kc3-lang/freetype/src/psaux/psfont.c

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• Hash : 179caf5a
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  Date : 2017-10-01T01:39:27
  

  [psaux] Formatting, minor fixes, whitespace, copyright notices.

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• src/psaux/psfont.c

• /***************************************************************************/
  /*                                                                         */
  /*  psfont.c                                                               */
  /*                                                                         */
  /*    Adobe's code for font instances (body).                              */
  /*                                                                         */
  /*  Copyright 2007-2014 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,              */
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  /*  patent claims licensable by such contributor that are necessarily      */
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  /*  submitted.  If You institute patent litigation against any entity      */
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  /*  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 <ft2build.h>
  #include FT_INTERNAL_CALC_H
  
  #include "psft.h"
  
  #include "psglue.h"
  #include "psfont.h"
  #include "pserror.h"
  #include "psintrp.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,
                          FT_Int*     darkenParams )
    {
      /*
       * Total darkening amount is computed in 1000 unit character space
       * using the modified 5 part curve as Adobe's Avalon rasterizer.
       * The darkening amount is smaller for thicker stems.
       * It becomes zero when the stem is thicker than 2.333 pixels.
       *
       * By default, we use
       *
       *   darkenAmount = 0.4 pixels   if scaledStem <= 0.5 pixels,
       *   darkenAmount = 0.275 pixels if 1 <= scaledStem <= 1.667 pixels,
       *   darkenAmount = 0 pixel      if scaledStem >= 2.333 pixels,
       *
       * and piecewise linear in-between:
       *
       *
       *   darkening
       *       ^
       *       |
       *       |      (x1,y1)
       *       |--------+
       *       |         \
       *       |          \
       *       |           \          (x3,y3)
       *       |            +----------+
       *       |        (x2,y2)         \
       *       |                         \
       *       |                          \
       *       |                           +-----------------
       *       |                         (x4,y4)
       *       +--------------------------------------------->   stem
       *                                                       thickness
       *
       *
       * This corresponds to the following values for the
       * `darkening-parameters' property:
       *
       *   (x1, y1) = (500, 400)
       *   (x2, y2) = (1000, 275)
       *   (x3, y3) = (1667, 275)
       *   (x4, y4) = (2333, 0)
       *
       */
  
      /* Internal calculations are done in units per thousand for */
      /* convenience. The x axis is scaled stem width in          */
      /* thousandths of a pixel. That is, 1000 is 1 pixel.        */
      /* The y axis is darkening amount in thousandths of a pixel.*/
      /* In the code, below, dividing by ppem and                 */
      /* adjusting for emRatio converts darkenAmount to character */
      /* space (font units).                                      */
      CF2_Fixed  stemWidthPer1000, scaledStem;
      FT_Int     logBase2;
  
  
      *darkenAmount = 0;
  
      if ( boldenAmount == 0 && !stemDarkened )
        return;
  
      /* protect against range problems and divide by zero */
      if ( emRatio < cf2_doubleToFixed( .01 ) )
        return;
  
      if ( stemDarkened )
      {
        FT_Int  x1 = darkenParams[0];
        FT_Int  y1 = darkenParams[1];
        FT_Int  x2 = darkenParams[2];
        FT_Int  y2 = darkenParams[3];
        FT_Int  x3 = darkenParams[4];
        FT_Int  y3 = darkenParams[5];
        FT_Int  x4 = darkenParams[6];
        FT_Int  y4 = darkenParams[7];
  
  
        /* convert from true character space to 1000 unit character space; */
        /* add synthetic emboldening effect                                */
  
        /* `stemWidthPer1000' will not overflow for a legitimate font      */
  
        stemWidthPer1000 = FT_MulFix( stemWidth + boldenAmount, emRatio );
  
        /* `scaledStem' can easily overflow, so we must clamp its maximum  */
        /* value; the test doesn't need to be precise, but must be         */
        /* conservative.  The clamp value (default 2333) where             */
        /* `darkenAmount' is zero is well below the overflow value of      */
        /* 32767.                                                          */
        /*                                                                 */
        /* FT_MSB computes the integer part of the base 2 logarithm.  The  */
        /* number of bits for the product is 1 or 2 more than the sum of   */
        /* logarithms; remembering that the 16 lowest bits of the fraction */
        /* are dropped this is correct to within a factor of almost 4.     */
        /* For example, 0x80.0000 * 0x80.0000 = 0x4000.0000 is 23+23 and   */
        /* is flagged as possible overflow because 0xFF.FFFF * 0xFF.FFFF = */
        /* 0xFFFF.FE00 is also 23+23.                                      */
  
        logBase2 = FT_MSB( (FT_UInt32)stemWidthPer1000 ) +
                     FT_MSB( (FT_UInt32)ppem );
  
        if ( logBase2 >= 46 )
          /* possible overflow */
          scaledStem = cf2_intToFixed( x4 );
        else
          scaledStem = FT_MulFix( stemWidthPer1000, ppem );
  
        /* now apply the darkening parameters */
  
        if ( scaledStem < cf2_intToFixed( x1 ) )
          *darkenAmount = FT_DivFix( cf2_intToFixed( y1 ), ppem );
  
        else if ( scaledStem < cf2_intToFixed( x2 ) )
        {
          FT_Int  xdelta = x2 - x1;
          FT_Int  ydelta = y2 - y1;
          FT_Int  x      = stemWidthPer1000 -
                             FT_DivFix( cf2_intToFixed( x1 ), ppem );
  
  
          if ( !xdelta )
            goto Try_x3;
  
          *darkenAmount = FT_MulDiv( x, ydelta, xdelta ) +
                            FT_DivFix( cf2_intToFixed( y1 ), ppem );
        }
  
        else if ( scaledStem < cf2_intToFixed( x3 ) )
        {
        Try_x3:
          {
            FT_Int  xdelta = x3 - x2;
            FT_Int  ydelta = y3 - y2;
            FT_Int  x      = stemWidthPer1000 -
                               FT_DivFix( cf2_intToFixed( x2 ), ppem );
  
  
            if ( !xdelta )
              goto Try_x4;
  
            *darkenAmount = FT_MulDiv( x, ydelta, xdelta ) +
                              FT_DivFix( cf2_intToFixed( y2 ), ppem );
          }
        }
  
        else if ( scaledStem < cf2_intToFixed( x4 ) )
        {
        Try_x4:
          {
            FT_Int  xdelta = x4 - x3;
            FT_Int  ydelta = y4 - y3;
            FT_Int  x      = stemWidthPer1000 -
                               FT_DivFix( cf2_intToFixed( x3 ), ppem );
  
  
            if ( !xdelta )
              goto Use_y4;
  
            *darkenAmount = FT_MulDiv( x, ydelta, xdelta ) +
                              FT_DivFix( cf2_intToFixed( y3 ), ppem );
          }
        }
  
        else
        {
        Use_y4:
          *darkenAmount = FT_DivFix( cf2_intToFixed( y4 ), ppem );
        }
  
        /* 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; */
    /* called for each glyph to be rendered               */
  
    /* 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 */
      PS_Decoder*  decoder = font->decoder;
  
      FT_Bool  needExtraSetup = FALSE;
  
      CFF_VStoreRec*  vstore;
      FT_Bool         hasVariations = FALSE;
  
      /* character space units */
      CF2_Fixed  boldenX = font->syntheticEmboldeningAmountX;
      CF2_Fixed  boldenY = font->syntheticEmboldeningAmountY;
  
      CFF_SubFont  subFont;
      CF2_Fixed    ppem;
  
      CF2_UInt   lenNormalizedV = 0;
      FT_Fixed*  normalizedV    = NULL;
  
      /* clear previous error */
      font->error = FT_Err_Ok;
  
      /* if a CID fontDict has changed, we need to recompute some cached */
      /* data                                                            */
      subFont = cf2_getSubfont( decoder );
      if ( font->lastSubfont != subFont )
      {
        font->lastSubfont = subFont;
        needExtraSetup    = TRUE;
      }
  
      if ( !font->isT1 )
      {
        FT_Service_CFFLoad  cffload = (FT_Service_CFFLoad)font->cffload;
  
  
        /* check for variation vectors */
        vstore        = cf2_getVStore( decoder );
        hasVariations = ( vstore->dataCount != 0 );
  
        if ( hasVariations )
        {
  #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
          /* check whether Private DICT in this subfont needs to be reparsed */
          font->error = cf2_getNormalizedVector( decoder,
                                                 &lenNormalizedV,
                                                 &normalizedV );
          if ( font->error )
            return;
  
          if ( cffload->blend_check_vector( &subFont->blend,
                                            subFont->private_dict.vsindex,
                                            lenNormalizedV,
                                            normalizedV ) )
          {
            /* blend has changed, reparse */
            cffload->load_private_dict( decoder->cff,
                                        subFont,
                                        lenNormalizedV,
                                        normalizedV );
            needExtraSetup = TRUE;
          }
  #endif
  
          /* copy from subfont */
          font->blend.font = subFont->blend.font;
  
          /* clear state of charstring blend */
          font->blend.usedBV = FALSE;
  
          /* initialize value for charstring */
          font->vsindex = subFont->private_dict.vsindex;
  
          /* store vector inputs for blends in charstring */
          font->lenNDV = lenNormalizedV;
          font->NDV    = normalizedV;
        }
      }
  
      /* 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 = (FT_Bool)( 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 =
          (FT_Bool)( 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,
                                font->darkenParams );
        }
        else
          cf2_computeDarkening( emRatio,
                                ppem,
                                font->stdVW,
                                &font->darkenX,
                                0,
                                font->stemDarkened,
                                font->darkenParams );
  
  #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 > MUL_INT32( 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,
                              font->darkenParams );
  
        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 );
  
      } /* needExtraSetup */
    }
  
  
    /* 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 */
  

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