577065 - bitmap font rendering problem on WinXP (overlapping letters)

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Ekanan Ketunuti]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:2.0b1) Gecko/20100630 Firefox/4.0b1
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:2.0b1) Gecko/20100630 Firefox/4.0b1

wrong rendering if webpage use MS Sans Serif font. http://www.tfex.co.th/tfex/dailyMarketReport.html

Reproducible: Always

Comment 1

[Ekanan Ketunuti]

Attachment: MS Sans Serif font rendering problem

Comment 2

[Marek Raida]

Yes, I agree, this bug https://bugzilla.mozilla.org/show_bug.cgi?id=436788 has returned. I'm uploading simplified testcase... In 1.9.2, in 1.9.3 broken...

Comment 3

[Marek Raida]

Attachment: Bad rendering of font MS Sans Serif in current Gecko 1.9.3

Comment 5

[Joe Drew (not getting mail)]

John, can you take a look at this once we have a regression window?

Comment 6

[j.j.]

Attachment: testcase with more broken fonts

Mozilla/5.0 (Windows; Windows NT 5.1; en-US; rv:2.0b2pre) Gecko/20100719 Minefield/4.0b2pre

Seems all Type 1 Fonts are broken. I see this bug with
 "MS Serif", "Roman", "Small Fonts", "System",
 also "Script" and "Modern".

Comment 7

[j.j.]

Attachment: testcase with more broken fonts

(this is the right one, sorry)

Comment 8

[John Daggett (:jtd)]

Tested trunk on Windows7, all the testcases look fine.  I suspect this is an XP-only regression related to the fix for bug 561304:

http://hg.mozilla.org/mozilla-central/rev/31c52b96e75e

Checkin date was 6/25.

Comment 9

[John Daggett (:jtd)]

Attachment: screenshot, testcase with broken fonts on win xp

Mozilla/5.0 (Windows; Windows NT 5.1; en-US; rv:2.0b2pre) Gecko/20100712 Minefield/4.0b2pre (.NET CLR 3.5.30729)

Comment 10

[John Daggett (:jtd)]

Yup, as suspected...

Rendering fine:
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.3a6pre) Gecko/20100624 Minefield/3.7a6pre (.NET CLR 3.5.30729)

Rendering wankered:
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.3a6pre) Gecko/20100626 Minefield/3.7a6pre (.NET CLR 3.5.30729)

Comment 11

[John Daggett (:jtd)]

Attachment: testcase, bitmap fonts with both GDI and Uniscribe rendering

Clearly it's the GDI rendering path that has the problem, Uniscribe looks fine.

Comment 12

[John Daggett (:jtd)]

The 1.9.2 Windows font code contains this comment:

// GetGlyphIndices is buggy for bitmap and vector fonts, so send them to uniscribe
// Also sent Symbol fonts through Uniscribe as it has special code to deal with them
if (!aFont->GetFontEntry()->IsTrueType() || aFont->GetFontEntry()->mSymbolFont)
    return PR_FALSE;

http://mxr.mozilla.org/mozilla1.9.2/source/gfx/thebes/src/gfxWindowsFonts.cpp#1555

Code to shunt bitmap/vectors fonts to Uniscribe wasn't carried over to the new gfxGDIFont code but since Uniscribe was enabled by default the bug was masked until bug 561304 forced us to use GDI on XP.

Comment 13

[John Daggett (:jtd)]

Attachment: patch, force bitmap fonts to uniscribe path

Fixes the wacky rendering problems but some fallback problems remain for MS Sans Serif, MS Serif and Courier.

Comment 14

[Jonathan Kew [:jfkthame]]

Comment on attachment 458594 [details] [diff] [review]
patch, force bitmap fonts to uniscribe path

This looks fine (though all these contortions make me sad - we should be able to just use Uniscribe for all fonts!)

Comment 15

[John Daggett (:jtd)]

Pushed to trunk
http://hg.mozilla.org/mozilla-central/rev/9a81894fc687