Re: Cairo with GTK GUI integration, getting inverse transformation matrix

Lawrence D'Oliveiro <[email protected]> Tue, 19 Jan 2016 12:35:53 +1300

Newsgroups	gmane.comp.lib.cairo
Organization	Geek Central
Message-ID	<[email protected]>

On Tue, 19 Jan 2016 00:05:31 +0100, Johannes Bauer wrote:

> I noticed the cairo_ctx matrix is pre-set to accomodate for the window
> (i.e. already has the correct panning displacement accounted for). So
> it's unwise to just overwrite it (messes up the coordinate system).

But you should still be able to make temporary changes to it, bracketed
by cairo_save()/cairo_restore(). Within these, you can use
cairo_translate/scale/rotate/transform
<http://cairographics.org/manual/cairo-Transformations.html> to
concatenate additional transformations onto the existing matrix.
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