i've implemented imageview zooming in scrollview application in my app.
i want to set the scrollview and imageview on the right top of the view. but it's not zooming there. when i placed it on centre of view it's zooming.
The code is given below
#interface przoomViewController : UIViewController<UIScrollViewDelegate>
{
IBOutlet UIScrollView *scrollView;
IBOutlet UIImageView *image;
}
-(void)viewDidLoad
{
[image setUserInteractionEnabled:YES];
[scrollView addSubview:image];
scrollView.scrollEnabled = YES;
scrollView.minimumZoomScale=1.0;
scrollView.maximumZoomScale=4.0;
[scrollView setContentSize:CGSizeMake(320, 180)];
scrollView.delegate=self;
}
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
return image;
}
please help me.
I have implemented image zooming in my app. Try scrollviewDelegate Method
- (void)scrollViewDidZoom:(UIScrollView *)scrollView
{
// The scroll view has zoomed, so we need to re-center the contents
[self centerScrollViewContents];
}
- (void)centerScrollViewContents
{
CGSize boundsSize = zoomingScrollView.bounds.size;
CGRect contentsFrame = ZImageView.frame;
if (contentsFrame.size.width < boundsSize.width)
{
contentsFrame.origin.x = (boundsSize.width - contentsFrame.size.width) / 2.0f;
}
else
{
contentsFrame.origin.x = 0.0f;
}
if (contentsFrame.size.height < boundsSize.height)
{
contentsFrame.origin.y = (boundsSize.height - contentsFrame.size.height) / 2.0f;
}
else
{
contentsFrame.origin.y = 0.0f;
}
ZImageView.frame = contentsFrame;
}
No need to set userInterAction enabled on imageView. If this does not help, I will share my implementation.
You should set value for zoomScale property of scrollview to start zooming as given below.
scrollView.zoomScale=1.0; // this will enable zooming.
Related
I use ImageScrollView to show image. At the begining I show only small image. And when user tries to zoom, I load big image. First I wanted to do this using this code:
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollViewCalled
{
ImageScrollView *scroll = (ImageScrollView *)scrollViewCalled;
UIImageView *imageView = (UIImageView *)[scroll imageView];
return imageView;
}
- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollViewCalled withView:(UIView *)view
{
ImageScrollView *scroll = (ImageScrollView *)scrollViewCalled;
if (scroll != scrollViewCalled || scroll.isImageBig)
{
return;
}
scroll.userInteractionEnabled = NO;
[self setBigImageInBackgroundForIndex:nil];
}
But it works strange: when I try to zoom, the big image is shown, but I see its maximum zoom scale, and I can't scroll to see the rest part of the image. But when I zoom one more time instead of scrolling the image, it begins to work properly and I finally can scroll the image. But I should zoom 2 times for that.
Then I tried scrollViewDidEndZooming instead scrollViewWillBeginZooming:
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollViewCalled withView:(UIView *)view atScale:(float)scale
{
ImageScrollView *scroll = (ImageScrollView *)scrollViewCalled;
if (scroll != scrollViewCalled || scroll.isImageBig)
{
return;
}
scroll.userInteractionEnabled = NO;
[self setBigImageInBackgroundForIndex:nil];
}
And everything became perfect except one thing: it's too late. I zoom small image, I see it's zoomed variant, then big image loaded and I see minimum zoom for big image. For user it seems , that image came back to it's previus zoom. And only if I try to zoom one more time, I can zoom perfectly.
Thank you in advance!
here is the code for ImageScrollView:
ImageScrollView.h
#import <UIKit/UIKit.h>
#interface ImageScrollView : UIScrollView <UIScrollViewDelegate> {
UIView *imageView;
NSUInteger index;
}
#property (assign) NSUInteger index;
#property (retain, nonatomic) UIView *imageView;
#property (assign, nonatomic) BOOL isImageBig;
#property (assign, nonatomic) BOOL hasImage;
- (void)displayImage:(UIImage *)image;
- (void)displayTiledImageNamed:(NSString *)imageName size:(CGSize)imageSize;
- (void)setMaxMinZoomScalesForCurrentBounds;
- (CGPoint)pointToCenterAfterRotation;
- (CGFloat)scaleToRestoreAfterRotation;
- (void)restoreCenterPoint:(CGPoint)oldCenter scale:(CGFloat)oldScale;
#end
ImageScrollView.m
#import "ImageScrollView.h"
#import "TilingView.h"
#implementation ImageScrollView
#synthesize index;
#synthesize imageView;
#synthesize isImageBig, hasImage;
- (id)initWithFrame:(CGRect)frame
{
if ((self = [super initWithFrame:frame])) {
self.showsVerticalScrollIndicator = NO;
self.showsHorizontalScrollIndicator = NO;
self.bouncesZoom = YES;
self.decelerationRate = UIScrollViewDecelerationRateFast;
self.delegate = self;
}
return self;
}
- (void)dealloc
{
[imageView release];
[super dealloc];
}
#pragma mark -
#pragma mark Override layoutSubviews to center content
- (void)layoutSubviews
{
[super layoutSubviews];
// center the image as it becomes smaller than the size of the screen
CGSize boundsSize = self.bounds.size;
CGRect frameToCenter = imageView.frame;
// center horizontally
if (frameToCenter.size.width < boundsSize.width)
frameToCenter.origin.x = (boundsSize.width - frameToCenter.size.width) / 2;
else
frameToCenter.origin.x = 0;
// center vertically
if (frameToCenter.size.height < boundsSize.height)
frameToCenter.origin.y = (boundsSize.height - frameToCenter.size.height) / 2;
else
frameToCenter.origin.y = 0;
imageView.frame = frameToCenter;
if ([imageView isKindOfClass:[TilingView class]]) {
// to handle the interaction between CATiledLayer and high resolution screens, we need to manually set the
// tiling view's contentScaleFactor to 1.0. (If we omitted this, it would be 2.0 on high resolution screens,
// which would cause the CATiledLayer to ask us for tiles of the wrong scales.)
imageView.contentScaleFactor = 1.0;
}
}
#pragma mark -
#pragma mark UIScrollView delegate methods
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
return imageView;
}
#pragma mark -
#pragma mark Configure scrollView to display new image (tiled or not)
- (void)displayImage:(UIImage *)image
{
// clear the previous imageView
[imageView removeFromSuperview];
[imageView release];
imageView = nil;
// reset our zoomScale to 1.0 before doing any further calculations
self.zoomScale = 1.0;
self.imageView = [[[UIImageView alloc] initWithImage:image] autorelease];
[self addSubview:imageView];
self.contentSize = [image size];
[self setMaxMinZoomScalesForCurrentBounds];
self.zoomScale = self.minimumZoomScale;
// self.zoomScale = self.maximumZoomScale;
}
- (void)setMaxMinZoomScalesForCurrentBounds
{
CGSize boundsSize = self.bounds.size;
CGSize imageSize = imageView.bounds.size;
// calculate min/max zoomscale
CGFloat xScale = boundsSize.width / imageSize.width; // the scale needed to perfectly fit the image width-wise
CGFloat yScale = boundsSize.height / imageSize.height; // the scale needed to perfectly fit the image height-wise
CGFloat minScale = MIN(xScale, yScale); // use minimum of these to allow the image to become fully visible
// on high resolution screens we have double the pixel density, so we will be seeing every pixel if we limit the
// maximum zoom scale to 0.5.
CGFloat maxScale = 1.0 / [[UIScreen mainScreen] scale];
// CGFloat maxScale = 4.0 / [[UIScreen mainScreen] scale];
// don't let minScale exceed maxScale. (If the image is smaller than the screen, we don't want to force it to be zoomed.)
if (minScale > maxScale) {
minScale = maxScale;
}
self.maximumZoomScale = maxScale;
self.minimumZoomScale = minScale;
}
#end
Add this method:
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return imageView;
}
You need not do that much in fact. Create a ScrollView. Create imageview with bigger image. Set imageview's frame and scrollview's frame similar. Set the contentsize of scrollview with the images' width and height. Now, from scrollview's delegate method, do following:
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return imageView;
}
I have a question in scroll view.
Right now I wrote a sample about image gallery with scroll view. I have plenty of images added into a scroll view. Each time, it display 3 images, the question is how can measure the scrolling properly. For example: the minimum each scroll is moving 1 image. Right now, I think each time I scroll, the minimum images moving are 3. That make me can't stop at the right image I want to see.
Below is the code.
- (void)layoutScrollImages
{
UIImageView *view = nil;
NSArray *subviews = [scroll subviews];
// reposition all image subviews in a horizontal serial fashion
CGFloat curXLoc = 0;
for (view in subviews)
{
if ([view isKindOfClass:[UIImageView class]] && view.tag > 0)
{
CGRect frame = view.frame;
frame.origin = CGPointMake(curXLoc, 0);
view.frame = frame;
curXLoc += (kScrollObjWidth);
}
}
// set the content size so it can be scrollable
[scroll setContentSize:CGSizeMake((kNumImages * kScrollObjWidth), [scroll bounds].size.height)];
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[super viewDidLoad];
// 1. setup the scrollview for multiple images and add it to the view controller
//
// note: the following can be done in Interface Builder, but we show this in code for clarity
[scroll setBackgroundColor:[UIColor blackColor]];
[scroll setCanCancelContentTouches:NO];
scroll.indicatorStyle = UIScrollViewIndicatorStyleWhite;
scroll.clipsToBounds = YES; // default is NO, we want to restrict drawing within our scrollview
scroll.scrollEnabled = YES;
// pagingEnabled property default is NO, if set the scroller will stop or snap at each photo
// if you want free-flowing scroll, don't set this property.
scroll.pagingEnabled = YES;
// load all the images from our bundle and add them to the scroll view
NSUInteger i;
for (i = 1; i <= kNumImages; i++)
{
NSString *imageName = [NSString stringWithFormat:#"image%d.jpg", i];
UIImage *image = [UIImage imageNamed:imageName];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
// setup each frame to a default height and width, it will be properly placed when we call "updateScrollList"
CGRect rect = imageView.frame;
rect.size.height = kScrollObjHeight;
rect.size.width = kScrollObjWidth;
imageView.frame = rect;
imageView.tag = i; // tag our images for later use when we place them in serial fashion
[scroll addSubview:imageView];
[imageView release];
}
[self layoutScrollImages];
}
Use this code......
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if(scroll.contentOffset.y> 320)
{
int y = scrollView.contentOffset.y;
y = y/3;
[scrollView setContentOffset:CGPointMake(0, y)];
}
}
Hope, this will help you...Chill
Subclass the content view and overwrite this function:
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
if ([self pointInside:point withEvent:event]) {
if ([[self subviews] count] > 0) {
//force return of first child, if exists
return [[self subviews] objectAtIndex:0];
} else {
return self;
}
}
return nil; }
See detail at https://github.com/taufikobet/ScrollViewCustomPaging.
I am trying to duplicate the Photos app on the iPhone. Meaning, a scrollview with multiple images, and each image can be pinched to zoom in/out.
The Apple ScrollViewSuite example code only deals with 1 image inside of a scrollview. I have found that with multiple images, scrolling through the images becomes unpredictable. Also, the view becomes uncentered after pinching to zoom.
I have found this on Stack Overflow: Zoom UIScrollView with multiple images
However, what am I supposed to write in the scrollview delegate functions?
This is what I found to work. Supports multiple images with paging and zooming. Enjoy!
#define VIEW_FOR_ZOOM_TAG (1)
#implementation SVViewController
- (void)viewDidLoad {
[super viewDidLoad];
UIScrollView *mainScrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds];
mainScrollView.pagingEnabled = YES;
mainScrollView.showsHorizontalScrollIndicator = NO;
mainScrollView.showsVerticalScrollIndicator = NO;
CGRect innerScrollFrame = mainScrollView.bounds;
for (NSInteger i = 0; i < 3; i++) {
UIImageView *imageForZooming = [[UIImageView alloc] initWithImage:[UIImage imageNamed:
[NSString stringWithFormat:#"page%d", i + 1]]];
imageForZooming.tag = VIEW_FOR_ZOOM_TAG;
UIScrollView *pageScrollView = [[UIScrollView alloc] initWithFrame:innerScrollFrame];
pageScrollView.minimumZoomScale = 1.0f;
pageScrollView.maximumZoomScale = 2.0f;
pageScrollView.zoomScale = 1.0f;
pageScrollView.contentSize = imageForZooming.bounds.size;
pageScrollView.delegate = self;
pageScrollView.showsHorizontalScrollIndicator = NO;
pageScrollView.showsVerticalScrollIndicator = NO;
[pageScrollView addSubview:imageForZooming];
[mainScrollView addSubview:pageScrollView];
if (i < 2) {
innerScrollFrame.origin.x += innerScrollFrame.size.width;
}
}
mainScrollView.contentSize = CGSizeMake(innerScrollFrame.origin.x +
innerScrollFrame.size.width, mainScrollView.bounds.size.height);
[self.view addSubview:mainScrollView];
}
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return [scrollView viewWithTag:VIEW_FOR_ZOOM_TAG];
}
- (NSUInteger)supportedInterfaceOrientations {
return UIInterfaceOrientationMaskPortrait;
}
- (BOOL)shouldAutorotate {
return NO;
}
#end
So I want to make a sliding image view gallery with preview of next and previous images. I want it to show partly the next image (if available) and the previous image (if there was one). What do I mean exactly? Assuming there are 3 images at all.
the very 1st image. So I want the 1st image to display at center (horizontally) and a part of next image as well, so user could see there is at least 1 image remaining.
Schematically: [&&&] [
the 2nd image. I want to show a part of 1st image (at left side) and a 2nd image (at center) and a part of 3rd image (at right). So any user could easily determine there is at least 1 image behind and at least 1 image remains.
Schematically: ] [###] [
the 3rd and last image. There are a part of 2nd image (at left) and 3rd image at center. So there is no doubt that there is no image remains and at least 1 image behind.
Schematically: ] [###].
So how to implement this idea in the right way?
I did it so:
// ItemGalleryVC.h
#import <UIKit/UIKit.h>
#interface ItemGalleryVC : UIViewController <UIScrollViewDelegate>{
IBOutlet UIScrollView *scrollView;
IBOutlet UIPageControl *pageControl;
BOOL pageControlIsChangingPage;
}
#property (nonatomic, retain) IBOutlet UIScrollView *scrollView;
#property (nonatomic, retain) IBOutlet UIPageControl *pageControl;
- (IBAction)changePage:(id)sender;
- (void)setupPage;
#end
and
// ItemGalleryVC.m
#import "ItemGalleryVC.h"
#implementation ItemGalleryVC
#synthesize scrollView;
#synthesize pageControl;
- (void)viewDidLoad
{
[self setupPage];
[super viewDidLoad];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
- (void)viewDidUnload
{
[scrollView release];
[pageControl release];
}
- (void)dealloc
{
[super dealloc];
}
- (void)setupPage
{
NSLog(#"setupPage");
scrollView.delegate = self;
[scrollView setCanCancelContentTouches:NO];
scrollView.indicatorStyle = UIScrollViewIndicatorStyleWhite;
scrollView.clipsToBounds = YES;
scrollView.scrollEnabled = YES;
scrollView.pagingEnabled = YES;
NSUInteger nimages = 0;
CGFloat cx = 0; //the total scroll width
CGRect rect = scrollView.frame; //image frame
rect.size.height = scrollView.frame.size.height;
rect.size.width = scrollView.frame.size.width - 100; //50px at left and right sides
rect.origin.y = scrollView.frame.origin.y+5; //down by 5 px
for (; ; nimages++) {
NSString *imageName = [NSString stringWithFormat:#"item_image0%d.jpg", (nimages + 1)];
UIImage *image = [UIImage imageNamed:imageName];
if (image == nil) {
NSLog(#"no more imagez");
break;
}
NSLog(#"setting up img: %#",imageName);
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
rect.origin.x = cx+50; //move right by 50px
imageView.frame = rect;
imageView.contentMode = UIViewContentModeScaleAspectFit;
imageView.backgroundColor = [UIColor blackColor];
[scrollView addSubview:imageView];
[imageView release];
cx += rect.size.width+30;
}
self.pageControl.numberOfPages = nimages;
// for the last image to be centered frame need to be wider by 100px
[scrollView setContentSize:CGSizeMake(cx+100, [scrollView bounds].size.height)];
}
- (void)scrollViewDidScroll:(UIScrollView *)_scrollView
{
if (pageControlIsChangingPage) {
return;
}
// calc page number according to its frame size
CGFloat pageWidth = _scrollView.frame.size.width;
int page = floor((_scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
pageControl.currentPage = page;
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)_scrollView
{
pageControlIsChangingPage = NO;
// this code added to correct image position (frame width) when using touch sliding
CGRect frame = scrollView.frame;
frame.origin.x = (frame.size.width-70) * pageControl.currentPage;
frame.origin.y = 0;
[scrollView scrollRectToVisible:frame animated:YES];
}
- (IBAction)changePage:(id)sender
{
/*
* Change the scroll view
*/
CGRect frame = scrollView.frame;
frame.origin.x = (frame.size.width-70) * pageControl.currentPage;
frame.origin.y = 0;
[scrollView scrollRectToVisible:frame animated:YES];
pageControlIsChangingPage = NO;
}
#end
The problem is the frame size (it's width). Its ScrollView.frame size but i need it smaller (less wide).
With this code If I use page control only to switch images everything works fine and animation looks right. But if I use sliding its totally bad.
The code above contains a fix (in scrollViewDidEndDecelerating) but it still works not native while sliding and it works good for 3 images. It slides to incorrect position and than it move a bit back. If there are more than 3 images slider wont slide to the last image.
I'm curious if there is some other and proper way to do it.
Actually I found another soultion - http://www.cocoacontrols.com/platforms/ios/controls/hgpagescrollview
this control is what I want.
Try, and the scrollView will draw outside its bounds.
[scrollView setClipsToBounds:NO];
I have been playing around with one of the iPhone examples from Apple' web site (ScrollViewSuite) . I am trying to tweak it a bit so that when I rotate the the iPad the image will fit into the screen in landscape mode vertical. I have been successful in getting the image to rotate, but the image is larger than the height of the landscape screen, so the bottom is below the screen. I would like to image to scale to the height of the landscape screen.
I have been playing around with various autoSizingMask attributes without success.
The imageView is called "zoomView" this is the actual image which loads into a scrollView called imageScrollView.
I am trying to achieve the screen to rotate and look like this.... sorry only 1 link allowed new user :(
olsonvox.com/photos/correct.png
However, this is what My screen is looking like.
http://www.olsonvox.com/photos/incorrect.png
I would really appreciate some advice or guidance. Below is the RootViewController.m for the project.
Blade
#
import "RootViewController.h"
#define ZOOM_VIEW_TAG 100
#define ZOOM_STEP 1.5
#define THUMB_HEIGHT 150
#define THUMB_V_PADDING 25
#define THUMB_H_PADDING 25
#define CREDIT_LABEL_HEIGHT 25
#define AUTOSCROLL_THRESHOLD 30
#interface RootViewController (ViewHandlingMethods)
- (void)toggleThumbView;
- (void)pickImageNamed:(NSString *)name;
- (NSArray *)imageNames;
- (void)createThumbScrollViewIfNecessary;
- (void)createSlideUpViewIfNecessary;
#end
#interface RootViewController (AutoscrollingMethods)
- (void)maybeAutoscrollForThumb:(ThumbImageView *)thumb;
- (void)autoscrollTimerFired:(NSTimer *)timer;
- (void)legalizeAutoscrollDistance;
- (float)autoscrollDistanceForProximityToEdge:(float)proximity;
#end
#interface RootViewController (UtilityMethods)
- (CGRect)zoomRectForScale:(float)scale withCenter:(CGPoint)center;
#end
#implementation RootViewController
- (void)loadView {
[super loadView];
imageScrollView = [[UIScrollView alloc] initWithFrame:[[self view]bounds]];
// this code makes the image resize to the width and height properly.
imageScrollView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin| UIViewAutoresizingFlexibleBottomMargin| UIViewAutoresizingFlexibleBottomMargin;
// TRY SETTNG CENTER HERE SOMEHOW>....
[imageScrollView setBackgroundColor:[UIColor blackColor]];
[imageScrollView setDelegate:self];
[imageScrollView setBouncesZoom:YES];
[[self view] addSubview:imageScrollView];
[self toggleThumbView];
// intitializes with the first image.
[self pickImageNamed:#"lookbook1"];
}
- (void)dealloc {
[imageScrollView release];
[slideUpView release];
[thumbScrollView release];
[super dealloc];
}
#pragma mark UIScrollViewDelegate methods
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
UIView *view = nil;
if (scrollView == imageScrollView) {
view = [imageScrollView viewWithTag:ZOOM_VIEW_TAG];
}
return view;
}
/************************************** NOTE **************************************/
/* The following delegate method works around a known bug in zoomToRect:animated: */
/* In the next release after 3.0 this workaround will no longer be necessary */
/**********************************************************************************/
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale {
[scrollView setZoomScale:scale+0.01 animated:NO];
[scrollView setZoomScale:scale animated:NO];
}
#pragma mark TapDetectingImageViewDelegate methods
- (void)tapDetectingImageView:(TapDetectingImageView *)view gotSingleTapAtPoint:(CGPoint)tapPoint {
// Single tap shows or hides drawer of thumbnails.
[self toggleThumbView];
}
- (void)tapDetectingImageView:(TapDetectingImageView *)view gotDoubleTapAtPoint:(CGPoint)tapPoint {
// double tap zooms in
float newScale = [imageScrollView zoomScale] * ZOOM_STEP;
CGRect zoomRect = [self zoomRectForScale:newScale withCenter:tapPoint];
[imageScrollView zoomToRect:zoomRect animated:YES];
}
- (void)tapDetectingImageView:(TapDetectingImageView *)view gotTwoFingerTapAtPoint:(CGPoint)tapPoint {
// two-finger tap zooms out
float newScale = [imageScrollView zoomScale] / ZOOM_STEP;
CGRect zoomRect = [self zoomRectForScale:newScale withCenter:tapPoint];
[imageScrollView zoomToRect:zoomRect animated:YES];
}
#pragma mark ThumbImageViewDelegate methods
- (void)thumbImageViewWasTapped:(ThumbImageView *)tiv {
[self pickImageNamed:[tiv imageName]];
[self toggleThumbView];
}
- (void)thumbImageViewStartedTracking:(ThumbImageView *)tiv {
[thumbScrollView bringSubviewToFront:tiv];
}
// CONTROLS DRAGGING AND DROPPING THUMBNAILS...
- (void)thumbImageViewMoved:(ThumbImageView *)draggingThumb {
// check if we've moved close enough to an edge to autoscroll, or far enough away to stop autoscrolling
[self maybeAutoscrollForThumb:draggingThumb];
/* The rest of this method handles the reordering of thumbnails in the thumbScrollView. See */
/* ThumbImageView.h and ThumbImageView.m for more information about how this works. */
// we'll reorder only if the thumb is overlapping the scroll view
if (CGRectIntersectsRect([draggingThumb frame], [thumbScrollView bounds])) {
BOOL draggingRight = [draggingThumb frame].origin.x > [draggingThumb home].origin.x ? YES : NO;
/* we're going to shift over all the thumbs who live between the home of the moving thumb */
/* and the current touch location. A thumb counts as living in this area if the midpoint */
/* of its home is contained in the area. */
NSMutableArray *thumbsToShift = [[NSMutableArray alloc] init];
// get the touch location in the coordinate system of the scroll view
CGPoint touchLocation = [draggingThumb convertPoint:[draggingThumb touchLocation] toView:thumbScrollView];
// calculate minimum and maximum boundaries of the affected area
float minX = draggingRight ? CGRectGetMaxX([draggingThumb home]) : touchLocation.x;
float maxX = draggingRight ? touchLocation.x : CGRectGetMinX([draggingThumb home]);
// iterate through thumbnails and see which ones need to move over
for (ThumbImageView *thumb in [thumbScrollView subviews]) {
// skip the thumb being dragged
if (thumb == draggingThumb) continue;
// skip non-thumb subviews of the scroll view (such as the scroll indicators)
if (! [thumb isMemberOfClass:[ThumbImageView class]]) continue;
float thumbMidpoint = CGRectGetMidX([thumb home]);
if (thumbMidpoint >= minX && thumbMidpoint <= maxX) {
[thumbsToShift addObject:thumb];
}
}
// shift over the other thumbs to make room for the dragging thumb. (if we're dragging right, they shift to the left)
float otherThumbShift = ([draggingThumb home].size.width + THUMB_H_PADDING) * (draggingRight ? -1 : 1);
// as we shift over the other thumbs, we'll calculate how much the dragging thumb's home is going to move
float draggingThumbShift = 0.0;
// send each of the shifting thumbs to its new home
for (ThumbImageView *otherThumb in thumbsToShift) {
CGRect home = [otherThumb home];
home.origin.x += otherThumbShift;
[otherThumb setHome:home];
[otherThumb goHome];
draggingThumbShift += ([otherThumb frame].size.width + THUMB_H_PADDING) * (draggingRight ? 1 : -1);
}
// change the home of the dragging thumb, but don't send it there because it's still being dragged
CGRect home = [draggingThumb home];
home.origin.x += draggingThumbShift;
[draggingThumb setHome:home];
}
}
- (void)thumbImageViewStoppedTracking:(ThumbImageView *)tiv {
// if the user lets go of the thumb image view, stop autoscrolling
[autoscrollTimer invalidate];
autoscrollTimer = nil;
}
#pragma mark Autoscrolling methods
- (void)maybeAutoscrollForThumb:(ThumbImageView *)thumb {
autoscrollDistance = 0;
// only autoscroll if the thumb is overlapping the thumbScrollView
if (CGRectIntersectsRect([thumb frame], [thumbScrollView bounds])) {
CGPoint touchLocation = [thumb convertPoint:[thumb touchLocation] toView:thumbScrollView];
float distanceFromLeftEdge = touchLocation.x - CGRectGetMinX([thumbScrollView bounds]);
float distanceFromRightEdge = CGRectGetMaxX([thumbScrollView bounds]) - touchLocation.x;
if (distanceFromLeftEdge < AUTOSCROLL_THRESHOLD) {
autoscrollDistance = [self autoscrollDistanceForProximityToEdge:distanceFromLeftEdge] * -1; // if scrolling left, distance is negative
} else if (distanceFromRightEdge < AUTOSCROLL_THRESHOLD) {
autoscrollDistance = [self autoscrollDistanceForProximityToEdge:distanceFromRightEdge];
}
}
// if no autoscrolling, stop and clear timer
if (autoscrollDistance == 0) {
[autoscrollTimer invalidate];
autoscrollTimer = nil;
}
// otherwise create and start timer (if we don't already have a timer going)
else if (autoscrollTimer == nil) {
autoscrollTimer = [NSTimer scheduledTimerWithTimeInterval:(1.0 / 60.0)
target:self
selector:#selector(autoscrollTimerFired:)
userInfo:thumb
repeats:YES];
}
}
- (float)autoscrollDistanceForProximityToEdge:(float)proximity {
// the scroll distance grows as the proximity to the edge decreases, so that moving the thumb
// further over results in faster scrolling.
return ceilf((AUTOSCROLL_THRESHOLD - proximity) / 5.0);
}
- (void)legalizeAutoscrollDistance {
// makes sure the autoscroll distance won't result in scrolling past the content of the scroll view
float minimumLegalDistance = [thumbScrollView contentOffset].x * -1;
float maximumLegalDistance = [thumbScrollView contentSize].width - ([thumbScrollView frame].size.width + [thumbScrollView contentOffset].x);
autoscrollDistance = MAX(autoscrollDistance, minimumLegalDistance);
autoscrollDistance = MIN(autoscrollDistance, maximumLegalDistance);
}
- (void)autoscrollTimerFired:(NSTimer*)timer {
[self legalizeAutoscrollDistance];
// autoscroll by changing content offset
CGPoint contentOffset = [thumbScrollView contentOffset];
contentOffset.x += autoscrollDistance;
[thumbScrollView setContentOffset:contentOffset];
// adjust thumb position so it appears to stay still
ThumbImageView *thumb = (ThumbImageView *)[timer userInfo];
[thumb moveByOffset:CGPointMake(autoscrollDistance, 0)];
}
#pragma mark View handling methods
- (void)toggleThumbView {
[self createSlideUpViewIfNecessary]; // no-op if slideUpView has already been created
CGRect frame = [slideUpView frame];
if (thumbViewShowing) {
frame.origin.y = 0;
} else {
frame.origin.y = -225;
}
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.3];
[slideUpView setFrame:frame];
[UIView commitAnimations];
thumbViewShowing = !thumbViewShowing;
}
- (void)pickImageNamed:(NSString *)name {
// first remove previous image view, if any
[[imageScrollView viewWithTag:ZOOM_VIEW_TAG] removeFromSuperview];
UIImage *image = [UIImage imageNamed:[NSString stringWithFormat:#"%#.jpg", name]];
TapDetectingImageView *zoomView = [[TapDetectingImageView alloc] initWithImage:image];
zoomView.autoresizingMask = UIViewAutoresizingFlexibleWidth ;
[zoomView setDelegate:self];
[zoomView setTag:ZOOM_VIEW_TAG];
[imageScrollView addSubview:zoomView];
[imageScrollView setContentSize:[zoomView frame].size];
[zoomView release];
// choose minimum scale so image width fits screen
float minScale = [imageScrollView frame].size.width / [zoomView frame].size.width;
[imageScrollView setMinimumZoomScale:minScale];
[imageScrollView setZoomScale:minScale];
[imageScrollView setContentOffset:CGPointZero];
}
- (NSArray *)imageNames {
// the filenames are stored in a plist in the app bundle, so create array by reading this plist
NSString *path = [[NSBundle mainBundle] pathForResource:#"Images" ofType:#"plist"];
NSData *plistData = [NSData dataWithContentsOfFile:path];
NSString *error; NSPropertyListFormat format;
NSArray *imageNames = [NSPropertyListSerialization propertyListFromData:plistData
mutabilityOption:NSPropertyListImmutable
format:&format
errorDescription:&error];
if (!imageNames) {
NSLog(#"Failed to read image names. Error: %#", error);
[error release];
}
return imageNames;
}
- (void)createSlideUpViewIfNecessary {
if (!slideUpView) {
[self createThumbScrollViewIfNecessary];
CGRect bounds = [[self view] bounds];
float thumbHeight = [thumbScrollView frame].size.height;
float labelHeight = CREDIT_LABEL_HEIGHT;
// create label giving credit for images
UILabel *creditLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, thumbHeight, bounds.size.width, labelHeight)];
[creditLabel setBackgroundColor:[UIColor clearColor]];
[creditLabel setTextColor:[UIColor whiteColor]];
// [creditLabel setFont:[UIFont fontWithName:#"Helvetica" size:16]];
// [creditLabel setText:#"SAMPLE TEXT"];
[creditLabel setTextAlignment:UITextAlignmentCenter];
// create container view that will hold scroll view and label
CGRect frame = CGRectMake(0.0, -225.00, bounds.size.width+256, thumbHeight + labelHeight);
slideUpView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleTopMargin;
slideUpView = [[UIView alloc] initWithFrame:frame];
[slideUpView setBackgroundColor:[UIColor blackColor]];
[slideUpView setOpaque:NO];
[slideUpView setAlpha:.75];
[[self view] addSubview:slideUpView];
// add subviews to container view
[slideUpView addSubview:thumbScrollView];
[slideUpView addSubview:creditLabel];
[creditLabel release];
}
}
- (void)createThumbScrollViewIfNecessary {
if (!thumbScrollView) {
float scrollViewHeight = THUMB_HEIGHT + THUMB_V_PADDING;
float scrollViewWidth = [[self view] bounds].size.width;
thumbScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, scrollViewWidth, scrollViewHeight)];
[thumbScrollView setCanCancelContentTouches:NO];
[thumbScrollView setClipsToBounds:NO];
// now place all the thumb views as subviews of the scroll view
// and in the course of doing so calculate the content width
float xPosition = THUMB_H_PADDING;
for (NSString *name in [self imageNames]) {
UIImage *thumbImage = [UIImage imageNamed:[NSString stringWithFormat:#"%#_thumb.jpg", name]];
if (thumbImage) {
ThumbImageView *thumbView = [[ThumbImageView alloc] initWithImage:thumbImage];
[thumbView setDelegate:self];
[thumbView setImageName:name];
CGRect frame = [thumbView frame];
frame.origin.y = THUMB_V_PADDING;
frame.origin.x = xPosition;
[thumbView setFrame:frame];
[thumbView setHome:frame];
[thumbScrollView addSubview:thumbView];
[thumbView release];
xPosition += (frame.size.width + THUMB_H_PADDING);
}
}
[thumbScrollView setContentSize:CGSizeMake(xPosition, scrollViewHeight)];
}
}
#pragma mark Utility methods
- (CGRect)zoomRectForScale:(float)scale withCenter:(CGPoint)center {
CGRect zoomRect;
// the zoom rect is in the content view's coordinates.
// At a zoom scale of 1.0, it would be the size of the imageScrollView's bounds.
// As the zoom scale decreases, so more content is visible, the size of the rect grows.
zoomRect.size.height = [imageScrollView frame].size.height / scale;
zoomRect.size.width = [imageScrollView frame].size.width / scale;
// choose an origin so as to get the right center.
zoomRect.origin.x = center.x - (zoomRect.size.width / 2.0);
zoomRect.origin.y = center.y - (zoomRect.size.height / 2.0);
return zoomRect;
}
#pragma mark -
#pragma mark Rotation support
// Ensure that the view controller supports rotation and that the split view can therefore show in both portrait and landscape.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
return YES;
}
#end
If you've set up your UIScrollView in a Nib file, make sure it is resizing properly when rotated (Use the Autosizing controls in the Size Inspector in Interface Builder: Both sets of arrows inside the box should be red)
Then use this to rescale when the iPad changes orientation:
- (void)willAnimateSecondHalfOfRotationFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation duration:(NSTimeInterval)duration{
//if your UIImageView is called zoomView use this
CGRect zoomRect=CGRectMake(0,0,zoomView.frame.size.width, zoomView.frame.size.height);
[scrollView zoomToRect:zoomRect animated:YES];}
(Sorry about the bad placement of the {} but it wasn't pasting properly as code for some reason)
Hope this helps!