I have a view controller which have 4 tabs(some tabs include scrollview with multiple views in it). I need to save all the contents of the tabs into 4 pictures. I managed to let each tab return me a UIImage for me to save. However i discovered a problem, if i didn't tap on the tab bar (which is to say didn't manually load them and show them on screen), the tabs can't return me an Image because there is no view for them to take reference to. So my question is, do I preload the tabs-view? If so, how?
If not preload, is there a better workaround?
Part of my codes:
View Controller use this to share:
UIActivityViewController *activityController = [[UIActivityViewController alloc] initWithActivityItems:#[shareText,[_summaryViewController getImageToShare],[_sessionLogViewController getImageToShare] ,[_breakdownViewController getImageToShare],[_skillsViewController getImageToShare]] applicationActivities:nil];
getImageToShare:
-(UIImage*) getImageToShare
{
UIImage *image = nil;
UIGraphicsBeginImageContextWithOptions(self.scrollView.contentSize, NO, 0.0);
{
CGPoint savedContentOffSet = self.scrollView.contentOffset;
CGRect savedFrame = self.scrollView.frame;
self.scrollView.contentOffset = CGPointZero;
self.scrollView.frame = CGRectMake(0, 0, self.scrollView.contentSize.width, self.scrollView.contentSize.height);
[self.scrollView.layer renderInContext:UIGraphicsGetCurrentContext()];
image = [ViewToImage ImageWithView:self.scrollView];
self.scrollView.contentOffset = savedContentOffSet;
self.scrollView.frame = savedFrame;
}
UIGraphicsEndImageContext();
if (image != nil) {
NSLog(#"there is something returned:%#",image);
}else
NSLog(#"nothign is returned");
return image;
}
Nvm, I figured it out, I just need to create copy of the tabs and then make them don't animate and just show the data. Then preload them and use their Image instead.
Related
I am using AVCapture to capture the images from camera.Everything works fine except this issue.
I need the final captured image as same like which is visible in camera.But the image shows more area(which is not like visible in camera).How can i get the same visible image as final stillImageOutput?
Any help would be highly appreciated.
use your view/imageview object name instead of contentScrollview. This will help you to render the view and provide you an image.
for reference:https://charangiri.wordpress.com/2014/09/18/how-to-render-screen-taking-screen-shot-programmatically/
- (UIImage *) createScreenshotOfCompleteScreen
{
UIImage* image = nil;
UIGraphicsBeginImageContext(contentScrollview.contentSize);
{
CGPoint savedContentOffset = contentScrollview.contentOffset;
CGRect savedFrame = contentScrollview.frame;
contentScrollview.contentOffset = CGPointZero;
contentScrollview.frame = CGRectMake(0, 0, contentScrollview.contentSize.width, contentScrollview.contentSize.height);
if ([[NSString versionofiOS] intValue]>=7)
{
[contentScrollview drawViewHierarchyInRect:contentScrollview.bounds afterScreenUpdates:YES];
}
else
{
[contentScrollview.layer renderInContext: UIGraphicsGetCurrentContext()];
}
image = UIGraphicsGetImageFromCurrentImageContext();
contentScrollview.contentOffset = savedContentOffset;
contentScrollview.frame = savedFrame;
}
UIGraphicsEndImageContext();
return image;
}
I am new in iOS. I want to capture screen shot of full content of web view, as webview may have webpage longer that could be scrollable and so not showing the full content in length more than screen size. I am using below code like:-
UIImage *screenImage=[[UIImage alloc] init];
UIScrollView *browserScrollableView=[[UIScrollView alloc] init];
browserScrollableView=browserView.scrollView;
UIGraphicsBeginImageContext(browserScrollableView.contentSize);
CGPoint savedContentOffset = browserScrollableView.contentOffset;
CGRect savedFrame = browserScrollableView.frame;
browserScrollableView.contentOffset = CGPointZero;
browserScrollableView.frame = CGRectMake(0, 0, browserScrollableView.contentSize.width, browserScrollableView.contentSize.height);
[browserScrollableView.layer renderInContext: UIGraphicsGetCurrentContext()];
screenImage = UIGraphicsGetImageFromCurrentImageContext();
browserScrollableView.contentOffset = savedContentOffset;
browserScrollableView.frame = savedFrame;
UIGraphicsEndImageContext();
NSLog(#"Captured image size is %f X %f",screenImage.size.width,screenImage.size.height);
UIImageWriteToSavedPhotosAlbum(screenImage, nil, nil, nil);
browserview is the webview. It's working on simulator why is it not working on device?
Under iOS 8 a call to UIView's
[self drawViewHierarchyInRect:self.bounds afterScreenUpdates:YES];
results in a 1 frame flash of the image. You can see it for a split second on the screen. It only happens when afterScreenUpdates parameter is YES.
This is my complete code to take screenshot:
UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, sf);
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextSaveGState(ctx);
CGContextConcatCTM(ctx, [self.layer affineTransform]);
if ([self respondsToSelector:#selector(drawViewHierarchyInRect:afterScreenUpdates:)]) { // iOS 7+
[self drawViewHierarchyInRect:self.bounds afterScreenUpdates:YES];
} else { // iOS 6
[self.layer renderInContext:ctx];
}
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
CGContextRestoreGState(ctx);
UIGraphicsEndImageContext();
Is there a workaround?
Provide #3x launch images to be used in iPhone6 and iPhone6 plus and this problem goes away.
Here's a possible workaround that solved my issue.
Use CATransaction.completionBlock to call UIView drawViewHierarchyInRect:afterScreenUpdates with the screen updates flag set to NO. I used this to workaround the same problem. It is semantically equivalent to setting the flag to YES in my case since I'm only invoking it after the current CATransaction has finished and the screen is in the desired state. That said, in my case, I don't have any animations, so this is pretty much immediate and captures exactly what I want. If there were animations, this may not be appropriate.
For my case, I have a collection view that is a collection of files. Each item is rendered as a snapshot of what the file looks like once the user opens it. Some files cause the UI to have hundreds of layers. When these complicated views were being snapshotted, I would get a black screen flash; or the last/current animation to partially rerun. My collection view is w/in a navigation controller, I was seeing partial reruns of the pop animation. I also have noticed reruns of rotation animations. For simpler files, there was often no issue. I noticed this on my iPad Air (iOs 8.1) and on various simulators. I tried putting appIcons and launchImages in place but they had no effect.
Here was the original code. It initializes a view controller, then adds the controller's view to the a utility view.
UIViewController *vlController = [[ComplicatedViewController alloc]init];
UIView *innerView = vlController.view;
[v addSubview:innerView];
innerView.transform = CGAffineTransformMakeScale(scalar, scalar);
innerView.center = CGRectCenterPoint(v.bounds);
auto sz = v.bounds.size;
innerView.bounds = {{0,0}, {sz.width/scalar, sz.height/scalar}};
UIGraphicsBeginImageContextWithOptions(v.bounds.size, YES, 0);
[v drawViewHierarchyInRect:v.bounds afterScreenUpdates:YES];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[innerView removeFromSuperview];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
[v addSubview:imageView];
The new code just moves the bottom half to the completion block of UIView animateWithDuration:completion. Notice that the duration of the UIView animation is 0, but that still seems to give that extra refresh cycle to update the screen with the new UI.
UIViewController *vlController = [[ComplicatedViewController alloc]init];
UIView *innerView = vlController.view;
[UIView animateWithDuration:0.0 animations:^{
[v addSubview:innerView];
innerView.transform = CGAffineTransformMakeScale(scalar, scalar);
innerView.center = CGRectCenterPoint(v.bounds);
auto sz = v.bounds.size;
innerView.bounds = {{0,0}, {sz.width/scalar, sz.height/scalar}};
} completion:^(BOOL finished) {
UIGraphicsBeginImageContextWithOptions(v.bounds.size, YES, 0);
BOOL drawResult = [v drawViewHierarchyInRect:v.bounds afterScreenUpdates:NO];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[innerView removeFromSuperview];
[self add:image forFile:v.filename withOrientation:v.orientation];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
[v addSubview:imageView];
}];
I'm trying to loop through some images in a single UIImageView when I tap a button. The image must disappear 0.1 seconds after the button is pressed.
Here's the code:
int tapCount = 0;
UIImage *image0 = [UIImage imageNamed:#"0.jpg"];
UIImage *image1 = [UIImage imageNamed:#"1.jpg"];
UIImage *image2 = [UIImage imageNamed:#"2.jpg"];
imagesArray = [[NSArray alloc] initWithObjects:image0, image1, image2, nil];
-(IBAction)backgroundButton:(id)sender{
self.myImageView.image = [imagesArray objectAtIndex:tapCount%3];
tapCount++;
[self performSelector:#selector(eraseImage) withObject:self afterDelay:0.1];
}
-(void)eraseImage{
self.myImageView.image = nil;
}
The problem is that the images don't appear until I've completed one entire loop (at the 4th tap).
I'm guessing that somehow I must initialize the images in the UIImageView because it takes some time between the tapping and the image appearing, and since it disappears after 0.1 seconds...it doesn't show at all.
I've tried loading them inside viewDidLoad like this:
for(int i = 0; i<[imagesArray count]; i++){
self.myImageView.image = [imagesArray objectAtIndex : i];
}
But it only works with the last image that loads (image2 in this case).
Should I loop between different UIImageView instead of looping through different UIImage inside a single UIImageView?
Any other hints?
Creating a UIImage doesn't actually load the image data (you need to render it to a context for that to happen). So, if your images are large then you could be hiding them before they are actually rendered to the screen. You won't be able to hold many images in memory at the same time, but you can force the image data to be loaded by creating a context and drawing the image into it (which can be done in the background, using CGContextDrawImage).
There are a few 3rd party bits of code which do this, like this or check this discussion.
Use the animationImages and animationDuration property of the UIImageView
https://developer.apple.com/library/ios/documentation/uikit/reference/UIImageView_Class/Reference/Reference.html#//apple_ref/occ/instp/UIImageView/animationImages
I think there is a much simpler way to achieve that animation you are going for. Try the following code:
-(IBAction)backgroundButton:(id)sender{
[UIView animateWithDuration:0.2
delay:nil
options:UIViewAnimationCurveEaseIn
animations:^{
self.myImageView.image = [imagesArray objectAtIndex:tapCount%3];
self.myImageView.image = nil;
}
completion:nil
];
tapCount++;
if (tapCount == 2) {
tapCount = 0;
}
}
I finally managed to work this around using this solution:
First I preload all the images in the background thread
-(void)preload:(UIImage *)image{
CGImageRef ref = image.CGImage;
size_t width = CGImageGetWidth(ref);
size_t height = CGImageGetHeight(ref);
CGColorSpaceRef space = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(NULL, width, height, 8, width * 4, space, kCGBitmapAlphaInfoMask & kCGImageAlphaPremultipliedFirst);
CGColorSpaceRelease(space);
CGContextDrawImage(context, CGRectMake(0, 0, width, height), ref);
CGContextRelease(context);
}
Then I execute the same action I had in the beginning:
-(IBAction)backgroundButton:(id)sender{
self.myImageView.image = [imagesArray objectAtIndex:tapCount%3];
tapCount++;
[self performSelector:#selector(eraseImage) withObject:self afterDelay:0.1];
}
-(void)eraseImage{
self.myImageView.image = nil;
}
I have an application which has a fullscreen UIScrollView, and within it there are seven images. The images are also meant to be full screen, and the scroll view is set to enable pagination.
I have a method which either creates or moves the image views:
-(void)rebuildImageView{
// set up images
float screenW = self.view.bounds.size.width;
float screenH = self.view.bounds.size.height;
int numImgs = self.soundNames.count;
self.mainScrollView.contentSize = CGSizeMake(screenW * numImgs, screenH);
for(int i=0; i<numImgs; i++){
UIImageView* imageView = (UIImageView*)[self.mainScrollView viewWithTag:i+100];
if(imageView == nil){
imageView = [[UIImageView alloc] init];
imageView.tag = i+100;
[self.mainScrollView addSubview:imageView];
imageView.image = [UIImage imageNamed:[NSString stringWithFormat:#"image%d.jpg",i]];
imageView.contentMode = UIViewContentModeScaleAspectFill;
imageView.clipsToBounds = YES;
[imageView release];
}
imageView.frame = CGRectMake(i * screenW, 0, screenW, screenH);
}
// scroll to the current one
[self.mainScrollView scrollRectToVisible:CGRectMake(self.currentSound*screenW, 0, screenW, screenH) animated:YES];
}
I also have this on the view controller:
-(void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration{
[UIView animateWithDuration:duration animations:^{
[self rebuildImageView];
}];
}
This code works fine when I autorotate while image 0 is being shown, but when I'm on image 7, you can briefly see most of image 6 when rotating. This video shows what's happening:
http://www.youtube.com/watch?v=1O3jOcTgVP8
Is there a better method I should use to reconfigure the scroll view and images when rotating the device?
Any frame changes put in the willAnimateRotationToInterfaceOrientation:duration method should automatically animate. So you could try removing it from the block?
Personally, I've had a lot more luck with this type of thing subclassing UIScrollView and putting the equivalent layout subview frame code in an override of the layoutSubviews method (don't forget to call super or you might end up with misplaced scroll bars).