Pinching/Panning a CCNode in Cocos2d 3.0 - ios

Question

I want to zoom in out a CCNode by pinching and panning the screen. The node has a background which is very large but the portionof it shown on the screen. That node also contains other sprites.
What I have done by now is that first I register UIPinchGestureRecognizer
UIPinchGestureRecognizer * pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:#selector(handlePinchFrom:)];
[[[CCDirector sharedDirector] view] addGestureRecognizer: pinchRecognizer];
-(void)handlePinchFrom:(UIPinchGestureRecognizer *) pinch
{
if(pinch.state == UIGestureRecognizerStateEnded) {
prevScale = 1;
}
else {
CGFloat dscale = [self scale] - prevScale + pinch.scale;
if(dscale > 0)
{
deltaScale = dscale;
}
CGAffineTransform transform = CGAffineTransformScale(pinch.view.transform, deltaScale, deltaScale);
[pinch.view setTransform: transform];
// [_contentNode setScale:deltaScale];
prevScale = pinch.scale;
}
}
The problem is that it scalw whole UIView not the CCNode. I have also tried to by setting the scale of my _contentNode.
**EDIT
I ave also tried this
- (void)handlePinchGesture:(UIPinchGestureRecognizer*)aPinchGestureRecognizer
{
if (pinch.state == UIGestureRecognizerStateBegan || pinch.state == UIGestureRecognizerStateChanged) {
CGPoint midpoint = [pinch locationInView:[CCDirector sharedDirector].view];
CGSize winSize = [CCDirector sharedDirector].viewSize;
float x = midpoint.x/winSize.width;
float y = midpoint.y/winSize.height;
_contentNode.anchorPoint = CGPointMake(x, y);
float scale = [pinch scale];
_contentNode.scale *= scale;
pinch.scale = 1;
}
}
But it zoom from the bottom left of the screen.

Answer 1

I had the same problem. I use CCScrollView, that contains CCNode that larger than device screen. I want scroll and zoom it, but node shouldnt scroll out of screen, and scale smaller than screen. So, i create my subclass of CCScrollView, where i handle pinch. It has some strange glitches, but it works fine at all.
When pinch began i set anchor point of my node to pinch center on node space. Then i need change position of my node proportional to shift of anchor point, so moving anchor point doesn't change nodes location on view:
- (void)handlePinch:(UIPinchGestureRecognizer*)recognizer
{
if (recognizer.state == UIGestureRecognizerStateEnded) {
_previousScale = self.contentNode.scale;
}
else if (recognizer.state == UIGestureRecognizerStateBegan) {
float X = [recognizer locationInNode:self.contentNode].x / self.contentNode.contentSize.width;
float Y = [recognizer locationInNode:self.contentNode].y / self.contentNode.contentSize.height;
float positionX = self.contentNode.position.x + self.contentNode.boundingBox.size.width * (X - self.contentNode.anchorPoint.x);
float positionY = self.contentNode.position.y + self.contentNode.boundingBox.size.height * (Y - self.contentNode.anchorPoint.y);
self.contentNode.anchorPoint = ccp(X, Y);
self.contentNode.position = ccp(positionX, positionY);
}
else {
CGFloat scale = _previousScale * recognizer.scale;
if (scale >= maxScale) {
self.contentNode.scale = maxScale;
}
else if (scale <= [self minScale]) {
self.contentNode.scale = [self minScale];
}
else {
self.contentNode.scale = scale;
}
}
}
Also i need change CCScrollView min and max scroll, so my node never scroll out of view. Default anchor point is (0,1), so i need shift min and max scroll proportional to the new anchor point.
- (float) maxScrollX
{
if (!self.contentNode) return 0;
float maxScroll = self.contentNode.boundingBox.size.width - self.contentSizeInPoints.width;
if (maxScroll < 0) maxScroll = 0;
return maxScroll - self.contentNode.boundingBox.size.width * self.contentNode.anchorPoint.x;
}
- (float) maxScrollY
{
if (!self.contentNode) return 0;
float maxScroll = self.contentNode.boundingBox.size.height - self.contentSizeInPoints.height;
if (maxScroll < 0) maxScroll = 0;
return maxScroll - self.contentNode.boundingBox.size.height * (1 - self.contentNode.anchorPoint.y);
}
- (float) minScrollX
{
float minScroll = [super minScrollX];
return minScroll - self.contentNode.boundingBox.size.width * self.contentNode.anchorPoint.x;
}
- (float) minScrollY
{
float minScroll = [super minScrollY];
return minScroll - self.contentNode.boundingBox.size.height * (1 - self.contentNode.anchorPoint.y);
}
UIGestureRecognizerStateEnded doesn't have locationInNode: method, so i added it by category. It just return touch location on node space:
#import "UIGestureRecognizer+locationInNode.h"
#implementation UIGestureRecognizer (locationInNode)
- (CGPoint) locationInNode:(CCNode*) node
{
CCDirector* dir = [CCDirector sharedDirector];
CGPoint touchLocation = [self locationInView: [self view]];
touchLocation = [dir convertToGL: touchLocation];
return [node convertToNodeSpace:touchLocation];
}
- (CGPoint) locationInWorld
{
CCDirector* dir = [CCDirector sharedDirector];
CGPoint touchLocation = [self locationInView: [self view]];
return [dir convertToGL: touchLocation];
}
#end