I've successfully implemented zooming of UIImageView in my UIScrollView but I have faced with a strange problem that irritates me.
Basically, when I zoom in the image
I can pan the view to actually scroll out of the image border and I'm left with a black area like this:
And as I zoom in more I can make the black border to fill the whole screen!
Meanwhile in the iPhone Photo app you can't zoom out the actual image. What's wrong here in my implementation?
It looks like this:
UIImage *imageToDisplay = [UIImage imageWithData:tmpImageData];
imageViewMain.image = imageToDisplay;
imageViewMain.frame = CGRectMake(0, 0, scrollViewMain.frame.size.width, scrollViewMain.frame.size.height);
imageViewMain.contentMode = UIViewContentModeScaleAspectFit;
scrollViewMain.delegate = self;
scrollViewMain.minimumZoomScale = 1.0;
scrollViewMain.maximumZoomScale = 9.0;
scrollViewMain.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
scrollViewMain.contentSize = imageViewMain.frame.size;
[self.view addSubview:scrollViewMain];
[scrollViewMain addSubview:imageViewMain];
And I also implement this method:
- (UIView*)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
return imageViewMain;
}
Thanks in advance!
EDIT:
When I first load the view I shrink my UIImageView to fit the scroll view and the image looks like this:
Just try this code.... change some code where it required... use UIPinchGestureRecognizer for your UIImageView and then add this image in your UIScrollView like bellow..
UIImageView *img = [[UIImageView alloc]init];
img.image = [UIImage imageWithData:tmpImageData];
img.userInteractionEnabled = YES;
img.frame = CGRectMake(210,100, 200, 200);/// define frame which you want...
[img sizeToFit];
UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:#selector(scale:)];
[pinchRecognizer setDelegate:self];
[img addGestureRecognizer:pinchRecognizer];
[pinchRecognizer release];
[scrollViewMain addSubview:img];
[scrollViewMain bringSubviewToFront:img];
[img release];
and just paste this bellow code in your .m file...
#pragma mark GestureRecognizer Methods
-(void)scale:(id)sender
{
UIView *imgTempGest = [sender view];
if([(UIPinchGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded)
{
lastScale = 1.0;
return;
}
CGFloat scale = 1.0 - (lastScale - [(UIPinchGestureRecognizer*)sender scale]);
CGAffineTransform currentTransform = [(UIPinchGestureRecognizer*)sender view].transform;
CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, scale, scale);
[[(UIPinchGestureRecognizer*)sender view] setTransform:newTransform];
[imgTempGest setTransform:newTransform];
lastScale = [(UIPinchGestureRecognizer*)sender scale];
}
Here for LastScale just define that variable in .h file like bellow...
CGFloat lastScale;
i hope this helpful to you...
Is the original image contains that border in top and bottom?. You can use the same code over there the output is not wrong if the actual image contains that black top and bottom black area. And add this code also,
scrollView.scrollEnabled = YES
also change,
scrollView.contentSize = imageView.bounds.size;
Also you are providing a zoom scale of 9. That much is needed for you?. Change it to 3 or 4 and try. Your problem will be fixed
Related
I have a UIImageView element as a subview of my main UIScrollView element.
I want the Image to fill out the whole screen at all times, but I can drag the edges a bit too far, so that the yellow "background" becomes visible.
If I lift my finger, the Image "bounces" back and fills out the screen correctly.
I want to prevent this dragging of the image off screen.
I do however want the image to bounce back once I drag it out of the "safety area".
This is my ScrollView initialization:
- (id)initWithFrame:(CGRect)frame{
self = [super initWithFrame:CGRectMake(0, 0, frame.size.height, frame.size.width)];
if (self) {
[self initImageValues];
self.showsVerticalScrollIndicator = NO;
self.showsHorizontalScrollIndicator = NO;
self.bouncesZoom = YES;
self.decelerationRate = UIScrollViewDecelerationRateFast;
self.delegate = self;
self.backgroundColor = [UIColor yellowColor];
self.minimumZoomScale = 1.0;
self.maximumZoomScale = 2.0;
[self setCanCancelContentTouches:YES];
self.clipsToBounds = YES;
// Load Image
imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:imageName]];
[self addSubview:imageView];
[self setContentSize: CGSizeMake(imageView.frame.size.width, imageView.frame.size.height)];
// Set bigger "bounce" zone (safety area)
self.contentInset=UIEdgeInsetsMake(-SAFETY_ZONE,-SAFETY_ZONE,-SAFETY_ZONE,-SAFETY_ZONE);
self.scrollEnabled = YES;
}
return self;}
Use these delegate methods:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
Then read the offset and return if it's out of the "safety area".
Could be that you need another delegate method from the UIScrollView though, but a workaround like this should fix your problem :)
try setting bounces on the scrollview:
self.bounces = NO;
TRY this:
**
self.scrollView.maximumZoomScale = 1.0;
self.scrollView.minimumZoomScale = 1.0;
**
Try setting its bounces property to NO.
- (void)viewDidLoad
{
UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(tapDetected:)];
tapGesture.numberOfTapsRequired = 1;
tapGesture.numberOfTouchesRequired = 1;
scrollView = [[UIScrollView alloc] initWithFrame:self.view.frame];
int numberOfImages = 32;
CGFloat currentX = 0.0f;
for (int i=1; i <= numberOfImages; i++) {
// create image
NSString *imageName = [NSString stringWithFormat:#"page-%d.jpg", i];
UIImage *image = [UIImage imageNamed:imageName];
imageView = [[UIImageView alloc] initWithImage:image];
// put image on correct position
CGRect rect = imageView.frame;
rect.origin.x = currentX;
imageView.frame = rect;
// update currentX
currentX +=454; //mageView.frame.size.width;
[scrollView addSubview:imageView];
[imageView release];
}
[scrollView addGestureRecognizer:tapGesture];
scrollView.contentSize = CGSizeMake(currentX, 800);
scrollView.pagingEnabled=YES;
scrollView.userInteractionEnabled = YES;
scrollView.maximumZoomScale = 15;
scrollView.minimumZoomScale = 0.5;
scrollView.bounces = NO;
scrollView.bouncesZoom = NO;
scrollView.delegate = self;
scrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin;
[self.view addSubview:scrollView];
[scrollView release];
[super viewDidLoad];
}
}
in above code when i apply zoom or tap event with a single image then it work for that. But when same event apply for array of image then not working. why is it happened?
Its quiet complex to implement zoom in this kind of image flow. Anyway i wil suggest you one idea,
Add the gesture to each imageView. In the method, add a new scrollview, with the respective imageView.. then implement zoom.
EDIT:
In the tapgesture method,
1.Find out the which imageView is visible at that time.
2.Then create a new scrollview,with that single imageview.
3.Implement zoom functionality in that new scrollview.
4.During zoom out,If the new scrollview size is equal to the actual value,remove the new scrollview fro the super view so that the array of images is visible.
Simplest way is create a big wrapper view first, and insert it into ScrollView.
And then add all your imageViews to the wrapper view.
So, I've managed to create a UIScrollView with zooming method programmatically, but I'm kind of stuck how to solve an issue I'm having with zooming:
When I zoom in or out the point at where it expands/retracts does not happen where I do the pinch gesture, it happens on a corner.
After zooming in or out, it will leave extra space outside the bounds, and I cannot scroll the image more than half the width & height of the image.
Other than this, I'm so close to getting it working 100%. I've tried playing around with achorpoints, but it looks like the scroll view and image view does not respond to this.
Here is the important stuff in the code listing:
UIScrollView *mapScrollView;
UIImageView *mapImageView;
CGFloat lastScale = 0;
NSMutableArray *map_List;
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
mainMenuAppDelegate *del = (mainMenuAppDelegate *)[[UIApplication sharedApplication] delegate];
map_List = [[NSMutableArray alloc] init];
[map_List addObject:#"Pacific_Map_8bit.png"];
[map_List addObject:#"Atlantic_Map_8bit.png"];
CGRect mapScrollViewFrame = CGRectMake(0, 0, 1024, 768);
mapScrollView = [[UIScrollView alloc] initWithFrame:mapScrollViewFrame];
mapScrollView.contentSize = CGSizeMake(2437, 1536);
UIImage *mapImage = [UIImage imageNamed:[map_List objectAtIndex:mapNum]];
mapImageView = [[UIImageView alloc] initWithImage: mapImage];
mapScrollView.bounces = NO;
[mapImage release];
[mapScrollView addSubview:mapImageView];
[self addSubview:mapScrollView];
mapImageView.userInteractionEnabled = YES;
UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:#selector(scale:)];
[mapImageView addGestureRecognizer:pinchRecognizer];
[pinchRecognizer release];
}
return self;
}
// the scale method thats triggered to zoom when pinching
-(void)scale:(id)sender {
if([(UIPinchGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) {
lastScale = 1.0;
return;
}
CGFloat scale = 1.0 - (lastScale - [(UIPinchGestureRecognizer*)sender scale]);
NSLog(#"map scale %f", scale);
CGFloat mapWidth = mapImageView.frame.size.width;
CGFloat mapHeight = mapImageView.frame.size.height;
NSLog(#"map width %f", mapWidth);
if(scale>=1 & mapWidth<=4000 || scale<1 & mapWidth>=1234){
CGAffineTransform currentTransform = [(UIPinchGestureRecognizer*)sender view].transform;
CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, scale, scale);
[[(UIPinchGestureRecognizer*)sender view] setTransform:newTransform];
lastScale = [(UIPinchGestureRecognizer*)sender scale];
}
mapScrollView.contentSize = CGSizeMake(mapWidth, mapHeight);
}
Thanks!
UIScrollView has built-in zooming support. All you need to do is set the minimumZoomScale and maximumZoomScale properties, and return a view to be used for zooming using viewForZoomingInScrollView.
I have a UIScrollView with a UIImage inside. The following code initializes the image properly (it's width is the same as the width of the scrollView):
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
[super viewDidLoad];
...
imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"map1.jpg"]];
imageView.userInteractionEnabled = YES;
imageView.autoresizingMask = ( UIViewAutoresizingFlexibleWidth );
[imageScrollView addSubview:imageView];
imageScrollView.contentSize = [imageView frame].size;
...
// calculate minimum scale to perfectly fit image width, and begin at that scale
float minimumScale = [imageScrollView frame].size.width / [imageView frame].size.width;
//imageScrollView.maximumZoomScale = 1.0;
imageScrollView.minimumZoomScale = minimumScale;
imageScrollView.zoomScale = minimumScale;
}
What I want to do is to set the size to perfectly fit (like above) when the device rotates. Here's what I've tried to do:
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation {
float newScale = [imageScrollView frame].size.width / [imageView frame].size.width;
imageScrollView.zoomScale = newScale;
}
For some reasons this doesn't work at all. The only way that I was able to make it work was to initialize another UIImage and do all the initialization process again, which doesn't feel right to me.
Probably you should also change .contentSize of scroll view.
I use the following code to load an image into an scroll view. The image always loads at 100% zoom. Is there a way to set it to load to another zoom level, say .37?
I have tried scrollView.zoomScale = .37 but it didnt seem to work
UIImageView *tempImage = [[UIImageView alloc]initWithImage:[UIImage imageWithData:data]];
self.imageView = tempImage;
scrollView.contentSize = CGSizeMake(imageView.frame.size.width , imageView.frame.size.height);
scrollView.maximumZoomScale = 1;
scrollView.minimumZoomScale = .37;
scrollView.clipsToBounds = YES;
scrollView.delegate = self;
[scrollView addSubview:imageView];
Zooming only works when you implement the viewForZoomingInScrollView: delegate callback.
-(UIView *) viewForZoomingInScrollView:(UIScrollView *)inScroll {
return imageView;
}
I figured it out... I was using scrollView.zoomScale = 0.37; before I loaded the image changed code and it works great.
UIImageView *tempImage = [[UIImageView alloc]initWithImage:[UIImage imageWithData:data]];
self.imageView = tempImage;
scrollView.contentSize = CGSizeMake(imageView.frame.size.width , imageView.frame.size.height);
scrollView.maximumZoomScale = 1;
scrollView.minimumZoomScale = .37;
scrollView.clipsToBounds = YES;
scrollView.delegate = self;
[scrollView addSubview:imageView];
scrollView.zoomScale = .37;
There is a zoomScale property that you can set.
I was facing same issue..
i used the built in method : scrollViewForImage
This will set the initial zoom to level 5
[self.scrollViewForImage setZoomScale:5 animated:YES];
code for minimum zoom level
self.scrollViewForImage.minimumZoomScale=1;
code for Maximum Zoom Level
self.scrollViewForImage.maximumZoomScale=12.0;
Hope this will help
You must set the initial zoom when the viewwillappear and not when the viewdidload for it too work.