[cairo] Too-large transparency groups

James Cloos cloos at jhcloos.com
Wed Jun 19 16:57:16 PDT 2013

I'm told that gecko's bug whereby even a single, small ARGB image
generates full-page transparency groups is definitively in cairo and not
in how gecko calls cairo.

And that bugs have been reported about it.

But I cannot find those bugs searching in the pdf/ps driver categories.

An image, even with alpha, composited onto a constant background should
immediately be blended pixel per pixel, rather than generating a trans-
parency group.  The result of such a blending is fixed; there are no
vector elements, only pixels.

And even if there were, when an alpha-image is pasted atop a background,
the transparency group shouldn't ever need to be larger than the image.

Which is already a raster, and thus doesn't need (or mind :) rasterization.

Does anyone have a pointer?  Thoughts or work towards a fix?

I haven't printed from the web recently, but the last few times I did I
had to print to pdf, edit the pdf to remove the ARGB logo and manualy
convert to ps to get a legible print.

(9600x600 text is a *hell* of a lot easier to read than the blotchy,
blurry crap that results from low-resolution rasters of each page.)

James Cloos <cloos at jhcloos.com>         OpenPGP: 1024D/ED7DAEA6

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