Re: Several suggestions for image support

[Jason Rumney]

David Kastrup wrote:

> Hmmm.  Do you have any evidence of it working?

When I wrote the image support for Windows, I tested a wide range of PNG 
test images. PNG support appears to be broken in the Windows port now 
though, as all images with transparency or alpha channels are appearing 
inverted. This may be something to do with the bug that YAMAMOTO 
Mitsuharu just pointed out.

> Anyway: if :heuristic-mask is true, but the majority of corner pixels
> is transparent, it would be nice if just transparency was used as the
> mask criterion.
>
> That way I get at least a heuristic mask if the image
> creating process does not support transparency, but get the
> transparence if it is available in the image.  It is not always easy
> to know in advance.

I see the problem. You don't want to have to know in advance whether the 
image has transparency or not.

What about: if the image already has a mask (due to the fact it is a 
transparent image), any heuristic mask property should be ignored. Would 
that be better than relying on corner pixels being transparent?