--- /dev/null
+/***************************************************************************/
+/* */
+/* afangles.c */
+/* */
+/* Routines used to compute vector angles with limited accuracy */
+/* and very high speed. It also contains sorting routines (body). */
+/* */
+/* Copyright 2003-2017 by */
+/* David Turner, Robert Wilhelm, and Werner Lemberg. */
+/* */
+/* This file is part of the FreeType project, and may only be used, */
+/* modified, and distributed under the terms of the FreeType project */
+/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
+/* this file you indicate that you have read the license and */
+/* understand and accept it fully. */
+/* */
+/***************************************************************************/
+
+
+#include "aftypes.h"
+
+
+ /*
+ * We are not using `af_angle_atan' anymore, but we keep the source
+ * code below just in case...
+ */
+
+
+#if 0
+
+
+ /*
+ * The trick here is to realize that we don't need a very accurate angle
+ * approximation. We are going to use the result of `af_angle_atan' to
+ * only compare the sign of angle differences, or check whether its
+ * magnitude is very small.
+ *
+ * The approximation
+ *
+ * dy * PI / (|dx|+|dy|)
+ *
+ * should be enough, and much faster to compute.
+ */
+ FT_LOCAL_DEF( AF_Angle )
+ af_angle_atan( FT_Fixed dx,
+ FT_Fixed dy )
+ {
+ AF_Angle angle;
+ FT_Fixed ax = dx;
+ FT_Fixed ay = dy;
+
+
+ if ( ax < 0 )
+ ax = -ax;
+ if ( ay < 0 )
+ ay = -ay;
+
+ ax += ay;
+
+ if ( ax == 0 )
+ angle = 0;
+ else
+ {
+ angle = ( AF_ANGLE_PI2 * dy ) / ( ax + ay );
+ if ( dx < 0 )
+ {
+ if ( angle >= 0 )
+ angle = AF_ANGLE_PI - angle;
+ else
+ angle = -AF_ANGLE_PI - angle;
+ }
+ }
+
+ return angle;
+ }
+
+
+#elif 0
+
+
+ /* the following table has been automatically generated with */
+ /* the `mather.py' Python script */
+
+#define AF_ATAN_BITS 8
+
+ static const FT_Byte af_arctan[1L << AF_ATAN_BITS] =
+ {
+ 0, 0, 1, 1, 1, 2, 2, 2,
+ 3, 3, 3, 3, 4, 4, 4, 5,
+ 5, 5, 6, 6, 6, 7, 7, 7,
+ 8, 8, 8, 9, 9, 9, 10, 10,
+ 10, 10, 11, 11, 11, 12, 12, 12,
+ 13, 13, 13, 14, 14, 14, 14, 15,
+ 15, 15, 16, 16, 16, 17, 17, 17,
+ 18, 18, 18, 18, 19, 19, 19, 20,
+ 20, 20, 21, 21, 21, 21, 22, 22,
+ 22, 23, 23, 23, 24, 24, 24, 24,
+ 25, 25, 25, 26, 26, 26, 26, 27,
+ 27, 27, 28, 28, 28, 28, 29, 29,
+ 29, 30, 30, 30, 30, 31, 31, 31,
+ 31, 32, 32, 32, 33, 33, 33, 33,
+ 34, 34, 34, 34, 35, 35, 35, 35,
+ 36, 36, 36, 36, 37, 37, 37, 38,
+ 38, 38, 38, 39, 39, 39, 39, 40,
+ 40, 40, 40, 41, 41, 41, 41, 42,
+ 42, 42, 42, 42, 43, 43, 43, 43,
+ 44, 44, 44, 44, 45, 45, 45, 45,
+ 46, 46, 46, 46, 46, 47, 47, 47,
+ 47, 48, 48, 48, 48, 48, 49, 49,
+ 49, 49, 50, 50, 50, 50, 50, 51,
+ 51, 51, 51, 51, 52, 52, 52, 52,
+ 52, 53, 53, 53, 53, 53, 54, 54,
+ 54, 54, 54, 55, 55, 55, 55, 55,
+ 56, 56, 56, 56, 56, 57, 57, 57,
+ 57, 57, 57, 58, 58, 58, 58, 58,
+ 59, 59, 59, 59, 59, 59, 60, 60,
+ 60, 60, 60, 61, 61, 61, 61, 61,
+ 61, 62, 62, 62, 62, 62, 62, 63,
+ 63, 63, 63, 63, 63, 64, 64, 64
+ };
+
+
+ FT_LOCAL_DEF( AF_Angle )
+ af_angle_atan( FT_Fixed dx,
+ FT_Fixed dy )
+ {
+ AF_Angle angle;
+
+
+ /* check trivial cases */
+ if ( dy == 0 )
+ {
+ angle = 0;
+ if ( dx < 0 )
+ angle = AF_ANGLE_PI;
+ return angle;
+ }
+ else if ( dx == 0 )
+ {
+ angle = AF_ANGLE_PI2;
+ if ( dy < 0 )
+ angle = -AF_ANGLE_PI2;
+ return angle;
+ }
+
+ angle = 0;
+ if ( dx < 0 )
+ {
+ dx = -dx;
+ dy = -dy;
+ angle = AF_ANGLE_PI;
+ }
+
+ if ( dy < 0 )
+ {
+ FT_Pos tmp;
+
+
+ tmp = dx;
+ dx = -dy;
+ dy = tmp;
+ angle -= AF_ANGLE_PI2;
+ }
+
+ if ( dx == 0 && dy == 0 )
+ return 0;
+
+ if ( dx == dy )
+ angle += AF_ANGLE_PI4;
+ else if ( dx > dy )
+ angle += af_arctan[FT_DivFix( dy, dx ) >> ( 16 - AF_ATAN_BITS )];
+ else
+ angle += AF_ANGLE_PI2 -
+ af_arctan[FT_DivFix( dx, dy ) >> ( 16 - AF_ATAN_BITS )];
+
+ if ( angle > AF_ANGLE_PI )
+ angle -= AF_ANGLE_2PI;
+
+ return angle;
+ }
+
+
+#endif /* 0 */
+
+
+ FT_LOCAL_DEF( void )
+ af_sort_pos( FT_UInt count,
+ FT_Pos* table )
+ {
+ FT_UInt i, j;
+ FT_Pos swap;
+
+
+ for ( i = 1; i < count; i++ )
+ {
+ for ( j = i; j > 0; j-- )
+ {
+ if ( table[j] >= table[j - 1] )
+ break;
+
+ swap = table[j];
+ table[j] = table[j - 1];
+ table[j - 1] = swap;
+ }
+ }
+ }
+
+
+ FT_LOCAL_DEF( void )
+ af_sort_and_quantize_widths( FT_UInt* count,
+ AF_Width table,
+ FT_Pos threshold )
+ {
+ FT_UInt i, j;
+ FT_UInt cur_idx;
+ FT_Pos cur_val;
+ FT_Pos sum;
+ AF_WidthRec swap;
+
+
+ if ( *count == 1 )
+ return;
+
+ /* sort */
+ for ( i = 1; i < *count; i++ )
+ {
+ for ( j = i; j > 0; j-- )
+ {
+ if ( table[j].org >= table[j - 1].org )
+ break;
+
+ swap = table[j];
+ table[j] = table[j - 1];
+ table[j - 1] = swap;
+ }
+ }
+
+ cur_idx = 0;
+ cur_val = table[cur_idx].org;
+
+ /* compute and use mean values for clusters not larger than */
+ /* `threshold'; this is very primitive and might not yield */
+ /* the best result, but normally, using reference character */
+ /* `o', `*count' is 2, so the code below is fully sufficient */
+ for ( i = 1; i < *count; i++ )
+ {
+ if ( table[i].org - cur_val > threshold ||
+ i == *count - 1 )
+ {
+ sum = 0;
+
+ /* fix loop for end of array */
+ if ( table[i].org - cur_val <= threshold &&
+ i == *count - 1 )
+ i++;
+
+ for ( j = cur_idx; j < i; j++ )
+ {
+ sum += table[j].org;
+ table[j].org = 0;
+ }
+ table[cur_idx].org = sum / (FT_Pos)j;
+
+ if ( i < *count - 1 )
+ {
+ cur_idx = i + 1;
+ cur_val = table[cur_idx].org;
+ }
+ }
+ }
+
+ cur_idx = 1;
+
+ /* compress array to remove zero values */
+ for ( i = 1; i < *count; i++ )
+ {
+ if ( table[i].org )
+ table[cur_idx++] = table[i];
+ }
+
+ *count = cur_idx;
+ }
+
+
+/* END */
projects / reactos.git / blobdiff