我创建了RotatedView子类UIView并添加UIImageView为子视图，RotatedView并使用与 imageView 的图像相同的方法绘制RotatedView图像drawRect:。我在 imageView 上应用了捏合和旋转手势。当我捏 imageView 绘图图像时也会改变。但是当我旋转 imageView 时，绘图图像不会改变。我使用了以下代码::
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
self.backgroundColor = [UIColor redColor];
imageView = [[UIImageView alloc] initWithFrame:CGRectMake(80, 150, 100, 150)];
imageView.image = [UIImage imageNamed:@"Images_6.jpg"];
imageView.userInteractionEnabled = YES;
[self addSubview:imageView];
UIRotationGestureRecognizer *rotationGesture = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotationMethod:)];
rotationGesture.delegate = self;
[imageView addGestureRecognizer:rotationGesture];
}
return self;
}
- (void)drawRect:(CGRect)rect
{
// Drawing code
CGContextRef context =UIGraphicsGetCurrentContext();
CGRect rectFrame = CGRectMake(0, 0, imageView.frame.size.width, imageView.frame.size.height);
CGContextSetStrokeColorWithColor(context, [UIColor blueColor].CGColor);
CGContextSetLineWidth(context, 10.0);
CGContextBeginPath(context);
CGContextMoveToPoint(context, 0, 0);
CGContextAddLineToPoint(context, 90, 0);
CGContextAddLineToPoint(context, 90, 90);
CGContextAddLineToPoint(context, 0, 90);
CGContextAddLineToPoint(context, 0, 0);
CGContextClip(context);
CGContextStrokePath(context);
CGContextDrawImage(context,rectFrame, imageView.image.CGImage);
}
-(void)rotationMethod:(UIRotationGestureRecognizer *)gestureRecognizer{
NSLog(@"rotationMethod");
if ([gestureRecognizer state]==UIGestureRecognizerStateBegan || [gestureRecognizer state]==UIGestureRecognizerStateChanged) {
CGAffineTransform transform = CGAffineTransformRotate(gestureRecognizer.view.transform, gestureRecognizer.rotation);
gestureRecognizer.view.transform = transform;
[gestureRecognizer setRotation:0];
}
[self setNeedsDisplay];
}
旋转 imageView 时，如何在 UIView 中获取旋转图像？
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编辑：
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我使用第一种方法得到了解决方案。现在我正在使用第二种方法。我认为这是简单和最好的，但我不确定哪个是最好的。在第二种方法中，图像被旋转但不在中心点。我正在努力解决这个问题。请帮我。
修改方法有：
- (void)drawRect:(CGRect)rect
{
NSLog(@"drawRect");
// Drawing code
CGContextRef context =UIGraphicsGetCurrentContext();
CGContextSetStrokeColorWithColor(context, [UIColor blueColor].CGColor);
CGContextSetLineWidth(context, 10.0);
CGContextBeginPath(context);
CGContextMoveToPoint(context, imageRect.origin.x, imageRect.origin.y);
CGContextAddLineToPoint(context, imageRect.size.width, imageRect.origin.y);
CGContextAddLineToPoint(context, imageRect.size.width, imageRect.size.height);
CGContextAddLineToPoint(context, imageRect.origin.x, imageRect.size.height);
CGContextAddLineToPoint(context, imageRect.origin.x, imageRect.origin.y);
CGContextClip(context);
CGContextStrokePath(context);
CGContextDrawImage(context, imageRect, [self rotateImage:imageView.image].CGImage);
}
-(void)rotationMethod:(UIRotationGestureRecognizer *)gestureRecognizer{
NSLog(@"rotationMethod");
if ([gestureRecognizer state]==UIGestureRecognizerStateBegan || [gestureRecognizer state]==UIGestureRecognizerStateChanged) {
CGAffineTransform transform = CGAffineTransformRotate(gestureRecognizer.view.transform, gestureRecognizer.rotation);
gestureRecognizer.view.transform = transform;
lastRotation = gestureRecognizer.rotation;
[gestureRecognizer setRotation:0];
}
[self setNeedsDisplay];
}
- (UIImage *)rotateImage:(UIImage *) img
{
NSLog(@"rotateImage");
CGAffineTransform transform = imageView.transform;
transform = CGAffineTransformTranslate(transform, img.size.width, img.size.height);
transform = CGAffineTransformRotate(transform, lastRotation);
transform = CGAffineTransformScale(transform, -1, -1);
CGContextRef ctx = CGBitmapContextCreate(NULL, img.size.width, img.size.height,
CGImageGetBitsPerComponent(img.CGImage), 0,
CGImageGetColorSpace(img.CGImage),
CGImageGetBitmapInfo(img.CGImage));
CGContextConcatCTM(ctx, transform);
CGContextDrawImage(ctx, CGRectMake(20,20,img.size.width,img.size.height), img.CGImage);
CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
UIImage *newImg = [UIImage imageWithCGImage:cgimg];
CGContextRelease(ctx);
CGImageRelease(cgimg);
return newImg;
}