606022 - "ASSERTION: Cannot draw partial ligatures without a dirty rect" with astral han in svg:text

Status: RESOLVED FIXED

(Core :: SVG, defect)

Description

[Jesse Ruderman]

Attachment: testcase

###!!! ASSERTION: Cannot draw partial ligatures without a dirty rect: 'Error', file gfx/thebes/gfxFont.cpp, line 3129

Comment 1

[Jonathan Kew [:jfkthame]]

Sounds like the SVG text-drawing code is iterating over the text in 16-bit code units, without checking for surrogate pairs.

(Actually, for better results it should probably iterate by default grapheme clusters rather than by characters, so that e.g. diacritics stay properly associated with their base letters. Hmm.... yes, note the comment "should make this iterate clusters instead" at http://mxr.mozilla.org/mozilla-central/source/layout/svg/base/src/nsSVGGlyphFrame.cpp#87.)

Comment 2

[Simon Montagu :smontagu]

The testcase doesn't assert in trunk (it also doesn't display anything, but that seems to be because the text is outside the viewport).

Fixed by bug 621918.

Comment 3

[Simon Montagu :smontagu]

Attachment: Astral characters on a path (RTL and LTR)

This is a nice showcase for Jonathan's and my recent SVG fixes.