400351 - Scrolling with Devanagari not rendering correctly

Status: RESOLVED WORKSFORME

(Core :: Graphics, defect)

Description

[John Daggett (:jtd)]

Attachment: First testcase, both refresh and text rendering problem

A page containing Devanagari joiners (two code points that merge to a single glyph) does not render correctly when scrolled.

Steps:

1. Load the first testcase attached
2. Scroll to the bottom using the down arrow on the keyboard

Result: joining does not occur and there are areas of the window that aren't refreshed correctly.  Clicking on the refresh button clears up the display problem but the characters remain unjoined.

Compare this to the second testcase.  This time the text is joined correctly but the refresh problem still occurs.  Playing around with the order of unstyled and styled text runs seems to affect the joining process.  I'm guessing we're doing something wrong in one case and the result gets cached somehow.

Comment 1

[John Daggett (:jtd)]

Attachment: Second testcase, slightly different order of text runs

Comment 2

[John Daggett (:jtd)]

Attachment: first testcase screenshot

Comment 3

[John Daggett (:jtd)]

Attachment: second testcase screenshot, arrow doesn't display correctly

Comment 4

[John Daggett (:jtd)]

Attachment: correct rendering

Comment 5

[John Daggett (:jtd)]

Attachment: Testcase with Arabic

Looks like there's some sort of state that gets kept around, causing joining to stop working after handling the text run that follows "One pair of joiners".

Comment 6

[John Daggett (:jtd)]

Attachment: Testcase with Arabic, with explicit font settings

Appears to be related to the presence of recent versions of Arial or Times New Roman or other fonts that provide cmap entries for Arabic, Devanagari or other complex scripts but do not contain morphing table needed by AAT.

Comment 7

[John Daggett (:jtd)]

Attachment: Testcase with Arabic, with explicit font settings

Testcase requires (1) Times New Roman v. 3.05 and higher and (2) Code 2000 font.  Both are OpenType fonts without morphing tables.

Comment 8

[Robert O'Callahan (:roc) (email my personal email if necessary)]

I guess the default Tiger install is OK. Will Leopard ship with these problematic fonts?

Comment 9

[John Daggett (:jtd)]

The problematic versions of Times New Roman ship with the latest version of MS Office *and* with Leopard but Leopard's version of ATSUMatchFonts seems to be more aware of OpenType fonts and does a better job of not matching against OpenType fonts that don't have AAT morphing tables in font fallback situations. 

Comment 10

[Joe Drew (not getting mail)]

Nightly on both 10.5 and 10.6 seem to work fine on those testcases; I'm presuming this is fixed.