393904 - entering chinese text into the toolbar search field leaves artifacts and produces spacing problems

Status: RESOLVED WORKSFORME

(Core :: General, defect)

Description

[Alexander Poquet]

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.6) Gecko/20070725 Firefox/2.0.0.6
Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.6) Gecko/20070725 Firefox/2.0.0.6

Often, when entering Chinese text into the toolbar search field, especially when entering simplified Chinese characters, Firefox will fail to advance the cursor past those characters (ie, the glyphs are drawn, but they are internally treated as if they are zero width).  If I continue typing at this point, the characters I just typed will be overwritten, although internally they remain in the buffer (making this a rendering problem only -- I may not be able to read what I type afterwards, but after pressing return, the search proceeds correctly).

Similarly, if I type some characters that Firefox fails to advance the cursor for, backspacing will not clear them off the screen (it does, however, remove them from the buffer -- again, a rendering problem only).  They will remain there until I type some text which is long enough to draw over them.  I will provide some screenshots.

I suspect this bug is related to bug 386568.

Reproducible: Always

Steps to Reproduce:
1. Type 徐静蕾 传记 in the Google toolbar, for example.
2. Notice that the last two characters are displayed, but after being typed, the cursor remains in front of 传记, rather than after it, as it should be.
3. For kicks, try hitting the backspace key.  Notice that parts of "徐静蕾" are erased, but "传记" remains -- but note that if you press return and allow the Google search to go forward, 传记 was actually deleted -- Firefox just didn't display it.
4. Note that no matter how many times you press backspace, "传记" remains in exactly the same position, until you type something that overwrites it.
Actual Results:  
See above...

Expected Results:  
Clearly, what is displayed in the search toolbar ought to be the same as what Firefox has internally in its buffer.  The latter is correct, but the rendering is broken.

Comment 1

[Alexander Poquet]

Attachment: Typing out 徐静蕾 传记 in the search toolbar -- so far so good.

Comment 2

[Alexander Poquet]

Attachment: The whole thing, typed out. You can't see it in this capture, but the cursor is *before* 传记 here

Comment 3

[Alexander Poquet]

Attachment: The situation after hitting backspace a few times -- notice that 传记 does not disappear

Comment 4

[Alexander Poquet]

Attachment: Here, I'm typing over the artifact left by my original entry.

Comment 5

[:Gavin Sharp [email: [e-mail]]]

Does this only happen in the search bar, or in other textboxes too (e.g. the URL bar)?

Comment 6

[Alexander Poquet]

It appears to happen in the URL bar as well... actually, now that I test it, it happens in any single-line textbox, including ones embedded in HTML documents (for example, the one at www.google.com).  It does not, however, happen in multiline textboxes like the one I'm using to add this comment.

Comment 7

[:Gavin Sharp [email: [e-mail]]]

Does it happen in a trunk build, like the one available at  http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-trunk/ ?

Comment 8

[Alexander Poquet]

No, it doesn't -- it works perfectly on the nightly I just downloaded.  That's great!  This version also appears to fix bug 386568, which I'm also watching, so I'll go mention that there.  Thanks a bunch!  I'll just keep the alpha around for now.

Comment 9

[Jason Bassford]

As this has already been fixed, but the patch that fixed it hasn't been identified, this should be:

-> WORKSFORME