Update freetype to latest version of ASOP.

src/cff/cf2font.c

+/***************************************************************************/
+/*                                                                         */
+/*  cf2font.c                                                              */
+/*                                                                         */
+/*    Adobe's code for font instances (body).                              */
+/*                                                                         */
+/*  Copyright 2007-2013 Adobe Systems Incorporated.                        */
+/*                                                                         */
+/*  This software, and all works of authorship, whether in source or       */
+/*  object code form as indicated by the copyright notice(s) included      */
+/*  herein (collectively, the "Work") is made available, and may only be   */
+/*  used, modified, and distributed under the FreeType Project License,    */
+/*  LICENSE.TXT.  Additionally, subject to the terms and conditions of the */
+/*  FreeType Project License, each contributor to the Work hereby grants   */
+/*  to any individual or legal entity exercising permissions granted by    */
+/*  the FreeType Project License and this section (hereafter, "You" or     */
+/*  "Your") a perpetual, worldwide, non-exclusive, no-charge,              */
+/*  royalty-free, irrevocable (except as stated in this section) patent    */
+/*  license to make, have made, use, offer to sell, sell, import, and      */
+/*  otherwise transfer the Work, where such license applies only to those  */
+/*  patent claims licensable by such contributor that are necessarily      */
+/*  infringed by their contribution(s) alone or by combination of their    */
+/*  contribution(s) with the Work to which such contribution(s) was        */
+/*  submitted.  If You institute patent litigation against any entity      */
+/*  (including a cross-claim or counterclaim in a lawsuit) alleging that   */
+/*  the Work or a contribution incorporated within the Work constitutes    */
+/*  direct or contributory patent infringement, then any patent licenses   */
+/*  granted to You under this License for that Work shall terminate as of  */
+/*  the date such litigation is filed.                                     */
+/*                                                                         */
+/*  By using, modifying, or distributing the Work you indicate that you    */
+/*  have read and understood the terms and conditions of the               */
+/*  FreeType Project License as well as those provided in this section,    */
+/*  and you accept them fully.                                             */
+/*                                                                         */
+/***************************************************************************/
+
+
+#include "cf2ft.h"
+
+#include "cf2glue.h"
+#include "cf2font.h"
+#include "cf2error.h"
+#include "cf2intrp.h"
+
+
+  /* Compute a stem darkening amount in character space. */
+  static void
+  cf2_computeDarkening( CF2_Fixed   emRatio,
+                        CF2_Fixed   ppem,
+                        CF2_Fixed   stemWidth,
+                        CF2_Fixed*  darkenAmount,
+                        CF2_Fixed   boldenAmount,
+                        FT_Bool     stemDarkened )
+  {
+    /* Internal calculations are done in units per thousand for */
+    /* convenience.                                             */
+    CF2_Fixed  stemWidthPer1000, scaledStem;
+
+
+    *darkenAmount = 0;
+
+    if ( boldenAmount == 0 && !stemDarkened )
+      return;
+
+    /* protect against range problems and divide by zero */
+    if ( emRatio < cf2_floatToFixed( .01 ) )
+      return;
+
+    if ( stemDarkened )
+    {
+      /* convert from true character space to 1000 unit character space; */
+      /* add synthetic emboldening effect                                */
+
+      /* we have to assure that the computation of `scaledStem' */
+      /* and `stemWidthPer1000' don't overflow                  */
+
+      stemWidthPer1000 = FT_MulFix( stemWidth + boldenAmount, emRatio );
+
+      if ( emRatio > CF2_FIXED_ONE                          &&
+           stemWidthPer1000 <= ( stemWidth + boldenAmount ) )
+      {
+        stemWidthPer1000 = 0;                      /* to pacify compiler */
+        scaledStem       = cf2_intToFixed( 2333 );
+      }
+      else
+      {
+        scaledStem = FT_MulFix( stemWidthPer1000, ppem );
+
+        if ( ppem > CF2_FIXED_ONE           &&
+             scaledStem <= stemWidthPer1000 )
+          scaledStem = cf2_intToFixed( 2333 );
+      }
+
+      /*
+       * Total darkening amount is computed in 1000 unit character space
+       * using the modified 5 part curve as Avalon rasterizer.
+       * The darkening amount is smaller for thicker stems.
+       * It becomes zero when the stem is thicker than 2.333 pixels.
+       *
+       * In Avalon rasterizer,
+       *
+       *   darkenAmount = 0.5 pixels   if scaledStem <= 0.5 pixels,
+       *   darkenAmount = 0.333 pixels if 1 <= scaledStem <= 1.667 pixels,
+       *   darkenAmount = 0 pixel      if scaledStem >= 2.333 pixels,
+       *
+       * and piecewise linear in-between.
+       *
+       */
+      if ( scaledStem < cf2_intToFixed( 500 ) )
+        *darkenAmount = FT_DivFix( cf2_intToFixed( 400 ), ppem );
+
+      else if ( scaledStem < cf2_intToFixed( 1000 ) )
+        *darkenAmount = FT_DivFix( cf2_intToFixed( 525 ), ppem ) -
+                          FT_MulFix( stemWidthPer1000,
+                                     cf2_floatToFixed( .25 ) );
+
+      else if ( scaledStem < cf2_intToFixed( 1667 ) )
+        *darkenAmount = FT_DivFix( cf2_intToFixed( 275 ), ppem );
+
+      else if ( scaledStem < cf2_intToFixed( 2333 ) )
+        *darkenAmount = FT_DivFix( cf2_intToFixed( 963 ), ppem ) -
+                          FT_MulFix( stemWidthPer1000,
+                                     cf2_floatToFixed( .413 ) );
+
+      /* use half the amount on each side and convert back to true */
+      /* character space                                           */
+      *darkenAmount = FT_DivFix( *darkenAmount, 2 * emRatio );
+    }
+
+    /* add synthetic emboldening effect in character space */
+    *darkenAmount += boldenAmount / 2;
+  }
+
+
+  /* set up values for the current FontDict and matrix */
+
+  /* caller's transform is adjusted for subpixel positioning */
+  static void
+  cf2_font_setup( CF2_Font           font,
+                  const CF2_Matrix*  transform )
+  {
+    /* pointer to parsed font object */
+    CFF_Decoder*  decoder = font->decoder;
+
+    FT_Bool  needExtraSetup;
+
+    /* character space units */
+    CF2_Fixed  boldenX = font->syntheticEmboldeningAmountX;
+    CF2_Fixed  boldenY = font->syntheticEmboldeningAmountY;
+
+    CF2_Fixed  ppem;
+
+
+    /* clear previous error */
+    font->error = FT_Err_Ok;
+
+    /* if a CID fontDict has changed, we need to recompute some cached */
+    /* data                                                            */
+    needExtraSetup = font->lastSubfont != cf2_getSubfont( decoder );
+
+    /* if ppem has changed, we need to recompute some cached data         */
+    /* note: because of CID font matrix concatenation, ppem and transform */
+    /*       do not necessarily track.                                    */
+    ppem = cf2_getPpemY( decoder );
+    if ( font->ppem != ppem )
+    {
+      font->ppem     = ppem;
+      needExtraSetup = TRUE;
+    }
+
+    /* copy hinted flag on each call */
+    font->hinted = font->renderingFlags & CF2_FlagsHinted;
+
+    /* determine if transform has changed;       */
+    /* include Fontmatrix but ignore translation */
+    if ( ft_memcmp( transform,
+                    &font->currentTransform,
+                    4 * sizeof ( CF2_Fixed ) ) != 0 )
+    {
+      /* save `key' information for `cache of one' matrix data; */
+      /* save client transform, without the translation         */
+      font->currentTransform    = *transform;
+      font->currentTransform.tx =
+      font->currentTransform.ty = cf2_intToFixed( 0 );
+
+      /* TODO: FreeType transform is simple scalar; for now, use identity */
+      /*       for outer                                                  */
+      font->innerTransform   = *transform;
+      font->outerTransform.a =
+      font->outerTransform.d = cf2_intToFixed( 1 );
+      font->outerTransform.b =
+      font->outerTransform.c = cf2_intToFixed( 0 );
+
+      needExtraSetup = TRUE;
+    }
+
+    /*
+     * font->darkened is set to true if there is a stem darkening request or
+     * the font is synthetic emboldened.
+     * font->darkened controls whether to adjust blue zones, winding order,
+     * and hinting.
+     *
+     */
+    if ( font->stemDarkened != ( font->renderingFlags & CF2_FlagsDarkened ) )
+    {
+      font->stemDarkened = font->renderingFlags & CF2_FlagsDarkened;
+
+      /* blue zones depend on darkened flag */
+      needExtraSetup = TRUE;
+    }
+
+    /* recompute variables that are dependent on transform or FontDict or */
+    /* darken flag                                                        */
+    if ( needExtraSetup )
+    {
+      /* StdVW is found in the private dictionary;                       */
+      /* recompute darkening amounts whenever private dictionary or      */
+      /* transform change                                                */
+      /* Note: a rendering flag turns darkening on or off, so we want to */
+      /*       store the `on' amounts;                                   */
+      /*       darkening amount is computed in character space           */
+      /* TODO: testing size-dependent darkening here;                    */
+      /*       what to do for rotations?                                 */
+
+      CF2_Fixed  emRatio;
+      CF2_Fixed  stdHW;
+      CF2_Int    unitsPerEm = font->unitsPerEm;
+
+
+      if ( unitsPerEm == 0 )
+        unitsPerEm = 1000;
+
+      ppem = FT_MAX( cf2_intToFixed( 4 ),
+                     font->ppem ); /* use minimum ppem of 4 */
+
+#if 0
+      /* since vstem is measured in the x-direction, we use the `a' member */
+      /* of the fontMatrix                                                 */
+      emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->a );
+#endif
+
+      /* Freetype does not preserve the fontMatrix when parsing; use */
+      /* unitsPerEm instead.                                         */
+      /* TODO: check precision of this                               */
+      emRatio     = cf2_intToFixed( 1000 ) / unitsPerEm;
+      font->stdVW = cf2_getStdVW( decoder );
+
+      if ( font->stdVW <= 0 )
+        font->stdVW = FT_DivFix( cf2_intToFixed( 75 ), emRatio );
+
+      if ( boldenX > 0 )
+      {
+        /* Ensure that boldenX is at least 1 pixel for synthetic bold font */
+        /* (similar to what Avalon does)                                   */
+        boldenX = FT_MAX( boldenX,
+                          FT_DivFix( cf2_intToFixed( unitsPerEm ), ppem ) );
+
+        /* Synthetic emboldening adds at least 1 pixel to darkenX, while */
+        /* stem darkening adds at most half pixel.  Since the purpose of */
+        /* stem darkening (readability at small sizes) is met with       */
+        /* synthetic emboldening, no need to add stem darkening for a    */
+        /* synthetic bold font.                                          */
+        cf2_computeDarkening( emRatio,
+                              ppem,
+                              font->stdVW,
+                              &font->darkenX,
+                              boldenX,
+                              FALSE );
+      }
+      else
+        cf2_computeDarkening( emRatio,
+                              ppem,
+                              font->stdVW,
+                              &font->darkenX,
+                              0,
+                              font->stemDarkened );
+
+#if 0
+      /* since hstem is measured in the y-direction, we use the `d' member */
+      /* of the fontMatrix                                                 */
+      /* TODO: use the same units per em as above; check this              */
+      emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->d );
+#endif
+
+      /* set the default stem width, because it must be the same for all */
+      /* family members;                                                 */
+      /* choose a constant for StdHW that depends on font contrast       */
+      stdHW = cf2_getStdHW( decoder );
+
+      if ( stdHW > 0 && font->stdVW > 2 * stdHW )
+        font->stdHW = FT_DivFix( cf2_intToFixed( 75 ), emRatio );
+      else
+      {
+        /* low contrast font gets less hstem darkening */
+        font->stdHW = FT_DivFix( cf2_intToFixed( 110 ), emRatio );
+      }
+
+      cf2_computeDarkening( emRatio,
+                            ppem,
+                            font->stdHW,
+                            &font->darkenY,
+                            boldenY,
+                            font->stemDarkened );
+
+      if ( font->darkenX != 0 || font->darkenY != 0 )
+        font->darkened = TRUE;
+      else
+        font->darkened = FALSE;
+
+      font->reverseWinding = FALSE; /* initial expectation is CCW */
+
+      /* compute blue zones for this instance */
+      cf2_blues_init( &font->blues, font );
+    }
+  }
+
+
+  /* equivalent to AdobeGetOutline */
+  FT_LOCAL_DEF( FT_Error )
+  cf2_getGlyphOutline( CF2_Font           font,
+                       CF2_Buffer         charstring,
+                       const CF2_Matrix*  transform,
+                       CF2_F16Dot16*      glyphWidth )
+  {
+    FT_Error  lastError = FT_Err_Ok;
+
+    FT_Vector  translation;
+
+#if 0
+    FT_Vector  advancePoint;
+#endif
+
+    CF2_Fixed  advWidth = 0;
+    FT_Bool    needWinding;
+
+
+    /* Note: use both integer and fraction for outlines.  This allows bbox */
+    /*       to come out directly.                                         */
+
+    translation.x = transform->tx;
+    translation.y = transform->ty;
+
+    /* set up values based on transform */
+    cf2_font_setup( font, transform );
+    if ( font->error )
+      goto exit;                      /* setup encountered an error */
+
+    /* reset darken direction */
+    font->reverseWinding = FALSE;
+
+    /* winding order only affects darkening */
+    needWinding = font->darkened;
+
+    while ( 1 )
+    {
+      /* reset output buffer */
+      cf2_outline_reset( &font->outline );
+
+      /* build the outline, passing the full translation */
+      cf2_interpT2CharString( font,
+                              charstring,
+                              (CF2_OutlineCallbacks)&font->outline,
+                              &translation,
+                              FALSE,
+                              0,
+                              0,
+                              &advWidth );
+
+      if ( font->error )
+        goto exit;
+
+      if ( !needWinding )
+        break;
+
+      /* check winding order */
+      if ( font->outline.root.windingMomentum >= 0 ) /* CFF is CCW */
+        break;
+
+      /* invert darkening and render again                            */
+      /* TODO: this should be a parameter to getOutline-computeOffset */
+      font->reverseWinding = TRUE;
+
+      needWinding = FALSE;    /* exit after next iteration */
+    }
+
+    /* finish storing client outline */
+    cf2_outline_close( &font->outline );
+
+  exit:
+    /* FreeType just wants the advance width; there is no translation */
+    *glyphWidth = advWidth;
+
+    /* free resources and collect errors from objects we've used */
+    cf2_setError( &font->error, lastError );
+
+    return font->error;
+  }
+
+
+/* END */