Coordinate Rotation at a Point
Coordinate Rotation at a Point
- Subject: Coordinate Rotation at a Point
- From: Gordon Apple <email@hidden>
- Date: Mon, 05 Nov 2007 23:33:50 -0600
Although I found references to rotating a Bezier path, searching for
rotating coordinates at a point wasn't fruitful. In my case, I wanted to
rotate a shape in place about its center, including shading and/or content.
I believe the following is about as simple as you can get and can be used to
rotate about any point.
@implementation NSAffineTransform (RTPTransformAdditions)
- (void)rotate:(float)angle atPoint:(NSPoint)point
{
[self rotateByDegrees:angle];
NSAffineTransform* pointXfrm = [NSAffineTransform transform];
[pointXfrm rotateByDegrees:-angle]; // Needed to get original
point in rotated coordinates.
NSPoint oldPoint = [pointXfrm transformPoint:point];
float x = oldPoint.x - point.x;
float y = oldPoint.y - point.y;
[self translateXBy:x yBy:y]; // Done in the rotated coordinates.
}
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden