[cairo] Problem with PNG file and CAIRO_SCALE

Dov Grobgeld dov.grobgeld at gmail.com
Thu Nov 25 07:09:42 PST 2010

My guess is that the source of the problem is explained in the following
quote from the cairo-xlib-surface documentation:

Currently, only TrueColor visuals are fully supported.

which means that you don't have alpha support when drawing. One way of
solving this is to create a second image surface on which you do your
drawing that you then draw to the xlib-surface without any scaling. This
basically means keeping an entire copy of the window as a backstore image
that you then copy to the xlib-surface when needed.

Perhaps someone else can give a better solution.


On Thu, Nov 25, 2010 at 16:37, fred PPP <fredppp at hotmail.com> wrote:

>  I try to use cairo with X11 ( cairo 1.10.1) .
> If I paint a surface with a  png file and  a scale ( CAIRO_SCALE ) I have
> problem with black lines around the rectangle surface ( verticales and
> horizontales lines).
> i don't have  these lines when i'm no using cairo_scale.
> I  try also  CAIRO_TRANSFORM  but the problem is the same.
> I send  the rar file of the test.
> What are the problem and how can i resolve it ?
> --
> cairo mailing list
> cairo at cairographics.org
> http://lists.cairographics.org/mailman/listinfo/cairo
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