My problem occurs only on iPad. There is always unrendered portion of MKMapView(right side on the picture below). As soon as I touch this window the mapview repaints itself just fine. But it never renders correctly right away. This problem occures in iOS 4.2 as well as in iOS 3.2 in Simulator and the Device. The code that constructs MKMapView is right below:
- (void)viewDidLoad {
[super viewDidLoad];
mapview = [[[MKMapView alloc] initWithFrame:CGRectMake(0,0,self.view.frame.size.width,230)] autorelease]; // because of apples bug
mapview.autoresizingMask = UIViewAutoresizingFlexibleWidth;
MKCoordinateSpan globe = MKCoordinateSpanMake(100, 100);
CLLocationCoordinate2D worldCenter; worldCenter.latitude = 42.032974; worldCenter.longitude =21.359375;
MKCoordinateRegion worldmap = MKCoordinateRegionMake(worldCenter, globe);
mapview.region = worldmap;
mapview.zoomEnabled = NO;
mapview.showsUserLocation = YES;
mapview.delegate = self;
NSRange theRange;
theRange.location = 1;
theRange.length = [annotations count]-1;
[mapview addAnnotations:[annotations subarrayWithRange:theRange]];
[self.view addSubview:mapview];
}
The problem manifests itself only in Landscape orientation.
UPDATE
This is how it spans after I touched the view.
Nonetheless it's Apple's bug. In iPad-landscape mode your longtitude span may not be enough to cover 360degree of the globe. it should autoscale with zoom, but it doesn't. it autozooms properly only if your centerMap is exactly at 0 degree longitude. Weird.
Workaround:
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
CLLocationCoordinate2D worldCenter; worldCenter.latitude = 42.032974;
worldCenter.longitude = UIDeviceOrientationIsLandscape(toInterfaceOrientation)? 0.0 : 21.359375;
mapview.centerCoordinate = worldCenter;
}
I did a quick test with your code and get the same result (which I expected). I still think it is not an issue with the map itself but with the way you are setting your center coordinates plus map span. You're trying to center the map too far to the left with max span and the only way for the map to fill the entire screen and maintain the center point would be for it to stretch itself, which is not desirable. If you set lat and long to 0 you get the same view without the missing part.
Related
I'm writing a Mac app that contains a collection view. This app is to be run on a large touchscreen display (55" EP series from Planar). Due to hardware limitation, the touchscreen doesn't send scroll events (or even any multitouch events). How can I go about tricking the app into thinking a "mousedown+drag" is the same as a "mousescroll"?
I got it working halfway by subclassing NSCollectionView and implementing my own NSPanGestureRecognizer handler in it. Unfortunately the result is clunky and doesn't have the feeling of a normal OS X scroll (i.e., the velocity effect at the end of a scroll, or scroll bounce at the ends of the content).
#implementation UCTouchScrollCollectionView
...
- (IBAction)showGestureForScrollGestureRecognizer:(NSPanGestureRecognizer *)recognizer
{
CGPoint location = [recognizer locationInView:self];
if (recognizer.state == NSGestureRecognizerStateBegan) {
touchStartPt = location;
startOrigin = [(NSClipView*)[self superview] documentVisibleRect].origin;
} else if (recognizer.state == NSGestureRecognizerStateEnded) {
/* Some notes here about a future feature: the Scroll Bounce
I don't want to have to reinvent the wheel here, but it
appears I already am. Crud.
1. when the touch ends, get the velocity in view
2. Using the velocity and a constant "deceleration" factor, you can determine
a. The time taken to decelerate to 0 velocity
b. the distance travelled in that time
3. If the final scroll point is out of bounds, update it.
4. set up an animation block to scroll the document to that point. Make sure it uses the proper easing to feel "natural".
5. make sure you retain a pointer or something to that animation so that a touch DURING the animation will cancel it (is this even possible?)
*/
[self.scrollDelegate.pointSmoother clearPoints];
refreshDelegateTriggered = NO;
} else if (recognizer.state == NSGestureRecognizerStateChanged) {
CGFloat dx = 0;
CGFloat dy = (startOrigin.y - self.scrollDelegate.scrollScaling * (location.y - touchStartPt.y));
NSPoint scrollPt = NSMakePoint(dx, dy);
[self.scrollDelegate.pointSmoother addPoint:scrollPt];
NSPoint smoothedPoint = [self.scrollDelegate.pointSmoother getSmoothedPoint];
[self scrollPoint:smoothedPoint];
CGFloat end = self.frame.size.height - self.superview.frame.size.height;
CGFloat threshold = self.superview.frame.size.height * kUCPullToRefreshScreenFactor;
if (smoothedPoint.y + threshold >= end &&
!refreshDelegateTriggered) {
NSLog(#"trigger pull to refresh");
refreshDelegateTriggered = YES;
[self.refreshDelegate scrollViewReachedBottom:self];
}
}
}
A note about this implementation: I put together scrollScaling and pointSmoother to try and improve the scroll UX. The touchscreen I'm using is IR-based and gets very jittery (especially when the sun is out).
In case it's relevant: I'm using Xcode 6 beta 6 (6A280e) on Yosemite beta (14A329r), and my build target is 10.10.
Thanks!
I managed to have some success using an NSPanGestureRecognizer and simulating the track-pad scroll wheel events. If you simulate them well you'll get the bounce from the NSScrollView 'for free'.
I don't have public code, but the best resource I found that explained what the NSScrollView expects is in the following unit test simulating a momentum scroll. (See mouseScrollByWithWheelAndMomentumPhases here).
https://github.com/WebKit/webkit/blob/master/LayoutTests/fast/scrolling/latching/scroll-iframe-in-overflow.html
The implementation of mouseScrollByWithWheelAndMomentumPhases gives some tips on how to synthesize the scroll events at a low level. One addition I found I needed was to actually set an incrementing timestamp in the event in order to get the scroll-view to play ball.
https://github.com/WebKit/webkit/blob/master/Tools/WebKitTestRunner/mac/EventSenderProxy.mm
Finally, in order to actually create the decaying velocity, I used a POPDecayAnimation and tweaked the velocity from the NSPanGestureRecognizer to feel similar. Its not perfect but it does stay true to NSScrollView's bounce.
I have a (dead) project on Github that does this with an NSTableView, so hopefully it will work well for an NSCollectionView.
Disclaimer: I wrote this while I was still learning GCD, so watch for retain cycles... I did not vet what I just posted for bugs. feel free to point any out :) I just tested this on Mac OS 10.9 and it does still work (originally written for 10.7 IIRC), not tested on 10.10.
This entire thing is a hack to be sure, it looks like it requires (seems to anyway) asynchronous UI manipulation (I think to prevent infinite recursion). There is probably a cleaner/better way and please share it when you discover it!
I havent touched this in months so I cant recall all the specifics, but the meat of it surely is in the NBBTableView code, which will paste snippets of.
first there is an NSAnimation subclass NBBScrollAnimation that handles the "rubber band" effect:
#implementation NBBScrollAnimation
#synthesize clipView;
#synthesize originPoint;
#synthesize targetPoint;
+ (NBBScrollAnimation*)scrollAnimationWithClipView:(NSClipView *)clipView
{
NBBScrollAnimation *animation = [[NBBScrollAnimation alloc] initWithDuration:0.6 animationCurve:NSAnimationEaseOut];
animation.clipView = clipView;
animation.originPoint = clipView.documentVisibleRect.origin;
animation.targetPoint = animation.originPoint;
return [animation autorelease];
}
- (void)setCurrentProgress:(NSAnimationProgress)progress
{
typedef float (^MyAnimationCurveBlock)(float, float, float);
MyAnimationCurveBlock cubicEaseOut = ^ float (float t, float start, float end) {
t--;
return end*(t * t * t + 1) + start;
};
dispatch_sync(dispatch_get_main_queue(), ^{
NSPoint progressPoint = self.originPoint;
progressPoint.x += cubicEaseOut(progress, 0, self.targetPoint.x - self.originPoint.x);
progressPoint.y += cubicEaseOut(progress, 0, self.targetPoint.y - self.originPoint.y);
NSPoint constraint = [self.clipView constrainScrollPoint:progressPoint];
if (!NSEqualPoints(constraint, progressPoint)) {
// constraining the point and reassigning to target gives us the "rubber band" effect
self.targetPoint = constraint;
}
[self.clipView scrollToPoint:progressPoint];
[self.clipView.enclosingScrollView reflectScrolledClipView:self.clipView];
[self.clipView.enclosingScrollView displayIfNeeded];
});
}
#end
You should be able to use the animation on any control that has an NSClipView by setting it up like this _scrollAnimation = [[NBBScrollAnimation scrollAnimationWithClipView:(NSClipView*)[self superview]] retain];
The trick here is that the superview of an NSTableView is an NSClipView; I dont know about NSCollectionView, but I suspect that any scrollable control uses NSClipView.
Next here is how the NBBTableView subclass makes use of that animation though the mouse events:
- (void)mouseDown:(NSEvent *)theEvent
{
_scrollDelta = 0.0;
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
if (_scrollAnimation && _scrollAnimation.isAnimating) {
[_scrollAnimation stopAnimation];
}
});
}
- (void)mouseUp:(NSEvent *)theEvent
{
if (_scrollDelta) {
[super mouseUp:theEvent];
// reset the scroll animation
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
NSClipView* cv = (NSClipView*)[self superview];
NSPoint newPoint = NSMakePoint(0.0, ([cv documentVisibleRect].origin.y - _scrollDelta));
NBBScrollAnimation* anim = (NBBScrollAnimation*)_scrollAnimation;
[anim setCurrentProgress:0.0];
anim.targetPoint = newPoint;
[anim startAnimation];
});
} else {
[super mouseDown:theEvent];
}
}
- (void)mouseDragged:(NSEvent *)theEvent
{
NSClipView* clipView=(NSClipView*)[self superview];
NSPoint newPoint = NSMakePoint(0.0, ([clipView documentVisibleRect].origin.y - [theEvent deltaY]));
CGFloat limit = self.frame.size.height;
if (newPoint.y >= limit) {
newPoint.y = limit - 1.0;
} else if (newPoint.y <= limit * -1) {
newPoint.y = (limit * -1) + 1;
}
// do NOT constrain the point here. we want to "rubber band"
[clipView scrollToPoint:newPoint];
[[self enclosingScrollView] reflectScrolledClipView:clipView];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
NBBScrollAnimation* anim = (NBBScrollAnimation*)_scrollAnimation;
anim.originPoint = newPoint;
});
// because we have to animate asyncronously, we must save the target value to use later
// instead of setting it in the animation here
_scrollDelta = [theEvent deltaY] * 3.5;
}
- (BOOL)autoscroll:(NSEvent *)theEvent
{
return NO;
}
I think that autoscroll override is essential for good behavior.
The entire code is on my github page, and it contains several other "touch screen" emulation tidbits, if you are interested, such as a simulation for the iOS springboard arrangeable icons (complete with "wiggle" animation using NSButtons.
Hope this helps :)
Edit: It appears that constrainScrollPoint: is deprecated in OS X 10.9. However, It should fairly trivial to reimplement as a category or something. Maybe you can adapt a solution from this SO question.
I'm having an issue with both a custom MKOverlayView and standard MKPolygonView being clipped at certain zoom levels when there are multiple overlays added to a map.
The overlay of Algeria at two double tap zoom level.
The overlay of Algeria at three double tap zoom level. Note the clipping.
A few observations:
This occurs regardless of whether or not I use a custom MKOverlayView or return an MKPolygonView with the same polygons.
If I only draw one overlay, this problem does not occur.
This does not occur for all overlays - only some.
As far as code goes: this adds the overlay to an NSMutableArray (borderOverlays), which is then accessed elsewhere to load the overlay for a specific country ID. minX/minY/maxX/maxY are latitude/longitude values; polygon is a path constructed from an ESRI shapefile.
CLLocationCoordinate2D mbrMin = CLLocationCoordinate2DMake(minY, minX);
CLLocationCoordinate2D mbrMax = CLLocationCoordinate2DMake(maxY, maxX);
MKMapPoint minPoint = MKMapPointForCoordinate(mbrMin);
MKMapPoint maxPoint = MKMapPointForCoordinate(mbrMax);
MKMapSize size = MKMapSizeMake(maxPoint.x - minPoint.x, maxPoint.y - minPoint.y);
MKMapRect rect = MKMapRectMake(minPoint.x, minPoint.y, size.width, size.height);
if ( spans180 ) {
rect = MKMapRectMake(minPoint.x, minPoint.y, MKMapSizeWorld.width * 2, size.height);
}
CustomMKOverlay* overlay = [[CustomMKOverlay alloc] initWithPolygon:polygon withBoundingMapRect:rect];
[borderOverlays addObject:overlay];
The overlay is added to the map via:
[mapView addOverlay:overlay];
viewForOverlay:
- (MKOverlayView *)mapView:(MKMapView*)aMapView viewForOverlay:(id<MKOverlay>)overlay
{
if ( [overlay isKindOfClass:[CustomMKOverlay class]] ) {
/* Note: the behaviour if this chunk is not commented is the exact same as below.
CustomMKOverlayView* overlayView = [[[CustomMKOverlayView alloc] initWithOverlay:overlay withMapView:aMapView] autorelease];
[borderViews addObject:overlayView];
return overlayView; */
MKPolygonView* view = [[[MKPolygonView alloc] initWithPolygon:((CustomMKOverlay*)overlay).polygon] autorelease];
view.fillColor = [((CustomMKOverlay*)overlay).colour colorWithAlphaComponent:0.5f];
view.lineWidth = 5.0f;
view.strokeColor = [UIColor blackColor];
[borderViews addObject:view];
return view;
}
}
When MKPolygonView is used, there is no drawing code (the example shown). For completion's sake, though, here's my custom drawing code, and the same issue occurs. The outlines normally draw - this is actually debugging drawing, which draws a rect around the boundingMapRect of the overlay and fills it without mucking around with the outlines.
- (void)drawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale inContext:(CGContextRef)context
{
CustomMKOverlay* overlay = (CustomMKOverlay*)self.overlay;
CGRect clipRect = [self rectForMapRect:overlay.boundingMapRect];
CGContextAddRect(context, clipRect);
CGContextClip(context);
UIColor* colour = [UIColor redColor];
colour = [colour colorWithAlphaComponent:0.5f];
CGContextSetFillColorWithColor(context, [colour CGColor]);
CGRect fillRect = [self rectForMapRect:overlay.boundingMapRect];
CGContextFillRect(context, fillRect);
}
Suffice to say, I'm a bit stumped at this point - it's almost as if the zoomed tiled that's being loaded draws over the overlay. I've poured over various examples regarding TileMap and HazardMap, but as I am not loading my own map tiles, they're not very helpful.
I'm probably missing something painfully obvious. Any help would be appreciated. I'm happy to provide more code/context if necessary.
It would appear that the culprit is:
CLLocationCoordinate2D mbrMin = CLLocationCoordinate2DMake(minY, minX);
CLLocationCoordinate2D mbrMax = CLLocationCoordinate2DMake(maxY, maxX);
Bounding rectangles for MKOverlays apparently need to be based on the northwest/southeast coordinates of the bounding region, and not southwest/northeast (which is the format the ESRI shapefile stores its bounding coordinates in). Changing the offending code to:
CLLocationCoordinate2D mbrMin = CLLocationCoordinate2DMake(maxY, minX);
CLLocationCoordinate2D mbrMax = CLLocationCoordinate2DMake(minY, maxX);
Appears to resolve all issues with zooming and strange outline anomalies. I hope this helps anyone who comes across this problem in the future (and I'd like to hear about it if it doesn't, since this solution works a treat for me).
Also: if anyone can point to any documentation that states this, I'd like to see it.
for clarification I'll just add 2 overlaid Screenshots, one in Interface Builder, the other on the device.
The lower UISegmentedControl is fresh out of the library with no properties edited, still it looks different on the Device (in this case a non-Retina iPad, though the problem is the same for Retina-iPhone) (Sorry for the quick and dirty photoshopping)
Any ideas?
EDIT: I obviously tried the "alignment" under "Control" in the Utilities-Tab in Interface Builder. Unfortunately none of the settings changed anything for the titles in the UISegment. I don't think they should as they are not changing titles in Interface Builder either.
EDIT2: Programmatically setting:
eyeSeg.contentHorizontalAlignment = UIControlContentHorizontalAlignmentCenter;
doesn't make a difference either.
Found the Problem "UISegmentedControlStyleBezeled is deprecated. Please use a different style."
See also what-should-i-use-instead-of-the-deprecated-uisegmentedcontrolstylebezeled-in-io
Hmm...have you checked the alignment? Maybe that's the case.
You can recursively search the subviews of the UISegmentedControl view for each of the UILabels in the segmented control and then change the properties of each UILabel including the textAlignment property as I've shown in a sample of my code. Credit to Primc's post in response to Change font size of UISegmented Control for suggesting this general approach to customizing the UILabels of a UISegmentedControl. I had been using this code with the UISegmentedControlStyleBezeled style by the way even after it was deprecated although I have recently switched to UISegmentedControlStyleBar with an adjusted frame height.
- (void)viewDidLoad {
[super viewDidLoad];
// Adjust the segment widths to fit the text. (Will need to calculate widths if localized text is ever used.)
[aspirationControl setWidth:66 forSegmentAtIndex:0]; // Navel Lint Collector
[aspirationControl setWidth:48 forSegmentAtIndex:1]; // Deep Thinker
[aspirationControl setWidth:49 forSegmentAtIndex:2]; // Mental Wizard
[aspirationControl setWidth:64 forSegmentAtIndex:3]; // Brilliant Professor
[aspirationControl setWidth:58 forSegmentAtIndex:4]; // Nobel Laureate
// Reduce the font size of the segmented aspiration control
[self adjustSegmentText:aspirationControl];
}
- (void)adjustSegmentText:(UIView*)view {
// A recursively called method for finding the subviews containing the segment text and adjusting frame size, text justification, word wrap and font size
NSArray *views = [view subviews];
int numSubviews = views.count;
for (int i=0; i<numSubviews; i++) {
UIView *thisView = [views objectAtIndex:i];
// Typecast thisView to see if it is a UILabel from one of the segment controls
UILabel *tmpLabel = (UILabel *) thisView;
if ([tmpLabel respondsToSelector:#selector(text)]) {
// Enlarge frame. Segments are set wider and narrower to accomodate the text.
CGRect segmentFrame = [tmpLabel frame];
// The following origin values were necessary to avoid text movement upon making an initial selection but became unnecessary after switching to a bar style segmented control
// segmentFrame.origin.x = 1;
// segmentFrame.origin.y = -1;
segmentFrame.size.height = 40;
// Frame widths are set equal to 2 points less than segment widths set in viewDidLoad
if ([[tmpLabel text] isEqualToString:#"Navel Lint Collector"]) {
segmentFrame.size.width = 64;
}
else if([[tmpLabel text] isEqualToString:#"Deep Thinker"]) {
segmentFrame.size.width = 46;
}
else if([[tmpLabel text] isEqualToString:#"Mental Wizard"]) {
segmentFrame.size.width = 47;
}
else if([[tmpLabel text] isEqualToString:#"Brilliant Professor"]) {
segmentFrame.size.width = 62;
}
else {
// #"Nobel Laureate"
segmentFrame.size.width = 56;
}
[tmpLabel setFrame:segmentFrame];
[tmpLabel setNumberOfLines:0]; // Change from the default of 1 line to 0 meaning use as many lines as needed
[tmpLabel setTextAlignment:UITextAlignmentCenter];
[tmpLabel setFont:[UIFont boldSystemFontOfSize:12]];
[tmpLabel setLineBreakMode:UILineBreakModeWordWrap];
}
if (thisView.subviews.count) {
[self adjustSegmentText:thisView];
}
}
}
The segmented control label text has an ugly appearance in IB but comes out perfectly centered and wrapped across 2 lines on the device and in the simulator using the above code.
I am relatively new to programming on the iPad and I was trying to put together a simple program. Basically, it's a children's book and I need the functionality of a comic book style (or photo) viewer, where people swipe to change "pages" (or images).
Each image is 1024x768. Currently, they are stored as JPGs because of the very large file sizes PNGs seem to produce. For this story, there are 28 pages.
I took a look at the PageControl example, implementing a UIScrollView. On initialization, I create a big enough scrollview area. Then as the user scrolls, I load in the previous and next images. Again, just like the example only without implementing the page control at the bottom.
The problem I am running into is a very slight pause in the animation when I am flipping. Once the images are loaded or cached, this doesn't happen. Now, I know the photo application doesn't do this and I'm not sure what is causing it.
Here is my code for the scrollViewDidScroll method. I keep up with the page number and it will only call the loadPageIntoScrollView when a page has changed - I was thinking that the insane number of calls it was making was causing the slight pause in animation, but it turned out not to be the case.
- (void) scrollViewDidScroll: (UIScrollView *) sender
{
CGFloat pageWidth = scrollView.frame.size.width;
int localPage = floor( (scrollView.contentOffset.x - pageWidth / 2 ) / pageWidth ) + 1;
if( localPage != currentPage )
{
currentPage = localPage;
[self loadPageIntoScrollView:localPage - 1];
[self loadPageIntoScrollView:localPage];
[self loadPageIntoScrollView:localPage + 1];
}
} // scrollViewDidScroll
And here is my loadPageIntoScrollView method. I'm only creating a UIImageView and loading an image into that - I don't see how that could be much "leaner". But somehow it's causing the pause. Again, it's not a HUGE pause, just one of those things you notice and is enough to make the scrolling look like it has a very. very slight hiccup.
Thank you in advance for any help you could provide.
- (void) loadPageIntoScrollView: (int)page
{
if( page < 0 || page >= kNumberOfPages )
return;
UIImageView *controller = [pages objectAtIndex:page];
NSLog( #"checking pages" );
if( (NSNull *)controller == [NSNull null] )
{
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleSingleTap:)];
NSString *pageName = [[NSString alloc] initWithFormat:#"%d.jpg", page];
controller = [[UIImageView alloc]initWithImage:[UIImage imageNamed:pageName]];
[controller setUserInteractionEnabled:YES];
[controller addGestureRecognizer:singleTap];
[pages replaceObjectAtIndex:page withObject:controller];
[controller release];
} // if controller == null
// add the page to the scrollview
if( controller.superview == nil )
{
NSLog(#"superview was nil, adding page %d", page );
CGRect frame = scrollView.frame;
frame.origin.x = frame.size.width * page;
frame.origin.y = 0;
controller.frame = frame;
[scrollView addSubview:controller];
} // if
} // loadPageIntoScrollView
Since you say after an image is loaded in it no longer lags, I'd suspect that it is disk access that is causing your lag, but you should run your app through instruments to try to rule out cpu-spikes as well as evaluate file system usage. You may try to pre-load images to the left and right of whatever image you are on so that the user doesn't perceive as much lag.
First off, you should be able to use PNG's just fine. I have build several apps that do exactly what you are doing here, you can fit 3 1024 x 768 PNGs in memory without running out (but you can't do much more). You should also use PNG's as they are the preferred format for iOS as they are optimized when the app is bundled together during build.
The slight lag is caused by loading the image, in this line:
controller = [[UIImageView alloc]initWithImage:[UIImage imageNamed:pageName]];
What I usually do is load the images in a separate thread, using something like this:
[self performSelectorInBackground:#selector(loadPageIntoScrollView:) withObject:[NSNumber numberWithInt:localPage]];
Note that you need to put your localPage integer into a NSNumber object to pass it along, so don't forget to change your loadPageIntoScrollView: method:
- (void) loadPageIntoScrollView: (NSNumber *)pageNumber
{
int page = [pageNumber intValue];
....
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.