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

[David Kastrup]

Richard Stallman <address@hidden> writes:

>     > What exactly is the workaround you recommend?
>
>     Use :mask ...
>
> Then how about changing the default value for :mask?

There is no sensible default.  What is useful as a mask depends on the
image in question.  Using heuristic-mask can mean that the whole image
flashes, but it can also mean that just a single corner pixel blinks.

Even when a mask is specified, using the whole mask as a cursor
indication is not a good idea, since a large image with a background
will then flash horribly.  The right fix in my opinion would be to use
the border of the image (extending into the image itself if the border
is too small, overwriting the image when no mask is given, but maybe
heeding the mask if it is given).  For a block cursor, there should be
a maximum number of pixels that is affected.  If this number is
exceeded, a box cursor would be used with a thickness that does not
cause the number of pixels to exceed the threshold, but lets it have
at least the thickness of a box cursor + 1 pixel.

Something like that.  Yes, sounds tiresome.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum