How to get rotated image of imageview in uiview? - ios

Question

I created RotatedView subclass of UIView and added UIImageView as subview of RotatedView and also draw a image on RotatedView using drawRect: method same as image of imageView. I applied pinch and rotate gestures on imageView. When i pinch the imageView drawing image is also changed. But when i rotate the imageView, the drawing image is not changed. I used following code::
- (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];
}
How do i get rotate image in UIView when the imageView is rotated?
**
Edited:
**
I got solution using first method. Now i am using second method. I think this is simple and best but I am not sure which one is best. In second method, image is rotated but not at center point. I am struggle to solve this problem. Please help me.
Modifying methods are:
- (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;
}

Answer 1

You need to use CGContextScaleCTM and CGContextRotateCTM (and possibly to appropriately transform your CGContextRef to match your UIImageView's transform.
Take a look at the Quartz 2D Programming Guide

Answer 2

Ok. Finally i got it using ANImageBitmapRep. I declared lastRotation, angle,rotateMe in RotatedView.h class.
-(void)rotationMethod:(UIRotationGestureRecognizer *)gestureRecognizer{
if ([gestureRecognizer state]==UIGestureRecognizerStateBegan) {
if (!rotateMe) {
rotateMe = [[ANImageBitmapRep alloc] initWithImage:displayImageView.image];
}else{
rotateMe =[ANImageBitmapRep imageBitmapRepWithImage:displayImageView.image];
}
}
CGFloat rotation = 0.0 - (lastRotation - [gestureRecognizer rotation]);
CGAffineTransform currentTransform = [gestureRecognizer view].transform;
CGAffineTransform newTransform = CGAffineTransformRotate(currentTransform,rotation);
[[gestureRecognizer view] setTransform:newTransform];
lastRotation = [gestureRecognizer rotation];
angle =lastRotation * (180 / M_PI);
[self setNeedsDisplay];
}
- (void)drawRect:(CGRect)rect
{
CGRect imageRect = CGRectMake(0, 0, 90, 90);
// 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);
UIImage *rotatedImage1=[UIImage imageWithCGImage:[rotateMe imageByRotating:angle]];
CGContextDrawImage(context, imageRect, rotatedImage1.CGImage);
}
I find this solution. If anyone find best solution, give me suggestions according this problem.