CGAffineTransformRotate 之后对 UIImage 进行 TouchMoved 拖动导致图像旋转离开屏幕
我不知道为什么在 UIImageView 上调用这个 CGAffineTransform 方法然后尝试拖动它后，会导致它旋转出视图。任何帮助表示赞赏。
- (void)setRotation:(Float32)rotation {
CGAffineTransform transform = CGAffineTransformIdentity;
transform = CGAffineTransformMakeTranslation(0.0,0.0);
transform = CGAffineTransformRotate(transform, degreesToRadians(rotation));
[self setTransform:transform];
}
- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event {
CGPoint pt = [[touches anyObject] locationInView:self];
CGRect frame = [self frame];
frame.origin.x += pt.x - startLocation.x;
frame.origin.y += pt.y - startLocation.y;
[self setFrame:frame];
}
I'm not sure why after calling this CGAffineTransform method on a UIImageView and then trying to drag it, causes it to spin out of view. Any help is appreciated.
- (void)setRotation:(Float32)rotation {
CGAffineTransform transform = CGAffineTransformIdentity;
transform = CGAffineTransformMakeTranslation(0.0,0.0);
transform = CGAffineTransformRotate(transform, degreesToRadians(rotation));
[self setTransform:transform];
}
- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event {
CGPoint pt = [[touches anyObject] locationInView:self];
CGRect frame = [self frame];
frame.origin.x += pt.x - startLocation.x;
frame.origin.y += pt.y - startLocation.y;
[self setFrame:frame];
}
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如果
transform属性不是标识，则frame属性未定义。您不应该从中读取或写入。相反，您应该使用center和bounds属性。同样在您的
-setRotation中，前两行是无用的。第一行分配一个值，然后被第二行覆盖。第二行的最终效果是将身份分配回变量（0, 0 的翻译是什么）。该方法可以只是If the
transformproperty is anything other than the identity, theframeproperty is undefined. You should not read from it or write to it. Instead you should use thecenterandboundsproperties.Also in your
-setRotation, the first 2 lines are useless. The first line assigns a value, which is then overwritten by the second line. The second line's net effect is to assign the identity back to the variable (a translation of 0, 0 is nothing). The method could instead just be