--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/misc/libfreetype/src/autofit/afwarp.c Mon Apr 25 01:46:54 2011 +0200
@@ -0,0 +1,374 @@
+/***************************************************************************/
+/* */
+/* afwarp.c */
+/* */
+/* Auto-fitter warping algorithm (body). */
+/* */
+/* Copyright 2006, 2007, 2011 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. */
+/* */
+/***************************************************************************/
+
+
+ /*
+ * The idea of the warping code is to slightly scale and shift a glyph
+ * within a single dimension so that as much of its segments are aligned
+ * (more or less) on the grid. To find out the optimal scaling and
+ * shifting value, various parameter combinations are tried and scored.
+ */
+
+#include "afwarp.h"
+
+#ifdef AF_CONFIG_OPTION_USE_WARPER
+
+ /*************************************************************************/
+ /* */
+ /* The macro FT_COMPONENT is used in trace mode. It is an implicit */
+ /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */
+ /* messages during execution. */
+ /* */
+#undef FT_COMPONENT
+#define FT_COMPONENT trace_afwarp
+
+
+ /* The weights cover the range 0/64 - 63/64 of a pixel. Obviously, */
+ /* values around a half pixel (which means exactly between two grid */
+ /* lines) gets the worst weight. */
+#if 1
+ static const AF_WarpScore
+ af_warper_weights[64] =
+ {
+ 35, 32, 30, 25, 20, 15, 12, 10, 5, 1, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, -1, -2, -5, -8,-10,-10,-20,-20,-30,-30,
+
+ -30,-30,-20,-20,-10,-10, -8, -5, -2, -1, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 1, 5, 10, 12, 15, 20, 25, 30, 32,
+ };
+#else
+ static const AF_WarpScore
+ af_warper_weights[64] =
+ {
+ 30, 20, 10, 5, 4, 4, 3, 2, 1, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, -1, -2, -2, -5, -5,-10,-10,-15,-20,
+
+ -20,-15,-15,-10,-10, -5, -5, -2, -2, -1, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 4, 5, 10, 20,
+ };
+#endif
+
+
+ /* Score segments for a given `scale' and `delta' in the range */
+ /* `xx1' to `xx2', and store the best result in `warper'. If */
+ /* the new best score is equal to the old one, prefer the */
+ /* value with a smaller distortion (around `base_distort'). */
+
+ static void
+ af_warper_compute_line_best( AF_Warper warper,
+ FT_Fixed scale,
+ FT_Pos delta,
+ FT_Pos xx1,
+ FT_Pos xx2,
+ AF_WarpScore base_distort,
+ AF_Segment segments,
+ FT_UInt num_segments )
+ {
+ FT_Int idx_min, idx_max, idx0;
+ FT_UInt nn;
+ AF_WarpScore scores[65];
+
+
+ for ( nn = 0; nn < 65; nn++ )
+ scores[nn] = 0;
+
+ idx0 = xx1 - warper->t1;
+
+ /* compute minimum and maximum indices */
+ {
+ FT_Pos xx1min = warper->x1min;
+ FT_Pos xx1max = warper->x1max;
+ FT_Pos w = xx2 - xx1;
+
+
+ if ( xx1min + w < warper->x2min )
+ xx1min = warper->x2min - w;
+
+ xx1max = warper->x1max;
+ if ( xx1max + w > warper->x2max )
+ xx1max = warper->x2max - w;
+
+ idx_min = xx1min - warper->t1;
+ idx_max = xx1max - warper->t1;
+
+ if ( idx_min < 0 || idx_min > idx_max || idx_max > 64 )
+ {
+ FT_TRACE5(( "invalid indices:\n"
+ " min=%d max=%d, xx1=%ld xx2=%ld,\n"
+ " x1min=%ld x1max=%ld, x2min=%ld x2max=%ld\n",
+ idx_min, idx_max, xx1, xx2,
+ warper->x1min, warper->x1max,
+ warper->x2min, warper->x2max ));
+ return;
+ }
+ }
+
+ for ( nn = 0; nn < num_segments; nn++ )
+ {
+ FT_Pos len = segments[nn].max_coord - segments[nn].min_coord;
+ FT_Pos y0 = FT_MulFix( segments[nn].pos, scale ) + delta;
+ FT_Pos y = y0 + ( idx_min - idx0 );
+ FT_Int idx;
+
+
+ /* score the length of the segments for the given range */
+ for ( idx = idx_min; idx <= idx_max; idx++, y++ )
+ scores[idx] += af_warper_weights[y & 63] * len;
+ }
+
+ /* find best score */
+ {
+ FT_Int idx;
+
+
+ for ( idx = idx_min; idx <= idx_max; idx++ )
+ {
+ AF_WarpScore score = scores[idx];
+ AF_WarpScore distort = base_distort + ( idx - idx0 );
+
+
+ if ( score > warper->best_score ||
+ ( score == warper->best_score &&
+ distort < warper->best_distort ) )
+ {
+ warper->best_score = score;
+ warper->best_distort = distort;
+ warper->best_scale = scale;
+ warper->best_delta = delta + ( idx - idx0 );
+ }
+ }
+ }
+ }
+
+
+ /* Compute optimal scaling and delta values for a given glyph and */
+ /* dimension. */
+
+ FT_LOCAL_DEF( void )
+ af_warper_compute( AF_Warper warper,
+ AF_GlyphHints hints,
+ AF_Dimension dim,
+ FT_Fixed *a_scale,
+ FT_Pos *a_delta )
+ {
+ AF_AxisHints axis;
+ AF_Point points;
+
+ FT_Fixed org_scale;
+ FT_Pos org_delta;
+
+ FT_UInt nn, num_points, num_segments;
+ FT_Int X1, X2;
+ FT_Int w;
+
+ AF_WarpScore base_distort;
+ AF_Segment segments;
+
+
+ /* get original scaling transformation */
+ if ( dim == AF_DIMENSION_VERT )
+ {
+ org_scale = hints->y_scale;
+ org_delta = hints->y_delta;
+ }
+ else
+ {
+ org_scale = hints->x_scale;
+ org_delta = hints->x_delta;
+ }
+
+ warper->best_scale = org_scale;
+ warper->best_delta = org_delta;
+ warper->best_score = INT_MIN;
+ warper->best_distort = 0;
+
+ axis = &hints->axis[dim];
+ segments = axis->segments;
+ num_segments = axis->num_segments;
+ points = hints->points;
+ num_points = hints->num_points;
+
+ *a_scale = org_scale;
+ *a_delta = org_delta;
+
+ /* get X1 and X2, minimum and maximum in original coordinates */
+ if ( num_segments < 1 )
+ return;
+
+#if 1
+ X1 = X2 = points[0].fx;
+ for ( nn = 1; nn < num_points; nn++ )
+ {
+ FT_Int X = points[nn].fx;
+
+
+ if ( X < X1 )
+ X1 = X;
+ if ( X > X2 )
+ X2 = X;
+ }
+#else
+ X1 = X2 = segments[0].pos;
+ for ( nn = 1; nn < num_segments; nn++ )
+ {
+ FT_Int X = segments[nn].pos;
+
+
+ if ( X < X1 )
+ X1 = X;
+ if ( X > X2 )
+ X2 = X;
+ }
+#endif
+
+ if ( X1 >= X2 )
+ return;
+
+ warper->x1 = FT_MulFix( X1, org_scale ) + org_delta;
+ warper->x2 = FT_MulFix( X2, org_scale ) + org_delta;
+
+ warper->t1 = AF_WARPER_FLOOR( warper->x1 );
+ warper->t2 = AF_WARPER_CEIL( warper->x2 );
+
+ /* examine a half pixel wide range around the maximum coordinates */
+ warper->x1min = warper->x1 & ~31;
+ warper->x1max = warper->x1min + 32;
+ warper->x2min = warper->x2 & ~31;
+ warper->x2max = warper->x2min + 32;
+
+ if ( warper->x1max > warper->x2 )
+ warper->x1max = warper->x2;
+
+ if ( warper->x2min < warper->x1 )
+ warper->x2min = warper->x1;
+
+ warper->w0 = warper->x2 - warper->x1;
+
+ if ( warper->w0 <= 64 )
+ {
+ warper->x1max = warper->x1;
+ warper->x2min = warper->x2;
+ }
+
+ /* examine (at most) a pixel wide range around the natural width */
+ warper->wmin = warper->x2min - warper->x1max;
+ warper->wmax = warper->x2max - warper->x1min;
+
+#if 1
+ /* some heuristics to reduce the number of widths to be examined */
+ {
+ int margin = 16;
+
+
+ if ( warper->w0 <= 128 )
+ {
+ margin = 8;
+ if ( warper->w0 <= 96 )
+ margin = 4;
+ }
+
+ if ( warper->wmin < warper->w0 - margin )
+ warper->wmin = warper->w0 - margin;
+
+ if ( warper->wmax > warper->w0 + margin )
+ warper->wmax = warper->w0 + margin;
+ }
+
+ if ( warper->wmin < warper->w0 * 3 / 4 )
+ warper->wmin = warper->w0 * 3 / 4;
+
+ if ( warper->wmax > warper->w0 * 5 / 4 )
+ warper->wmax = warper->w0 * 5 / 4;
+#else
+ /* no scaling, just translation */
+ warper->wmin = warper->wmax = warper->w0;
+#endif
+
+ for ( w = warper->wmin; w <= warper->wmax; w++ )
+ {
+ FT_Fixed new_scale;
+ FT_Pos new_delta;
+ FT_Pos xx1, xx2;
+
+
+ /* compute min and max positions for given width, */
+ /* assuring that they stay within the coordinate ranges */
+ xx1 = warper->x1;
+ xx2 = warper->x2;
+ if ( w >= warper->w0 )
+ {
+ xx1 -= w - warper->w0;
+ if ( xx1 < warper->x1min )
+ {
+ xx2 += warper->x1min - xx1;
+ xx1 = warper->x1min;
+ }
+ }
+ else
+ {
+ xx1 -= w - warper->w0;
+ if ( xx1 > warper->x1max )
+ {
+ xx2 -= xx1 - warper->x1max;
+ xx1 = warper->x1max;
+ }
+ }
+
+ if ( xx1 < warper->x1 )
+ base_distort = warper->x1 - xx1;
+ else
+ base_distort = xx1 - warper->x1;
+
+ if ( xx2 < warper->x2 )
+ base_distort += warper->x2 - xx2;
+ else
+ base_distort += xx2 - warper->x2;
+
+ /* give base distortion a greater weight while scoring */
+ base_distort *= 10;
+
+ new_scale = org_scale + FT_DivFix( w - warper->w0, X2 - X1 );
+ new_delta = xx1 - FT_MulFix( X1, new_scale );
+
+ af_warper_compute_line_best( warper, new_scale, new_delta, xx1, xx2,
+ base_distort,
+ segments, num_segments );
+ }
+
+ {
+ FT_Fixed best_scale = warper->best_scale;
+ FT_Pos best_delta = warper->best_delta;
+
+
+ hints->xmin_delta = FT_MulFix( X1, best_scale - org_scale )
+ + best_delta;
+ hints->xmax_delta = FT_MulFix( X2, best_scale - org_scale )
+ + best_delta;
+
+ *a_scale = best_scale;
+ *a_delta = best_delta;
+ }
+ }
+
+#else /* !AF_CONFIG_OPTION_USE_WARPER */
+
+ /* ANSI C doesn't like empty source files */
+ typedef int _af_warp_dummy;
+
+#endif /* !AF_CONFIG_OPTION_USE_WARPER */
+
+/* END */