On Oct 1, 2011, at 3:14 PM, Florian Berger wrote:
When such an image is scaled down a little and exported as PNG, it shows some poor interpolation artefacts. These artefacts are less obvious or not present in the actual Inkscape display, but very visible after export.
Yes, interactive display vs. export do hit different code paths.
Here is an illustriation of the problem:
http://img594.imageshack.us/img594/769/inkscapeinterpolation.png
(Please view at original size first to prevent additional interpolation.)
Thanks, that is very helpful.
Please note that some of these interpolations do not seem to make sense, e.g. using bright grey in the brown / dark red hair of the character.
Tricky code paths. Not sure if it's GTK, pixbuf, cairo or which. But is something we can track down.
I am very aware that Inkscape may not be the weapon of choice for this kind of operation. Still, my questions:
- Is there any way to prevent Inkscape from interpolation /
anti-aliasing upon exporting such an image?
There's not a good way at the moment. However, I think this is basically the same issue people hit with regards to blurry text.
- If this is an interpolation issue: why does Inkscape use such
inappropriate colors?
It's definitely due to one or more of the libraries we use. It definitely looks like a generic algorithm that is probably tuned to give good results for common photos, etc.
- Shall I file a bug? :)
Yes. Though you might see if there is an existing bug about text rendering, sharp edges, interpolation, etc. Getting this working well for you would definitely benefit a large number of people.