为什么在使用Graphics.ScaleTransform时出现OverflowException？

Question

I have some drawing code for an editor I am working on. It draws a few lines and an image buffer. After adding a zoom features and calling ScaleTransform I get an OverflowException thrown in my paint method.

Is something being scaled outside the bounds? My scaling factor is 2.0 and I have even tried 1.0 and making sure all the window sizes / buffers are large enough.

Answer 1

The Graphics.Transform property is not reset to the identity matrix. You have to do this yourself at the beginning of your paint method:

g.Tranfsorm = new Matrix();
g.ScaleTransform(2.0, 2.0);

Otherwise after a few exponents it will overflow (at 60 frames per second as in my application this would seem instantaneous)