1287144 - Synthetic bolding of fonts in <canvas> is broken by the switch to Skia canvas backend

Status: RESOLVED DUPLICATE of bug 1287552

(Core :: Graphics: Text, defect)

Description

[Jonathan Kew [:jfkthame]]

See testcase at http://jsfiddle.net/env8zvmd/ (assumes availability of the DejaVu Serif font).

The second line of canvas text, which should be emboldened, is not rendered correctly. The glyph spacing is increased, in line with the expected spacing of emboldened glyphs, but the actual glyphs themselves are not modified; just the regular glyphs are rendered.

In contrast, synthetic bold *does* work as expected for the HTML DOM text in the testcase.

Setting gfx.canvas.azure.backends to 'cairo' results in the expected synthetic bold rendering. So this is a regression from the switch to Skia.

Comment 1

[Lee Salzman [:lsalzman]]

This is because the SkFontHost_cairo backend does not process emboldening yet. That slipped under the radar. I have some in-progress work on revising it to be more feature complete in preparation for Skia content that should resolve this.

Need-infoing myself here to remind me I need to mark this bug as dependent on the SkFontHost_cairo rewrite bug once I set it up.

Comment 2

[Lee Salzman [:lsalzman]]

Need-info: once more, with feeling...

Comment 3

[Lee Salzman [:lsalzman]]

Once bug 1287552 lands, this should be fixed.

Comment 4

[Jonathan Kew [:jfkthame]]

Thanks, Lee. I can confirm this now works correctly in my testing. So I think we can resolve as a dupe of bug 1287552; this was a visible symptom of that underlying problem.