I have this code for gesture in a view
- (void)rightSwipeHandle:(UIPanGestureRecognizer*)gestureRecognizer{
CGPoint touchBegan;
CGPoint pointEnd;
if (gestureRecognizer.state == UIGestureRecognizerStateBegan)
{
CGPoint touchBegan = [gestureRecognizer locationInView: gestureRecognizer.view];
NSLog(#"pointBegan:%#",NSStringFromCGPoint(touchBegan));
}
else if (gestureRecognizer.state == UIGestureRecognizerStateChanged)
{
}
else if (gestureRecognizer.state == UIGestureRecognizerStateEnded ||
gestureRecognizer.state == UIGestureRecognizerStateCancelled ||
gestureRecognizer.state == UIGestureRecognizerStateFailed)
{
pointEnd = [gestureRecognizer locationInView:gestureRecognizer.view];
NSLog(#"pointEnd:%#", NSStringFromCGPoint(pointEnd));
CGFloat xDist = (pointEnd.x - touchBegan.x);
CGFloat yDist = (pointEnd.y - touchBegan.y);
CGFloat distance = sqrt((xDist * xDist) + (yDist * yDist));
NSLog(#"distance:%f", distance);
}
}
but it don't work fine and I don't know where is the problem...
if the swipe is from the bottom to the top, it calculate a distance and if you do the opposite it calculate a big different distance, I don'tr understand
Define the points as static, otherwise the touchBegan point will lose its value. It happens because setting the values of each point occurs in different method calls and with each one, you redefine the points at the beginning.
static CGPoint touchBegan;
static CGPoint pointEnd;
Related
I'm trying to track the horizontal distance that a user has swiped using a UIPanGestureRecognizer, but I'm having difficulty interpreting the results. Here is the code that I am using:
- (IBAction)handlePan:(UIPanGestureRecognizer *)recognizer {
CGPoint startLocation;
if (recognizer.state == UIGestureRecognizerStateBegan) {
startLocation = [recognizer locationInView:self.view];
}
if (recognizer.state == UIGestureRecognizerStateEnded) {
CGPoint stopLocation = [recognizer locationInView:self.view];
CGFloat dx = stopLocation.x - startLocation.x;
NSLog(#"dx: %f", dx);
}
}
If I swipe left-to-right, I get output something like this:
dx: 50328911327402404790403072.000000
My screen is only 320 pixels wide, so my end result cannot be greater than 320. Is there a problem with my code or am I just interpreting this number incorrectly? How can I get this value stated in pixels? Thanks!
startLocation doesn't persist after handlePan: returns, so you're getting garbage.
Either declare startLocation as static or save it in an instance variable / property.
You can use UIPanGestureRecognizer as below:-
CGPoint translatedPoint = [(UIPanGestureRecognizer*)sender translationInView:self.view];
if ([(UIPanGestureRecognizer*)sender state] == UIGestureRecognizerStateBegan) {
firstX = [[sender view] center].x;
firstY = [[sender view] center].y;
}
translatedPoint = CGPointMake(firstX+translatedPoint.x, firstY);
[[sender view] setCenter:translatedPoint];
if ([(UIPanGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) {
CGFloat velocityX = (0.2*[(UIPanGestureRecognizer*)sender velocityInView:self.view].x);
CGFloat finalX = translatedPoint.x + velocityX;
CGFloat finalY = firstY;
I'm trying to use UIPanGestureRecognizer to flip an UIView. I'm using below code to handle flipping the view,
- (void)handlePan:(UIPanGestureRecognizer*)gesture{
CGPoint translation = [gesture translationInView:self.view];
NSLog(#"PAN X VALUE %f", translation.x );
double percentageOfWidth = translation.x / (gesture.view.frame.size.width / 2);
float angle = (percentageOfWidth * 100) * M_PI_2 / 180.0f;
CALayer *layer = testView.layer;
CATransform3D flipTransform = CATransform3DIdentity;
flipTransform.m34 = -0.002f;
flipTransform = CATransform3DRotate(flipTransform, angle, 0.0f, 1.0f, 0.0f);
layer.transform = flipTransform;
}
My problem is when i pan, sometimes there are some quick jumpings happen, I believe thats because translation.x(PAN X VALUE) value jumps from few points ahead, In my case i need it to be very smooth.
Any help greatly appreciated.
Thanks in advance.
You can use the gestureRecognizerShouldBegin method, which u can limit the UIPanGestureRecognizer sensitivity.
Example:
- (BOOL)gestureRecognizerShouldBegin:(UIPanGestureRecognizer *)panGestureRecognizer {
CGPoint translation = [panGestureRecognizer translationInView:self.view];
return fabs(translation.y) < fabs(translation.x);
}
Here's how I solved this for a cube rotation - just take the amount dragged and divide:
- (void)panHandle:(UIPanGestureRecognizer*)recognizer;
{
if ([recognizer state] == UIGestureRecognizerStateBegan)
{
CGPoint translation = [recognizer translationInView:[self superview]];
_startingX = translation.x;
}
else if ([recognizer state] == UIGestureRecognizerStateChanged)
{
CGPoint translation = [recognizer translationInView:[self superview]];
CGFloat angle = -(_startingX - translation.x) / 4;
//Now do translation with angle
_transitionContainer.layer.sublayerTransform = [self->_currentMetrics asTransformWithAngle:angle];
}
else if ([recognizer state] == UIGestureRecognizerStateEnded)
{
[self transitionOrReturnToOrigin];
}
}
I am currently designing a little game as a learning project and it is basically the following, a image is rotated and scaled on viewDidLoad and another image is a direct copy of the original image.
So basically there is a image that is a little bit different from the other, the objective is to scale it back down, rotate it and move it on top of the other image with 5 pixels, 5 degrees of rotate and 5 percent scale.
I have run into an issue. I "skew" the image using the following code...
CGAffineTransform transform = CGAffineTransformMakeRotation(M_PI/2.5);
image.transform = CGAffineTransformScale(transform, 1.25, 1.25);
My pan gesture does not perform correctly after rotating the image and then scaling it 125%.
Does anyone know what could be going on here? By incorrectly I mean that it doesn't move around with my finger.. It seems to glide or go the opposite direction. Video .
My pan gesture method is below.
if (gesture.state == UIGestureRecognizerStateBegan || gesture.state == UIGestureRecognizerStateChanged) {
CGPoint translation = [gesture translationInView:image];
//if within game field
if((image.center.x + translation.x) > 50.0 && (image.center.x + translation.x) < 255.0 && (image.center.y + translation.y) > 50.0 && (image.center.y + translation.y) < 302) {
[image setCenter:CGPointMake([image center].x + translation.x, [image center].y + translation.y)]; //move it
}
}
[gesture setTranslation:CGPointZero inView:[image superview]];
if(gesture.state == UIGestureRecognizerStateEnded) [self didWin]; // not relevant to question
Does anyone know why pan performs incorrectly after I rotate and scale my image? When I comment out those first two lines of code the pan performs correctly and moves around with the users finger.
Thanks in advance for any suggestions or help!
Rotation might have changed the frame. I used cosf and sinf function to deal with it.
handlePan and handleRotate are the callback functions, in which I can control the subview of self.view. Here, you should replace image with your own view.
static CGFloat _rotation = 0;
- (void)handlePan:(UIPanGestureRecognizer*)recognizer
{
UIImageView *image = nil;
for (UIImageView *tmp in recognizer.view.subviews) { // pick the subview
if (tmp.tag == AXIS_TAG) {
image = tmp;
}
}
CGPoint translation = [recognizer translationInView:image];
// I have found any related documents yet, but these equations do work!//////
CGFloat dx = translation.x * cosf(_rotation) - translation.y*sinf(_rotation);
CGFloat dy = translation.x * sinf(_rotation) + translation.y*cosf(_rotation);
/////////////////////////////////////////////////////////////////////////////
image.center = CGPointMake(image.center.x+dx, dy+image.center.y);
[recognizer setTranslation:CGPointMake(0, 0) inView:image];
}
- (void)handleRotate:(UIRotationGestureRecognizer*)recognizer
{
UIImageView *image = nil;
for (UIImageView *tmp in recognizer.view.subviews) { // pick the subview
if (tmp.tag == AXIS_TAG) {
image = tmp;
}
}
CGFloat r = [recognizer rotation];
if ((recognizer.state == UIGestureRecognizerStateBegan || recognizer.state == UIGestureRecognizerStateChanged)
&& recognizer.numberOfTouches == 2) {
image.transform = CGAffineTransformMakeRotation(_rotation+r);
} else if (recognizer.state == UIGestureRecognizerStateEnded) {
_rotation+=r; // Record the final rotation
}
}
The solution was to change the pan code just a tiny bit..
if (gesture.state == UIGestureRecognizerStateBegan || gesture.state == UIGestureRecognizerStateChanged) {
CGPoint translation = [gesture translationInView:self.view]; //CHANGED
//if within game field
if((image.center.x + translation.x) > 50.0 && (image.center.x + translation.x) < 255.0 && (image.center.y + translation.y) > 50.0 && (image.center.y + translation.y) < 302) {
[image setCenter:CGPointMake([image center].x + translation.x, [image center].y + translation.y)]; //move it
}
}
[gesture setTranslation:CGPointZero inView:self.view];
I changed in view:self.view and translationInView:self.view];
I am working on pinch in and pinch out feature on pdf pages. My pinch in and panning(moving) is working properly, but when user continuously moves the zoomed view, the zoom view goes outside the super view bounds.Something like this:
how can i limit the pan move so that user could not move the zoomed view/pdf outside the superview.
the relevant code i am using is:
// This method will handle the PINCH / ZOOM gesture
- (void)pinchZoom:(UIPinchGestureRecognizer *)gestureRecognizer
{
if([gestureRecognizer state] == UIGestureRecognizerStateBegan) {
// Reset the last scale, necessary if there are multiple objects with different scales
lastScale = [gestureRecognizer scale];
}
if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {
if (!zoomActive) {
zoomActive = YES;
panActive = YES;
UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(panMove:)];
[panGesture setMaximumNumberOfTouches:2];
[panGesture setDelegate:self];
[self addGestureRecognizer:panGesture];
[panGesture release];
}
CGFloat currentScale = [[[gestureRecognizer view].layer valueForKeyPath:#"transform.scale"] floatValue];
// Constants to adjust the max/min values of zoom
const CGFloat kMaxScale = 2.0;
const CGFloat kMinScale = 1.0;
CGFloat newScale = 1 - (lastScale - [gestureRecognizer scale]);
newScale = MIN(newScale, kMaxScale / currentScale);
newScale = MAX(newScale, kMinScale / currentScale);
CGAffineTransform transform = CGAffineTransformScale([[gestureRecognizer view] transform], newScale, newScale);
[gestureRecognizer view].transform = transform;
lastScale = [gestureRecognizer scale]; // Store the previous scale factor for the next pinch gesture call
[delegate leavesView:self zoomingCurrentView:[gestureRecognizer scale]];
}
}
the method where i am handling the pan move:
// This method will handle the PAN / MOVE gesture
- (void)panMove:(UIPanGestureRecognizer *)gestureRecognizer
{
if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {
CGPoint translation = [gestureRecognizer translationInView:[[gestureRecognizer view] superview]];
[[gestureRecognizer view] setCenter:CGPointMake([[gestureRecognizer view] center].x + translation.x, [[gestureRecognizer view] center].y + translation.y)];
[gestureRecognizer setTranslation:CGPointZero inView:[[gestureRecognizer view] superview]];
}
}
Please suggest how to handle pan/move limiting panning within its superview bounds.
Try this code in you panMove method. Its working fine in my case.
static CGPoint initialCenter;
if (recognizer.state == UIGestureRecognizerStateBegan)
{
initialCenter = recognizer.view.center;
}
CGPoint translation = [recognizer translationInView:recognizer.view];
CGPoint newCenter = CGPointMake(initialCenter.x + translation.x,
initialCenter.y + translation.y);
CGRect newFrame = recognizer.view.frame;
CGRect superViewBounds = recognizer.view.superview.bounds;
CGPoint superViewOrigin = recognizer.view.superview.frame.origin;
if(newCenter.x-(newFrame.size.width/2) >= (superViewBounds.size.width+superViewOrigin.x)-200 /*right*/
||
newCenter.x+(newFrame.size.width/2) <= (superViewOrigin.x+200) /*left*/
||
newCenter.y-(newFrame.size.height/2) >= (superViewBounds.size.height+superViewOrigin.y)-200 /*bottom*/
||
newCenter.y+(newFrame.size.height/2) <= (superViewOrigin.y+100)) /*top*/
{
return;
}else{
recognizer.view.center = newCenter;
}
You can add something like this to the code: (This is a little rough so you may have to work out some errors)
if([gestureRecognizer view].frame.bounds.x < self.view.bounds.x - panExapantion)
{
//then don't move it
}
//... repeat this for all sides (this is left), bottom, right, and top.
Edit:
Ok, consider a box inside of a boxes, thus we have an inside box and an outer box. If we don't want the inside box to go outside the outer box then we must have all these statements be true:
The moved left side of the inside box is not outside the left side of the outer box.
The moved right side of the inside box is not outside the right side of the outer box.
The moved bottom side of the inside box is not outside the bottom side of the outer box.
The moved top side of the inside box is not outside the top side of the outer box.
In your case the PDF is the inside box and the iPad is the outer box. In order to stop the pdf from going outside the box we need to check if each of these statements is true, and if one is false we do not move the PDF to it's new location OR we move the PDF just near the edge of the iPhone screen.
The problem is if the pinch and zoom is used then the suddenly the box will always be outside the outer box, so how do we fix it? We get how much pixels were added to the inside box when it was zoomed (for the sack of this explanation lets just call this the expansion). So we get how much the box was expanded by and subtract that value. Like so: (This is a dumbed down if statement and will not work in code)
If(outerBox.leftSide is less than innerBox.leftSide - panExpantion)
{
//Then the innerBox is outside the outterBox
}
I hoped this helped clarify!
I successfully implemented a pinch a zoom of a view. However, the view doesn't position itself where I wished it to be. For the stackoverflowers with an iPad, I would like my view to be centered like on the iPad Photos.app : when you pinch&zoom on an album, the photos present themselves in a view that is expanding. This view is approximately centered with the top right hand corner on the first finger and the bottom left hand finger on the other finger. I mixed it with a pan recognizer, but this way the user always has to pinch, and then pan to adjust.
Here are so graphic explanation, I could post a video of my app if that's unclear (no secret, i'm trying to reproduce the Photos.app of the iPad...)
So for an initial position of the fingers, begining zooming :
This is the actual "zoomed" frame for now. The square is bigger, but the position is below the fingers
Here is what I would like to have : same size, but different origin.x and y :
(sorry about my poor photoshop skills ^^)
You can get the CGPoint of the midpoint between two fingers via the following code in the method handlingPinchGesture.
CGPoint point = [sender locationInView:self];
My whole handlePinchGesture method is below.
/*
instance variables
CGFloat lastScale;
CGPoint lastPoint;
*/
- (void)handlePinchGesture:(UIPinchGestureRecognizer *)sender {
if ([sender numberOfTouches] < 2)
return;
if (sender.state == UIGestureRecognizerStateBegan) {
lastScale = 1.0;
lastPoint = [sender locationInView:self];
}
// Scale
CGFloat scale = 1.0 - (lastScale - sender.scale);
[self.layer setAffineTransform:
CGAffineTransformScale([self.layer affineTransform],
scale,
scale)];
lastScale = sender.scale;
// Translate
CGPoint point = [sender locationInView:self];
[self.layer setAffineTransform:
CGAffineTransformTranslate([self.layer affineTransform],
point.x - lastPoint.x,
point.y - lastPoint.y)];
lastPoint = [sender locationInView:self];
}
Have a look at the Touches sample project. Specifically these methods could help you:
// scale and rotation transforms are applied relative to the layer's anchor point
// this method moves a gesture recognizer's view's anchor point between the user's fingers
- (void)adjustAnchorPointForGestureRecognizer:(UIGestureRecognizer *)gestureRecognizer {
if (gestureRecognizer.state == UIGestureRecognizerStateBegan) {
UIView *piece = gestureRecognizer.view;
CGPoint locationInView = [gestureRecognizer locationInView:piece];
CGPoint locationInSuperview = [gestureRecognizer locationInView:piece.superview];
piece.layer.anchorPoint = CGPointMake(locationInView.x / piece.bounds.size.width, locationInView.y / piece.bounds.size.height);
piece.center = locationInSuperview;
}
}
// scale the piece by the current scale
// reset the gesture recognizer's rotation to 0 after applying so the next callback is a delta from the current scale
- (void)scalePiece:(UIPinchGestureRecognizer *)gestureRecognizer
{
[self adjustAnchorPointForGestureRecognizer:gestureRecognizer];
if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {
[gestureRecognizer view].transform = CGAffineTransformScale([[gestureRecognizer view] transform], [gestureRecognizer scale], [gestureRecognizer scale]);
[gestureRecognizer setScale:1];
}
}