I want to take a screenshot from my app programmatically and the code working fine but I have a UIVisualEffectView with blur effect and the screenshot gave me the image without blur!
How I can make the screenshot take the blur also?
UIGraphicsBeginImageContextWithOptions(fullView.bounds.size, true, 1)
self.fullView.layer.renderInContext(UIGraphicsGetCurrentContext())
var viewImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil)
To retain the UIVisualEffectView Blur when taking an image of the screen programmatically, you must be taking an image of the entire screen.
Here is a more technical definition provided by Apple:
Many effects require support from the window that hosts the
UIVisualEffectView. Attempting to take a snapshot of only the
UIVisualEffectView will result in a snapshot that does not contain the
effect. To take a snapshot of a view hierarchy that contains a
UIVisualEffectView, you must take a snapshot of the entire UIWindow or
UIScreen that contains it. - Apple Documentation
After taking a screenshot, a blur effect can be added programmatically. Here's an example of using the GPUImage library, which can be installed using CocoaPods. A similar effect can also be achieved using native Apple libraries.
GPUImagePicture *picture = [[GPUImagePicture alloc] initWithImage:snapShot];
GPUImageiOSBlurFilter *blurFilter = [[GPUImageiOSBlurFilter alloc] init];
[blurFilter setBlurRadiusInPixels:4];
[picture addTarget:blurFilter];
[blurFilter useNextFrameForImageCapture];
[picture processImage];
UIImage *processed = [blurFilter imageFromCurrentFramebuffer];
I had this same problem. I had a view controller with a visual effect (blur) applied to a background image and some other non-blurred view on top and I wanted to take a screenshot of that controller.
As highlighted by #user3721428 trying to capture the view doesn't work. For my surprise trying to render the window layer in context doesn't work.
What worked is to get a snapshotView from UIScreen:
let view = UIScreen.main.snapshotView(afterScreenUpdates: true)
And then grab an image from that view using a method like in #neave answer here
Related
Looking for a way to capture a screenshot or video of the ARScene without the buttons and other subviews
Traditional screen capture captures everything visible on the screen including UI controls
ARSCNViews have a built in snapshot method that returns a UIImage of the ARScene
So in Objective-C you could do:
UIImage *image = [sceneView snapshot];
and in Swift
var image = sceneView.snapshot()
I know a few methods to blur images - the Apple class(ApplyLightEffect) , and the CIFilter , but they are all takes UIImage and create a blur.
I need to simply create some layer above images that are moving, and blur this layer so everything behind is blur. the blur effect should be very gentle.
How would i get that in a simple way ? are there more ways to apply similar effects to blur that i can check ? (which are dynamic )
Thanks .
Check out this iOS Framework:
https://github.com/nicklockwood/FXBlurView
Instead of instantiating your view like this:
UIView *view = [[UIView alloc] init];
Import FXBlurView and do this:
FXBlurView *blurredView = [[FXBlurView alloc] init];
You can also set some custom parameters:
[blurredView setBlurRadius:30]; //Sets radius of blur
[blurredView setDynamic:NO]; //Disables whether the blur updates in real time.
[blurredView setBlurEnables:YES]; //Enables/disables the blur.
[blurredView setTintColor:nil]; //Set to nil to get rid of the blue glow from the default iOS tint color.
That should do it.
I am trying to implement sharing app with facebook.
I used this code to take the screenshot:
CGSize imageSize = CGSizeMake(self.view.bounds.size.width, self.view.bounds.size.height);
UIGraphicsBeginImageContext(imageSize);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
It works great on iOS 6, but in iOS 7 the image looks very bad.
I used this answer: iOS: what's the fastest, most performant way to make a screenshot programmatically?
for trying to fix it, and it helped, still the screenshot looks bad.
The screen gets another color, and some objects (like labels) aren't showing on the image taken.
Any help?
----Update----
I managed to solve the most objects, by change them to retain instead of weak. My main problem remained my tableview, that shown as a big white block (It supposed to be transparent, with labels with white text, so all we see is white cells). I did try to define the table background as clearcolor,not helps..
----Last Update---
There are wonderful answers here that not really regarding to my issue.. I wanted to make it work on device that runs with iOS7 but without using iOS7 SDK, since it takes to much effort to switch the project SDK in this point, when the project is almost done.
Anyway, I added the peace of code that finally solved my issue:
This change simply solve the problem:
UIGraphicsBeginImageContextWithOptions(imageSize, NO , 0.0f);
instead of:
UIGraphicsBeginImageContext(imageSize);
New API has been added since iOS 7, that should provide efficient way of getting snapshot
snapshotViewAfterScreenUpdates: renders the view into a UIView with unmodifiable content
resizableSnapshotViewFromRect:afterScreenUpdates:withCapInsets : same thing, but with resizable insets
drawViewHierarchyInRect:afterScreenUpdates: : same thing if you need all subviews to be drawn too (like labels, buttons...)
You can use the UIView returned for any UI effect, or render in into an image like you did if you need to export.
I don't know how good this new method performs VS the one you provided (although I remember Apple engineers saying this new API was more efficient)
you can try this
- (UIImage *) screenshot {
UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, NO, [UIScreen mainScreen].scale);
[self.view drawViewHierarchyInRect:self.view.bounds afterScreenUpdates:YES];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
in iOS 8 : this is how i am doing to get ScreenShot
just added one UIImageView and Method to take screenshot in .h file
#property (weak, nonatomic) IBOutlet UIImageView *imageView;
-(IBAction)takeSnapShot:(id)sender;
2 added code snip for taking screen shot and set on UIImageView in .m file
- (IBAction)takeSnapShot:(id)sender
{
UIGraphicsBeginImageContext(self.view.bounds.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *snapShotImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
imageView.image = snapShotImage;
}
below is the output i got.
On iOS7 you can have glitches if you use
[view drawViewHierarchyInRect:view.bounds afterScreenUpdates:YES]
during ongoing animation. Set afterScreenUpdates = NO to get rid of glitches.
Make sure that opaque is set to NO
I believe the NDA is down, so I can ask this question. I have a UIView subclass:
BlurView *blurredView = ((BlurView *)[self.view snapshotViewAfterScreenUpdates:NO]);
blurredView.frame = self.view.frame;
[self.view addSubview:blurredView];
It does its job so far in capturing the screen, but now I want to blur that view. How exactly do I go about this? From what I've read I need to capture the current contents of the view (context?!) and convert it to CIImage (no?) and then apply a CIGaussianBlur to it and draw it back on the view.
How exactly do I do that?
P.S. The view is not animated, so it should be OK performance wise.
EDIT: Here is what I have so far. The problem is that I can't capture the snapshot to a UIImage, I get a black screen. But if I add the view as a subview directly, I can see the snapshot is there.
// Snapshot
UIView *view = [self.view snapshotViewAfterScreenUpdates:NO];
// Convert to UIImage
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, 0.0);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// Apply the UIImage to a UIImageView
BlurView *blurredView = [[BlurView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
[self.view addSubview:blurredView];
blurredView.imageView.image = img;
// Black screen -.-
BlurView.m:
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
// Initialization code
self.imageView = [[UIImageView alloc] init];
self.imageView.frame = CGRectMake(20, 20, 200, 200);
[self addSubview:self.imageView];
}
return self;
}
Half of this question didn't get answered, so I thought it worth adding.
The problem with UIScreen's
- (UIView *)snapshotViewAfterScreenUpdates:(BOOL)afterUpdates
and UIView's
- (UIView *)resizableSnapshotViewFromRect:(CGRect)rect
afterScreenUpdates:(BOOL)afterUpdates
withCapInsets:(UIEdgeInsets)capInsets
Is that you can't derive a UIImage from them - the 'black screen' problem.
In iOS7 Apple provides a third piece of API for extracting UIImages, a method on UIView
- (BOOL)drawViewHierarchyInRect:(CGRect)rect
afterScreenUpdates:(BOOL)afterUpdates
It is not as fast as snapshotView, but not bad compared to renderInContext (in the example provided by Apple it is five times faster than renderInContext and three times slower than snapshotView)
Example use:
UIGraphicsBeginImageContextWithOptions(image.size, NULL, 0);
[view drawViewHierarchyInRect:rect];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Then to get a blurred version
UIImage* lightImage = [newImage applyLightEffect];
where applyLightEffect is one of those Blur category methods on Apple's UIImage+ImageEffects category mentioned in the accepted answer (the enticing link to this code sample in the accepted answer doesn't work, but this one will get you to the right page: the file you want is iOS_UIImageEffects).
The main reference is to WWDC2013 session 226, Implementing Engaging UI on iOS
By the way, there is an intriguing note in Apple's reference docs for renderInContext that hints at the black screen problem..
Important: The OS X v10.5 implementation of this method does not support the entire Core Animation composition model. QCCompositionLayer, CAOpenGLLayer, and QTMovieLayer layers are not rendered. Additionally, layers that use 3D transforms are not rendered, nor are layers that specify backgroundFilters, filters, compositingFilter, or a mask values. Future versions of OS X may add support for rendering these layers and properties.
The note hasn't been updated since 10.5, so I guess 'future versions' may still be a while off, and we can add our new CASnapshotLayer (or whatever) to the list.
Sample Code from WWDC ios_uiimageeffects
There is a UIImage category named UIImage+ImageEffects
Here is its API:
- (UIImage *)applyLightEffect;
- (UIImage *)applyExtraLightEffect;
- (UIImage *)applyDarkEffect;
- (UIImage *)applyTintEffectWithColor:(UIColor *)tintColor;
- (UIImage *)applyBlurWithRadius:(CGFloat)blurRadius
tintColor:(UIColor *)tintColor
saturationDeltaFactor:(CGFloat)saturationDeltaFactor
maskImage:(UIImage *)maskImage;
For legal reason I can't show the implementation here, there is a demo project in it. should be pretty easy to get start with.
To summarize how to do this with foundry's sample code, use the following:
I wanted to blur the entire screen just slightly so for my purposes so I'll use the main screen bounds.
CGRect screenCaptureRect = [UIScreen mainScreen].bounds;
UIView *viewWhereYouWantToScreenCapture = [[UIApplication sharedApplication] keyWindow];
//screen capture code
UIGraphicsBeginImageContextWithOptions(screenCaptureRect.size, NO, [UIScreen mainScreen].scale);
[viewWhereYouWantToScreenCapture drawViewHierarchyInRect:screenCaptureRect afterScreenUpdates:NO];
UIImage *capturedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
//blur code
UIColor *tintColor = [UIColor colorWithWhite:1.0 alpha:0];
UIImage *blurredImage = [capturedImage applyBlurWithRadius:1.5 tintColor:tintColor saturationDeltaFactor:1.2 maskImage:nil];
//or use [capturedImage applyLightAffect] but I thought that was too much for me
//use blurredImage in whatever way you so desire!
Notes on the screen capture part
UIGraphicsBeginImageContextWithOptions() 2nd argument is opacity. It should be NO unless you have nothing with any alpha other than 1. If you return yes the screen capture will not look at transparency values so it will go faster but will probably be wrong.
UIGraphicsBeginImageContextWithOptions() 3rd argument is the scale. Probably want to put in the scale of the device like I did to make sure and differentiate between retina and non-retina. But I haven't really tested this and I think 0.0f also works.
drawViewHierarchyInRect:afterScreenUpdates: watch out what you return for the screen updates BOOL. I tried to do this right before backgrounding and if I didn't put NO the app would go crazy with glitches when I returned to the foreground. You might be able to get away with YES though if you're not leaving the app.
Notes on blurring
I have a very light blur here. Changing the blurRadius will make it blurrier, and you can change the tint color and alpha to make all sorts of other effects.
Also you need to add a category for the blur methods to work...
How to add the UIImage+ImageEffects category
You need to download the category UIImage+ImageEffects for the blur to work. Download it here after logging in: https://developer.apple.com/downloads/index.action?name=WWDC%202013
Search for "UIImageEffects" and you'll find it. Just pull out the 2 necessary files and add them to your project. UIImage+ImageEffects.h and UIImage+ImageEffects.m.
Also, I had to Enable Modules in my build settings because I had a project that wasn't created with xCode 5. To do this go to your target build settings and search for "modules" and make sure that "Enable Modules" and "Link Frameworks Automatically" are both set to yes or you'll have compiler errors with the new category.
Good luck blurring!
Check WWDC 2013 sample application "running with a snap".
The blurring is there implemented as a category.
I would like to quickly animate a blur on a UIView to use as a transition in my app. I'm having trouble knowing where to start. I believe core image is the proper tool for the job. Can anyone point me to a sample of how to blur a UIView? I'm assuming I will need to convert the view into a single UIImage, but I don't know where to proceed from there.
Thanks in advance!
Taking a snapshot of the View and using GPUImage from Brad Larson (the GPUImageGaussianBlurFilter) got me some nice results.
To animate the view I created a ImageView with the blurred image and animated the alpha channel from 0 to 1 to make the blur appear progressively.
Alternatively, I presume its possible to increase the blursize per frame.
#import "GPUImage.h"
...
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
...
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
...
GPUImageGaussianBlurFilter * filter = [[GPUImageGaussianBlurFilter alloc] init];
filter.blurSize = 0.5;
UIImage * blurred = [filter imageByFilteringImage:image];
rasterizeScale of a uiview's layer is what you need, Here is the code for adding blur effect to UIVIew:
CALayer *layer = [self.blurView layer];
[layer setRasterizationScale:0.3];
[layer setShouldRasterize:YES];
For details refer to Apple Documentation of CALayer, Also this tutorial might help You, hope that helps
I recently did some tests with blurring a series of images at different blur settings and animating them simply with UIImageView. You might want to take a look:
AnimatedGaussianBlur