Most of the sample code on the net assumes your UIScrollView will be full-screen.
I'm trying to create a UIScrollView with just a UIImageView inside it, and just want to be able to pinch zoom as would normally happen. My UIScrollView only fills a part of the screen, so I can't just use autosizing to keep it the right size, as the sample applications seem to do.
The closest I've got is to add this to the UIScrollViewDelegate:
- (void)scrollViewDidZoom:(UIScrollView *)scrollView {
CGPoint cOffset = imageScrollView.contentOffset;
float cScale = imageScrollView.contentScaleFactor;
CGRect imageFrame = ptImage.frame;
float scale = scrollView.zoomScale;
imageFrame.size.width *= scale;
imageFrame.size.height *= scale;
ptImage.frame = imageFrame;
scrollView.zoomScale = 1.0;
scrollView.frame = CGRectMake(0.0, 0.0, scrollContainerView.frame.size.width, scrollContainerView.frame.size.height);
scrollView.bounds = CGRectMake(cOffset.x * cScale * scale , cOffset.y * cScale * scale, scrollView.bounds.size.width, scrollView.bounds.size.height);
scrollView.contentSize = imageFrame.size;
}
The only problem here is that the bounds offset (scrollView.bounds = ...) is incorrect.
Surely it's far simpler than I've done here?
Any help?
Try returning your UIImageView in :
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
And remove the code you put in the didZoom method and see if that works.
Related
I have made UIScrollView with three UIScrollViews inside and UImageView inside those three scollviews (Like in this answer: https://stackoverflow.com/a/25768875/2911156). Almost everything works, but zooming in landscape mode is broken. When user zoom in image, after zooming is finished, image is moved to the right edge and cut. How to center image after zoom, or what is wrong here?
UI Structure:
Main Scroll view Constraints:
Image View constraint (all three had same pattern)
I'm not doing much in code (ScrollViews and ImageViews are based on autolayout), just done this:
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return _photoImage;
}
and this:
- (void) setMaxMinZoomScaleForBonds {
self.contentInset = UIEdgeInsetsZero; //need to reset it before load image, because previous insets can be wrong
self.minimumZoomScale = 1.0;
self.zoomScale = 1.0;
self.maximumZoomScale = 2*[UIScreen mainScreen].scale;
}
One more thing done, but it does not work:
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(CGFloat)scale {
//center image when zooming.
CGFloat x = 0;
CGFloat y = 0;
CGFloat screenWidth = [[UIScreen mainScreen] bounds].size.width;
CGFloat screenHight = [[UIScreen mainScreen] bounds].size.height;
CGFloat viewWidth = view.frame.size.width;
CGFloat viewHight = view.frame.size.height;
if(viewWidth < screenWidth)
x = screenWidth/ 2;
if(viewHight < screenHight)
y = screenHight / 2 ;
if(scale<=1.1)
self.contentInset = UIEdgeInsetsZero;
else
self.contentInset = UIEdgeInsetsMake(y, x, y, x);
}
That is all related to zoom action.
I have created a paginated UIScrollView with three subviews. It works great when testing on an iPhone 5 in landscape (the orientation I designed at) but it breaks whenever the device resolution changes.
How can I make the frame scale to the correct resolution, no matter the device or orientation?
- (void)viewDidLoad {
CGRect frame;
frame.origin.x = self.scrollView.frame.size.width * i;
frame.origin.y = 0;
frame.size = self.scrollView.frame.size;
}
- (IBAction)changePage {
CGRect frame;
frame.origin.x = self.scrollView.frame.size.width * self.pageControl.currentPage;
frame.origin.y = 0;
frame.size = self.scrollView.frame.size;
[self.scrollView scrollRectToVisible:frame animated:YES];
pageControlBeingUsed = YES;
}
Put your scroll view inside another, custom view. In the custom view, implement layoutSubviews something like this.
#interface ViewScalesOneSubview : UIView
#property UIView *scalingSubview;//subview to scale
#end
#implementation ViewScalesOneSubview
-(void) layoutSubviews {
[super layoutSubviews];
CGRect parentBounds = [self bounds];
CGRect childBounds = [scalingSubview bounds];//unscaled
CGFloat scale = parentBounds.width / childBounds.width;
CGAffineTransform transform = CGAffineTransformMakeScale( scale , scale );
//fiddle with x,y translation to position as you like
scalingSubview.transform = transform;
}
#end
Give the custom view autoresizing so it fits the window or whatever container and changes with rotation. Do not give the scroll view autoresizing, as it will conflict with this custom layoutSubviews. When the custom view changes size, it will scale the scalingSubview to fit. By using the same scale for both axis, it will preserve aspect ratio. You could scale to fit instead, or use height instead of width or whatever.
Edit:
To resize the view, as opposed to scaling the view, set the autoresizing mask.
scrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
https://developer.apple.com/library/ios/documentation/uikit/reference/UIView_Class/UIView/UIView.html#//apple_ref/occ/instp/UIView/autoresizingMask
You can also do this in interface builder.
I suppose it's not strictly in line with Apple guidelines but I guess it must be possible somehow. I'd like to change the height of navigation bar inside UINavigationController and the height of UIBarButtonItem elements inside that bar.
Using a trick from this question I managed to change the height of navigation bar but I can see no way of adjusting the height of bar button items.
If anyone knows how to change the size of bar button items, please help me out.
This is my solution. It works very well.
#interface UINavigationBar (CustomHeight)
#end
#implementation UINavigationBar (CustomHeight)
- (CGSize)sizeThatFits:(CGSize)size {
// Change navigation bar height. The height must be even, otherwise there will be a white line above the navigation bar.
CGSize newSize = CGSizeMake(self.frame.size.width, 40);
return newSize;
}
-(void)layoutSubviews {
[super layoutSubviews];
// Make items on navigation bar vertically centered.
int i = 0;
for (UIView *view in self.subviews) {
NSLog(#"%i. %#", i, [view description]);
i++;
if (i == 0)
continue;
float centerY = self.bounds.size.height / 2.0f;
CGPoint center = view.center;
center.y = centerY;
view.center = center;
}
}
Maybe this tutorial about a customized navbar will help you: Recreating the iBooks wood themed navigation bar
If you create a BarButtonItem with a UIImageView you can maybe change the framesize/boundsize of the custom UIImageView
UIImageView* imageView = [[[UIImageView alloc] initWithFrame:navigationController.navigationBar.frame] autorelease];
imageView.contentMode = UIViewContentModeLeft;
imageView.image = [UIImage imageNamed:#"NavBar-iPhone.png"];
[navigationController.navigationBar insertSubview:imageView atIndex:0];
So for your need you would give the -initWithFrame method appropriate values.
static CGFloat const CustomNavigationBarHeight = 74;
#implementation WTNavigationBar
- (CGSize)sizeThatFits:(CGSize)size{
size.width = 1024;
size.height = CustomNavigationBarHeight;
return size;
}
-(void)layoutSubviews {
[super layoutSubviews];
for (UIView *view in self.subviews) {
SFLog(#"view.class=%#",[view class]);
if ([view isKindOfClass:NSClassFromString(#"UINavigationItemButtonView")]) {
float centerY = self.bounds.size.height / 2.0f;
CGPoint center = view.center;
center.y = centerY;
view.center = center;
}
}
}
#end
in my iPad app,which has a fixed landscape orientation,I found I have to hardcode the size's width
I managed to do something similar by subclassing UINavigationBar and overriding -layoutSubviews. The code looks like:
-(void)layoutSubviews {
[super layoutSubviews];
int i = 0;
for (UIView *view in self.subviews) {
NSLog(#"%i. %#", i++, [view description]);
if ([view isKindOfClass:NSClassFromString(#"UINavigationButton")]) {
view.frame = CGRectMake(0, 0, 100, 50);
}
}
}
If you need to know how to subclass UINavigationBar, have a look at this very good answer.
I am not really sure about the NSClassFromString(#"UINavigationButton")] part. It works, but I did this as an experiment, and I'm not sure if this will get approved by Apple. I hope someone with a better knowledge might shed some light.
For the UINavigationbar
In iOS SDK 4.3 and beyond, there is a way (hack) to change the height of the UINavigationBar.
To change the height of UINavigationController, change its frame size in viewWillAppear:animated: function. Then, the height will stay customized throughout whole app.
For the UIBarButtonItems
I've actually run into this myself and the only thing I could come up with was leveraging initWithCustomView and passing in a UIButton with a defined frame.
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
/*
* Insert button styling
*/
button.frame = CGRectMake(0, 0, width, height);
UIBarButtonItem *barButtonItem = [[UIBarButtonItem alloc] initWithCustomView:button];
Otherwise UIBarButtonItem only has a width property that can be set but unfortunately not a height property. Another nifty thing I've done with initWithCustomView is to pass in a toolbar with a button and other things like activity indicators. Hope this helps.
How badly do you want this? And, how thin (or thick) do you want to make your navbar?
One approach would be to set the transform of the navbar to scale and translate it. If you scale it too much the title and button text will look wonky, but if you only need to shave a few pixels you might be allright.
Here's the result of scaling it to be 75% of full height (33 pixels tall):
And the code that produced this:
- (void)viewDidLoad
{
[super viewDidLoad];
self.navigationItem.title = #"Thin Navigation Bar";
self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc] initWithTitle: #"Press Me" style:UIBarButtonItemStyleBordered target: nil action: NULL ] autorelease];
CGFloat scale = .75;
CGFloat cy = 44.0 - ( 44.0 * scale );
self.navigationController.navigationBar.transform = CGAffineTransformScale( CGAffineTransformMakeTranslation( 0, -cy / 2.0 ), 1.0, scale ) ;
}
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
CGFloat scale = .75;
CGFloat cy = 44.0 - ( 44.0 * scale );
CGRect r = self.view.frame;
r.origin.y -= cy;
r.size.height += cy;
self.view.frame = r;
}
Now, this does have a number of problems, which may or may not be solvable. #1 is that you're fighting with the UINavigationController to size and position the navbar and the view-controller views. Animating between view controllers that use this technique is likely going to look weird.
I'd be curious if you could solve the related issues...
One last thought: If you dont use a UINavigationController then there really aren't a whole lot of issues with this other than squished text. Or, you could use a navigation controller but hide the default navbar, and add the thin navbar to each of your child-view controller views. You could even subclass UINavigationBar and set the transform from within:
#interface TSThinNavBar : UINavigationBar
{
}
#end
#implementation TSThinNavBar
// assuming we'll always be constructed from a nib
- (id) initWithCoder:(NSCoder *)aDecoder
{
self = [super initWithCoder: aDecoder];
if ( self != nil )
{
CGFloat scale = .75;
CGFloat cy = 44.0 - ( 44.0 * scale );
self.transform = CGAffineTransformScale( CGAffineTransformMakeTranslation( 0, -cy / 2.0 ), 1.0, scale ) ;
}
return self;
}
#end
I am trying to create a higher resolution image of a UIView, specifically UITextView.
This question and answer is exactly what I am trying to figure out:
Retain the resolution of the label after scaling in iphone
But, when I do the same, my text is still blurry:
self.view.transform = CGAffineTransformMakeScale(2.f, 2.f);
[myText setContentScaleFactor:2.f]; // myText is a subview of self.view object
I have also tried the same in the Apple sample project "UICatalog" to UILabel and it is also blurry.
I can't understand why it would work for Warrior from the other question and not for me. I would have asked there — but I can't seem to leave a comment or a question there.
Setting the contentScaleFactor and contentsScale is in fact the key, as #dbotha pointed out, however you have to walk the view and layer hierarchies separately in order to reach every internal CATiledLayer that actually does the text rendering. Adding the screen scale might also make sense.
So the correct implementation would be something like this:
- (void)updateForZoomScale:(CGFloat)zoomScale {
CGFloat screenAndZoomScale = zoomScale * [UIScreen mainScreen].scale;
// Walk the layer and view hierarchies separately. We need to reach all tiled layers.
[self applyScale:(zoomScale * [UIScreen mainScreen].scale) toView:self.textView];
[self applyScale:(zoomScale * [UIScreen mainScreen].scale) toLayer:self.textView.layer];
}
- (void)applyScale:(CGFloat)scale toView:(UIView *)view {
view.contentScaleFactor = scale;
for (UIView *subview in view.subviews) {
[self applyScale:scale toView:subview];
}
}
- (void)applyScale:(CGFloat)scale toLayer:(CALayer *)layer {
layer.contentsScale = scale;
for (CALayer *sublayer in layer.sublayers) {
[self applyScale:scale toLayer:sublayer];
}
}
UITextView has textInputView property, which "both draws the text and provides a coordinate system" (https://developer.apple.com/reference/uikit/uitextinput/1614564-textinputview)
So i'm using the following code to scale UITextView - without any font changes, without using any "CALayer" property and keeping high quality:
float screenScaleFactor = [[UIScreen mainScreen] scale];
float scale = 5.0;
textView.transform = CGAffineTransformMakeScale(scale, scale);
textView.textInputView.contentScaleFactor = screenScaleFactor * scale;
Comment the last line if you need low quality (but better performance) scaling.
Transform uses view.center as scaling center point, so adding a 'translate transform' is needed to scale around view corner.
Be sure to apply the contentScaleFactor to all subviews of the UITextView. I've just tested the following with a UITextView and found it to work:
- (void)applyScale:(CGFloat)scale toView:(UIView *)view {
view.contentScaleFactor = scale;
view.layer.contentsScale = scale;
for (UIView *subview in view.subviews) {
[self applyScale:scale toView:subview];
}
}
I am struggeling with my UIScrollview to get it to zoom-in the underlying UIImageView. In my view controller I set
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return myImageView;
}
In the viewDidLoad method I try to set the zoomScale to 2 as follows (note the UIImageView and Image is set in Interface Builder):
- (void)viewDidLoad {
[super viewDidLoad];
myScrollView.contentSize = CGSizeMake(myImageView.frame.size.width, myImageView.frame.size.height);
myScrollView.contentOffset = CGPointMake(941.0, 990.0);
myScrollView.minimumZoomScale = 0.1;
myScrollView.maximumZoomScale = 10.0;
myScrollView.zoomScale = 0.7;
myScrollView.clipsToBounds = YES;
myScrollView.delegate = self;
NSLog(#"zoomScale: %.1f, minZoolScale: %.3f", myScrollView.zoomScale, myScrollView.minimumZoomScale);
}
I tried a few variations of this, but the NSLog always shows a zoomScale of 1.0.
Any ideas where I screw this one up?
I finally got this to work. what caused the problem was the delegate call being at the end. I now moved it up and .... here we go.
New code looks like this:
- (void)viewDidLoad {
[super viewDidLoad];
myScrollView.delegate = self;
myScrollView.contentSize = CGSizeMake(myImageView.frame.size.width, myImageView.frame.size.height);
myScrollView.contentOffset = CGPointMake(941.0, 990.0);
myScrollView.minimumZoomScale = 0.1;
myScrollView.maximumZoomScale = 10.0;
myScrollView.zoomScale = 0.7;
myScrollView.clipsToBounds = YES;
}
Here is another example I made. This one is using an image that is included in the resource folder. Compared to the one you have this one adds the UIImageView to the view as a subview and then changes the zoom to the whole view.
-(void)viewDidLoad{
[super viewDidLoad];
UIImage *image = [UIImage imageNamed:#"random.jpg"];
imageView = [[UIImageView alloc] initWithImage:image];
[self.view addSubview:imageView];
[(UIScrollView *) self.view setContentSize:[image size]];
[(UIScrollView *) self.view setMaximumZoomScale:2.0];
[(UIScrollView *) self.view setMinimumZoomScale:0.5];
}
I know this is quite late as answers go, but the problem is that your code calls zoomScale before it sets the delegate. You are right the other things in there don't require the delegate, but zoomScale does because it has to be able to call back when the zoom is complete. At least that's how I think it works.
My code must be completely crazy because the scale that I use is completely opposite to what tutorials and others are doing. For me, minScale = 1 which indicates that the image is fully zoomed out and fits the UIImageView that contains it.
Here's my code:
[self.imageView setImage:image];
// Makes the content size the same size as the imageView size.
// Since the image size and the scroll view size should be the same, the scroll view shouldn't scroll, only bounce.
self.scrollView.contentSize = self.imageView.frame.size;
// despite what tutorials say, the scale actually goes from one (image sized to fit screen) to max (image at actual resolution)
CGRect scrollViewFrame = self.scrollView.frame;
CGFloat minScale = 1;
// max is calculated by finding the max ratio factor of the image size to the scroll view size (which will change based on the device)
CGFloat scaleWidth = image.size.width / scrollViewFrame.size.width;
CGFloat scaleHeight = image.size.height / scrollViewFrame.size.height;
self.scrollView.maximumZoomScale = MAX(scaleWidth, scaleHeight);
self.scrollView.minimumZoomScale = minScale;
// ensure we are zoomed out fully
self.scrollView.zoomScale = minScale;
This works as I expect. When I load the image into the UIImageView, it is fully zoomed out. I can then zoom in and then I can pan the image.