[cairo] Where's the bottleneck in using glitz/cairo/librsvg?

[Carl Worth]

On Thu, 8 Jun 2006 09:20:45 +0300, "Koichi Mori" wrote:
> Scaling raster image, especially down scaling, does not necessarily generate
> horrible result if filtered. Even bi-linear filtering should give quite good
> enough quality for icons.

Cairo's software has a bi-linear filter. And when downscaling at a
factor greater than 2 the quality gets increasingly objectionable,
(and quite soon gets to something I would call horrible) . So unless
bi-linear means something very different than what cairo is doing,
it's definitely not sufficient for all downscaling.

Incidentally, this ugly downscaling is one of the few ways in which
cairo will produce poor-quality results even when give high-quality
input[*]. So it's definitely something that I'd like to see fixed in
cairo.

Some people have proposed doing some sort of mip-mapping or Laplacian
pyramid for better-quality downscaling, but I haven't seen any
implementation progress on this front yet.

Anyone still looking for a fun project for the summer?

-Carl

[*] As opposed to getting poor-quality results with poor-quality input
which all operations do---as so amply illustrated by any demo I've
ever written.
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