[英]Limitting UIImageView size while using CGAffineTransform
我想在使用CGAffineTransform时限制uiimageview的大小。 我正在限制比例,但不能限制uiimageview的大小。 当我运行该应用程序时,我看到它受到限制,但是在后台,我的uiimageview的大小一直在增加。 我该怎么做?
这是我的代码:
- (id)initWithFrame:(CGRect)frame
{
if ([super initWithFrame:frame] == nil) {
return nil;
}
originalTransform = CGAffineTransformIdentity;
touchBeginPoints = CFDictionaryCreateMutable(NULL, 0, NULL, NULL);
self.userInteractionEnabled = YES;
self.multipleTouchEnabled = YES;
self.exclusiveTouch = YES;
return self;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSMutableSet *currentTouches = [[[event touchesForView:self] mutableCopy] autorelease];
[currentTouches minusSet:touches];
if ([currentTouches count] > 0) {
[self updateOriginalTransformForTouches:currentTouches];
[self cacheBeginPointForTouches:currentTouches];
}
[super touchesBegan:touches withEvent:event];
[self cacheBeginPointForTouches:touches];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
CGAffineTransform incrementalTransform = [self incrementalTransformWithTouches:[event touchesForView:self]];
self.transform = CGAffineTransformConcat(originalTransform, incrementalTransform);
CGAffineTransform transform = self.transform;
float scale = sqrt(transform.a*transform.a + transform.c*transform.c);
NSLog(@"%f",self.frame.size.height);
if (scale > SCALE_MAX){
self.transform = CGAffineTransformScale(transform, SCALE_MAX/scale, SCALE_MAX/scale);
}
else if (scale < SCALE_MIN){
self.transform = CGAffineTransformScale(transform, SCALE_MIN/scale, SCALE_MIN/scale);
}
[super touchesMoved:touches withEvent:event];
}
-(void)updateOriginalTransformForTouches:(NSSet *)touches{
CGAffineTransform transform = self.transform;
float scale = sqrt(transform.a*transform.a + transform.c*transform.c);
if (scale > SCALE_MAX){
self.transform = CGAffineTransformScale(transform, SCALE_MAX/scale, SCALE_MAX/scale);
}
else if (scale < SCALE_MIN){
self.transform = CGAffineTransformScale(transform, SCALE_MIN/scale, SCALE_MIN/scale);
}
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
for (UITouch *touch in touches) {
if (touch.tapCount >= 2) {
[self.superview bringSubviewToFront:self];
}
}
[self updateOriginalTransformForTouches:[event touchesForView:self]];
[self removeTouchesFromCache:touches];
NSMutableSet *remainingTouches = [[[event touchesForView:self] mutableCopy] autorelease];
[remainingTouches minusSet:touches];
[super touchesEnded:touches withEvent:event];
[self cacheBeginPointForTouches:remainingTouches];
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
[self touchesEnded:touches withEvent:event];
}
您可以CGRect
对UIImagView
进行转换之前了解CGRect
,如下例所示:
//Create transform
CGAffineTransform scaleTransform = CGAffineTransformMakeScale(1.2, 1.2);
//Apply transform on UIImageView to get CGRect
CRect newRect = CGRectApplyAffineTransform(yourImgView.frame, scaleTransform);
//Check if rect is in valid limitation
if(newRect.size.height > 200 && newRect.size.width >200) //your condition to limit UIImageView's Size
{
//Valid so apply transform
yourImageView.transform = scaleTransform
}
else
{
//rect increases so no transform
// no transform to UIImageView
NSLog(@"%@",NSStringFromCGRect(yourImageView.frame))
}
我遇到了类似的问题,我有一个图像视图,该图像根据指南针航向数据旋转,并且还必须根据界面方向上的设备更改来移动位置
我创建了一个tempImageView来帮助维护框架,并随着设备方向的每次更改不断重置它
- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
// equal tempImageView to imageView
_tempImageView = [[UIImageView alloc] initWithFrame:CGRectMake(self.view.frame.size.width-75, 150, 64, 61)];
[_tempImageView setImage:[UIImage imageNamed:@"image.gif"]];
_tempImageView.transform = _imageView.transform;
// reset imageView
[_imageView removeFromSuperview];
_imageView = _tempImageView;
[self.view insertSubview:_imageView atIndex:1];
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.