Custom Gesture for Increase the size of the view - ios

Question

How can i write custom gesture for increase the size of the view in all the direction (i.e) in origin side and size of the view.
Example:
the user should touch the view in any one of the corner. either near to origin side or view end side.
Example: View frame size is (100,100,200,200). and minimum touch distance is 15 pixel from any side.
so, if the user touch location is (X=15,Y=40) in
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
method means that touch near to the origin side.
same if the user touch location is (X=15, Y=190) in
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
method means the touch is near to the size side.
My code:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesBegan:touches withEvent:event];
if([touches count] != self.touchMinimumCount ||
[[touches anyObject] tapCount] > self.tapMinimumCount)
{
self.state = UIGestureRecognizerStateFailed;
return;
}
self.startPoint = [[touches anyObject] locationInView:self.view];
self.viewFrame = self.view.frame;
if(((self.startPoint.x - self.view.bounds.origin.x) <= self.minimumTouchDistance) ||
((self.startPoint.y - self.view.bounds.origin.y) <= self.minimumTouchDistance) ||
((ABS(self.startPoint.x - self.view.bounds.size.width)) <= self.minimumTouchDistance) ||
((ABS(self.startPoint.y - self.view.bounds.size.height)) <= self.minimumTouchDistance))
{
self.state = UIGestureRecognizerStatePossible;
if(((self.startPoint.x - self.view.bounds.origin.x) <= self.minimumTouchDistance) ||
((self.startPoint.y - self.view.bounds.origin.y) <= self.minimumTouchDistance) )
{
self.currentTouchPosition = touchPositionIsOrigin;
}
else if(((ABS(self.startPoint.x - self.view.bounds.size.width)) <= self.minimumTouchDistance) ||
((ABS(self.startPoint.y - self.view.bounds.size.height)) <= self.minimumTouchDistance))
{
self.currentTouchPosition = touchPositionIsSize;
}
}
else
{
self.state = UIGestureRecognizerStateFailed;
}
}
My gesture possible state setting if the touch in side the touch distance only.
Now i want to resize the view frame according to the user finger move.
if the user touch the origin side and move towards the left direction means, want to change the origin.x of the view and the width also want to increase.
if the user touch the origin side and move towards the top direction means, want to change the origin.y of the view and the width also want to increase.
if the user touch the origin side and move towards the right direction means, want to change the origin.x of the view.
if the user touch the origin side and move towards the bottom direction means, want to change the origin.y of the view.
if the user touch the size side and move towards the left direction means, want to reduce the width of the view.
if the user touch the size side and move towards the top direction means, want to reduce the height of the view.
if the user touch the size side and move towards the right direction means, want to increase the width of the view.
if the user touch the size side and move towards the bottom direction means, want to increase the height of the view.
this all change according tho the user finger in that view while moving.
My code:
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesMoved:touches withEvent:event];
if(self.state == UIGestureRecognizerStateFailed) return;
direction currentDirection;
CGPoint currentLocation = [[touches anyObject] locationInView:self.view];
if(self.state == UIGestureRecognizerStatePossible ||
self.state == UIGestureRecognizerStateChanged)
{
if((currentLocation.x - self.startPoint.x) > 0)
{
currentDirection = directionRight;
self.state = UIGestureRecognizerStateChanged;
if(self.currentTouchPosition == touchPositionIsOrigin)
{
distanceInOriginX = // need to implement.
distanceInSizeX = // need to implement.
}
else if(self.currentTouchPosition == touchPositionIsSize)
{
distanceInSizeX = // need to implement.
}
}
else if((currentLocation.x - self.startPoint.x) < 0)
{
currentDirection = directionLeft;
self.state = UIGestureRecognizerStateChanged;
if(self.currentTouchPosition == touchPositionIsOrigin)
{
distanceInOriginX = // need to implement.
distanceInSizeX = // need to implement.
}
else if(self.currentTouchPosition == touchPositionIsSize)
{
distanceInSizeX = // need to implement.
}
}
else if((currentLocation.y - self.startPoint.y) >= 0)
{
currentDirection = directionBottom;
self.state = UIGestureRecognizerStateChanged;
if(self.currentTouchPosition == touchPositionIsOrigin)
{
distanceInOriginY = // need to implement.
distanceInSizeY = // need to implement.
}
else if(self.currentTouchPosition == touchPositionIsSize)
{
distanceInSizeY = // need to implement.
}
}
else if((currentLocation.y - self.startPoint.y) < 0)
{
currentDirection = directionTop;
self.state = UIGestureRecognizerStateChanged;
if(self.currentTouchPosition == touchPositionIsOrigin)
{
distanceInOriginY = // need to implement.
distanceInSizeY = // need to implement.
}
else if(self.currentTouchPosition == touchPositionIsSize)
{
distanceInSizeY = // need to implement.
}
}
else
{
currentDirection = directionUnknown;
}
self.originPoint = CGPointMake(distanceInOriginX, distanceInOriginY);
self.sizePoint = CGPointMake(distanceInSizeX, distanceInSizeY);
}
}
i mentioned the // need to implement. where ever i want the code for to achieve the functionality which i mentioned in that points. so, kindly help to go ahed.
if my was is wrong means, share the best way to do the same type of gesture.
any example is there also kindly share here. thanks in advance....

Answer 1

If you want to scale the size of a view, then use UIPinchGestureRecognizer. An example code is given here
UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:#selector(scale:)];
pinchRecognizer.delegate = self;
[self addGestureRecognizer:pinchRecognizer];
handler method is
#pragma mark - Gesture handling functions
-(void)scale:(UIPinchGestureRecognizer*)recognizer {
if ([recognizer state] == UIGestureRecognizerStateBegan) {
_lastScale = 1.0;
}
CGFloat scale = 1.0 - (_lastScale - [recognizer scale]);
CGAffineTransform currentTransform = self.imgView.transform;
CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, scale, scale);
self.imgView.transform = newTransform;
_lastScale = [recognizer scale];
}