Only increase height or width using pinch gesture [duplicate] - objective-c

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Closed 10 years ago.
Possible Duplicate:
Using UIPinchGestureRecognizer to scale uiviews in single direction
My code is below:
UIPinchGestureRecognizer *croperViewGessture = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:#selector(croperViewScale:)];
croperViewGessture.delegate=self;
[croperView addGestureRecognizer:croperViewGessture];
-(void)CanvasScale:(id)sender
{
if([(UIPinchGestureRecognizer *)sender state]==UIGestureRecognizerStateBegan)
{
if ([sender numberOfTouches] == 2) {
_pntOrig[0] = [(UIPinchGestureRecognizer *)sender locationOfTouch:0 inView:cropedAngle];
_pntOrig[1] = [(UIPinchGestureRecognizer *)sender locationOfTouch:1 inView:cropedAngle];
} else {
_pntOrig[0] = [(UIPinchGestureRecognizer *)sender locationInView:cropedAngle];
_pntOrig[1] = _pntOrig[0];
}
_lenOrigX = fabs(_pntOrig[1].x - _pntOrig[0].x);
_lenOrigY = fabs(_pntOrig[1].y - _pntOrig[0].y);
_xScale = 1.0;
_yScale = 1.0;
}
if ([(UIPinchGestureRecognizer *)sender state] == UIGestureRecognizerStateChanged) {
if ([sender numberOfTouches] == 2) {
CGPoint pntNew[2];
pntNew[0] = [(UIPinchGestureRecognizer *)sender locationOfTouch:0 inView:cropedAngle];
pntNew[1] = [(UIPinchGestureRecognizer *)sender locationOfTouch:1 inView:cropedAngle];
CGFloat lenX = fabs(pntNew[1].x - pntNew[0].x);
CGFloat lenY = fabs(pntNew[1].y - pntNew[0].y);
CGFloat dX = fabs(lenX - _lenOrigX);
CGFloat dY = fabs(lenY - _lenOrigY);
CGFloat tot = dX + dY;
CGFloat pX = dX / tot;
CGFloat pY = dY / tot;
CGFloat scale = [(UIPinchGestureRecognizer *)sender scale];
CGFloat dscale = scale - 1.0;
_xScale = dscale * pX + 1;
_yScale = dscale * pY + 1;
}
}
CGAffineTransform transform = cropedAngle.transform;
CGAffineTransform newTarnsform = CGAffineTransformScale(transform, _lenOrigX, _lenOrigY);
[cropedAngle setTransform:newTarnsform];
}
But problem is that when I do Zoomin OR Zoomout then view spread on all over the screen and after it disable Please view my code and tell me what is wrong .
Please help me in this issue
i am Thankfull in advance.

Answer 1

I wrote my own custom extension to UIPinchGestureRecognizer to provide an xScale and a yScale, in addition to the normal scale. This is a drop in replacement for UIPinchGestureRecognizer. You now have the option of looking at the normal scale or the new xScale and yScale. Use these values accordingly to scale your view based on how the user does the pinch gesture.
RMPinchGestureRecognizer.h
#import <Foundation/Foundation.h>
#import <UIKit/UIGestureRecognizerSubclass.h>
#interface RMPinchGestureRecognizer : UIPinchGestureRecognizer {
CGPoint _pntOrig[2];
CGFloat _lenOrigX;
CGFloat _lenOrigY;
CGFloat _xScale;
CGFloat _yScale;
}
#property (nonatomic, readonly) CGFloat xScale;
#property (nonatomic, readonly) CGFloat yScale;
#end
RMPinchGestureRecognizer.m
#import "RMPinchGestureRecognizer.h"
#implementation RMPinchGestureRecognizer
#synthesize xScale = _xScale;
#synthesize yScale = _yScale;
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesMoved:touches withEvent:event];
if (self.state == UIGestureRecognizerStateChanged) {
if ([self numberOfTouches] == 2) {
CGPoint pntNew[2];
pntNew[0] = [self locationOfTouch:0 inView:self.view];
pntNew[1] = [self locationOfTouch:1 inView:self.view];
CGFloat lenX = fabs(pntNew[1].x - pntNew[0].x);
CGFloat lenY = fabs(pntNew[1].y - pntNew[0].y);
CGFloat dX = fabs(lenX - _lenOrigX);
CGFloat dY = fabs(lenY - _lenOrigY);
CGFloat tot = dX + dY;
CGFloat pX = dX / tot;
CGFloat pY = dY / tot;
CGFloat scale = [self scale];
CGFloat dscale = scale - 1.0;
_xScale = dscale * pX + 1;
_yScale = dscale * pY + 1;
}
}
}
- (void)setState:(UIGestureRecognizerState)state {
if (state == UIGestureRecognizerStateBegan) {
if ([self numberOfTouches] == 2) {
_pntOrig[0] = [self locationOfTouch:0 inView:self.view];
_pntOrig[1] = [self locationOfTouch:1 inView:self.view];
} else {
_pntOrig[0] = [self locationInView:self.view];
_pntOrig[1] = _pntOrig[0];
}
_lenOrigX = fabs(_pntOrig[1].x - _pntOrig[0].x);
_lenOrigY = fabs(_pntOrig[1].y - _pntOrig[0].y);
_xScale = 1.0;
_yScale = 1.0;
}
[super setState:state];
}
#end

Answer 2

Take a look HERE
Your line CGAffineTransformScale(transform, scaleTemp,scaleTemp); uses the same scaleTemp variable to modify both the x and y values of the transform.