533631 - Cursor gradually becomes completely inaccurate as more text is added to a single line

Status: RESOLVED INVALID

(Skywriter Graveyard :: Editor, defect)

Description

[Andrew Petersen]

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_2; en-us) AppleWebKit/531.21.8 (KHTML, like Gecko) Version/4.0.4 Safari/531.21.10
Build Identifier: BespinEmbedded 0.5



As you type on a single line, the cursor alignment becomes completely inaccurate compared to kerning, as if it's not using a monospaced font for calculating cursor position. After about 30-40 characters, the cursor is at least 30 pixels off. I have only seen this on Windows XP, in Firefox 3.5 and Chrome 3, untested in IE (obviously). On a mac, the alignment is as expected in every browser (Safari 4, Firefox 3.5, Chome 3 developer).



Reproducible: Always

Steps to Reproduce:
1. In google wave, create a new wave
2. Add the BespinWave experimental gadget by clicking the "add gadget by url" button in the wave editor toolbar, and use the following url: http://johnnytatlock.com/svn/BespinWave/trunk/BespinWave.xml (it's a slow server, give it time).
3. Begin typing, and notice that after a few characters the cursor become misaligned with the text.
Actual Results:  
On a mac, everything is as expected. On a PC running Windows XP, the misalignment increases exponentially as more characters are added to a single line. 

Expected Results:  
Proper cursor alignment: the cursor is between letters, not on top of them or in empty space.

This has only been observed by me in Wave, and only on a Windows XP computer.

Comment 1

[James Cox]

I can confirm this behavior in Chromium 5.0.330.0 on Linux (Mint) x86_64, works fine in Firefox 3.5.7.  

I'm not familiar with how you calculate the x-position of your cursor.  But you could perhaps do it by calculating the length of the sub-string up to the cursors position.

Comment 2

[Andrew Petersen]

I'm not actually calculating anything, just relying on Bespin's internal mechanisms.

Comment 3

[Gordon P. Hemsley [:GPHemsley]]

Does this still occur in the latest version of Bespin (currently 0.6.2)?

Comment 4

[Kevin Dangoor]

ACETRANSITION

The Skywriter project has merged with Ajax.org's Ace project (the full server part of which is their Cloud9 IDE project). Background on the change is here:

http://mozillalabs.com/skywriter/2011/01/18/mozilla-skywriter-has-been-merged-into-ace/

The bugs in the Skywriter product are not necessarily relevant for Ace and quite a bit of code has changed. For that reason, I'm closing all of these bugs. Problems that you have with Ace should be filed in the Ace issue tracker at GitHub:

https://github.com/ajaxorg/ace/issues