Rotate, scale and drag more than one UIImageView

[Sketchiie]

I've got one UIImageView which you can scale, rotate or move. But now I want to move, scale and rotate two or more objects. I tried the following code, but it doesn't work.

    - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    	
    	NSArray *allTouches = [touches allObjects];
    	
    	UITouch* t;
    	if([[event allTouches] count]==1){
    		if (CGRectContainsPoint([Birdie frame], [[allTouches objectAtIndex:0] locationInView:theimageView]) && (CGRectContainsPoint([imageViewauto frame], [[allTouches objectAtIndex:1] locationInView:theimageView])) {
    			t=[[[event allTouches] allObjects] objectAtIndex:0];
    			touch1=[t locationInView:nil];
    		}
    	}else{
    		t=[[[event allTouches] allObjects] objectAtIndex:0];
    		touch1=[t locationInView:nil];
    		t=[[[event allTouches] allObjects] objectAtIndex:1];
    		touch2=[t locationInView:nil];
    	}
    }
    
    -(double)distance:(CGPoint)point1 toPoint:(CGPoint)point2
    {
    	double deltaX, deltaY;
    	deltaX = point1.x - point2.x;
    	deltaY = point1.y - point2.y;
    	return sqrt(deltaX * deltaX + deltaY * deltaY);
    }
    
    - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    	
    	CGPoint currentTouch1;
    	CGPoint currentTouch2;
    	NSArray *allTouches = [touches allObjects];
    	UITouch* t;
    	float scale,rotation;
    	
    	if([[event allTouches] count]==1){
    		t=[[[event allTouches] allObjects] objectAtIndex:0];
    		if (CGRectContainsPoint([Birdie frame], [[allTouches objectAtIndex:0] locationInView:theimageView]) && CGRectContainsPoint([imageViewauto frame], [[allTouches objectAtIndex:1] locationInView:theimageView]))
    		{ 
    			touch2=[t locationInView:nil];
    			Birdie.center=CGPointMake(Birdie.center.x+touch2.x-touch1.x,Birdie.center.y+touch2.y-touch1.y);
    			touch1=touch2;
    		}
    	}
    	else if([[event allTouches] count]==2)
    	{
    		t=[[[event allTouches] allObjects] objectAtIndex:0];
    		currentTouch1=[t locationInView:nil];
    		
    		t=[[[event allTouches] allObjects] objectAtIndex:1];
    		currentTouch2=[t locationInView:nil];
    		
    		double distance1 =  [self distance:currentTouch1 toPoint:currentTouch2];
    		double distance2 = [self distance:touch1 toPoint:touch2];
    		
    		if (distance2 == 0)
    		{
    			//handle the case where distance is zero
    		}
    		else {
    			scale =distance1 / distance2;}
    
    		rotation=atan2(currentTouch2.y-currentTouch1.y, currentTouch2.x-currentTouch1.x)-atan2(touch2.y-touch1.y,touch2.x-touch1.x);
    		if(isnan(scale)){
    			scale=1.0f;
    		}
    		NSLog(@"rotation %f",rotation);
    		
    		NSLog(@"scale %f",scale);
    		
    		if (CGRectContainsPoint([Birdie frame], [[allTouches objectAtIndex:0] locationInView:theimageView]) && CGRectContainsPoint([imageViewauto frame], [[allTouches objectAtIndex:1] locationInView:theimageView]))
    		{
    			
    			Birdie.transform=CGAffineTransformScale(Birdie.transform, scale,scale);
    			Birdie.transform=CGAffineTransformRotate(Birdie.transform, rotation);
    
    			imageViewauto.transform=CGAffineTransformScale(imageViewauto.transform, scale,scale);
    			imageViewauto.transform=CGAffineTransformRotate(imageViewauto.transform, rotation);
    		}
    		else // In case of scaling or rotating the background imageView
    		{
    			imageView.transform=CGAffineTransformScale(imageView.transform, scale,scale);
    			imageView.transform=CGAffineTransformRotate(imageView.transform, rotation);
    
    imageViewauto.transform=CGAffineTransformScale(imageViewauto.transform, scale,scale);
    			imageViewauto.transform=CGAffineTransformRotate(imageViewauto.transform, rotation);
    		}
    		
    		touch1=currentTouch1;
    		touch2=currentTouch2;
    	}
    }

The first UIImageView is called Birdie, this one worked before. But the one I wanted to add is called imageViewauto.

Thanks in advanced!

[Sketchiie]

I've got it so far that I can move, scale and rotate all the objects, but the multiple objects all move together. I want them to move seperate. I guess I have to change the objectatIndex to 1, but it just crashes.

I've used the following code:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
	
	NSArray *allTouches = [touches allObjects];
	
	UITouch* t;
	if([[event allTouches] count]==1){
		if (CGRectContainsPoint([Birdie frame], [[allTouches objectAtIndex:0] locationInView:theimageView]) && CGRectContainsPoint([imageViewauto frame], [[allTouches objectAtIndex:0] locationInView:theimageView])) {
			t=[[[event allTouches] allObjects] objectAtIndex:0];
			touch1=[t locationInView:nil];
		}
	}else{
		t=[[[event allTouches] allObjects] objectAtIndex:0];
		touch1=[t locationInView:nil];
		t=[[[event allTouches] allObjects] objectAtIndex:1];
		touch2=[t locationInView:nil];
	}
}

-(double)distance:(CGPoint)point1 toPoint:(CGPoint)point2
{
	double deltaX, deltaY;
	deltaX = point1.x - point2.x;
	deltaY = point1.y - point2.y;
	return sqrt(deltaX * deltaX + deltaY * deltaY);
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
	
	CGPoint currentTouch1;
	CGPoint currentTouch2;
	NSArray *allTouches = [touches allObjects];
	UITouch* t;
	float scale,rotation;
	
	if([[event allTouches] count]==1){
		t=[[[event allTouches] allObjects] objectAtIndex:0];
		if (CGRectContainsPoint([Birdie frame], [[allTouches objectAtIndex:0] locationInView:theimageView]) && CGRectContainsPoint([imageViewauto frame], [[allTouches objectAtIndex:0] locationInView:theimageView]))
		{ 
			touch2=[t locationInView:nil];
			Birdie.center=CGPointMake(Birdie.center.x+touch2.x-touch1.x,Birdie.center.y+touch2.y-touch1.y);
			imageViewauto.center=CGPointMake(imageViewauto.center.x+touch2.x-touch1.x,imageViewauto.center.y+touch2.y-touch1.y);
			touch1=touch2;
		}
	}
	else if([[event allTouches] count]==2)
	{
		t=[[[event allTouches] allObjects] objectAtIndex:0];
		currentTouch1=[t locationInView:nil];
		
		t=[[[event allTouches] allObjects] objectAtIndex:1];
		currentTouch2=[t locationInView:nil];
		
		double distance1 =  [self distance:currentTouch1 toPoint:currentTouch2];
		double distance2 = [self distance:touch1 toPoint:touch2];
		
		if (distance2 == 0)
		{
			//handle the case where distance is zero
		}
		else {
			scale =distance1 / distance2;}

		rotation=atan2(currentTouch2.y-currentTouch1.y, currentTouch2.x-currentTouch1.x)-atan2(touch2.y-touch1.y,touch2.x-touch1.x);
		if(isnan(scale)){
			scale=1.0f;
		}
		NSLog(@"rotation %f",rotation);
		
		NSLog(@"scale %f",scale);
		
		if (CGRectContainsPoint([Birdie frame], [[allTouches objectAtIndex:0] locationInView:theimageView]) && CGRectContainsPoint([imageViewauto frame], [[allTouches objectAtIndex:0] locationInView:theimageView]))
		{
			
			Birdie.transform=CGAffineTransformScale(Birdie.transform, scale,scale);
			Birdie.transform=CGAffineTransformRotate(Birdie.transform, rotation);
			
			imageViewauto.transform=CGAffineTransformScale(imageViewauto.transform, scale,scale);
			imageViewauto.transform=CGAffineTransformRotate(imageViewauto.transform, rotation);
		}
		else // In case of scaling or rotating the background imageView
		{
			imageView.transform=CGAffineTransformScale(imageView.transform, scale,scale);
			imageView.transform=CGAffineTransformRotate(imageView.transform, rotation);
		}
		
		touch1=currentTouch1;
		touch2=currentTouch2;
	}
}

[Duncan C]

Originally Posted by Sketchiie

I've got it so far that I can move, scale and rotate all the objects, but the multiple objects all move together. I want them to move seperate. I guess I have to change the objectatIndex to 1, but it just crashes.

I've used the following code:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
	
	NSArray *allTouches = [touches allObjects];
	
	UITouch* t;
	if([[event allTouches] count]==1){
		if (CGRectContainsPoint([Birdie frame], [[allTouches objectAtIndex:0] locationInView:theimageView]) && CGRectContainsPoint([imageViewauto frame], [[allTouches objectAtIndex:0] locationInView:theimageView])) {
			t=[[[event allTouches] allObjects] objectAtIndex:0];
			touch1=[t locationInView:nil];
		}
	}else{
		t=[[[event allTouches] allObjects] objectAtIndex:0];
		touch1=[t locationInView:nil];
		t=[[[event allTouches] allObjects] objectAtIndex:1];
		touch2=[t locationInView:nil];
	}
}

-(double)distance:(CGPoint)point1 toPoint:(CGPoint)point2
{
	double deltaX, deltaY;
	deltaX = point1.x - point2.x;
	deltaY = point1.y - point2.y;
	return sqrt(deltaX * deltaX + deltaY * deltaY);
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
	
	CGPoint currentTouch1;
	CGPoint currentTouch2;
	NSArray *allTouches = [touches allObjects];
	UITouch* t;
	float scale,rotation;
	
	if([[event allTouches] count]==1){
		t=[[[event allTouches] allObjects] objectAtIndex:0];
		if (CGRectContainsPoint([Birdie frame], [[allTouches objectAtIndex:0] locationInView:theimageView]) && CGRectContainsPoint([imageViewauto frame], [[allTouches objectAtIndex:0] locationInView:theimageView]))
		{ 
			touch2=[t locationInView:nil];
			Birdie.center=CGPointMake(Birdie.center.x+touch2.x-touch1.x,Birdie.center.y+touch2.y-touch1.y);
			imageViewauto.center=CGPointMake(imageViewauto.center.x+touch2.x-touch1.x,imageViewauto.center.y+touch2.y-touch1.y);
			touch1=touch2;
		}
	}
	else if([[event allTouches] count]==2)
	{
		t=[[[event allTouches] allObjects] objectAtIndex:0];
		currentTouch1=[t locationInView:nil];
		
		t=[[[event allTouches] allObjects] objectAtIndex:1];
		currentTouch2=[t locationInView:nil];
		
		double distance1 =  [self distance:currentTouch1 toPoint:currentTouch2];
		double distance2 = [self distance:touch1 toPoint:touch2];
		
		if (distance2 == 0)
		{
			//handle the case where distance is zero
		}
		else {
			scale =distance1 / distance2;}

		rotation=atan2(currentTouch2.y-currentTouch1.y, currentTouch2.x-currentTouch1.x)-atan2(touch2.y-touch1.y,touch2.x-touch1.x);
		if(isnan(scale)){
			scale=1.0f;
		}
		NSLog(@"rotation %f",rotation);
		
		NSLog(@"scale %f",scale);
		
		if (CGRectContainsPoint([Birdie frame], [[allTouches objectAtIndex:0] locationInView:theimageView]) && CGRectContainsPoint([imageViewauto frame], [[allTouches objectAtIndex:0] locationInView:theimageView]))
		{
			
			Birdie.transform=CGAffineTransformScale(Birdie.transform, scale,scale);
			Birdie.transform=CGAffineTransformRotate(Birdie.transform, rotation);
			
			imageViewauto.transform=CGAffineTransformScale(imageViewauto.transform, scale,scale);
			imageViewauto.transform=CGAffineTransformRotate(imageViewauto.transform, rotation);
		}
		else // In case of scaling or rotating the background imageView
		{
			imageView.transform=CGAffineTransformScale(imageView.transform, scale,scale);
			imageView.transform=CGAffineTransformRotate(imageView.transform, rotation);
		}
		
		touch1=currentTouch1;
		touch2=currentTouch2;
	}
}

I'm not clear on what you want to do. You want to be able to put your fingers on multiple objects simultaneously and drag them all around the screen independently of each other? And you want to be able to scale and rotate all the objects at the same time too? That sounds like it would be confusing to the user, and also very hard to sort out programmatically. Would the user do pinch/rotate gestures on multiple objects at once? I don't think it's really practical to do a pinch/rotate gesture with any fingers other than index finger and thumb, and then you need your other hand to hold the device.

If you do want to support something complex like this, you first need to think through, in great detail, exactly what you want the multiple gestures to do, and how you would distinguish between different combinations of gestures, like touching and dragging multiple objects at once vs. pinch/zooming a single object with two fingers.

Once you've figured out the UI you want, you'd need to roll up your sleeves and figure out how to code it. I haven't done a lot of multi-touch gestures outside of the standard ones, so I don't have a lot of specific experience to offer. The documentation seems pretty good, though, and I've always been able to figure it out when I have something I need to implement.

[BlackBook]

This is awesome! Thank you so for sharing!

[Duncan C]

Originally Posted by Harlow58

you want to be able to scale and rotate all the objects at the same time too? That sounds like it would be confusing to the user, and also very hard to sort out programmatically.

Is there an echo in here? Are you a copy/paste bot?