Re: cursor doesn't show through transparent images in emacs 22, unlike emacs 21

[David Kastrup <dak@gnu.org>]

storm@cua.dk (Kim F. Storm) writes:

> "Ken Manheimer" <ken.manheimer@gmail.com> writes:
>
>> as i think i suggested in a previous message, the solution i would
>> prefer would be to have some way to qualify icons so that they get a
>> solid cursor in their transparent areas, and the default would be to
>> have it inactive.  eg, a qualifier for xpm, png, gif, and other
>> transparent-capable images, like :solid-cursor:
>>
>> `:solid-cursor-shows BOOLEAN'
>>       When true, the cursor will appear solid through the transparent
>> regions of the image
>>       when the cursor is situated on the image and the window is
>> active.  The default is for
>>       only the cursor border to show, whether or not the window is active.
>>
>> by having the default be off, then the disruption of oversize blinking
>> icons will be avoided.
>
> Below is a patch which adds a new image :cursor property where you can
> specify the actual type of cursor to show on the image in the selected
> window (that is more flexible than your suggestion, and just as easy
> to do).
>
> Due to limitations in what cursors can be displayed for an image (bar
> and hbar both gives a solid box??), it only works to set it to
> box, hollow, and t (which means use whatever cursor-type is in the
> buffer).
>
>
> As an additional part of the patch, it only changes the cursor
> from box to hollow for images which as greater than 4 times the
> frame's default font size i.e. small images will behave like
> normal glyphs with respect to the box cursor.
>
>
> We can use either or both methods -- WDYT ?

I don't like the hardwired factor of 4: after all, nothing like this
will be applied if you use large fonts.  I think we should try to make
characters and images behave comparably.  Having a general size
limitation variable available for block cursors, whether we are
talking images or characters, would be more consistent.

This size limitation could be specified as either float (multiple of
default font size) or integer (pixels?  Or 10ths of points?).

Of course, if an image has no transparency, we probably need to use a
box cursor, anyway.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum