Screenshot Only Part of Screen - Swift - ios

I'm using this Swift code to take a screenshot of my app:
UIGraphicsBeginImageContextWithOptions(UIScreen.mainScreen().bounds.size, false, 0);
self.view.drawViewHierarchyInRect(view.bounds, afterScreenUpdates: true)
var image:UIImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
How would I go about taking a screenshot of only part of the screen, and not all of it, as I do here?

For example if you want to take the screen shot of the UIView rectangle at position (50,50) with height of (100,150).
First set the Image Context to the size of the rectangle. This sets the image size.
UIGraphicsBeginImageContextWithOptions(CGSizeMake(100,150), false, 0);
Now draw the view in this context in such a way that, the visible part of the screenshot starts at (50,50)
self.view.drawViewHierarchyInRect(CGRectMake(-50,-50,view.bounds.size.width,view.bounds.size.height) afterScreenUpdates: true)
This clips the screen shot at (100,150) because we set the size of our context. Now take the UIImage from this.
var image:UIImage = UIGraphicsGetImageFromCurrentImageContext();

I think this is the best Answer to take a shot of part of the screen:
func screenShot() {
UIGraphicsBeginImageContextWithOptions(CGSizeMake(self.frame.size.width*0.99,self.frame.size.height*0.70), false, 0)
var image:UIImage = UIGraphicsGetImageFromCurrentImageContext();
self.view?.drawViewHierarchyInRect(CGRectMake(-01, -01, self.frame.size.width, self.frame.size.height), afterScreenUpdates: true)
var screenShot = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
}

for taking a snapshot selecting by area of another UIView
// viewObject: UIView linked from storyboard
var bounds= CGRect(x: -viewObject.frame.minX,y: -viewObject.frame.minY,width: view.bounds.size.width,height: view.bounds.size.height)
UIGraphicsBeginImageContext(viewObject.frame.size)
view.drawHierarchy(in: bounds, afterScreenUpdates: true)
let outputImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()

func captureView(view: UIView) -> UIImage {
var screenRect: CGRect = view.bounds
UIGraphicsBeginImageContext(screenRect.size)
UIGraphicsBeginImageContextWithOptions(screenRect.size, true, 0)
var ctx: CGContext = UIGraphicsGetCurrentContext()!
UIColor.black.set()
ctx.fill(screenRect)
view.layer.render(in: ctx)
var newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return newImage
}

Related

Take a screenshot of an area covered by an UIImageView object

I am trying to take a screenshot of an area covered by a UIImageview object. I have overlaid the image with some UILabel objects and want to save the shot of just the area
I have tried
UIGraphicsBeginImageContext(self.view.frame.size)
view.drawHierarchy(in: self.view.frame, afterScreenUpdates: true)
let memedImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
but it is giving my a shot of the whole screen
I have also tried
UIGraphicsBeginImageContext(imageHolder.frame.size)
view.drawHierarchy(in: self.view.frame, afterScreenUpdates: true)
let memedImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
That is giving me a rectangle of the top half of the screen
If you add the UILabel as a subview to the UIImageView you can use an extension function like this to capture an image context of the image view and its subviews (the labels).
extension UIImageView {
func renderSubviewsToImage() -> UIImage? {
guard let image = image else { return nil }
let scale = UIScreen.main.scale
UIGraphicsBeginImageContextWithOptions(image.size, false, scale)
guard let context = UIGraphicsGetCurrentContext() else { return nil }
self.layer.render(in: context)
let renderedImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return renderedImage
}
}
view.drawHierachy actually accept the boundary as bounds rather than frame
i will assume that image is actually the UIImageView
var bounds= CGRect(x: -image.frame.minX,y: -image.frame.minY,width: view.bounds.size.width,height: view.bounds.size.height)
UIGraphicsBeginImageContext(image.frame.size)
view.drawHierarchy(in: bounds, afterScreenUpdates: true)
let outputImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()

screenshot is not in proper size IOS

In my IOS App Code I am taking screenshot of UIimageView but when I take it it's not taken properly by following code.
func captureView() -> UIImage {
// let rect: CGRect = self.imageView.bounds
UIGraphicsBeginImageContextWithOptions(imageView.bounds.size, false, 0.0)//add this line
let context: CGContextRef = UIGraphicsGetCurrentContext()!
self.view.layer.renderInContext(context)
let img: UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return img
}
I want the exect screen shot of the image in imageView because there are more images on it.
Kindly suggest me proper code for getting exact UIImageView Screenshot
How about you add UIScreen.mainScreen().scale instead of 0.0 in UIGraphicsBeginImageContextWithOptions(bounds.size, false, UIScreen.mainScreen().scale)
func captureView() -> UIImage {
UIGraphicsBeginImageContextWithOptions(bounds.size, false, UIScreen.mainScreen().scale)
drawViewHierarchyInRect(bounds, afterScreenUpdates: true)
let img = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return img!
}

Taking Screenshot of UIImageView I need only image IOS

In my IOS App I am taking screenshot of UIImageView. It's very perfect as shown in attachment Photo. But here, I have taken UIImageView content mode aspect fit . I've used this code.
func captureView() -> UIImage {
UIGraphicsBeginImageContextWithOptions(imageView.bounds.size, false,UIScreen.mainScreen().scale)//add this line
let context: CGContextRef = UIGraphicsGetCurrentContext()!
self.backView.layer.renderInContext(context)
let img: UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return img
}
Simply I need the snapshot of Image, Not the ImageView. Help me into this.
Try this code:
func captureView() -> UIImage() {
UIGraphicsBeginImageContext(YourimageView.frame.size)
YourimageView.layer.renderInContext(UIGraphicsGetCurrentContext()!)
let img = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
UIImageWriteToSavedPhotosAlbum(img, nil, nil, nil)
return img
}

DrawView save combined image (multiply)

I have 2 UIImageViews - one is at the bottom and shows a default image (like an Photo) - on the second UIImageView where you can draw.
I would like to create an UIImage from both images, and save it as new image.
How can i do that? Ill tried with:
func saveImage() {
print("save combined image")
let topImage = self.canvasView.image
let bottomImage = self.backgroundImageView.image
let size = CGSizeMake(topImage!.size.width, topImage!.size.height)
UIGraphicsBeginImageContextWithOptions(size, false, 0.0)
[topImage!.drawInRect(CGRectMake(0,0,size.width, topImage!.size.height))];
[bottomImage!.drawInRect(CGRectMake(0,0,size.width, bottomImage!.size.height))];
let newImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
UIImageWriteToSavedPhotosAlbum(newImage, self, #selector(CanvasViewController.image(_:didFinishSavingWithError:contextInfo:)), nil)
}
But the result is not correct (stretched and no overlay)
Any ideas?
Ok ill found an solution for that, just need to add "multiply" as blend mode.
let topImage = self.canvasView.image
let bottomImage = self.backgroundImageView.image
let size = CGSizeMake(bottomImage!.size.width, bottomImage!.size.height)
UIGraphicsBeginImageContextWithOptions(size, false, 0.0)
[bottomImage!.drawInRect(CGRectMake(0,0,size.width, bottomImage!.size.height))];
[topImage!.drawInRect(CGRectMake(0,0,size.width, bottomImage!.size.height), blendMode: CGBlendMode.Multiply , alpha: 1.0)];
let newImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

How to take screenshot of UIScrollView visible area?

How do I take a 1:1 screenshot of UIScrollView visible area? The content may be larger or smaller than UIScrollView bounds as well as half-hidden (I've implemented custom scrolling for smaller content, so it's not in the top-left corner).
I've achieved desired result on simulator, but not on device itself:
-(UIImage *)imageFromCombinedContext:(UIView *)background {
UIImage *image;
CGRect vis = background.bounds;
CGSize size = vis.size;
UIGraphicsBeginImageContext(size);
[background.layer affineTransform];
[background.layer renderInontext:UIGraphicsGetCurrentContext()];
image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRef imref = CGImageCreateWithImageInRect([image CGImage], vis);
image = [UIImage imageWithCGImage:imref];
CGImageRelease(imref);
return image;
}
Another approach would be to use the contentOffset to adjust the layer's visible area and capture only the currently visible area of UIScrollView.
UIScrollView *contentScrollView;....//scrollview instance
UIGraphicsBeginImageContextWithOptions(contentScrollView.bounds.size,
YES,
[UIScreen mainScreen].scale);
//this is the key
CGPoint offset=contentScrollView.contentOffset;
CGContextTranslateCTM(UIGraphicsGetCurrentContext(), -offset.x, -offset.y);
[contentScrollView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *visibleScrollViewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Cheers :)
Swift version of Abduliam Rehmanius answer.
func screenshot() -> UIImage {
UIGraphicsBeginImageContextWithOptions(self.scrollCrop.bounds.size, true, UIScreen.mainScreen().scale);
//this is the key
let offset:CGPoint = self.scrollCrop.contentOffset;
CGContextTranslateCTM(UIGraphicsGetCurrentContext(), -offset.x, -offset.y);
self.scrollCrop.layer.renderInContext(UIGraphicsGetCurrentContext()!);
let visibleScrollViewImage: UIImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return visibleScrollViewImage;
}
Swift 4 version:
func screenshot() -> UIImage {
UIGraphicsBeginImageContextWithOptions(self.scrollCrop.bounds.size, false, UIScreen.main.scale)
let offset = self.scrollCrop.contentOffset
let thisContext = UIGraphicsGetCurrentContext()
thisContext?.translateBy(x: -offset.x, y: -offset.y)
self.scrollCrop.layer.render(in: thisContext!)
let visibleScrollViewImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return visibleScrollViewImage
}
I've found a solution myself - I took screenshot of the whole view and then crop it to the size and position of UIScrollView frame.
-(UIImage *)imageFromCombinedContext:(UIView *)background
{
UIImage *image;
CGSize size = self.view.frame.size;
UIGraphicsBeginImageContext(size);
[background.layer affineTransform];
[self.view.layer.layer renderInContext:UIGraphicsGetCurrentContext()];
image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRef imgRef = CGImageCreateWithImageInRect([image CGImage],background.frame);
image = [UIImage imageWithCGImage:imref];
CGImageRelease(imref);
return image;
}
Swift 4 version of Abduliam Rehmanius answer as UIScrollView extension with translation, no slow cropping
extension UIScrollView {
var snapshotVisibleArea: UIImage? {
UIGraphicsBeginImageContext(bounds.size)
UIGraphicsGetCurrentContext()?.translateBy(x: -contentOffset.x, y: -contentOffset.y)
layer.render(in: UIGraphicsGetCurrentContext()!)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image
}
}
Jeffery Sun has the right answer. Just put your scroll view inside another view. Get container view to render in context. done.
In the code below, cropView contains the scroll view to be captured. The solution is really just that simple.
As I understand the question and why I found this page, the whole content of the scroll view isn't wanted - just the visible portion.
func captureCrop() -> UIImage {
UIGraphicsBeginImageContextWithOptions(self.cropView.frame.size, true, 0.0)
self.cropView.layer.renderInContext(UIGraphicsGetCurrentContext())
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image;
}
#Abduliam Rehmanius's answer has poor performance, since if the UIScrollView contains a large content area, we will draw that entire content area (even outside the visible bounds).
#Concuror's answer has the issue that it will also draw anything that is on top of the UIScrollView.
My solution was to put the UIScrollView inside a UIView called containerView with the same bounds and then render containerView:
containerView.renderInContext(context)
Swift 3.0 :
func captureScreen() -> UIImage? {
UIGraphicsBeginImageContextWithOptions(self.yourScrollViewName.bounds.size, true, UIScreen.main.scale)
let offset:CGPoint = self.yourScrollViewName.contentOffset;
UIGraphicsGetCurrentContext()!.translateBy(x: -offset.x, y: -offset.y);
self.yourScrollViewName.layer.render(in: UIGraphicsGetCurrentContext()!)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image
}
and use it as :
let Image = captureScreen()
Update swift 3+, 4 on #Concuror code
func getImage(fromCombinedContext background: UIView) -> UIImage {
var image: UIImage?
let size: CGSize = view.frame.size
UIGraphicsBeginImageContext(size)
background.layer.affineTransform()
view.layer.render(in: UIGraphicsGetCurrentContext()!)
image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
let imgRef = image?.cgImage?.cropping(to: background.frame)
image = UIImage(cgImage: imgRef!)
// CGImageRelease(imgRef!) // Removing on Swift - 'CGImageRelease' is unavailable: Core Foundation objects are automatically memory managed
return image ?? UIImage()
}
A lot of the answers use UIGraphicsBeginImageContext (pre iOS 10.0) to create an image, this creates an image missing the P3 colour gamut - reference https://stackoverflow.com/a/41288197/2481602
extension UIScrollView {
func asImage() -> UIImage {
let renderer = UIGraphicsImageRenderer(bounds: bounds)
return renderer.image { rendererContext in
inputView?.layer.render(in: rendererContext.cgContext)
layer.render(in: rendererContext.cgContext)
}
}
}
The above will result in a better quality image being produced.
The second image is clearer, and showing more of the colours - this was done with the UIGraphicsImageRenderer rather than the UIGraphicsBeginImageContext (first Image)

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