[Gtk-sharp-list] [gtk-sharp] Matrix.Scale and Context.Scale anomaly?
hywel.w.thomas at gmail.com
Thu Apr 11 19:03:54 UTC 2013
Answering my own question, I have just realised that although scaling
with a zero value for sx or sy is valid mathematically, the resulting
matrix is non-invertible, and so gets picked up by Context.Scale, giving
an error immediately (rather than perhaps later down the line, in a more
obscure situation). Perhaps this might help others who wonder what is
On 11/04/13 13:14, Hywel wrote:
> Using a Cairo.Matrix.Scale (sx, sy) with a zero value for either sx or
> sy gives the correct result (the Xx or the Yy component of the matrix
> is zero'd), but using Context.Scale with either zero value for sx or
> sy gives the wrong result for the Context Transformation Matrix.
> There seems to be no valid reason why these should differ
> (mathematically they are valid, though perhaps unlikely, operations).
> I'm not sure how the two functions call back into the Cairo 'C' code -
> can anyone help or shed any light on this apparent anomaly?
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