-/* Place a 32-bit number into a buffer in PNG byte order. We work
- * with unsigned numbers for convenience, although one supported
- * ancillary chunk uses signed (two's complement) numbers.
- */
-void PNGAPI
-png_save_uint_32(png_bytep buf, png_uint_32 i)
-{
- buf[0] = (png_byte)((i >> 24) & 0xffU);
- buf[1] = (png_byte)((i >> 16) & 0xffU);
- buf[2] = (png_byte)((i >> 8) & 0xffU);
- buf[3] = (png_byte)( i & 0xffU);
-}
-
-/* Place a 16-bit number into a buffer in PNG byte order.
- * The parameter is declared unsigned int, not png_uint_16,
- * just to avoid potential problems on pre-ANSI C compilers.
- */
-void PNGAPI
-png_save_uint_16(png_bytep buf, unsigned int i)
-{
- buf[0] = (png_byte)((i >> 8) & 0xffU);
- buf[1] = (png_byte)( i & 0xffU);
-}
-#endif
-
-/* Simple function to write the signature. If we have already written
- * the magic bytes of the signature, or more likely, the PNG stream is
- * being embedded into another stream and doesn't need its own signature,
- * we should call png_set_sig_bytes() to tell libpng how many of the
- * bytes have already been written.
- */
-void PNGAPI
-png_write_sig(png_structrp png_ptr)
-{
- png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
-
-#ifdef PNG_IO_STATE_SUPPORTED
- /* Inform the I/O callback that the signature is being written */
- png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE;
-#endif
-
- /* Write the rest of the 8 byte signature */
- png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
- (png_size_t)(8 - png_ptr->sig_bytes));
-
- if (png_ptr->sig_bytes < 3)
- png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
-}
-
-/* Write the start of a PNG chunk. The type is the chunk type.
- * The total_length is the sum of the lengths of all the data you will be
- * passing in png_write_chunk_data().
- */
-static void
-png_write_chunk_header(png_structrp png_ptr, png_uint_32 chunk_name,
- png_uint_32 length)
-{
- png_byte buf[8];
-
-#if defined(PNG_DEBUG) && (PNG_DEBUG > 0)
- PNG_CSTRING_FROM_CHUNK(buf, chunk_name);
- png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length);
-#endif
-
- if (png_ptr == NULL)
- return;
-
-#ifdef PNG_IO_STATE_SUPPORTED
- /* Inform the I/O callback that the chunk header is being written.
- * PNG_IO_CHUNK_HDR requires a single I/O call.
- */
- png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR;
-#endif
-
- /* Write the length and the chunk name */
- png_save_uint_32(buf, length);
- png_save_uint_32(buf + 4, chunk_name);
- png_write_data(png_ptr, buf, 8);
-
- /* Put the chunk name into png_ptr->chunk_name */
- png_ptr->chunk_name = chunk_name;
-
- /* Reset the crc and run it over the chunk name */
- png_reset_crc(png_ptr);
-
- png_calculate_crc(png_ptr, buf + 4, 4);
-
-#ifdef PNG_IO_STATE_SUPPORTED
- /* Inform the I/O callback that chunk data will (possibly) be written.
- * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls.
- */
- png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA;
-#endif
-}
-
-void PNGAPI
-png_write_chunk_start(png_structrp png_ptr, png_const_bytep chunk_string,
- png_uint_32 length)
-{
- png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length);
-}
-
-/* Write the data of a PNG chunk started with png_write_chunk_header().
- * Note that multiple calls to this function are allowed, and that the
- * sum of the lengths from these calls *must* add up to the total_length
- * given to png_write_chunk_header().
- */
-void PNGAPI
-png_write_chunk_data(png_structrp png_ptr, png_const_bytep data,
- png_size_t length)
-{
- /* Write the data, and run the CRC over it */
- if (png_ptr == NULL)
- return;
-
- if (data != NULL && length > 0)
- {
- png_write_data(png_ptr, data, length);
-
- /* Update the CRC after writing the data,
- * in case the user I/O routine alters it.
- */
- png_calculate_crc(png_ptr, data, length);
- }
-}
-
-/* Finish a chunk started with png_write_chunk_header(). */
-void PNGAPI
-png_write_chunk_end(png_structrp png_ptr)
-{
- png_byte buf[4];
-
- if (png_ptr == NULL) return;
-
-#ifdef PNG_IO_STATE_SUPPORTED
- /* Inform the I/O callback that the chunk CRC is being written.
- * PNG_IO_CHUNK_CRC requires a single I/O function call.
- */
- png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC;
-#endif
-
- /* Write the crc in a single operation */
- png_save_uint_32(buf, png_ptr->crc);
-
- png_write_data(png_ptr, buf, (png_size_t)4);
-}
-
-/* Write a PNG chunk all at once. The type is an array of ASCII characters
- * representing the chunk name. The array must be at least 4 bytes in
- * length, and does not need to be null terminated. To be safe, pass the
- * pre-defined chunk names here, and if you need a new one, define it
- * where the others are defined. The length is the length of the data.
- * All the data must be present. If that is not possible, use the
- * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
- * functions instead.
- */
-static void
-png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,
- png_const_bytep data, png_size_t length)
-{
- if (png_ptr == NULL)
- return;
-
- /* On 64-bit architectures 'length' may not fit in a png_uint_32. */
- if (length > PNG_UINT_31_MAX)
- png_error(png_ptr, "length exceeds PNG maximum");
-
- png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
- png_write_chunk_data(png_ptr, data, length);
- png_write_chunk_end(png_ptr);
-}
-
-/* This is the API that calls the internal function above. */
-void PNGAPI
-png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string,
- png_const_bytep data, png_size_t length)
-{
- png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,
- length);
-}
-
-/* This is used below to find the size of an image to pass to png_deflate_claim,
- * so it only needs to be accurate if the size is less than 16384 bytes (the
- * point at which a lower LZ window size can be used.)
- */
-static png_alloc_size_t
-png_image_size(png_structrp png_ptr)
-{
- /* Only return sizes up to the maximum of a png_uint_32; do this by limiting
- * the width and height used to 15 bits.
- */
- png_uint_32 h = png_ptr->height;
-
- if (png_ptr->rowbytes < 32768 && h < 32768)
- {
- if (png_ptr->interlaced != 0)
- {
- /* Interlacing makes the image larger because of the replication of
- * both the filter byte and the padding to a byte boundary.
- */
- png_uint_32 w = png_ptr->width;
- unsigned int pd = png_ptr->pixel_depth;
- png_alloc_size_t cb_base;
- int pass;
-
- for (cb_base=0, pass=0; pass<=6; ++pass)
- {
- png_uint_32 pw = PNG_PASS_COLS(w, pass);
-
- if (pw > 0)
- cb_base += (PNG_ROWBYTES(pd, pw)+1) * PNG_PASS_ROWS(h, pass);
- }
-
- return cb_base;
- }
-
- else
- return (png_ptr->rowbytes+1) * h;
- }
-
- else
- return 0xffffffffU;
-}
-
-#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
- /* This is the code to hack the first two bytes of the deflate stream (the
- * deflate header) to correct the windowBits value to match the actual data
- * size. Note that the second argument is the *uncompressed* size but the
- * first argument is the *compressed* data (and it must be deflate
- * compressed.)
- */
-static void
-optimize_cmf(png_bytep data, png_alloc_size_t data_size)
-{
- /* Optimize the CMF field in the zlib stream. The resultant zlib stream is
- * still compliant to the stream specification.
- */
- if (data_size <= 16384) /* else windowBits must be 15 */
- {
- unsigned int z_cmf = data[0]; /* zlib compression method and flags */
-
- if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
- {
- unsigned int z_cinfo;
- unsigned int half_z_window_size;
-
- z_cinfo = z_cmf >> 4;
- half_z_window_size = 1U << (z_cinfo + 7);
-
- if (data_size <= half_z_window_size) /* else no change */
- {
- unsigned int tmp;
-
- do
- {
- half_z_window_size >>= 1;
- --z_cinfo;
- }
- while (z_cinfo > 0 && data_size <= half_z_window_size);
-
- z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
-
- data[0] = (png_byte)z_cmf;
- tmp = data[1] & 0xe0;
- tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
- data[1] = (png_byte)tmp;
- }
- }
- }
-}
-#endif /* WRITE_OPTIMIZE_CMF */
-
-/* Initialize the compressor for the appropriate type of compression. */
-static int
-png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
- png_alloc_size_t data_size)
-{
- if (png_ptr->zowner != 0)
- {
-#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
- char msg[64];
-
- PNG_STRING_FROM_CHUNK(msg, owner);
- msg[4] = ':';
- msg[5] = ' ';
- PNG_STRING_FROM_CHUNK(msg+6, png_ptr->zowner);
- /* So the message that results is "<chunk> using zstream"; this is an
- * internal error, but is very useful for debugging. i18n requirements
- * are minimal.
- */
- (void)png_safecat(msg, (sizeof msg), 10, " using zstream");
-#endif
-#if PNG_RELEASE_BUILD
- png_warning(png_ptr, msg);
-
- /* Attempt sane error recovery */
- if (png_ptr->zowner == png_IDAT) /* don't steal from IDAT */
- {
- png_ptr->zstream.msg = PNGZ_MSG_CAST("in use by IDAT");
- return Z_STREAM_ERROR;
- }
-
- png_ptr->zowner = 0;
-#else
- png_error(png_ptr, msg);
-#endif
- }
-
- {
- int level = png_ptr->zlib_level;
- int method = png_ptr->zlib_method;
- int windowBits = png_ptr->zlib_window_bits;
- int memLevel = png_ptr->zlib_mem_level;
- int strategy; /* set below */
- int ret; /* zlib return code */
-
- if (owner == png_IDAT)
- {
- if ((png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) != 0)
- strategy = png_ptr->zlib_strategy;
-
- else if (png_ptr->do_filter != PNG_FILTER_NONE)
- strategy = PNG_Z_DEFAULT_STRATEGY;
-
- else
- strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY;
- }
-
- else
- {
-#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
- level = png_ptr->zlib_text_level;
- method = png_ptr->zlib_text_method;
- windowBits = png_ptr->zlib_text_window_bits;
- memLevel = png_ptr->zlib_text_mem_level;
- strategy = png_ptr->zlib_text_strategy;
-#else
- /* If customization is not supported the values all come from the
- * IDAT values except for the strategy, which is fixed to the
- * default. (This is the pre-1.6.0 behavior too, although it was
- * implemented in a very different way.)
- */
- strategy = Z_DEFAULT_STRATEGY;
-#endif
- }
-
- /* Adjust 'windowBits' down if larger than 'data_size'; to stop this
- * happening just pass 32768 as the data_size parameter. Notice that zlib
- * requires an extra 262 bytes in the window in addition to the data to be
- * able to see the whole of the data, so if data_size+262 takes us to the
- * next windowBits size we need to fix up the value later. (Because even
- * though deflate needs the extra window, inflate does not!)
- */
- if (data_size <= 16384)
- {
- /* IMPLEMENTATION NOTE: this 'half_window_size' stuff is only here to
- * work round a Microsoft Visual C misbehavior which, contrary to C-90,
- * widens the result of the following shift to 64-bits if (and,
- * apparently, only if) it is used in a test.
- */
- unsigned int half_window_size = 1U << (windowBits-1);
-
- while (data_size + 262 <= half_window_size)
- {
- half_window_size >>= 1;
- --windowBits;
- }
- }
-
- /* Check against the previous initialized values, if any. */
- if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0 &&
- (png_ptr->zlib_set_level != level ||
- png_ptr->zlib_set_method != method ||
- png_ptr->zlib_set_window_bits != windowBits ||
- png_ptr->zlib_set_mem_level != memLevel ||
- png_ptr->zlib_set_strategy != strategy))
- {
- if (deflateEnd(&png_ptr->zstream) != Z_OK)
- png_warning(png_ptr, "deflateEnd failed (ignored)");
-
- png_ptr->flags &= ~PNG_FLAG_ZSTREAM_INITIALIZED;
- }
-
- /* For safety clear out the input and output pointers (currently zlib
- * doesn't use them on Init, but it might in the future).
- */
- png_ptr->zstream.next_in = NULL;
- png_ptr->zstream.avail_in = 0;
- png_ptr->zstream.next_out = NULL;
- png_ptr->zstream.avail_out = 0;
-
- /* Now initialize if required, setting the new parameters, otherwise just
- * do a simple reset to the previous parameters.
- */
- if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
- ret = deflateReset(&png_ptr->zstream);
-
- else
- {
- ret = deflateInit2(&png_ptr->zstream, level, method, windowBits,
- memLevel, strategy);
-
- if (ret == Z_OK)
- png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
- }
-
- /* The return code is from either deflateReset or deflateInit2; they have
- * pretty much the same set of error codes.
- */
- if (ret == Z_OK)
- png_ptr->zowner = owner;
-
- else
- png_zstream_error(png_ptr, ret);
-
- return ret;
- }
-}
-
-/* Clean up (or trim) a linked list of compression buffers. */
-void /* PRIVATE */
-png_free_buffer_list(png_structrp png_ptr, png_compression_bufferp *listp)
-{
- png_compression_bufferp list = *listp;
-
- if (list != NULL)
- {
- *listp = NULL;
-
- do
- {
- png_compression_bufferp next = list->next;
-
- png_free(png_ptr, list);
- list = next;
- }
- while (list != NULL);
- }
-}
-
-#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
-/* This pair of functions encapsulates the operation of (a) compressing a
- * text string, and (b) issuing it later as a series of chunk data writes.
- * The compression_state structure is shared context for these functions
- * set up by the caller to allow access to the relevant local variables.
- *
- * compression_buffer (new in 1.6.0) is just a linked list of zbuffer_size
- * temporary buffers. From 1.6.0 it is retained in png_struct so that it will
- * be correctly freed in the event of a write error (previous implementations
- * just leaked memory.)
- */
-typedef struct
-{
- png_const_bytep input; /* The uncompressed input data */
- png_alloc_size_t input_len; /* Its length */
- png_uint_32 output_len; /* Final compressed length */
- png_byte output[1024]; /* First block of output */
-} compression_state;
-
-static void
-png_text_compress_init(compression_state *comp, png_const_bytep input,
- png_alloc_size_t input_len)
-{
- comp->input = input;
- comp->input_len = input_len;
- comp->output_len = 0;
-}
-
-/* Compress the data in the compression state input */
-static int
-png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
- compression_state *comp, png_uint_32 prefix_len)
-{
- int ret;
-
- /* To find the length of the output it is necessary to first compress the
- * input. The result is buffered rather than using the two-pass algorithm
- * that is used on the inflate side; deflate is assumed to be slower and a
- * PNG writer is assumed to have more memory available than a PNG reader.
- *
- * IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an
- * upper limit on the output size, but it is always bigger than the input
- * size so it is likely to be more efficient to use this linked-list
- * approach.
- */
- ret = png_deflate_claim(png_ptr, chunk_name, comp->input_len);
-
- if (ret != Z_OK)
- return ret;
-
- /* Set up the compression buffers, we need a loop here to avoid overflowing a
- * uInt. Use ZLIB_IO_MAX to limit the input. The output is always limited
- * by the output buffer size, so there is no need to check that. Since this
- * is ANSI-C we know that an 'int', hence a uInt, is always at least 16 bits
- * in size.
- */
- {
- png_compression_bufferp *end = &png_ptr->zbuffer_list;
- png_alloc_size_t input_len = comp->input_len; /* may be zero! */
- png_uint_32 output_len;
-
- /* zlib updates these for us: */
- png_ptr->zstream.next_in = PNGZ_INPUT_CAST(comp->input);
- png_ptr->zstream.avail_in = 0; /* Set below */
- png_ptr->zstream.next_out = comp->output;
- png_ptr->zstream.avail_out = (sizeof comp->output);
-
- output_len = png_ptr->zstream.avail_out;
-
- do
- {
- uInt avail_in = ZLIB_IO_MAX;
-
- if (avail_in > input_len)
- avail_in = (uInt)input_len;
-
- input_len -= avail_in;
-
- png_ptr->zstream.avail_in = avail_in;
-
- if (png_ptr->zstream.avail_out == 0)
- {
- png_compression_buffer *next;
-
- /* Chunk data is limited to 2^31 bytes in length, so the prefix
- * length must be counted here.
- */
- if (output_len + prefix_len > PNG_UINT_31_MAX)
- {
- ret = Z_MEM_ERROR;
- break;
- }
-
- /* Need a new (malloc'ed) buffer, but there may be one present
- * already.
- */
- next = *end;
- if (next == NULL)
- {
- next = png_voidcast(png_compression_bufferp, png_malloc_base
- (png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
-
- if (next == NULL)
- {
- ret = Z_MEM_ERROR;
- break;
- }
-
- /* Link in this buffer (so that it will be freed later) */
- next->next = NULL;
- *end = next;
- }
-
- png_ptr->zstream.next_out = next->output;
- png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
- output_len += png_ptr->zstream.avail_out;
-
- /* Move 'end' to the next buffer pointer. */
- end = &next->next;
- }
-
- /* Compress the data */
- ret = deflate(&png_ptr->zstream,
- input_len > 0 ? Z_NO_FLUSH : Z_FINISH);
-
- /* Claw back input data that was not consumed (because avail_in is
- * reset above every time round the loop).
- */
- input_len += png_ptr->zstream.avail_in;
- png_ptr->zstream.avail_in = 0; /* safety */
- }
- while (ret == Z_OK);
-
- /* There may be some space left in the last output buffer. This needs to
- * be subtracted from output_len.
- */
- output_len -= png_ptr->zstream.avail_out;
- png_ptr->zstream.avail_out = 0; /* safety */
- comp->output_len = output_len;
-
- /* Now double check the output length, put in a custom message if it is
- * too long. Otherwise ensure the z_stream::msg pointer is set to
- * something.
- */
- if (output_len + prefix_len >= PNG_UINT_31_MAX)
- {
- png_ptr->zstream.msg = PNGZ_MSG_CAST("compressed data too long");
- ret = Z_MEM_ERROR;
- }
-
- else
- png_zstream_error(png_ptr, ret);
-
- /* Reset zlib for another zTXt/iTXt or image data */
- png_ptr->zowner = 0;
-
- /* The only success case is Z_STREAM_END, input_len must be 0; if not this
- * is an internal error.
- */
- if (ret == Z_STREAM_END && input_len == 0)
- {
-#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
- /* Fix up the deflate header, if required */
- optimize_cmf(comp->output, comp->input_len);
-#endif
- /* But Z_OK is returned, not Z_STREAM_END; this allows the claim
- * function above to return Z_STREAM_END on an error (though it never
- * does in the current versions of zlib.)
- */
- return Z_OK;
- }
-
- else
- return ret;
- }
-}
-
-/* Ship the compressed text out via chunk writes */
-static void
-png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp)
-{
- png_uint_32 output_len = comp->output_len;
- png_const_bytep output = comp->output;
- png_uint_32 avail = (sizeof comp->output);
- png_compression_buffer *next = png_ptr->zbuffer_list;
-
- for (;;)
- {
- if (avail > output_len)
- avail = output_len;
-
- png_write_chunk_data(png_ptr, output, avail);
-
- output_len -= avail;
-
- if (output_len == 0 || next == NULL)
- break;
-
- avail = png_ptr->zbuffer_size;
- output = next->output;
- next = next->next;
- }
-
- /* This is an internal error; 'next' must have been NULL! */
- if (output_len > 0)
- png_error(png_ptr, "error writing ancillary chunked compressed data");
-}
-#endif /* WRITE_COMPRESSED_TEXT */
-
-/* Write the IHDR chunk, and update the png_struct with the necessary
- * information. Note that the rest of this code depends upon this
- * information being correct.
- */
-void /* PRIVATE */
-png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
- int bit_depth, int color_type, int compression_type, int filter_type,
- int interlace_type)
-{
- png_byte buf[13]; /* Buffer to store the IHDR info */
- int is_invalid_depth;
-
- png_debug(1, "in png_write_IHDR");
-
- /* Check that we have valid input data from the application info */
- switch (color_type)
- {
- case PNG_COLOR_TYPE_GRAY:
- switch (bit_depth)
- {
- case 1:
- case 2:
- case 4:
- case 8:
-#ifdef PNG_WRITE_16BIT_SUPPORTED
- case 16:
-#endif
- png_ptr->channels = 1; break;
-
- default:
- png_error(png_ptr,
- "Invalid bit depth for grayscale image");
- }
- break;
-
- case PNG_COLOR_TYPE_RGB:
- is_invalid_depth = (bit_depth != 8);
-#ifdef PNG_WRITE_16BIT_SUPPORTED
- is_invalid_depth = (is_invalid_depth && bit_depth != 16);
-#endif
- if (is_invalid_depth)
- png_error(png_ptr, "Invalid bit depth for RGB image");
-
- png_ptr->channels = 3;
- break;
-
- case PNG_COLOR_TYPE_PALETTE:
- switch (bit_depth)
- {
- case 1:
- case 2:
- case 4:
- case 8:
- png_ptr->channels = 1;
- break;
-
- default:
- png_error(png_ptr, "Invalid bit depth for paletted image");
- }
- break;
-
- case PNG_COLOR_TYPE_GRAY_ALPHA:
- is_invalid_depth = (bit_depth != 8);
-#ifdef PNG_WRITE_16BIT_SUPPORTED
- is_invalid_depth = (is_invalid_depth && bit_depth != 16);
-#endif
- if (is_invalid_depth)
- png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
-
- png_ptr->channels = 2;
- break;
-
- case PNG_COLOR_TYPE_RGB_ALPHA:
- is_invalid_depth = (bit_depth != 8);
-#ifdef PNG_WRITE_16BIT_SUPPORTED
- is_invalid_depth = (is_invalid_depth && bit_depth != 16);
-#endif
- if (is_invalid_depth)
- png_error(png_ptr, "Invalid bit depth for RGBA image");
-
- png_ptr->channels = 4;
- break;
-
- default:
- png_error(png_ptr, "Invalid image color type specified");
- }
-
- if (compression_type != PNG_COMPRESSION_TYPE_BASE)
- {
- png_warning(png_ptr, "Invalid compression type specified");
- compression_type = PNG_COMPRESSION_TYPE_BASE;
- }
-
- /* Write filter_method 64 (intrapixel differencing) only if
- * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
- * 2. Libpng did not write a PNG signature (this filter_method is only
- * used in PNG datastreams that are embedded in MNG datastreams) and
- * 3. The application called png_permit_mng_features with a mask that
- * included PNG_FLAG_MNG_FILTER_64 and
- * 4. The filter_method is 64 and
- * 5. The color_type is RGB or RGBA
- */
- if (
-#ifdef PNG_MNG_FEATURES_SUPPORTED
- !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
- ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
- (color_type == PNG_COLOR_TYPE_RGB ||
- color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
- (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
-#endif
- filter_type != PNG_FILTER_TYPE_BASE)
- {
- png_warning(png_ptr, "Invalid filter type specified");
- filter_type = PNG_FILTER_TYPE_BASE;
- }
-
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
- if (interlace_type != PNG_INTERLACE_NONE &&
- interlace_type != PNG_INTERLACE_ADAM7)
- {
- png_warning(png_ptr, "Invalid interlace type specified");
- interlace_type = PNG_INTERLACE_ADAM7;
- }
-#else
- interlace_type=PNG_INTERLACE_NONE;
-#endif
-
- /* Save the relevant information */
- png_ptr->bit_depth = (png_byte)bit_depth;
- png_ptr->color_type = (png_byte)color_type;
- png_ptr->interlaced = (png_byte)interlace_type;
-#ifdef PNG_MNG_FEATURES_SUPPORTED
- png_ptr->filter_type = (png_byte)filter_type;
-#endif
- png_ptr->compression_type = (png_byte)compression_type;
- png_ptr->width = width;
- png_ptr->height = height;
-
- png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
- png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
- /* Set the usr info, so any transformations can modify it */
- png_ptr->usr_width = png_ptr->width;
- png_ptr->usr_bit_depth = png_ptr->bit_depth;
- png_ptr->usr_channels = png_ptr->channels;
-
- /* Pack the header information into the buffer */
- png_save_uint_32(buf, width);
- png_save_uint_32(buf + 4, height);
- buf[8] = (png_byte)bit_depth;
- buf[9] = (png_byte)color_type;
- buf[10] = (png_byte)compression_type;
- buf[11] = (png_byte)filter_type;
- buf[12] = (png_byte)interlace_type;
-
- /* Write the chunk */
- png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
-
- if ((png_ptr->do_filter) == PNG_NO_FILTERS)
- {
- if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
- png_ptr->bit_depth < 8)
- png_ptr->do_filter = PNG_FILTER_NONE;
-
- else
- png_ptr->do_filter = PNG_ALL_FILTERS;
- }
-
- png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */
-}
-
-/* Write the palette. We are careful not to trust png_color to be in the
- * correct order for PNG, so people can redefine it to any convenient
- * structure.
- */
-void /* PRIVATE */
-png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
- png_uint_32 num_pal)
-{
- png_uint_32 max_palette_length, i;
- png_const_colorp pal_ptr;
- png_byte buf[3];
-
- png_debug(1, "in png_write_PLTE");
-
- max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
- (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
-
- if ((
-#ifdef PNG_MNG_FEATURES_SUPPORTED
- (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 &&
-#endif
- num_pal == 0) || num_pal > max_palette_length)
- {
- if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
- {
- png_error(png_ptr, "Invalid number of colors in palette");
- }
-
- else
- {
- png_warning(png_ptr, "Invalid number of colors in palette");
- return;
- }
- }
-
- if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
- {
- png_warning(png_ptr,
- "Ignoring request to write a PLTE chunk in grayscale PNG");
-
- return;
- }
-
- png_ptr->num_palette = (png_uint_16)num_pal;
- png_debug1(3, "num_palette = %d", png_ptr->num_palette);
-
- png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));
-#ifdef PNG_POINTER_INDEXING_SUPPORTED
-
- for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
- {
- buf[0] = pal_ptr->red;
- buf[1] = pal_ptr->green;
- buf[2] = pal_ptr->blue;
- png_write_chunk_data(png_ptr, buf, (png_size_t)3);
- }
-
-#else
- /* This is a little slower but some buggy compilers need to do this
- * instead
- */
- pal_ptr=palette;
-
- for (i = 0; i < num_pal; i++)
- {
- buf[0] = pal_ptr[i].red;
- buf[1] = pal_ptr[i].green;
- buf[2] = pal_ptr[i].blue;
- png_write_chunk_data(png_ptr, buf, (png_size_t)3);
- }
-
-#endif
- png_write_chunk_end(png_ptr);
- png_ptr->mode |= PNG_HAVE_PLTE;
-}
-
-/* This is similar to png_text_compress, above, except that it does not require
- * all of the data at once and, instead of buffering the compressed result,
- * writes it as IDAT chunks. Unlike png_text_compress it *can* png_error out
- * because it calls the write interface. As a result it does its own error
- * reporting and does not return an error code. In the event of error it will
- * just call png_error. The input data length may exceed 32-bits. The 'flush'
- * parameter is exactly the same as that to deflate, with the following
- * meanings:
- *
- * Z_NO_FLUSH: normal incremental output of compressed data
- * Z_SYNC_FLUSH: do a SYNC_FLUSH, used by png_write_flush
- * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up
- *
- * The routine manages the acquire and release of the png_ptr->zstream by
- * checking and (at the end) clearing png_ptr->zowner; it does some sanity
- * checks on the 'mode' flags while doing this.
- */
-void /* PRIVATE */
-png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
- png_alloc_size_t input_len, int flush)
-{
- if (png_ptr->zowner != png_IDAT)
- {
- /* First time. Ensure we have a temporary buffer for compression and
- * trim the buffer list if it has more than one entry to free memory.
- * If 'WRITE_COMPRESSED_TEXT' is not set the list will never have been
- * created at this point, but the check here is quick and safe.
- */
- if (png_ptr->zbuffer_list == NULL)
- {
- png_ptr->zbuffer_list = png_voidcast(png_compression_bufferp,
- png_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
- png_ptr->zbuffer_list->next = NULL;
- }
-
- else
- png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list->next);
-
- /* It is a terminal error if we can't claim the zstream. */
- if (png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)) != Z_OK)
- png_error(png_ptr, png_ptr->zstream.msg);
-
- /* The output state is maintained in png_ptr->zstream, so it must be
- * initialized here after the claim.
- */
- png_ptr->zstream.next_out = png_ptr->zbuffer_list->output;
- png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
- }
-
- /* Now loop reading and writing until all the input is consumed or an error
- * terminates the operation. The _out values are maintained across calls to
- * this function, but the input must be reset each time.
- */
- png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
- png_ptr->zstream.avail_in = 0; /* set below */
- for (;;)
- {
- int ret;
-
- /* INPUT: from the row data */
- uInt avail = ZLIB_IO_MAX;
-
- if (avail > input_len)
- avail = (uInt)input_len; /* safe because of the check */
-
- png_ptr->zstream.avail_in = avail;
- input_len -= avail;
-
- ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : flush);
-
- /* Include as-yet unconsumed input */
- input_len += png_ptr->zstream.avail_in;
- png_ptr->zstream.avail_in = 0;
-
- /* OUTPUT: write complete IDAT chunks when avail_out drops to zero. Note
- * that these two zstream fields are preserved across the calls, therefore
- * there is no need to set these up on entry to the loop.
- */
- if (png_ptr->zstream.avail_out == 0)
- {
- png_bytep data = png_ptr->zbuffer_list->output;
- uInt size = png_ptr->zbuffer_size;
-
- /* Write an IDAT containing the data then reset the buffer. The
- * first IDAT may need deflate header optimization.
- */
-#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
- if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
- png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
- optimize_cmf(data, png_image_size(png_ptr));
-#endif
-
- if (size > 0)
- png_write_complete_chunk(png_ptr, png_IDAT, data, size);
- png_ptr->mode |= PNG_HAVE_IDAT;
-
- png_ptr->zstream.next_out = data;
- png_ptr->zstream.avail_out = size;
-
- /* For SYNC_FLUSH or FINISH it is essential to keep calling zlib with
- * the same flush parameter until it has finished output, for NO_FLUSH
- * it doesn't matter.
- */
- if (ret == Z_OK && flush != Z_NO_FLUSH)
- continue;
- }
-
- /* The order of these checks doesn't matter much; it just affects which
- * possible error might be detected if multiple things go wrong at once.
- */
- if (ret == Z_OK) /* most likely return code! */
- {
- /* If all the input has been consumed then just return. If Z_FINISH
- * was used as the flush parameter something has gone wrong if we get
- * here.
- */
- if (input_len == 0)
- {
- if (flush == Z_FINISH)
- png_error(png_ptr, "Z_OK on Z_FINISH with output space");
-
- return;
- }
- }
-
- else if (ret == Z_STREAM_END && flush == Z_FINISH)
- {
- /* This is the end of the IDAT data; any pending output must be
- * flushed. For small PNG files we may still be at the beginning.
- */
- png_bytep data = png_ptr->zbuffer_list->output;
- uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out;
-
-#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
- if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
- png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
- optimize_cmf(data, png_image_size(png_ptr));
-#endif
-
- if (size > 0)
- png_write_complete_chunk(png_ptr, png_IDAT, data, size);
- png_ptr->zstream.avail_out = 0;
- png_ptr->zstream.next_out = NULL;
- png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT;
-
- png_ptr->zowner = 0; /* Release the stream */
- return;
- }
-
- else
- {
- /* This is an error condition. */
- png_zstream_error(png_ptr, ret);
- png_error(png_ptr, png_ptr->zstream.msg);
- }
- }
-}
-
-/* Write an IEND chunk */
-void /* PRIVATE */
-png_write_IEND(png_structrp png_ptr)
-{
- png_debug(1, "in png_write_IEND");
-
- png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0);
- png_ptr->mode |= PNG_HAVE_IEND;
-}
-
-#ifdef PNG_WRITE_gAMA_SUPPORTED
-/* Write a gAMA chunk */
-void /* PRIVATE */
-png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma)
-{
- png_byte buf[4];
-
- png_debug(1, "in png_write_gAMA");
-
- /* file_gamma is saved in 1/100,000ths */
- png_save_uint_32(buf, (png_uint_32)file_gamma);
- png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);
-}
-#endif
-
-#ifdef PNG_WRITE_sRGB_SUPPORTED
-/* Write a sRGB chunk */
-void /* PRIVATE */
-png_write_sRGB(png_structrp png_ptr, int srgb_intent)
-{
- png_byte buf[1];
-
- png_debug(1, "in png_write_sRGB");
-
- if (srgb_intent >= PNG_sRGB_INTENT_LAST)
- png_warning(png_ptr,
- "Invalid sRGB rendering intent specified");
-
- buf[0]=(png_byte)srgb_intent;
- png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);
-}
-#endif
-
-#ifdef PNG_WRITE_iCCP_SUPPORTED
-/* Write an iCCP chunk */
-void /* PRIVATE */
-png_write_iCCP(png_structrp png_ptr, png_const_charp name,
- png_const_bytep profile)
-{
- png_uint_32 name_len;
- png_uint_32 profile_len;
- png_byte new_name[81]; /* 1 byte for the compression byte */
- compression_state comp;
- png_uint_32 temp;
-
- png_debug(1, "in png_write_iCCP");
-
- /* These are all internal problems: the profile should have been checked
- * before when it was stored.
- */
- if (profile == NULL)
- png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */
-
- profile_len = png_get_uint_32(profile);
-
- if (profile_len < 132)
- png_error(png_ptr, "ICC profile too short");
-
- temp = (png_uint_32) (*(profile+8));
- if (temp > 3 && (profile_len & 0x03))
- png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)");
-
- {
- png_uint_32 embedded_profile_len = png_get_uint_32(profile);
-
- if (profile_len != embedded_profile_len)
- png_error(png_ptr, "Profile length does not match profile");
- }
-
- name_len = png_check_keyword(png_ptr, name, new_name);
-
- if (name_len == 0)
- png_error(png_ptr, "iCCP: invalid keyword");
-
- new_name[++name_len] = PNG_COMPRESSION_TYPE_BASE;
-
- /* Make sure we include the NULL after the name and the compression type */
- ++name_len;
-
- png_text_compress_init(&comp, profile, profile_len);
-
- /* Allow for keyword terminator and compression byte */
- if (png_text_compress(png_ptr, png_iCCP, &comp, name_len) != Z_OK)
- png_error(png_ptr, png_ptr->zstream.msg);
-
- png_write_chunk_header(png_ptr, png_iCCP, name_len + comp.output_len);
-
- png_write_chunk_data(png_ptr, new_name, name_len);
-
- png_write_compressed_data_out(png_ptr, &comp);
-
- png_write_chunk_end(png_ptr);
-}
-#endif
-
-#ifdef PNG_WRITE_sPLT_SUPPORTED
-/* Write a sPLT chunk */
-void /* PRIVATE */
-png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette)
-{
- png_uint_32 name_len;
- png_byte new_name[80];
- png_byte entrybuf[10];
- png_size_t entry_size = (spalette->depth == 8 ? 6 : 10);
- png_size_t palette_size = entry_size * (png_size_t)spalette->nentries;
- png_sPLT_entryp ep;
-#ifndef PNG_POINTER_INDEXING_SUPPORTED
- int i;
-#endif
-
- png_debug(1, "in png_write_sPLT");
-
- name_len = png_check_keyword(png_ptr, spalette->name, new_name);
-
- if (name_len == 0)
- png_error(png_ptr, "sPLT: invalid keyword");
-
- /* Make sure we include the NULL after the name */
- png_write_chunk_header(png_ptr, png_sPLT,
- (png_uint_32)(name_len + 2 + palette_size));
-
- png_write_chunk_data(png_ptr, (png_bytep)new_name,
- (png_size_t)(name_len + 1));
-
- png_write_chunk_data(png_ptr, &spalette->depth, (png_size_t)1);
-
- /* Loop through each palette entry, writing appropriately */
-#ifdef PNG_POINTER_INDEXING_SUPPORTED
- for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
- {
- if (spalette->depth == 8)
- {
- entrybuf[0] = (png_byte)ep->red;
- entrybuf[1] = (png_byte)ep->green;
- entrybuf[2] = (png_byte)ep->blue;
- entrybuf[3] = (png_byte)ep->alpha;
- png_save_uint_16(entrybuf + 4, ep->frequency);
- }
-
- else
- {
- png_save_uint_16(entrybuf + 0, ep->red);
- png_save_uint_16(entrybuf + 2, ep->green);
- png_save_uint_16(entrybuf + 4, ep->blue);
- png_save_uint_16(entrybuf + 6, ep->alpha);
- png_save_uint_16(entrybuf + 8, ep->frequency);
- }
-
- png_write_chunk_data(png_ptr, entrybuf, entry_size);
- }
-#else
- ep=spalette->entries;
- for (i = 0; i>spalette->nentries; i++)
- {
- if (spalette->depth == 8)
- {
- entrybuf[0] = (png_byte)ep[i].red;
- entrybuf[1] = (png_byte)ep[i].green;
- entrybuf[2] = (png_byte)ep[i].blue;
- entrybuf[3] = (png_byte)ep[i].alpha;
- png_save_uint_16(entrybuf + 4, ep[i].frequency);
- }
-
- else
- {
- png_save_uint_16(entrybuf + 0, ep[i].red);
- png_save_uint_16(entrybuf + 2, ep[i].green);
- png_save_uint_16(entrybuf + 4, ep[i].blue);
- png_save_uint_16(entrybuf + 6, ep[i].alpha);
- png_save_uint_16(entrybuf + 8, ep[i].frequency);
- }
-
- png_write_chunk_data(png_ptr, entrybuf, entry_size);
- }
-#endif
-
- png_write_chunk_end(png_ptr);
-}
-#endif
-
-#ifdef PNG_WRITE_sBIT_SUPPORTED
-/* Write the sBIT chunk */
-void /* PRIVATE */
-png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
-{
- png_byte buf[4];
- png_size_t size;
-
- png_debug(1, "in png_write_sBIT");
-
- /* Make sure we don't depend upon the order of PNG_COLOR_8 */
- if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
- {
- png_byte maxbits;
-
- maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
- png_ptr->usr_bit_depth);
-
- if (sbit->red == 0 || sbit->red > maxbits ||
- sbit->green == 0 || sbit->green > maxbits ||
- sbit->blue == 0 || sbit->blue > maxbits)
- {
- png_warning(png_ptr, "Invalid sBIT depth specified");
- return;
- }
-
- buf[0] = sbit->red;
- buf[1] = sbit->green;
- buf[2] = sbit->blue;
- size = 3;
- }
-
- else
- {
- if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
- {
- png_warning(png_ptr, "Invalid sBIT depth specified");
- return;
- }
-
- buf[0] = sbit->gray;
- size = 1;
- }
-
- if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
- {
- if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
- {
- png_warning(png_ptr, "Invalid sBIT depth specified");
- return;
- }
-
- buf[size++] = sbit->alpha;
- }
-
- png_write_complete_chunk(png_ptr, png_sBIT, buf, size);
-}
-#endif
-
-#ifdef PNG_WRITE_cHRM_SUPPORTED
-/* Write the cHRM chunk */
-void /* PRIVATE */
-png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy)
-{
- png_byte buf[32];
-
- png_debug(1, "in png_write_cHRM");
-
- /* Each value is saved in 1/100,000ths */
- png_save_int_32(buf, xy->whitex);
- png_save_int_32(buf + 4, xy->whitey);
-
- png_save_int_32(buf + 8, xy->redx);
- png_save_int_32(buf + 12, xy->redy);
-
- png_save_int_32(buf + 16, xy->greenx);
- png_save_int_32(buf + 20, xy->greeny);
-
- png_save_int_32(buf + 24, xy->bluex);
- png_save_int_32(buf + 28, xy->bluey);
-
- png_write_complete_chunk(png_ptr, png_cHRM, buf, 32);
-}
-#endif
-
-#ifdef PNG_WRITE_tRNS_SUPPORTED
-/* Write the tRNS chunk */
-void /* PRIVATE */
-png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
- png_const_color_16p tran, int num_trans, int color_type)
-{
- png_byte buf[6];
-
- png_debug(1, "in png_write_tRNS");
-
- if (color_type == PNG_COLOR_TYPE_PALETTE)
- {
- if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
- {
- png_app_warning(png_ptr,
- "Invalid number of transparent colors specified");
- return;
- }
-
- /* Write the chunk out as it is */
- png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha,
- (png_size_t)num_trans);
- }
-
- else if (color_type == PNG_COLOR_TYPE_GRAY)
- {
- /* One 16-bit value */
- if (tran->gray >= (1 << png_ptr->bit_depth))
- {
- png_app_warning(png_ptr,
- "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
-
- return;
- }
-
- png_save_uint_16(buf, tran->gray);
- png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);
- }
-
- else if (color_type == PNG_COLOR_TYPE_RGB)
- {
- /* Three 16-bit values */
- png_save_uint_16(buf, tran->red);
- png_save_uint_16(buf + 2, tran->green);
- png_save_uint_16(buf + 4, tran->blue);
-#ifdef PNG_WRITE_16BIT_SUPPORTED
- if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
-#else
- if ((buf[0] | buf[2] | buf[4]) != 0)
-#endif
- {
- png_app_warning(png_ptr,
- "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
- return;
- }
-
- png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
- }
-
- else
- {
- png_app_warning(png_ptr, "Can't write tRNS with an alpha channel");
- }
-}
-#endif
-
-#ifdef PNG_WRITE_bKGD_SUPPORTED
-/* Write the background chunk */
-void /* PRIVATE */
-png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
-{
- png_byte buf[6];
-
- png_debug(1, "in png_write_bKGD");
-
- if (color_type == PNG_COLOR_TYPE_PALETTE)
- {
- if (
-#ifdef PNG_MNG_FEATURES_SUPPORTED
- (png_ptr->num_palette != 0 ||
- (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) &&
-#endif
- back->index >= png_ptr->num_palette)
- {
- png_warning(png_ptr, "Invalid background palette index");
- return;
- }
-
- buf[0] = back->index;
- png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
- }
-
- else if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
- {
- png_save_uint_16(buf, back->red);
- png_save_uint_16(buf + 2, back->green);
- png_save_uint_16(buf + 4, back->blue);
-#ifdef PNG_WRITE_16BIT_SUPPORTED
- if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
-#else
- if ((buf[0] | buf[2] | buf[4]) != 0)
-#endif
- {
- png_warning(png_ptr,
- "Ignoring attempt to write 16-bit bKGD chunk "
- "when bit_depth is 8");
-
- return;
- }
-
- png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
- }
-
- else
- {
- if (back->gray >= (1 << png_ptr->bit_depth))
- {
- png_warning(png_ptr,
- "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
-
- return;
- }
-
- png_save_uint_16(buf, back->gray);
- png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
- }
-}
-#endif
-
-#ifdef PNG_WRITE_eXIf_SUPPORTED
-/* Write the Exif data */
-void /* PRIVATE */
-png_write_eXIf(png_structrp png_ptr, png_bytep exif, int num_exif)
-{
- int i;
- png_byte buf[1];
-
- png_debug(1, "in png_write_eXIf");
-
- png_write_chunk_header(png_ptr, png_eXIf, (png_uint_32)(num_exif));
-
- for (i = 0; i < num_exif; i++)
- {
- buf[0] = exif[i];
- png_write_chunk_data(png_ptr, buf, (png_size_t)1);
- }
-
- png_write_chunk_end(png_ptr);
-}
-#endif
-
-#ifdef PNG_WRITE_hIST_SUPPORTED
-/* Write the histogram */
-void /* PRIVATE */
-png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist)
-{
- int i;
- png_byte buf[3];
-
- png_debug(1, "in png_write_hIST");
-
- if (num_hist > (int)png_ptr->num_palette)
- {
- png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
- png_ptr->num_palette);
-
- png_warning(png_ptr, "Invalid number of histogram entries specified");
- return;
- }
-
- png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
-
- for (i = 0; i < num_hist; i++)
- {
- png_save_uint_16(buf, hist[i]);
- png_write_chunk_data(png_ptr, buf, (png_size_t)2);
- }
-
- png_write_chunk_end(png_ptr);
-}
-#endif
-
-#ifdef PNG_WRITE_tEXt_SUPPORTED
-/* Write a tEXt chunk */
-void /* PRIVATE */
-png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
- png_size_t text_len)
-{
- png_uint_32 key_len;
- png_byte new_key[80];
-
- png_debug(1, "in png_write_tEXt");
-
- key_len = png_check_keyword(png_ptr, key, new_key);
-
- if (key_len == 0)
- png_error(png_ptr, "tEXt: invalid keyword");
-
- if (text == NULL || *text == '\0')
- text_len = 0;
-
- else
- text_len = strlen(text);
-
- if (text_len > PNG_UINT_31_MAX - (key_len+1))
- png_error(png_ptr, "tEXt: text too long");
-
- /* Make sure we include the 0 after the key */
- png_write_chunk_header(png_ptr, png_tEXt,
- (png_uint_32)/*checked above*/(key_len + text_len + 1));
- /*
- * We leave it to the application to meet PNG-1.0 requirements on the
- * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
- * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
- * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
- */
- png_write_chunk_data(png_ptr, new_key, key_len + 1);
-
- if (text_len != 0)
- png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len);
-
- png_write_chunk_end(png_ptr);
-}
-#endif
-
-#ifdef PNG_WRITE_zTXt_SUPPORTED
-/* Write a compressed text chunk */
-void /* PRIVATE */
-png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
- int compression)
-{
- png_uint_32 key_len;
- png_byte new_key[81];
- compression_state comp;
-
- png_debug(1, "in png_write_zTXt");
-
- if (compression == PNG_TEXT_COMPRESSION_NONE)
- {
- png_write_tEXt(png_ptr, key, text, 0);
- return;
- }
-
- if (compression != PNG_TEXT_COMPRESSION_zTXt)
- png_error(png_ptr, "zTXt: invalid compression type");
-
- key_len = png_check_keyword(png_ptr, key, new_key);
-
- if (key_len == 0)
- png_error(png_ptr, "zTXt: invalid keyword");
-
- /* Add the compression method and 1 for the keyword separator. */
- new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
- ++key_len;
-
- /* Compute the compressed data; do it now for the length */
- png_text_compress_init(&comp, (png_const_bytep)text,
- text == NULL ? 0 : strlen(text));
-
- if (png_text_compress(png_ptr, png_zTXt, &comp, key_len) != Z_OK)
- png_error(png_ptr, png_ptr->zstream.msg);
-
- /* Write start of chunk */
- png_write_chunk_header(png_ptr, png_zTXt, key_len + comp.output_len);
-
- /* Write key */
- png_write_chunk_data(png_ptr, new_key, key_len);
-
- /* Write the compressed data */
- png_write_compressed_data_out(png_ptr, &comp);
-
- /* Close the chunk */
- png_write_chunk_end(png_ptr);
-}
-#endif
-
-#ifdef PNG_WRITE_iTXt_SUPPORTED
-/* Write an iTXt chunk */
-void /* PRIVATE */
-png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key,
- png_const_charp lang, png_const_charp lang_key, png_const_charp text)
-{
- png_uint_32 key_len, prefix_len;
- png_size_t lang_len, lang_key_len;
- png_byte new_key[82];
- compression_state comp;
-
- png_debug(1, "in png_write_iTXt");
-
- key_len = png_check_keyword(png_ptr, key, new_key);
-
- if (key_len == 0)
- png_error(png_ptr, "iTXt: invalid keyword");
-
- /* Set the compression flag */
- switch (compression)
- {
- case PNG_ITXT_COMPRESSION_NONE:
- case PNG_TEXT_COMPRESSION_NONE:
- compression = new_key[++key_len] = 0; /* no compression */
- break;
-
- case PNG_TEXT_COMPRESSION_zTXt:
- case PNG_ITXT_COMPRESSION_zTXt:
- compression = new_key[++key_len] = 1; /* compressed */
- break;
-
- default:
- png_error(png_ptr, "iTXt: invalid compression");
- }
-
- new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
- ++key_len; /* for the keywod separator */
-
- /* We leave it to the application to meet PNG-1.0 requirements on the
- * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
- * any non-Latin-1 characters except for NEWLINE. ISO PNG, however,
- * specifies that the text is UTF-8 and this really doesn't require any
- * checking.
- *
- * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
- *
- * TODO: validate the language tag correctly (see the spec.)
- */
- if (lang == NULL) lang = ""; /* empty language is valid */
- lang_len = strlen(lang)+1;
- if (lang_key == NULL) lang_key = ""; /* may be empty */
- lang_key_len = strlen(lang_key)+1;
- if (text == NULL) text = ""; /* may be empty */
-
- prefix_len = key_len;
- if (lang_len > PNG_UINT_31_MAX-prefix_len)
- prefix_len = PNG_UINT_31_MAX;
- else
- prefix_len = (png_uint_32)(prefix_len + lang_len);
-
- if (lang_key_len > PNG_UINT_31_MAX-prefix_len)
- prefix_len = PNG_UINT_31_MAX;
- else
- prefix_len = (png_uint_32)(prefix_len + lang_key_len);
-
- png_text_compress_init(&comp, (png_const_bytep)text, strlen(text));
-
- if (compression != 0)
- {
- if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK)
- png_error(png_ptr, png_ptr->zstream.msg);
- }
-
- else
- {
- if (comp.input_len > PNG_UINT_31_MAX-prefix_len)
- png_error(png_ptr, "iTXt: uncompressed text too long");
-
- /* So the string will fit in a chunk: */
- comp.output_len = (png_uint_32)/*SAFE*/comp.input_len;
- }
-
- png_write_chunk_header(png_ptr, png_iTXt, comp.output_len + prefix_len);
-
- png_write_chunk_data(png_ptr, new_key, key_len);
-
- png_write_chunk_data(png_ptr, (png_const_bytep)lang, lang_len);
-
- png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len);
-
- if (compression != 0)
- png_write_compressed_data_out(png_ptr, &comp);
-
- else
- png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.output_len);
-
- png_write_chunk_end(png_ptr);
-}
-#endif
-
-#ifdef PNG_WRITE_oFFs_SUPPORTED
-/* Write the oFFs chunk */
-void /* PRIVATE */
-png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
- int unit_type)
-{
- png_byte buf[9];
-
- png_debug(1, "in png_write_oFFs");
-
- if (unit_type >= PNG_OFFSET_LAST)
- png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
-
- png_save_int_32(buf, x_offset);
- png_save_int_32(buf + 4, y_offset);
- buf[8] = (png_byte)unit_type;
-
- png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);
-}
-#endif
-#ifdef PNG_WRITE_pCAL_SUPPORTED
-/* Write the pCAL chunk (described in the PNG extensions document) */
-void /* PRIVATE */
-png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0,
- png_int_32 X1, int type, int nparams, png_const_charp units,
- png_charpp params)
-{
- png_uint_32 purpose_len;
- png_size_t units_len, total_len;
- png_size_tp params_len;
- png_byte buf[10];
- png_byte new_purpose[80];
- int i;
-
- png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
-
- if (type >= PNG_EQUATION_LAST)
- png_error(png_ptr, "Unrecognized equation type for pCAL chunk");
-
- purpose_len = png_check_keyword(png_ptr, purpose, new_purpose);
-
- if (purpose_len == 0)
- png_error(png_ptr, "pCAL: invalid keyword");
-
- ++purpose_len; /* terminator */
-
- png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);
- units_len = strlen(units) + (nparams == 0 ? 0 : 1);
- png_debug1(3, "pCAL units length = %d", (int)units_len);
- total_len = purpose_len + units_len + 10;
-
- params_len = (png_size_tp)png_malloc(png_ptr,
- (png_alloc_size_t)((png_alloc_size_t)nparams * (sizeof (png_size_t))));
-
- /* Find the length of each parameter, making sure we don't count the
- * null terminator for the last parameter.
- */
- for (i = 0; i < nparams; i++)
- {
- params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
- png_debug2(3, "pCAL parameter %d length = %lu", i,
- (unsigned long)params_len[i]);
- total_len += params_len[i];
- }
-
- png_debug1(3, "pCAL total length = %d", (int)total_len);
- png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len);
- png_write_chunk_data(png_ptr, new_purpose, purpose_len);
- png_save_int_32(buf, X0);
- png_save_int_32(buf + 4, X1);
- buf[8] = (png_byte)type;
- buf[9] = (png_byte)nparams;
- png_write_chunk_data(png_ptr, buf, (png_size_t)10);
- png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len);
-
- for (i = 0; i < nparams; i++)
- {
- png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]);
- }
-
- png_free(png_ptr, params_len);
- png_write_chunk_end(png_ptr);
-}
-#endif
-
-#ifdef PNG_WRITE_sCAL_SUPPORTED
-/* Write the sCAL chunk */
-void /* PRIVATE */
-png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width,
- png_const_charp height)
-{
- png_byte buf[64];
- png_size_t wlen, hlen, total_len;
-
- png_debug(1, "in png_write_sCAL_s");
-
- wlen = strlen(width);
- hlen = strlen(height);
- total_len = wlen + hlen + 2;
-
- if (total_len > 64)
- {
- png_warning(png_ptr, "Can't write sCAL (buffer too small)");
- return;
- }
-
- buf[0] = (png_byte)unit;
- memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */
- memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */
-
- png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
- png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len);
-}
-#endif
-
-#ifdef PNG_WRITE_pHYs_SUPPORTED
-/* Write the pHYs chunk */
-void /* PRIVATE */
-png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit,
- png_uint_32 y_pixels_per_unit,
- int unit_type)
-{
- png_byte buf[9];
-
- png_debug(1, "in png_write_pHYs");
-
- if (unit_type >= PNG_RESOLUTION_LAST)
- png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
-
- png_save_uint_32(buf, x_pixels_per_unit);
- png_save_uint_32(buf + 4, y_pixels_per_unit);
- buf[8] = (png_byte)unit_type;
-
- png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);
-}
-#endif
-
-#ifdef PNG_WRITE_tIME_SUPPORTED
-/* Write the tIME chunk. Use either png_convert_from_struct_tm()
- * or png_convert_from_time_t(), or fill in the structure yourself.
- */
-void /* PRIVATE */
-png_write_tIME(png_structrp png_ptr, png_const_timep mod_time)
-{
- png_byte buf[7];
-
- png_debug(1, "in png_write_tIME");
-
- if (mod_time->month > 12 || mod_time->month < 1 ||
- mod_time->day > 31 || mod_time->day < 1 ||
- mod_time->hour > 23 || mod_time->second > 60)
- {
- png_warning(png_ptr, "Invalid time specified for tIME chunk");
- return;
- }
-
- png_save_uint_16(buf, mod_time->year);
- buf[2] = mod_time->month;
- buf[3] = mod_time->day;
- buf[4] = mod_time->hour;
- buf[5] = mod_time->minute;
- buf[6] = mod_time->second;
-
- png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7);
-}
-#endif
-
-/* Initializes the row writing capability of libpng */
-void /* PRIVATE */
-png_write_start_row(png_structrp png_ptr)
-{
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
- /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
- /* Start of interlace block */
- static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
-
- /* Offset to next interlace block */
- static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
- /* Start of interlace block in the y direction */
- static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
-
- /* Offset to next interlace block in the y direction */
- static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
-#endif
-
- png_alloc_size_t buf_size;
- int usr_pixel_depth;
-
-#ifdef PNG_WRITE_FILTER_SUPPORTED
- png_byte filters;
-#endif
-
- png_debug(1, "in png_write_start_row");
-
- usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
- buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1;
-
- /* 1.5.6: added to allow checking in the row write code. */
- png_ptr->transformed_pixel_depth = png_ptr->pixel_depth;
- png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;
-
- /* Set up row buffer */
- png_ptr->row_buf = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
-
- png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
-
-#ifdef PNG_WRITE_FILTER_SUPPORTED
- filters = png_ptr->do_filter;
-
- if (png_ptr->height == 1)
- filters &= 0xff & ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
-
- if (png_ptr->width == 1)
- filters &= 0xff & ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
-
- if (filters == 0)
- filters = PNG_FILTER_NONE;
-
- png_ptr->do_filter = filters;
-
- if (((filters & (PNG_FILTER_SUB | PNG_FILTER_UP | PNG_FILTER_AVG |
- PNG_FILTER_PAETH)) != 0) && png_ptr->try_row == NULL)
- {
- int num_filters = 0;
-
- png_ptr->try_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
-
- if (filters & PNG_FILTER_SUB)
- num_filters++;
-
- if (filters & PNG_FILTER_UP)
- num_filters++;
-
- if (filters & PNG_FILTER_AVG)
- num_filters++;
-
- if (filters & PNG_FILTER_PAETH)
- num_filters++;
-
- if (num_filters > 1)
- png_ptr->tst_row = png_voidcast(png_bytep, png_malloc(png_ptr,
- buf_size));
- }
-
- /* We only need to keep the previous row if we are using one of the following
- * filters.
- */
- if ((filters & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) != 0)
- png_ptr->prev_row = png_voidcast(png_bytep,
- png_calloc(png_ptr, buf_size));
-#endif /* WRITE_FILTER */
-
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
- /* If interlaced, we need to set up width and height of pass */
- if (png_ptr->interlaced != 0)
- {
- if ((png_ptr->transformations & PNG_INTERLACE) == 0)
- {
- png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
- png_pass_ystart[0]) / png_pass_yinc[0];
-
- png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
- png_pass_start[0]) / png_pass_inc[0];
- }
-
- else
- {
- png_ptr->num_rows = png_ptr->height;
- png_ptr->usr_width = png_ptr->width;
- }
- }
-
- else
-#endif
- {
- png_ptr->num_rows = png_ptr->height;
- png_ptr->usr_width = png_ptr->width;
- }
-}
-
-/* Internal use only. Called when finished processing a row of data. */
-void /* PRIVATE */
-png_write_finish_row(png_structrp png_ptr)
-{
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
- /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
- /* Start of interlace block */
- static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
-
- /* Offset to next interlace block */
- static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
- /* Start of interlace block in the y direction */
- static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
-
- /* Offset to next interlace block in the y direction */
- static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
-#endif
-
- png_debug(1, "in png_write_finish_row");
-
- /* Next row */
- png_ptr->row_number++;
-
- /* See if we are done */
- if (png_ptr->row_number < png_ptr->num_rows)
- return;
-
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
- /* If interlaced, go to next pass */
- if (png_ptr->interlaced != 0)
- {
- png_ptr->row_number = 0;
- if ((png_ptr->transformations & PNG_INTERLACE) != 0)
- {
- png_ptr->pass++;
- }
-
- else
- {
- /* Loop until we find a non-zero width or height pass */
- do
- {
- png_ptr->pass++;
-
- if (png_ptr->pass >= 7)
- break;
-
- png_ptr->usr_width = (png_ptr->width +
- png_pass_inc[png_ptr->pass] - 1 -
- png_pass_start[png_ptr->pass]) /
- png_pass_inc[png_ptr->pass];
-
- png_ptr->num_rows = (png_ptr->height +
- png_pass_yinc[png_ptr->pass] - 1 -
- png_pass_ystart[png_ptr->pass]) /
- png_pass_yinc[png_ptr->pass];
-
- if ((png_ptr->transformations & PNG_INTERLACE) != 0)
- break;
-
- } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
-
- }
-
- /* Reset the row above the image for the next pass */
- if (png_ptr->pass < 7)
- {
- if (png_ptr->prev_row != NULL)
- memset(png_ptr->prev_row, 0,
- (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
- png_ptr->usr_bit_depth, png_ptr->width)) + 1);
-
- return;
- }
- }
-#endif
-
- /* If we get here, we've just written the last row, so we need
- to flush the compressor */
- png_compress_IDAT(png_ptr, NULL, 0, Z_FINISH);
-}
-
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
-/* Pick out the correct pixels for the interlace pass.
- * The basic idea here is to go through the row with a source
- * pointer and a destination pointer (sp and dp), and copy the
- * correct pixels for the pass. As the row gets compacted,
- * sp will always be >= dp, so we should never overwrite anything.
- * See the default: case for the easiest code to understand.
- */
-void /* PRIVATE */
-png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
-{
- /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
- /* Start of interlace block */
- static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
-
- /* Offset to next interlace block */
- static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
- png_debug(1, "in png_do_write_interlace");
-
- /* We don't have to do anything on the last pass (6) */
- if (pass < 6)
- {
- /* Each pixel depth is handled separately */
- switch (row_info->pixel_depth)
- {
- case 1:
- {
- png_bytep sp;
- png_bytep dp;
- unsigned int shift;
- int d;
- int value;
- png_uint_32 i;
- png_uint_32 row_width = row_info->width;
-
- dp = row;
- d = 0;
- shift = 7;
-
- for (i = png_pass_start[pass]; i < row_width;
- i += png_pass_inc[pass])
- {
- sp = row + (png_size_t)(i >> 3);
- value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
- d |= (value << shift);
-
- if (shift == 0)
- {
- shift = 7;
- *dp++ = (png_byte)d;
- d = 0;
- }
-
- else
- shift--;
-
- }
- if (shift != 7)
- *dp = (png_byte)d;
-
- break;
- }
-
- case 2:
- {
- png_bytep sp;
- png_bytep dp;
- unsigned int shift;
- int d;
- int value;
- png_uint_32 i;
- png_uint_32 row_width = row_info->width;
-
- dp = row;
- shift = 6;
- d = 0;
-
- for (i = png_pass_start[pass]; i < row_width;
- i += png_pass_inc[pass])
- {
- sp = row + (png_size_t)(i >> 2);
- value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
- d |= (value << shift);
-
- if (shift == 0)
- {
- shift = 6;
- *dp++ = (png_byte)d;
- d = 0;
- }
-
- else
- shift -= 2;
- }
- if (shift != 6)
- *dp = (png_byte)d;
-
- break;
- }
-
- case 4:
- {
- png_bytep sp;
- png_bytep dp;
- unsigned int shift;
- int d;
- int value;
- png_uint_32 i;
- png_uint_32 row_width = row_info->width;
-
- dp = row;
- shift = 4;
- d = 0;
- for (i = png_pass_start[pass]; i < row_width;
- i += png_pass_inc[pass])
- {
- sp = row + (png_size_t)(i >> 1);
- value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
- d |= (value << shift);
-
- if (shift == 0)
- {
- shift = 4;
- *dp++ = (png_byte)d;
- d = 0;
- }
-
- else
- shift -= 4;
- }
- if (shift != 4)
- *dp = (png_byte)d;
-
- break;
- }
-
- default:
- {
- png_bytep sp;
- png_bytep dp;
- png_uint_32 i;
- png_uint_32 row_width = row_info->width;
- png_size_t pixel_bytes;
-
- /* Start at the beginning */
- dp = row;
-
- /* Find out how many bytes each pixel takes up */
- pixel_bytes = (row_info->pixel_depth >> 3);
-
- /* Loop through the row, only looking at the pixels that matter */
- for (i = png_pass_start[pass]; i < row_width;
- i += png_pass_inc[pass])
- {
- /* Find out where the original pixel is */
- sp = row + (png_size_t)i * pixel_bytes;
-
- /* Move the pixel */
- if (dp != sp)
- memcpy(dp, sp, pixel_bytes);
-
- /* Next pixel */
- dp += pixel_bytes;
- }
- break;
- }
- }
- /* Set new row width */
- row_info->width = (row_info->width +
- png_pass_inc[pass] - 1 -
- png_pass_start[pass]) /
- png_pass_inc[pass];
-
- row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
- row_info->width);
- }
-}
-#endif
-
-
-/* This filters the row, chooses which filter to use, if it has not already
- * been specified by the application, and then writes the row out with the
- * chosen filter.
- */
-static void /* PRIVATE */
-png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
- png_size_t row_bytes);
-
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-static png_size_t /* PRIVATE */
-png_setup_sub_row(png_structrp png_ptr, const png_uint_32 bpp,
- const png_size_t row_bytes, const png_size_t lmins)
-{
- png_bytep rp, dp, lp;
- png_size_t i;
- png_size_t sum = 0;
- unsigned int v;
-
- png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
-
- for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp;
- i++, rp++, dp++)
- {
- v = *dp = *rp;
-#ifdef PNG_USE_ABS
- sum += 128 - abs((int)v - 128);
-#else
- sum += (v < 128) ? v : 256 - v;
-#endif
- }
-
- for (lp = png_ptr->row_buf + 1; i < row_bytes;
- i++, rp++, lp++, dp++)
- {
- v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
-#ifdef PNG_USE_ABS
- sum += 128 - abs((int)v - 128);
-#else
- sum += (v < 128) ? v : 256 - v;
-#endif
-
- if (sum > lmins) /* We are already worse, don't continue. */
- break;
- }
-
- return (sum);
-}
-
-static void /* PRIVATE */
-png_setup_sub_row_only(png_structrp png_ptr, const png_uint_32 bpp,
- const png_size_t row_bytes)
-{
- png_bytep rp, dp, lp;
- png_size_t i;
-
- png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
-
- for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp;
- i++, rp++, dp++)
- {
- *dp = *rp;
- }
-
- for (lp = png_ptr->row_buf + 1; i < row_bytes;
- i++, rp++, lp++, dp++)
- {
- *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
- }
-}
-
-static png_size_t /* PRIVATE */
-png_setup_up_row(png_structrp png_ptr, const png_size_t row_bytes,
- const png_size_t lmins)
-{
- png_bytep rp, dp, pp;
- png_size_t i;
- png_size_t sum = 0;
- unsigned int v;
-
- png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
-
- for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
- pp = png_ptr->prev_row + 1; i < row_bytes;
- i++, rp++, pp++, dp++)
- {
- v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
-#ifdef PNG_USE_ABS
- sum += 128 - abs((int)v - 128);
-#else
- sum += (v < 128) ? v : 256 - v;
-#endif
-
- if (sum > lmins) /* We are already worse, don't continue. */
- break;
- }
-
- return (sum);
-}
-static void /* PRIVATE */
-png_setup_up_row_only(png_structrp png_ptr, const png_size_t row_bytes)
-{
- png_bytep rp, dp, pp;
- png_size_t i;
-
- png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
-
- for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
- pp = png_ptr->prev_row + 1; i < row_bytes;
- i++, rp++, pp++, dp++)
- {
- *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
- }
-}
-
-static png_size_t /* PRIVATE */
-png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp,
- const png_size_t row_bytes, const png_size_t lmins)
-{
- png_bytep rp, dp, pp, lp;
- png_uint_32 i;
- png_size_t sum = 0;
- unsigned int v;
-
- png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
-
- for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
- pp = png_ptr->prev_row + 1; i < bpp; i++)
- {
- v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
-
-#ifdef PNG_USE_ABS
- sum += 128 - abs((int)v - 128);
-#else
- sum += (v < 128) ? v : 256 - v;
-#endif
- }
-
- for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
- {
- v = *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
- & 0xff);
-
-#ifdef PNG_USE_ABS
- sum += 128 - abs((int)v - 128);
-#else
- sum += (v < 128) ? v : 256 - v;
-#endif
-
- if (sum > lmins) /* We are already worse, don't continue. */
- break;
- }
-
- return (sum);
-}
-static void /* PRIVATE */
-png_setup_avg_row_only(png_structrp png_ptr, const png_uint_32 bpp,
- const png_size_t row_bytes)
-{
- png_bytep rp, dp, pp, lp;
- png_uint_32 i;
-
- png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
-
- for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
- pp = png_ptr->prev_row + 1; i < bpp; i++)
- {
- *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
- }
-
- for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
- {
- *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
- & 0xff);
- }
-}
-
-static png_size_t /* PRIVATE */
-png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp,
- const png_size_t row_bytes, const png_size_t lmins)
-{
- png_bytep rp, dp, pp, cp, lp;
- png_size_t i;
- png_size_t sum = 0;
- unsigned int v;
-
- png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
-
- for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
- pp = png_ptr->prev_row + 1; i < bpp; i++)
- {
- v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
-
-#ifdef PNG_USE_ABS
- sum += 128 - abs((int)v - 128);
-#else
- sum += (v < 128) ? v : 256 - v;
-#endif
- }
-
- for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes;
- i++)
- {
- int a, b, c, pa, pb, pc, p;
-
- b = *pp++;
- c = *cp++;
- a = *lp++;
-
- p = b - c;
- pc = a - c;
-
-#ifdef PNG_USE_ABS
- pa = abs(p);
- pb = abs(pc);
- pc = abs(p + pc);
-#else
- pa = p < 0 ? -p : p;
- pb = pc < 0 ? -pc : pc;
- pc = (p + pc) < 0 ? -(p + pc) : p + pc;
-#endif
-
- p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
-
- v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
-
-#ifdef PNG_USE_ABS
- sum += 128 - abs((int)v - 128);
-#else
- sum += (v < 128) ? v : 256 - v;
-#endif
-
- if (sum > lmins) /* We are already worse, don't continue. */
- break;
- }
-
- return (sum);
-}
-static void /* PRIVATE */
-png_setup_paeth_row_only(png_structrp png_ptr, const png_uint_32 bpp,
- const png_size_t row_bytes)
-{
- png_bytep rp, dp, pp, cp, lp;
- png_size_t i;
-
- png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
-
- for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
- pp = png_ptr->prev_row + 1; i < bpp; i++)
- {
- *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
- }
-
- for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes;
- i++)
- {
- int a, b, c, pa, pb, pc, p;
-
- b = *pp++;
- c = *cp++;
- a = *lp++;
-
- p = b - c;
- pc = a - c;
-
-#ifdef PNG_USE_ABS
- pa = abs(p);
- pb = abs(pc);
- pc = abs(p + pc);
-#else
- pa = p < 0 ? -p : p;
- pb = pc < 0 ? -pc : pc;
- pc = (p + pc) < 0 ? -(p + pc) : p + pc;
-#endif
-
- p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
-
- *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
- }
-}
-#endif /* WRITE_FILTER */
-
-void /* PRIVATE */
-png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
-{
-#ifndef PNG_WRITE_FILTER_SUPPORTED
- png_write_filtered_row(png_ptr, png_ptr->row_buf, row_info->rowbytes+1);
-#else
- unsigned int filter_to_do = png_ptr->do_filter;
- png_bytep row_buf;
- png_bytep best_row;
- png_uint_32 bpp;
- png_size_t mins;
- png_size_t row_bytes = row_info->rowbytes;
-
- png_debug(1, "in png_write_find_filter");
-
- /* Find out how many bytes offset each pixel is */
- bpp = (row_info->pixel_depth + 7) >> 3;
-
- row_buf = png_ptr->row_buf;
- mins = PNG_SIZE_MAX - 256/* so we can detect potential overflow of the
- running sum */;
-
- /* The prediction method we use is to find which method provides the
- * smallest value when summing the absolute values of the distances
- * from zero, using anything >= 128 as negative numbers. This is known
- * as the "minimum sum of absolute differences" heuristic. Other
- * heuristics are the "weighted minimum sum of absolute differences"
- * (experimental and can in theory improve compression), and the "zlib
- * predictive" method (not implemented yet), which does test compressions
- * of lines using different filter methods, and then chooses the
- * (series of) filter(s) that give minimum compressed data size (VERY
- * computationally expensive).
- *
- * GRR 980525: consider also
- *
- * (1) minimum sum of absolute differences from running average (i.e.,
- * keep running sum of non-absolute differences & count of bytes)
- * [track dispersion, too? restart average if dispersion too large?]
- *
- * (1b) minimum sum of absolute differences from sliding average, probably
- * with window size <= deflate window (usually 32K)
- *
- * (2) minimum sum of squared differences from zero or running average
- * (i.e., ~ root-mean-square approach)
- */
-
-
- /* We don't need to test the 'no filter' case if this is the only filter
- * that has been chosen, as it doesn't actually do anything to the data.
- */
- best_row = png_ptr->row_buf;
-
- if (PNG_SIZE_MAX/128 <= row_bytes)
- {
- /* Overflow can occur in the calculation, just select the lowest set
- * filter.
- */
- filter_to_do &= 0U-filter_to_do;
- }
- else if ((filter_to_do & PNG_FILTER_NONE) != 0 &&
- filter_to_do != PNG_FILTER_NONE)
- {
- /* Overflow not possible and multiple filters in the list, including the
- * 'none' filter.
- */
- png_bytep rp;
- png_size_t sum = 0;
- png_size_t i;
- unsigned int v;
-
- {
- for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
- {
- v = *rp;
-#ifdef PNG_USE_ABS
- sum += 128 - abs((int)v - 128);
-#else
- sum += (v < 128) ? v : 256 - v;
-#endif
- }
- }
-
- mins = sum;
- }
-
- /* Sub filter */
- if (filter_to_do == PNG_FILTER_SUB)
- /* It's the only filter so no testing is needed */
- {
- png_setup_sub_row_only(png_ptr, bpp, row_bytes);
- best_row = png_ptr->try_row;
- }
-
- else if ((filter_to_do & PNG_FILTER_SUB) != 0)
- {
- png_size_t sum;
- png_size_t lmins = mins;
-
- sum = png_setup_sub_row(png_ptr, bpp, row_bytes, lmins);
-
- if (sum < mins)
- {
- mins = sum;
- best_row = png_ptr->try_row;
- if (png_ptr->tst_row != NULL)
- {
- png_ptr->try_row = png_ptr->tst_row;
- png_ptr->tst_row = best_row;
- }
- }
- }
-
- /* Up filter */
- if (filter_to_do == PNG_FILTER_UP)
- {
- png_setup_up_row_only(png_ptr, row_bytes);
- best_row = png_ptr->try_row;
- }
-
- else if ((filter_to_do & PNG_FILTER_UP) != 0)
- {
- png_size_t sum;
- png_size_t lmins = mins;
-
- sum = png_setup_up_row(png_ptr, row_bytes, lmins);
-
- if (sum < mins)
- {
- mins = sum;
- best_row = png_ptr->try_row;
- if (png_ptr->tst_row != NULL)
- {
- png_ptr->try_row = png_ptr->tst_row;
- png_ptr->tst_row = best_row;
- }
- }
- }
-
- /* Avg filter */
- if (filter_to_do == PNG_FILTER_AVG)
- {
- png_setup_avg_row_only(png_ptr, bpp, row_bytes);
- best_row = png_ptr->try_row;
- }
-
- else if ((filter_to_do & PNG_FILTER_AVG) != 0)
- {
- png_size_t sum;
- png_size_t lmins = mins;
-
- sum= png_setup_avg_row(png_ptr, bpp, row_bytes, lmins);
-
- if (sum < mins)
- {
- mins = sum;
- best_row = png_ptr->try_row;
- if (png_ptr->tst_row != NULL)
- {
- png_ptr->try_row = png_ptr->tst_row;
- png_ptr->tst_row = best_row;
- }
- }
- }
-
- /* Paeth filter */
- if (filter_to_do == PNG_FILTER_PAETH)
- {
- png_setup_paeth_row_only(png_ptr, bpp, row_bytes);
- best_row = png_ptr->try_row;
- }
-
- else if ((filter_to_do & PNG_FILTER_PAETH) != 0)
- {
- png_size_t sum;
- png_size_t lmins = mins;
-
- sum = png_setup_paeth_row(png_ptr, bpp, row_bytes, lmins);
-
- if (sum < mins)
- {
- best_row = png_ptr->try_row;
- if (png_ptr->tst_row != NULL)
- {
- png_ptr->try_row = png_ptr->tst_row;
- png_ptr->tst_row = best_row;
- }
- }
- }
-
- /* Do the actual writing of the filtered row data from the chosen filter. */
- png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
-
-#endif /* WRITE_FILTER */
-}
-
-
-/* Do the actual writing of a previously filtered row. */
-static void
-png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
- png_size_t full_row_length/*includes filter byte*/)
-{
- png_debug(1, "in png_write_filtered_row");
-
- png_debug1(2, "filter = %d", filtered_row[0]);
-
- png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH);
-
-#ifdef PNG_WRITE_FILTER_SUPPORTED
- /* Swap the current and previous rows */
- if (png_ptr->prev_row != NULL)
- {
- png_bytep tptr;
-
- tptr = png_ptr->prev_row;
- png_ptr->prev_row = png_ptr->row_buf;
- png_ptr->row_buf = tptr;
- }
-#endif /* WRITE_FILTER */
-
- /* Finish row - updates counters and flushes zlib if last row */
- png_write_finish_row(png_ptr);
-
-#ifdef PNG_WRITE_FLUSH_SUPPORTED
- png_ptr->flush_rows++;
-
- if (png_ptr->flush_dist > 0 &&
- png_ptr->flush_rows >= png_ptr->flush_dist)
- {
- png_write_flush(png_ptr);
- }
-#endif /* WRITE_FLUSH */
-}
-#endif /* WRITE */
projects / reactos.git / blobdiff