AffineTransform a CGPoint

Question

我整个早上都在做研究。到目前为止还没有运气。我试图围绕我的视图中心旋转一个CGPoint。

以下是我为UIBezierPath所做的工作：

CGRect bounds = self.bounds; // might want to use CGPathGetPathBoundingBox
CGPoint center = CGPointMake(CGRectGetMidX(bounds), CGRectGetMidY(bounds));
CGAffineTransform transform = CGAffineTransformIdentity;
transform = CGAffineTransformTranslate(transform, center.x, center.y);
transform = CGAffineTransformRotate(transform, DEGREES_TO_RADIANS(degreesOfRotation));
transform = CGAffineTransformTranslate(transform, -center.x, -center.y);
currentLayer.path = CGPathCreateCopyByTransformingPath(pathTwo.CGPath, &transform);

效果很好。我找到了这篇文章，What is the best way to rotate a CGPoint on a grid?，但它只是不起作用。

我真的需要一种方法来旋转CGPoint在我的边界中心。

有什么想法吗？

Answer 1

计算转换的代码是正确的。您所需要做的就是将转换应用到重点上。

CGRect bounds = self.bounds;
CGPoint center = CGPointMake(CGRectGetMidX(bounds), CGRectGetMidY(bounds));
CGAffineTransform transform = CGAffineTransformIdentity;
transform = CGAffineTransformTranslate(transform, center.x, center.y);
transform = CGAffineTransformRotate(transform, DEGREES_TO_RADIANS(degreesOfRotation));
transform = CGAffineTransformTranslate(transform, -center.x, -center.y);

CGPoint point = CGPointMake(bounds.size.width - 10, center.y);  // some point
CGPoint point2 = CGPointApplyAffineTransform(point, transform); // some point rotated about the center of the view