C# rotate bitmap 90 degrees

Question

I\'m trying to rotate a bitmap 90 degrees using the following function. The problem with it is that it cuts off part of the image when the height and width are not equal.

Answer 1

The bug is in your first call to TranslateTransform:

g.TranslateTransform((float)b.Width / 2, (float)b.Height / 2);

This transform needs to be in the coordinate space of returnBitmap rather than b, so this should be:

g.TranslateTransform((float)b.Height / 2, (float)b.Width / 2);

or equivalently

g.TranslateTransform((float)returnBitmap.Width / 2, (float)returnBitmap.Height / 2);

Your second TranslateTransform is correct, because it will be applied before the rotation.

However you're probably better off with the simpler RotateFlip method, as Rubens Farias suggested.