gfx/cairo/dwrite-glyph-extents.patch

   1 diff --git a/gfx/cairo/cairo/src/cairo-dwrite-font.cpp b/gfx/cairo/cairo/src/cairo-dwrite-font.cpp
   2 --- a/gfx/cairo/cairo/src/cairo-dwrite-font.cpp
   3 +++ b/gfx/cairo/cairo/src/cairo-dwrite-font.cpp
   4 @@ -582,22 +582,37 @@ _cairo_dwrite_scaled_font_init_glyph_met
   5      DWRITE_FONT_METRICS fontMetrics;
   6      font_face->dwriteface->GetMetrics(&fontMetrics);
   7      HRESULT hr = font_face->dwriteface->GetDesignGlyphMetrics(&charIndex, 1, &metrics);
   8      if (FAILED(hr)) {
   9         return CAIRO_INT_STATUS_UNSUPPORTED;
  10      }
  11
  12      // TODO: Treat swap_xy.
  13 -    extents.width = (FLOAT)(metrics.advanceWidth - metrics.leftSideBearing - metrics.rightSideBearing) / fontMetrics.designUnitsPerEm;
  14 -    extents.height = (FLOAT)(metrics.advanceHeight - metrics.topSideBearing - metrics.bottomSideBearing) / fontMetrics.designUnitsPerEm;
  15 +    extents.width = (FLOAT)(metrics.advanceWidth - metrics.leftSideBearing - metrics.rightSideBearing) /
  16 +        fontMetrics.designUnitsPerEm;
  17 +    extents.height = (FLOAT)(metrics.advanceHeight - metrics.topSideBearing - metrics.bottomSideBearing) /
  18 +        fontMetrics.designUnitsPerEm;
  19      extents.x_advance = (FLOAT)metrics.advanceWidth / fontMetrics.designUnitsPerEm;
  20      extents.x_bearing = (FLOAT)metrics.leftSideBearing / fontMetrics.designUnitsPerEm;
  21      extents.y_advance = 0.0;
  22 -    extents.y_bearing = (FLOAT)(metrics.topSideBearing - metrics.verticalOriginY) / fontMetrics.designUnitsPerEm;
  23 +    extents.y_bearing = (FLOAT)(metrics.topSideBearing - metrics.verticalOriginY) /
  24 +        fontMetrics.designUnitsPerEm;
  25 +
  26 +    // We pad the extents here because GetDesignGlyphMetrics returns "ideal" metrics
  27 +    // for the glyph outline, without accounting for hinting/gridfitting/antialiasing,
  28 +    // and therefore it does not always cover all pixels that will actually be touched.
  29 +    if (scaled_font->base.options.antialias != CAIRO_ANTIALIAS_NONE &&
  30 +        extents.width > 0 && extents.height > 0) {
  31 +        extents.width += scaled_font->mat_inverse.xx * 2;
  32 +        extents.x_bearing -= scaled_font->mat_inverse.xx;
  33 +        extents.height += scaled_font->mat_inverse.yy * 2;
  34 +        extents.y_bearing -= scaled_font->mat_inverse.yy;
  35 +    }
  36 +
  37      _cairo_scaled_glyph_set_metrics (scaled_glyph,
  38                                      &scaled_font->base,
  39                                      &extents);
  40      return CAIRO_INT_STATUS_SUCCESS;
  41  }
  42
  43  /**
  44   * Stack-based helper implementing IDWriteGeometrySink.