Re: misplaced cursor when a double-width character is near the lower-right corner

[Benno Schulenberg]

Op 27-01-2021 om 14:20 schreef sunnycemetery@gmail.com:
> 2021-01-13, 12:28, Benno Schulenberg:
>> When a double-width character is close to the right edge of the bottom row 
>> of a
>> subwindow, and a single-width character is added, then the cursor can get
>> misplaced, resulting in a misdrawing of the content when a further character 
>> is
>> added.
> 
> I recently noticed similar misbehavior in my own ncurses programs using 6.2,
> although not with the cursor but with character placement using wmove 
> followed by
> waddwstr.

On the bottom row?  Near the right edge?  And with a double-width character
involved?  On what terminal?

> Interestingly, executing "mvwchgat (p, bottom, 0, width, WA_REVERSE,
> 1, NULL)" on such a pad seems to move affected characters into their correct
> columns.

That is not a surprise.  If small movements near the right edge have caused
ncurses to lose track of where exactly the cursor is (and thus misplacing
some characters), restarting at the left edge and writing the full width
will draw all characters in their proper place.

> Have you been
> able to reproduce this using any of the example programs?

I wouldn't know where to start looking.

Benno

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