Adjust drawing positions and glyph metrics to fit entire glyph within drawn area, better align to baseline.

Includes code to extract glyph metrics, but the results don't match anything I'd expect so I'm not using them.

1 files changed, 29 insertions, 8 deletions

diff --git a/platform/darwin/src/local_glyph_rasterizer.mm b/platform/darwin/src/local_glyph_rasterizer.mm
index f7304b18f4..043b91fdd5 100644
--- a/platform/darwin/src/local_glyph_rasterizer.mm
+++ b/platform/darwin/src/local_glyph_rasterizer.mm
@@ -47,14 +47,15 @@ Glyph LocalGlyphRasterizer::rasterizeGlyph(const FontStack&, GlyphID glyphID) {
     Glyph fixedMetrics;
     fixedMetrics.id = glyphID;
 
-    fixedMetrics.metrics.width = 24;
-    fixedMetrics.metrics.height = 24;
-    fixedMetrics.metrics.left = 0;
-    fixedMetrics.metrics.top = -8;
+    uint32_t width = 40;
+    uint32_t height = 40;
+    
+    fixedMetrics.metrics.width = width;
+    fixedMetrics.metrics.height = height;
+    fixedMetrics.metrics.left = 3;
+    fixedMetrics.metrics.top = -1;
     fixedMetrics.metrics.advance = 24;
 
-    uint32_t width = 30;
-    uint32_t height = 30;
     Size size(width, height);
 
     fixedMetrics.bitmap = AlphaImage(size);
@@ -114,12 +115,32 @@ Glyph LocalGlyphRasterizer::rasterizeGlyph(const FontStack&, GlyphID glyphID) {
 
     CTLineRef line = CTLineCreateWithAttributedString(attrString); // TODO: Get glyph runs (for metric extraction) and use showGlyphs API instead?
 
+    CFArrayRef glyphRuns = CTLineGetGlyphRuns(line);
+    CFIndex runCount = CFArrayGetCount(glyphRuns);
+    assert(runCount == 1);
+    CTRunRef run = (CTRunRef)CFArrayGetValueAtIndex(glyphRuns, 0);
+    CFIndex glyphCount = CTRunGetGlyphCount(run);
+    assert(glyphCount == 1);
+    const CGGlyph *glyphs = CTRunGetGlyphsPtr(run);
+
+    CGRect boundingRects[1];
+    boundingRects[0] = CGRectMake(0, 0, 0, 0);
+    CGSize advances[1];
+    advances[0] = CGSizeMake(0,0);
+    CGRect totalBoundingRect = CTFontGetBoundingRectsForGlyphs(font, kCTFontOrientationDefault, glyphs, boundingRects, 1);
+    double totalAdvance = CTFontGetAdvancesForGlyphs(font, kCTFontOrientationDefault, glyphs, advances, 1);
+    
+    // Break in the debugger to see these values: translating from "user coordinates" to bitmap pixel coordinates
+    // should be OK, but a lot of glyphs seem to have empty bounding boxes...?
+    (void)totalBoundingRect;
+    (void)totalAdvance;
+    
     // Set text position and draw the line into the graphics context
-    CGContextSetTextPosition(*context, 0.0, 0.0);
+    CGContextSetTextPosition(*context, 0.0, 10.0);
     CTLineDraw(line, *context);
+    
     CFRelease(line);
     CFRelease(font);
-    CFRelease(string); // TODO: Surely leaking something here, wrap these up!
     
     for (uint32_t i = 0; i < width * height; i++) {
         fixedMetrics.bitmap.data[i] = image.data[4 * i + 3]; // alpha value