diff options
| -rw-r--r-- | src/autofit/afhints.c | 2 | ||||
| -rw-r--r-- | src/autofit/afwarp.c | 33 |
2 files changed, 31 insertions, 4 deletions
diff --git a/src/autofit/afhints.c b/src/autofit/afhints.c index 98593700..a68ce423 100644 --- a/src/autofit/afhints.c +++ b/src/autofit/afhints.c @@ -1152,6 +1152,8 @@ #ifdef AF_USE_WARPER + /* Apply (small) warp scale and warp delta for given dimension. */ + FT_LOCAL_DEF( void ) af_glyph_hints_scale_dim( AF_GlyphHints hints, AF_Dimension dim, diff --git a/src/autofit/afwarp.c b/src/autofit/afwarp.c index f5bb9b18..801ff312 100644 --- a/src/autofit/afwarp.c +++ b/src/autofit/afwarp.c @@ -4,7 +4,7 @@ /* */ /* Auto-fitter warping algorithm (body). */ /* */ -/* Copyright 2006, 2007 by */ +/* 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, */ @@ -16,10 +16,20 @@ /***************************************************************************/ + /* + * 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_USE_WARPER + /* 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] = @@ -43,6 +53,11 @@ #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, @@ -100,6 +115,7 @@ 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; } @@ -115,9 +131,9 @@ AF_WarpScore distort = base_distort + ( idx - idx0 ); - if ( score > warper->best_score || + if ( score > warper->best_score || ( score == warper->best_score && - distort < warper->best_distort ) ) + distort < warper->best_distort ) ) { warper->best_score = score; warper->best_distort = distort; @@ -129,6 +145,9 @@ } + /* 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, @@ -215,6 +234,7 @@ 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; @@ -234,10 +254,12 @@ 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; @@ -273,6 +295,8 @@ 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 ) @@ -304,6 +328,7 @@ 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 ); @@ -331,7 +356,7 @@ #else /* !AF_USE_WARPER */ -char af_warper_dummy = 0; /* make compiler happy */ + char af_warper_dummy = 0; /* make compiler happy */ #endif /* !AF_USE_WARPER */ |