I have a view and inside it there's a UIImage. The image isn't static and I can move it around if I drag my finger around (using drag events) The problem is that sometimes the picture moves outside of the UIView frame. What's the appropriate way to keep it inside the parent frame bounds?
--UIViewA
--------UIViewB
--------------UIImage
--------------UIButton
I want to keep UIImage inside UIViewB
- (IBAction)myButtonSingleTap:(UIButton *)sender {
imDragging = YES;
[_myButton addTarget:self action:#selector(dragBegan:withEvent:) forControlEvents: UIControlEventTouchDown];
}
- (IBAction)myButtonDragInside:(UIButton *)sender
{
[_myButton addTarget:self action:#selector(draging:withEvent:) forControlEvents: UIControlEventTouchDragInside];
}
- (void)dragBegan:(UIControl *)c withEvent:ev {
UITouch *touch = [[ev allTouches] anyObject];
startingTouchPoint = [touch locationInView:self.view];
}
- (void)draging:(UIControl *)c withEvent:ev {
UITouch *touch = [[ev allTouches] anyObject];
currentTouchPoint = [touch locationInView:self.view];
_movingPic.frame = CGRectMake(currentTouchPoint.x, currentTouchPoint.y, 28, 23);
}
You will need to check the location of the view during the dragging.
At some point you will be setting the frame of the image depending on the user's drag direction, etc...
During this you should have a logic check like...
If new location x value is less than 0 then set new location x = 0.
If new location x value plus image width is greater than view width then set new location x = view width - image width.
etc...
Then use the new location as the point to move the image to.
Try adding the touch recogniser to the parent view and not the entire view
Before setting the new frame, make sure it is contained by the moving view's superview's bounds.
- (void)draging:(UIControl *)c withEvent:ev
{
UITouch *touch = [[ev allTouches] anyObject];
currentTouchPoint = [touch locationInView:self.view];
CGRect newFrame = CGRectMake(currentTouchPoint.x, currentTouchPoint.y, 28, 23);
newFrame.x = MAX(newFrame.x, 0);
newFrame.y = MAX(newFrame.y, 0);
newFrame.x = MIN(newFrame.x, _movingPic.superview.bounds.size.width - 28);
newFrame.y = MIN(newFrame.y, _movingPic.superview.bounds.size.height - 23);
_movingPic.frame = newFrame;
}
Related
I have an Image in an Iphone App, I would like when a user taps a location within a defined area (range of locations or an area defined by the rectangle), it triggers another event. I know how to get a single location, But I don't know how to define a rectangular area. I am looking for a simple way to implement it. Thank you
If you want to make the rectangle visible you can add image view to your view and set up the tap recogniser. But if you don't want to make the rectangle visible you can override touchesBegan:withEvent: method and use CGRectContainsPoint:
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [[event allTouches] anyObject];
CGPoint touchLocation = [touch locationInView:self.view];
CGRect rect = CGRectMake(0.0, 0.0, 100, 100); //<- this is the rectangle you do check on
if (CGRectContainsPoint(rect, touchLocation)) {
NSLog(#"You tapped inside rectangle");
}
else {
NSLog(#"You missed rectangle");
}
}
Define your area as a CGRect and get the CGPoint of the touch. Then use CGRectContainsPoint to check for a hit.
If you need to create the CGRect from a list of points then you need to iterate the points and find the max and min x and y values, then you can create the CGRect with:
CGRectMake(minX, minY, maxX - minX, maxY - minY);
Maybe you can create a UIView and add a gesture recognizer like this:
UIView *customView = [UIView new];
customView.frame = CGRectMake(....); // as Wain suggest
[self.view addSubview:customView];
UITapGestureRecognizer *tapGesture =
[[UITapGestureRecognizer alloc] initWithTarget: self
action: #selector(someMethod)];
[customView addGestureRecognizer:tapGesture];
I have a 400x400 UIViewController(lets call it ViewB) in center of my RootController. Inside the ViewB I have few UIButton (Customised UIButton Class with touch UIResponder methods).
I'm able to move the buttons around, but when the touch goes out of the ViewB, the button does cancel the touch!
What I really want is to totally cancel the touch and leave the button near the edge of ViewB.
Try this,
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [[event allTouches] anyObject];
....
CGRect viewBFrame = ViewB.view.frame;
CGRect buttonToRect = //calculated button frame
CGPoint buttonOrigin = buttonToRect.origin;
CGFloat xMax = CGRectGetWidth(viewBFrame) - CGRectGetWidth(buttonToRect);
CGFloat yMax = CGRectGetHeight(viewBFrame) - CGRectGetHeight(buttonToRect);
buttonOrigin.x = MAX(0, buttonOrigin.x);
buttonOrigin.x = MIN(xMax, buttonOrigin.x);
buttonOrigin.y = MAX(0, buttonOrigin.y);
buttonOrigin.y = MIN(yMax, buttonOrigin.y);
//set buttonToRect to Button
}
Note : Assuming button is subView of ViewB
Okay basically what this code currently does is drag an image up and down along the Y axis depending on where the user drags it, and it returns to its original position. My problem is that if someone were to not touch directly on the center of the UIImageView and start dragging it would jolt (very not smooth). Wherever someone is touching the UIImageView and starts dragging the UIImageView jolts a little to go directly on the center of the touch event.
I was thinking about using animation just to move it where the image needs to go, or is there another way?
I apologize if this is an inefficient way to do this. I'm fairly new to the IOS world.
Here's what I have:
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
//Gets location of UIImageView.
self.originalFrame = self.foregroundImage.frame;
}
//This method is used for moving the UIImageView along the y axis depending on touch events.
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [[event allTouches] anyObject];
if([touch view]==self.foregroundImage) {
CGPoint location = [touch locationInView:self.view];
location.x=self.foregroundImage.center.x;
self.foregroundImage.center=location;
}
}
//This method sets the UIImageView back to its original position.
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
CGRect newFrame = self.foregroundImage.frame;
newFrame.origin.y = self.originalFrame.origin.y;
[UIView animateWithDuration:1.1 animations:^{
self.foregroundImage.frame = newFrame;
}];
}
You also need to save the first location in touchesBegan, relative to the parent view. Then, you can use that to change the frame by the difference between the previous location and the new location. Please see the following code.
- (void) touchesBegan: (NSSet*) touches
withEvent: (UIEvent*) event
{
if (touches.count == 1)
{
UITouch* touch = [touches anyObject];
self.touchLocation = [touch locationInView: self.view];
}
}
- (void) touchesMoved: (NSSet*) touches
withEvent: (UIEvent*) event
{
if (touches.count == 1)
{
UITouch* touch = [touches anyObject];
CGPoint newTouchLocation = [touch locationInView: self.view];
if (touch.view == self.foregroundImage)
{
/* Determine the difference between the last touch locations */
CGFloat deltaX = newTouchLocation.x - self.touchLocation.x;
CGFloat deltaY = newTouchLocation.y - self.touchLocation.y;
/* Offset the foreground image */
self.foregroundImage.center
= CGPointMake(self.foregroundImage.center.x + deltaX,
self.foregroundImage.center.y + deltaY);
}
/* Keep track of the new touch location */
self.touchLocation = newTouchLocation;
}
}
I currently have an application where a user takes a photo or chooses from their library.
On the next controller it will show the image that was selected/taken.
What I would like to do now is show a view of some sort on top of the image view. The view would be translucent round the edges and have a circle which would show the image beneath (not transulcent). Basically this is selected a part of the image.
I then need to save some how where the view is on screen, as it should also be moveable by the user.
What is the best way to approach this?
I need an overlay view which can be moved. The circle would be a fixed size always the inside shows the imageview beneath and the outside would be a 0.5 translucency so you can still see the image but not completely. Then to save the location of the moved around circle?
---- EDIT -----
This is the example image I have created.
I have a view which has a photo as the UIImageView (bottom layer). On top of this I am trying to add a view (like the picture above). Note, the picture above is actually a png as suggested. However, this overlay is moveable. The circle is transparent (0) so you can completely see the photo below it. The outer (grey) is transparent partially (0.5) so you can still see just not completely.
The top view (circle part) would be moved around on the photo to mark a specific point on the photo. In this example if the circle is moved the side (grey) ends on screen, therefore I would need to make a huge image which takes into account the moving of the view -- which is not the best way to do this surely?
EDIT 2 ----
I now have one UIImageView over the top of the photoView (another UIImageView). The overlay is 4 times the screen with a circle in the middle of it.
When the item is moved I have a gesture recognizer that runs:
-(void)handlePan:(UIPanGestureRecognizer *)gesture {
NSLog(#"Pan Gesture");
gesture.view.center = [gesture locationInView:self.view];
}
At present from the above the UIImageView is moved from the middle point, that way the circle is what looks to be moving when the finger moves.
That is all great, but how do I implement the suggested answers into my handlePan method. So I need to check that the middle point is not too close the edge. Ideally I would like a 50 margin around the screen so the circle does not look to go completely (or mostly) off screen?
I understand from the question that you know how to do the movement of the overlay, so what I meant is just that you can simply use image views big enough to make sure that their border isn't visible.
Let's say the UIImageView would be called
UIImageView *photoImageView;
And the overlay with translucent and semi-translucent areas would be
UIImageView *imageOverlayView;
The way I see it, you need 3 different images for that imageOverlayView, depending on the device it's running on - 1 for iPad, 1 for iPhone 5 and 1 for other iPhones.
Width of that image should be equal to (screen width - circle radius) * 2, height should
CGFloat circleRadius; //this would be the radius of translucent circle
So if you set the frame of the overlay properly:
CGRect imageFrame = photoImageView.frame;
imageOverlayView.frame = CGRectMake(circleRadius - imageFrame.size.width/2, circleRadius - imageFrame.size.height/2, (imageFrame.size.width - circleRadius)*2, (imageFrame.size.height - circleRadius)*2); //origin is set to the middle of the image.
you'd never see the edge of the grey area. MZimmerman6's answer for implementation of the movement is good, but you should also make sure you block the circle from getting out of the borders of underlying image.
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint new = [touch locationInView:imageOverlayView];
delX = new.x - prevPoint.x;
delY = new.y - prevPoint.y;
CGRect overFrame = imageOverlayView.frame;
overFrame.origin.x += delX;
if (overFrame.origin.x < -imageFrame.size.width) {
overFrame.origin.x = -imageFrame.size.width;
}
else if (overFrame.origin.x > 0) {
overFrame.origin.x = 0;
}
overFrame.origin.y += delY;
if (overFrame.origin.y < -imageFrame.size.height) {
overFrame.origin.y = -imageFrame.size.height;
}
else if (overFrame.origin.y > 0) {
overFrame.origin.y = 0;
}
[overlayView setFrame:overFrame];
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint new = [touch locationInView:imageOverlayView];
delX = new.x - prevPoint.x;
delY = new.y - prevPoint.y;
CGRect overFrame = imageOverlayView.frame;
overFrame.origin.x += delX;
if (overFrame.origin.x < -imageFrame.size.width) {
overFrame.origin.x = -imageFrame.size.width;
}
else if (overFrame.origin.x > 0) {
overFrame.origin.x = 0;
}
overFrame.origin.y += delY;
if (overFrame.origin.y < -imageFrame.size.height) {
overFrame.origin.y = -imageFrame.size.height;
}
else if (overFrame.origin.y > 0) {
overFrame.origin.y = 0;
}
[overlayView setFrame:overFrame];
}
EDIT
With your pan gesture recognizer, checking if you aren't going too far needs a little change to the handlePan: method.
-(void)handlePan:(UIPanGestureRecognizer *)gesture {
CGPoint newCenter = [gesture locationInView:self.view];
if (newCenter.x < 50) {
newCenter.x = 50;
}
else if (newCenter.x > self.view.frame.size.width - 50) {
newCenter.x = self.view.frame.size.width - 50;
}
if (newCenter.y < 50) {
newCenter.y = 50;
}
else if (newCenter.y > self.view.frame.size.height - 50) {
newCenter.y = self.view.frame.size.height - 50;
}
gesture.view.center = newCenter;
}
If that 50 points margin is equal to circle radius, this will make sure your circle able to touch the edges of the screen, but unable to go beyond them.
I would first initialize some UIImageView with a png image in it that will easily handle this moving frame with a hole in the center. You can the add this to your screen. Once this is done, use the touchesBegan, touchesMoved and other touch commands to find whether a user is touching that box and from that determine how far the user has moved from the previous point. Use this difference to then add or subtract values from the images current frame origin or center, and voila you have a moving box.
EDIT
In View.h
CGPoint prevPoint;
float delX;
float delY;
UIView *overlayView;
In View.m
-(void) viewDidLoad {
overlayView = [UIView alloc] initWithFrame:CGRectMake(100,100,100,100)];
[overlayView setBackgroundColor:[UIColor clearColor]];
[self.view addSubview:overlayView];
UIImageView *circImage = [[UIImageView alloc] initWithFrame:CGRectMake(0,0,overlayView.frame.width,overlayView.frame.height)];
[circImage setImage:[UIImage imageNamed:#"SomeImage.png"]];
[overlayView addSubview:circImage];
[self.view setNeedsDisplay];
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
prevPoint = [touch locationInView:overlayView];
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint new = [touch locationInView:overlayView];
delX = new.x - prevPoint.x;
delY = new.y - prevPoint.y;
CGRect overFrame = overlayView.frame;
overFrame.x += delX;
overFrame.y += delY;
[overlayView setFrame:overFrame];
[self.view setNeedsDisplay];
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint new = [touch locationInView:overlayView];
delX = new.x - prevPoint.x;
delY = new.y - prevPoint.y;
CGRect overFrame = overlayView.frame;
overFrame.x += delX;
overFrame.y += delY;
[overlayView setFrame:overFrame];
[self.view setNeedsDisplay];
}
I'm trying to create a draggable image, but i'm trying to confine it's dragging to within a small square rather than the full screen. Could someone tell me where i'm going wrong?. I've placed the code that I have so far below:
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [[event allTouches] anyObject];
if([touch view] == dot) {
CGPoint location = [touch locationInView:self.view];
dot.center = location;
if (location.x >10) {
location.x =10;
} else if (location.x <10) {
location.x = 10;
}
if (location.y >20) {
location.y =20;
} else if (location.y < 20) {
location.y = 20;
}
}
}
You are assigning location before you are making changes to it.
Apply your limits to location first then assign it to dot.
Also, your limits you are showing would lock your position to 10,20 since you are not allowing it to be more than 10 or less than 10. Likewise with 20.
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [[event allTouches] anyObject];
if([touch view] == dot) {
CGPoint location = [touch locationInView:self.view];
location.x = MIN(MAX(location.x, 0),10);
location.y = MIN(MAX(location.y, 0),20);
dot.center = location;
}
}
I have implemented an image dragging function recently like this. I use the PAN Gesture to move the image which results in two CGFloats "endPointX and endPointY". In the code below between the comments "Stay on Screen Check" and "End Stay on Screen check", I check if these are on the screen. If not I adjust them to prevent the image moving off the screen.
I hope that helps. If you want to move the image within a small part of the total screen then I would add the image to a holder subview and then check the holder view .bounds.size.width/height above instead.
CGFloat endPointX = translatedPoint.x + (.35*[(UIPanGestureRecognizer*)sender
velocityInView:self.view].x);
CGFloat endPointY = translatedPoint.y + (.35*[(UIPanGestureRecognizer*)sender velocityInView:self.view].y);
// Stay on the screen check
if(endPointX < 0) {
endPointX = 0;
} else if(endPointX > self.view.bounds.size.width) {
endPointX = self.view.bounds.size.width;
}
if(endPointY < 0) {
endPointY = 0;
} else if(endPointY > self.view.bounds.size.height) {
endPointY = self.view.bounds.size.height;
}
// End of the Stay on Screen check
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:.35];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
[[sender view] setCenter:CGPointMake(endPointX, endPointY)];
[UIView commitAnimations];