UIImageView Rotation and zooming in iPhone Sdk

Question

i'm implementing zooming and rotation using UIImageview in my project, i'm facing problem in zoom in and zoom out after rotating the image,

Here is my code follows:

in .h file

@interface ViewController : UIViewController{
 float degrees;
 float height;
 float width;

float moveLeft;
float moveRight;
}

@property(nonatomic,retain)UIImageView *imageView;

-(IBAction)rotationLeft:(id)sender;
-(IBAction)rotationRight:(id)sender;
-(IBAction)zoomIn:(id)sender;
-(IBAction)zoomOut:(id)sender;

-(IBAction)moveLeft:(id)sender;
-(IBAction)moveRight:(id)sender; 

in .m file

- (void)viewDidLoad
{
[super viewDidLoad];



height=50;
width=50;
degrees=20;
moveLeft=20;
moveRight=20;
imageView=[[UIImageView alloc]initWithImage:[UIImage imageNamed:@"1.png"]];
imageView.frame=CGRectMake(100, 100,width, height);
[self.view addSubview:imageView];



// Do any additional setup after loading the view, typically from a nib.
}
-(IBAction)rotationLeft:(id)sender{
//the value in degrees
imageView.transform = CGAffineTransformMakeRotation(degrees*M_PI/180);
degrees=degrees+25;
}

-(IBAction)rotationRight:(id)sender{
//the value in degrees
degrees=degrees-25;
imageView.transform = CGAffineTransformMakeRotation(degrees*M_PI/180);

}
-(IBAction)zoomIn:(id)sender{
height=height-15;
width=width-15;
imageView.frame=CGRectMake(100, 100,width, height);
}
-(IBAction)zoomOut:(id)sender{
height=height+15;
width=width+15;
imageView.frame=CGRectMake(100, 100,width, height);
}

Please find the attached image for your reference.

Answer 1

you should use CGAffineTransformMakeScale for zooming purposes, instead of forcing the frame.

define somewhere a global foal x = 1; then:

-(IBAction)zoomIn:(id)sender{
   x += 0.3;
   imageView.transform = CGAffineTransformMakeScale(x, x);
}

-(IBAction)zoomOut:(id)sender{
   x -= 0.3;
   imageView.transform = CGAffineTransformMakeScale(x, x);
}

Answer 2

I would recommend scaling the image using a very similar method to the rotation code that you have:

CGAffineTransformMakeScale(CGFloat sx, CGFloat sy);

Just send it more than 1.0 to scale up and less than 1.0 to scale down;

Answer 3

Below code worked for me perfect!!!

-(IBAction)rotationLeft:(id)sender{
//the value in degrees
    degrees=degrees+25;
    CGAffineTransform t;
    t=CGAffineTransformMakeScale(x, x);
    // imageView.transform = CGAffineTransformMakeRotation(degrees*M_PI/180,x,x);
    imageView.transform=CGAffineTransformRotate(t, degrees*M_PI/180);
}

-(IBAction)rotationRight:(id)sender{
    degrees=degrees-25;
    CGAffineTransform t;
    t=CGAffineTransformMakeScale(x, x);
    imageView.transform=CGAffineTransformRotate(t, degrees*M_PI/180);

 }
 -(IBAction)zoomIn:(id)sender{
    x += 0.3;
    CGAffineTransform t;
    t=CGAffineTransformMakeRotation(degrees*M_PI/180);
    imageView.transform=CGAffineTransformScale(t, x, x);
 }

 -(IBAction)zoomOut:(id)sender{
     x -= 0.3;
    CGAffineTransform t;
    t=CGAffineTransformMakeRotation(degrees*M_PI/180);
    imageView.transform=CGAffineTransformScale(t, x, x);
 }