Antialiasing changes shape color when exported to image file

[Genete]

When rendering a shape to a image file with alpha (png) the anti aliased pixels have a different RGB values than the source which is anti aliased.
Using Inkscape 0.47 build 22583 on Ubuntu 10.04 LTS
Attached is a SVG file to be used.
Steps to show the pixels with different RGB values:
1) Open the attached svg file with Inkscape
2) Export it to image (png) use the entire page.
3) Open the exported image on Gimp
4) On Gimp go to Menu->Layer->Transparency->Threshold Alpha
5) On the pop up dialog select Threshold to be 0 and accept.
6) Notice that the not all the pixels have the same RGB values.

I would expect to have only variations of the alpha value on the rendered image pixels.

[su_v (suv-lp)]

> Attached is a SVG file to be used.

You didn't attach the SVG file - or is you report about how imported bitmap images change when to bitmap in Inkscape?

[Genete (genetita-gmail)]

Sorry I attached the result. Please let me attach the svg later. I'm not on my computer.

[Genete (genetita-gmail)]

That's the needed SVG file.

[su_v (suv-lp)]

Reproduced with Inkscape 0.47, 0.48.0, 0.48.1, 0.48.2 (on Mac OS X 10.5.8):
all exported bitmap images report 7 unique colors in GIMP (2.6.11).

Inkscape 0.48+devel r10697, cairo 1.10.2 differs slightly:
exported bitmap image reports 15 unique colors in GIMP (2.6.11).

Number of unique colors appears to vary depending on the color used in Inkscape (not reproduced e.g. with #ff0000, #00ff00 and #0000ff).

[su_v (suv-lp)]

The color of the background
- default template: white, fully transparent
- sample SVG file: black, fully transparent
does not effect the number of unique colors used in the anti-aliased edges of the shape.

[Beluga (buovjaga)]

Still repro.

Win 7 64-bit
Inkscape 0.92pre1_64bit r15016
GIMP 2.8.14

[su_v (suv-lp)]

Possibly related later report:
* Bug #1660954 “exporting to png produces wrong colours on transparent pixels”
  https://bugs.launchpad.net/inkscape/+bug/1660954