[Git][freetype/freetype][wl/sbix] [truetype] Fix 'sbix' table handling.

Werner Lemberg pushed to branch wl/sbix at FreeType / FreeType

Commits:

747cb143

by Werner Lemberg at 2022-02-07T22:08:16+01:00

[truetype] Fix 'sbix' table handling.

* src/sfnt/sfobjs.c (sfnt_load_face): Don't set `has_outline` for 'sbix'
embedded bitmaps.
* src/sfnt/ttsbit.c (tt_face_load_sbix_image): Correct calculation of
'metrics->horiBearingY'.

* src/truetype/ttgload.c (TT_Load_Glyph): For 'sbix' embedded bitmaps, apply
bbox offset and bearing values of the corresponding glyph in the 'glyf'
table if it exists and has a contour.

Fixes issue #998.

3 changed files:

src/sfnt/sfobjs.c
src/sfnt/ttsbit.c
src/truetype/ttgload.c

Changes:

src/sfnt/sfobjs.c

@@ -851,12 +851,6 @@
      is_apple_sbit = 0;
      is_apple_sbix = !face->goto_table( face, TTAG_sbix, stream, 0 );
 -    /* Apple 'sbix' color bitmaps are rendered scaled and then the 'glyf'
 -     * outline rendered on top.  We don't support that yet, so just ignore
 -     * the 'glyf' outline and advertise it as a bitmap-only font. */
 -    if ( is_apple_sbix )
 -      has_outline = FALSE;
+-
      /* if this font doesn't contain outlines, we try to load */
      /* a `bhed' table                                        */
      if ( !has_outline && sfnt->load_bhed )

src/sfnt/ttsbit.c

@@ -1587,7 +1587,7 @@
        tt_face_get_metrics( face, FALSE, glyph_index, &abearing, &aadvance );
        metrics->horiBearingX = (FT_Short)originOffsetX;
 -      metrics->horiBearingY = (FT_Short)( -originOffsetY + metrics->height );
 +      metrics->horiBearingY = (FT_Short)( originOffsetY + metrics->height );
        metrics->horiAdvance  = (FT_UShort)( aadvance *
                                             face->root.size->metrics.x_ppem /
                                             face->header.Units_Per_EM );

src/truetype/ttgload.c

@@ -2899,6 +2899,9 @@
+       {
          if ( FT_IS_SCALABLE( glyph->face ) )
+         {
 +          TT_Face  face = (TT_Face)glyph->face;
++
++
            /* for the bbox we need the header only */
            (void)tt_loader_init( &loader, size, glyph, load_flags, TRUE );
            (void)load_truetype_glyph( &loader, glyph_index, 0, TRUE );
@@ -2906,6 +2909,27 @@
            glyph->linearHoriAdvance = loader.linear;
            glyph->linearVertAdvance = loader.vadvance;
 +          /* bitmaps from the `sbix' table need special treatment:  */
 +          /* if there is a glyph contour, the bitmap origin must be */
 +          /* shifted to be relative to the lower left corner of the */
 +          /* glyph bounding box, also taking the left-side bearing  */
 +          /* (or top bearing) into account                          */
 +          if ( face->sbit_table_type == TT_SBIT_TABLE_TYPE_SBIX &&
 +               loader.n_contours > 0                            )
 +          {
 +            FT_Int  bitmap_left = loader.bbox.xMin;
 +            FT_Int  bitmap_top  = loader.bbox.yMin;
++
++
 +            if ( load_flags & FT_LOAD_VERTICAL_LAYOUT )
 +              bitmap_top += loader.top_bearing;
 +            else
 +              bitmap_left += loader.left_bearing;
++
 +            glyph->bitmap_left += FT_MulFix( bitmap_left, x_scale ) >> 6;
 +            glyph->bitmap_top  += FT_MulFix( bitmap_top,  y_scale ) >> 6;
 +          }
++
            /* sanity checks: if `xxxAdvance' in the sbit metric */
            /* structure isn't set, use `linearXXXAdvance'      */
            if ( !glyph->metrics.horiAdvance && glyph->linearHoriAdvance )

From:	Werner Lemberg (@wl)
Subject:	[Git][freetype/freetype][wl/sbix] [truetype] Fix 'sbix' table handling.
Date:	Mon, 07 Feb 2022 21:08:39 +0000