196748 - text cursor off by one at end of string in text box; XORs with last character, sometimes hard to read

Status: VERIFIED DUPLICATE of bug 98564

(Core :: DOM: Editor, defect)

Description

[Daniel B.]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.3b) Gecko/20030210
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.3b) Gecko/20030210

In a text box for an input element of type "text", when the insertion point is 
after the last character, the text cursor seems to be drawn one pixel to the 
left(*) of where it should be.  For small fonts, the overlap of the text
cursor with the last character frequently makes that last character unreadable.

(*Assuming a left-to-right language.)




Reproducible: Always

Steps to Reproduce:
1. Display a web page with a text box (<input type="text" ...>) or a text area
   ("<textarea ...>").  A box or area with a small, non-serif font show the 
   problem more clearly.  The Summary box on this Mozilla bug-reporting page 
   seems to a good example (at least with my font-size settings).

2. In the text box or text area, enter a three or four instances of the same  
   narrow character (e.g., "l", "i" ).

3. Position the text cursor between an adjacent pair of characters.  Notice
   whether and how the text cursor overlaps the preceding character.

4. Position the text cursor between another adjacent pair of characters.  Notice
   that the cursors position with this pair's preceding characters is the same
   as in step 3.

5. Now position the text cursor at the end of the string.  Notice how it 
   overlaps the preceding character differently, being one pixel further to
   the left (relative to that preceding character) than in the previous two 
   cases.

Actual Results:  
The text cursor overlaps the last column of pixels of the last character.  With a
small character (and especially with a sans-serif font), that last character can
be hard to read.


Expected Results:  
I would think you'd want the text cursor to be positioned consistently, and
to not obscure the last character.


Given that cursor positioning with a string seems to be okay, and given that
the change only occurs at the end of the string, I'd guess that there is an
off-by-one error in code that knows about the end of the string.

Comment 1

[Boris Zbarsky [:bzbarsky]]

core editor

Comment 2

[Kathleen :Brade]

dupe

*** This bug has been marked as a duplicate of 98564 ***

Comment 3

[Henrik Skupin [:whimboo][⌚️UTC+2] (away 10/03 - 10/13)]

verified.