Update freetype sources (2.6.2) in third party.

third_party/freetype2/src/src/autofit/afwarp.c

Index: third_party/freetype2/src/src/autofit/afwarp.c
diff --git a/third_party/freetype2/src/src/autofit/afwarp.c b/third_party/freetype2/src/src/autofit/afwarp.c
new file mode 100644
index 0000000000000000000000000000000000000000..59af4f02bda7f016b46218708151c4fe3059f692
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+++ b/third_party/freetype2/src/src/autofit/afwarp.c
@@ -0,0 +1,374 @@
+/***************************************************************************/
+/*                                                                         */
+/*  afwarp.c                                                               */
+/*                                                                         */
+/*    Auto-fitter warping algorithm (body).                                */
+/*                                                                         */
+/*  Copyright 2006-2015 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_Int        num_segments )
+  {
+    FT_Int        idx_min, idx_max, idx0;
+    FT_Int        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_Int        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 */