[ios] How to take a screenshot programmatically on iOS

I want a screenshot of the image on the screen saved into the saved photo library.

Below method works for OPENGL objects also

//iOS7 or above
- (UIImage *) screenshot {

    CGSize size = CGSizeMake(your_width, your_height);

    UIGraphicsBeginImageContextWithOptions(size, NO, [UIScreen mainScreen].scale);

    CGRect rec = CGRectMake(0, 0, your_width, your_height);
    [_viewController.view drawViewHierarchyInRect:rec afterScreenUpdates:YES];

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

Two options available at bellow site:

OPTION 1: using UIWindow (tried and work perfectly)

// create graphics context with screen size
CGRect screenRect = [[UIScreen mainScreen] bounds];
UIGraphicsBeginImageContext(screenRect.size);
CGContextRef ctx = UIGraphicsGetCurrentContext();
[[UIColor blackColor] set];
CGContextFillRect(ctx, screenRect);

// grab reference to our window
UIWindow *window = [UIApplication sharedApplication].keyWindow;

// transfer content into our context
[window.layer renderInContext:ctx];
UIImage *screengrab = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

OPTION 2: using UIView

// grab reference to the view you'd like to capture
UIView *wholeScreen = self.splitViewController.view;

// define the size and grab a UIImage from it
UIGraphicsBeginImageContextWithOptions(wholeScreen.bounds.size, wholeScreen.opaque, 0.0);
[wholeScreen.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *screengrab = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

For retina screen (as DenNukem answer)

// grab reference to our window
    UIWindow *window = [UIApplication sharedApplication].keyWindow;

    // create graphics context with screen size
    CGRect screenRect = [[UIScreen mainScreen] bounds];
    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)]) {
        UIGraphicsBeginImageContextWithOptions(screenRect.size, NO, [UIScreen mainScreen].scale);
    } else {
        UIGraphicsBeginImageContext(screenRect.size);
        [window.layer renderInContext:UIGraphicsGetCurrentContext()];
    }

for more detail: http://pinkstone.co.uk/how-to-take-a-screeshot-in-ios-programmatically/

I think the following snippet would help if you want to take a full screen(except for status bar),just replace AppDelegate with your app delegate name if necessary.

- (UIImage *)captureFullScreen {

    AppDelegate *_appDelegate = (AppDelegate *)[UIApplication sharedApplication].delegate;

    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)]) {
        // for retina-display
        UIGraphicsBeginImageContextWithOptions(_appDelegate.window.bounds.size, NO, [UIScreen mainScreen].scale);
        [_appDelegate.window drawViewHierarchyInRect:_appDelegate.window.bounds afterScreenUpdates:NO];
    } else {
        // non-retina-display
        UIGraphicsBeginImageContext(_bodyView.bounds.size);
        [_appDelegate.window drawViewHierarchyInRect:_appDelegate.window.bounds afterScreenUpdates:NO];
    }

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

In Swift you can use following code.

if UIScreen.mainScreen().respondsToSelector(Selector("scale")) {
    UIGraphicsBeginImageContextWithOptions(self.window!.bounds.size, false, UIScreen.mainScreen().scale)
}
else{
    UIGraphicsBeginImageContext(self.window!.bounds.size)
}
self.window?.layer.renderInContext(UIGraphicsGetCurrentContext())
var image : UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)

Get Screenshot From View

-(UIImage *)getScreenshotImage {
    if ([[UIScreen mainScreen] scale] == 2.0) {
        UIGraphicsBeginImageContextWithOptions(self.view.frame.size, FALSE, 2.0);
    } else {
        UIGraphicsBeginImageContextWithOptions(self.view.frame.size, FALSE, 1.0);
    }

    [self.view.window.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage * result = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return result;
}

Save Image to Photos

UIImageWriteToSavedPhotosAlbum(YOUR_IMAGE, nil, nil, nil);

How-To

UIImageWriteToSavedPhotosAlbum([self getScreenshotImage], nil, nil, nil);

This will work with swift 4.2, the screenshot will be saved in library, but please don't forget to edit the info.plist @ NSPhotoLibraryAddUsageDescription :

  @IBAction func takeScreenshot(_ sender: UIButton) {

    //Start full Screenshot
    print("full Screenshot")
    UIGraphicsBeginImageContext(card.frame.size)
    view.layer.render(in: UIGraphicsGetCurrentContext()!)
    var sourceImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    UIImageWriteToSavedPhotosAlbum(sourceImage!, nil, nil, nil)

    //Start partial Screenshot
    print("partial Screenshot")
    UIGraphicsBeginImageContext(card.frame.size)
    sourceImage?.draw(at: CGPoint(x:-25,y:-100)) //the screenshot starts at -25, -100
    var croppedImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    UIImageWriteToSavedPhotosAlbum(croppedImage!, nil, nil, nil)

}

Considering a check for retina display use the following code snippet:

#import <QuartzCore/QuartzCore.h> 

if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)]) {
    UIGraphicsBeginImageContextWithOptions(self.window.bounds.size, NO, [UIScreen mainScreen].scale);
} else {
    UIGraphicsBeginImageContext(self.window.bounds.size);
}

[self.window.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSData *imageData = UIImagePNGRepresentation(image);
if (imageData) {
    [imageData writeToFile:@"screenshot.png" atomically:YES];
} else {
    NSLog(@"error while taking screenshot");
}

For iOS 7.0 or above..

If you want to take screenshots of view say(myView), you can do this with single line:

[myView snapshotViewAfterScreenUpdates:NO];

See this post it looks like you can use UIGetScreenImage() for now.

Get Screenshot From View :

- (UIImage *)takeSnapshotView {
    CGRect rect = [myView bounds];//Here you can change your view with myView
    UIGraphicsBeginImageContextWithOptions(rect.size,YES,0.0f);
    CGContextRef context = UIGraphicsGetCurrentContext();
    [myView.layer renderInContext:context];
    UIImage *capturedScreen = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return capturedScreen;//capturedScreen is the image of your view
}

Hope, this is what you're looking for. Any concern get back to me. :)

- (UIImage*) getGLScreenshot {
    NSInteger myDataLength = 320 * 480 * 4;

    // allocate array and read pixels into it.
    GLubyte *buffer = (GLubyte *) malloc(myDataLength);
    glReadPixels(0, 0, 320, 480, GL_RGBA, GL_UNSIGNED_BYTE, buffer);

    // gl renders "upside down" so swap top to bottom into new array.
    // there's gotta be a better way, but this works.
    GLubyte *buffer2 = (GLubyte *) malloc(myDataLength);
    for(int y = 0; y <480; y++)
    {
        for(int x = 0; x <320 * 4; x++)
        {
            buffer2[(479 - y) * 320 * 4 + x] = buffer[y * 4 * 320 + x];
        }
    }

    // make data provider with data.
    CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, buffer2, myDataLength, NULL);

    // prep the ingredients
    int bitsPerComponent = 8;
    int bitsPerPixel = 32;
    int bytesPerRow = 4 * 320;
    CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
    CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault;
    CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;

    // make the cgimage
    CGImageRef imageRef = CGImageCreate(320, 480, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);

    // then make the uiimage from that
    UIImage *myImage = [UIImage imageWithCGImage:imageRef];
    return myImage;
}

- (void)saveGLScreenshotToPhotosAlbum {
    UIImageWriteToSavedPhotosAlbum([self getGLScreenshot], nil, nil, nil);  
}

Source.

UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, self.view.opaque, 0.0);
[self.myView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

NSData *imageData = UIImageJPEGRepresentation(image, 1.0 ); //you can use PNG too
[imageData writeToFile:@"image1.jpeg" atomically:YES];

As of iOS10, this gets a bit simpler. UIKit comes with UIGraphicsImageRender that allows you to

... accomplish drawing tasks, without having to handle configuration such as color depth and image scale, or manage Core Graphics contexts

Apple Docs - UIGraphicsImageRenderer

So you can now do something like this:

let renderer = UIGraphicsImageRenderer(size: someView.bounds.size)

let image = renderer.image(actions: { context in
    someView.drawHierarchy(in: someView.bounds, afterScreenUpdates: true)
})

Many of the answers here worked for me in most cases. But when trying to take a snapshot of an ARSCNView, I was only able to do it using the method described above. Although it might be worth noting that at this time, ARKit is still in beta and Xcode is in beta 4

IN SWIFT

func captureScreen() -> UIImage
{

    UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, false, 0);

    self.view.drawViewHierarchyInRect(view.bounds, afterScreenUpdates: true)

    let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()

    UIGraphicsEndImageContext()

    return image
}

Just a small contribution, I've done this with a button but the pressing also means the button is captured pressed. So first I unhighlight.

- (IBAction)screenShot:(id)sender {
    // Unpress screen shot button
    screenShotButton.highlighted = NO;

    // create graphics context with screen size
    CGRect screenRect = [[UIScreen mainScreen] bounds];

    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)]) {
        UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, NO, [UIScreen mainScreen].scale);
    } else {
        UIGraphicsBeginImageContext(self.view.bounds.size);
    }

    CGContextRef ctx = UIGraphicsGetCurrentContext();
    [[UIColor blackColor] set];
    CGContextFillRect(ctx, screenRect);

    // grab reference to our window
    UIWindow *window = [UIApplication sharedApplication].keyWindow;

    // transfer content into our context
    [window.layer renderInContext:ctx];
    UIImage *screengrab = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    // save screengrab to Camera Roll
    UIImageWriteToSavedPhotosAlbum(screengrab, nil, nil, nil);
}

I got the main body of the code from: http://pinkstone.co.uk/how-to-take-a-screeshot-in-ios-programmatically/ where I used option 1, option 2 didn't seem to work for me. Added the adjustments for Rentina screen sizes from this thread, and the unhighlighting of the screenShotButton. The view I'm using it on is a StoryBoarded screen of buttons and labels and with several UIView added later via the program.

Swift 4:

func makeImage(withView view: UIView) -> UIImage? {

    let rect = view.bounds

    UIGraphicsBeginImageContextWithOptions(rect.size, true, 0)

    guard let context = UIGraphicsGetCurrentContext() else {
      assertionFailure()
      return nil
    }

    view.layer.render(in: context)

    guard let image = UIGraphicsGetImageFromCurrentImageContext() else {
      assertionFailure()
      return nil
    }

    UIGraphicsEndImageContext()

    return image
}

This will save a screenshot and as well return the screenshot too.

-(UIImage *)capture{
    UIGraphicsBeginImageContext(self.view.bounds.size);
    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *imageView = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    UIImageWriteToSavedPhotosAlbum(imageView, nil, nil, nil); //if you need to save
    return imageView;
}

Another option is to use the Automation tool on instruments. You write a script to put the screen into whatever you state you want, then take the shots. Here is the script I used for one of my apps. Obviously, the details of the script will be different for your app.

var target = UIATarget.localTarget();
var app = target.frontMostApp();
var window = app.mainWindow();
var picker = window.pickers()[0];
var wheel = picker.wheels()[2];
var buttons = window.buttons();
var button1 = buttons.firstWithPredicate("name == 'dateButton1'");
var button2 = buttons.firstWithPredicate("name == 'dateButton2'");

function setYear(picker, year) {
    var yearName = year.toString();
    var yearWheel = picker.wheels()[2];
    yearWheel.selectValue(yearName);
}

function setMonth(picker, monthName) {
    var wheel = picker.wheels()[0];
    wheel.selectValue(monthName);
}

function setDay(picker, day) {
    var wheel = picker.wheels()[1];
    var name = day.toString();
    wheel.selectValue(name);
}

target.delay(1);
setYear(picker, 2015);
setMonth(picker, "July");
setDay(picker, 4);
button1.tap();
setYear(picker, 2015);
setMonth(picker, "December");
setDay(picker, 25);

target.captureScreenWithName("daysShot1");

var nButtons = buttons.length;
UIALogger.logMessage(nButtons + " buttons");
for (var i=0; i<nButtons; i++) {
    UIALogger.logMessage("button " + buttons[i].name());
}

var tabBar = window.tabBars()[0];
var barButtons = tabBar.buttons();

var nBarButtons = barButtons.length;
UIALogger.logMessage(nBarButtons + " buttons on tab bar");

for (var i=0; i<nBarButtons; i++) {
    UIALogger.logMessage("button " + barButtons[i].name());
}

var weeksButton = barButtons[1];
var monthsButton = barButtons[2];
var yearsButton = barButtons[3];

target.delay(2);
weeksButton.tap();
target.captureScreenWithName("daysShot2");
target.delay(2);
monthsButton.tap();
target.captureScreenWithName("daysShot3");
target.delay(2);
yearsButton.tap();
target.delay(2);
button2.tap();
target.delay(2);
setYear(picker, 2018);
target.delay(2);
target.captureScreenWithName("daysShot4");

I couldn't find an answer with Swift 3 implementation. So here it goes.

static func screenshotOf(window: UIWindow) -> UIImage? {

    UIGraphicsBeginImageContextWithOptions(window.bounds.size, true, UIScreen.main.scale)

    guard let currentContext = UIGraphicsGetCurrentContext() else {
        return nil
    }

    window.layer.render(in: currentContext)
    guard let image = UIGraphicsGetImageFromCurrentImageContext() else {
        UIGraphicsEndImageContext()
        return nil
    }

    UIGraphicsEndImageContext()
    return image
}