How to calibrate a sprites touchLocation after zoom - ios

Question

I add a sprite on the background sprite and then zoom (pinch) the background and by that the sprite as well.
After the zoom i want to be able to click right on the "zoomed" sprite and then move (pan) it. However, to catch the sprite i have to click outside of the sprite. I guess that is due to the zoom and coordinates.
I would really need some help how to make it so that i always only need to click on the actual sprite if it is in it's original state or zoomed up or down.
I will also implement UIScrollView so i can move around the background but would like to fix this first.
Here is the code i use to test this:
- (void)didMoveToView:(SKView *)view {
_background = [SKSpriteNode spriteNodeWithImageNamed:#"background"];
_background.name = #"background";
[_background setAnchorPoint:CGPointZero];
// _background.anchorPoint = CGPointMake(0.0, 0.1);
self.scaleMode = SKSceneScaleModeResizeFill;
[self addChild:_background];
SKLabelNode *texT = [SKLabelNode labelNodeWithFontNamed:#"Ariel"];
texT.text = #"X";
texT.position = CGPointMake(160, 260);
[_background addChild:texT];
_panGesture = [[UIPanGestureRecognizer alloc]initWithTarget:self action:#selector(handlePan:)];
[self.view addGestureRecognizer:_panGesture];
_pinchGesture = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:#selector(handlePinch:)];
[self.view addGestureRecognizer:_pinchGesture];
/* Setup your scene here */
self.backgroundColor = [SKColor colorWithRed:0.15 green:0.15 blue:0.3 alpha:1.0];
SKSpriteNode *sprite = [SKSpriteNode spriteNodeWithImageNamed:#"Spaceship"];
sprite.xScale = 0.2;
sprite.yScale = 0.2;
sprite.position = CGPointMake(160, 260);
sprite.name = #"sprite";
[_background addChild:sprite];
}
- (void)handlePan:(UIPanGestureRecognizer *)sender {
NSLog(#"handlePan:");
if (![_currentNode.name isEqualToString:#"background"]) {
_touchLocation = [sender locationInView:sender.view];
_touchLocation = [self convertPointFromView:_touchLocation];
_currentNode.position = _touchLocation;
}
}
- (void)handlePinch:(UIPinchGestureRecognizer *) sender {
NSLog(#"handlePinch: %f",sender.scale);
[self runAction:[SKAction scaleBy:sender.scale duration:0]];
sender.scale = 1;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"touchesBegan");
//////DO THE FIRST TOUCH//////
_actualTouch = [touches anyObject];
_touchLocation = [_actualTouch locationInNode:self];
_currentNode = [self nodeAtPoint:_touchLocation];
NSLog(#"TouchBegan:_touchLocation:%#", NSStringFromCGPoint(_touchLocation));
NSLog(#"_currentNode.name: %#", _currentNode.name);
}
#end

Answer 1

I had this same problem and I found that the solution is to resize instead of scale. The physics seem to still work as expected and now the touch events will too. I came across this solution here. The scaleMode in your didMoveToView needs to be changed as well, see below.
self.scaleMode = SKSceneScaleModeAspectFill;
- (void)handlePinch:(UIPinchGestureRecognizer *) sender {
NSLog(#"handlePinch: %f",sender.scale);
//[self runAction:[SKAction scaleBy:sender.scale duration:0]];
self.size = CGSizeMake(self.size.width/sender.scale,self.size.height/sender.scale);
sender.scale = 1;
}
In my own implementation I had set upper and lower limits to the zoom level as well.