Re: PNG image files with alpha channel

[Jason Rumney]

Miles Bader wrote:

> Perhaps there's some header info that emacs wants which isn't there?
>
> I write the header like:
>
>   png_set_IHDR (libpng_struct, libpng_info, width, height,
>                 8, PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
>                 PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
>   png_set_gAMA (libpng_struct, libpng_info, gamma_correction);
>   

Is there any program that can dump a PNG header in some readable format, 
so we can compare yours with the image that Gimp saves?

Or maybe someone needs to step through the PNG display code in Emacs, 
and see where it (or libpng) makes the wrong decision.