[cairo] how to interprete extents of rotated path

Behdad Esfahbod behdad at behdad.org
Mon May 26 14:55:06 PDT 2008

On Mon, 2008-05-26 at 22:07 +0200, Theo Veenker wrote:
> Hi,
> I'm trying to get the bounding box of a path using cairo_stroke_extents().
> The returned numbers are OK when the path is not rotated, but when it is
> rotated the bounding box returned doesn't make sense to me.
> See http://www.let.uu.nl/~Theo.Veenker/personal/extents/ for my test
> program and two images.

Ugh.  Didn't know about this.

> What am I doing wrong here?

Nothing.  Wrong is the way we compute things internally.  It's the same
effect that I explained here, in another context:


Just last night I was thinking about writing a stroke/path extents
implementation that works on the double path directly, without any
tesselation.  That can easily fix this problem.

> Theo


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 Temporary Safety, deserve neither Liberty nor Safety."
        -- Benjamin Franklin, 1759

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