DWrite: Inflate glyph bounds 1px vertically too

The most top and bottom lines of glyphs were clipped in some fonts and
conditions. The glyph bounds were inflated 1px horizontally. It should
inflate vertically too.

Fixes cairo/cairo#569

1 files changed, 9 insertions, 4 deletions

diff --git a/src/win32/cairo-dwrite-font.cpp b/src/win32/cairo-dwrite-font.cpp
index 438bfb15d..33c976e08 100644
--- a/src/win32/cairo-dwrite-font.cpp
+++ b/src/win32/cairo-dwrite-font.cpp
@@ -716,10 +716,15 @@ _cairo_dwrite_scaled_font_init_glyph_metrics(cairo_dwrite_scaled_font_t *scaled_
     // We pad the extents here because GetDesignGlyphMetrics returns "ideal" metrics
     // for the glyph outline, without accounting for hinting/gridfitting/antialiasing,
     // and therefore it does not always cover all pixels that will actually be touched.
-    if (scaled_font->base.options.antialias != CAIRO_ANTIALIAS_NONE &&
-	extents.width > 0 && extents.height > 0) {
-	extents.width += scaled_font->mat_inverse.xx * 2;
-	extents.x_bearing -= scaled_font->mat_inverse.xx;
+    if (extents.width > 0 && extents.height > 0) {
+	double x = 1, y = 1;
+	cairo_matrix_transform_distance (&scaled_font->mat_inverse, &x, &y);
+	x = fabs(x);
+	y = fabs(y);
+	extents.width += x * 2;
+	extents.x_bearing -= x;
+	extents.height += y * 2;
+	extents.y_bearing -= y;
     }
 
     _cairo_scaled_glyph_set_metrics (scaled_glyph,