I'm looking for a way to write the contents of the screen to an image. Any idea how to achieve that? Does it involve using Quartz?
Thanks
Add this code to your UIViewController to create a screen dump of its UIView.
// create screen dump of the view of this view controller
UIGraphicsBeginImageContext(self.view.bounds.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *screenShot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// save image to photos
UIImageWriteToSavedPhotosAlbum(screenShot, self, nil, nil);
In a nutshell:
CGImageRef screen = UIGetScreenImage();
UIImage *screenImage = [UIImage imageWithCGImage:screen];
Related
In my app, the user is able to put stickers on top of a photo. When they go to save their creation, I do a screen grab and store it in a UIImage:
UIGraphicsBeginImageContextWithOptions(self.mainView.bounds.size, NO, [UIScreen mainScreen].scale);
[self.mainView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *resultImage = [UIGraphicsGetImageFromCurrentImageContext() retain];
UIGraphicsEndImageContext();
(where self.mainView has a subview UIImageView which holds the photo, and another subview UIView which holds the stickers).
I am wondering, is it possible to do a screen shot in this manner, and maintain the resolution of the aforementioned photo?
The following will 'flatten' two UIImages into one while maintaining the resolution of the original image(s):
CGSize photoSize = photoImage.size;
UIGraphicsBeginImageContextWithOptions(photoSize, NO, 0.0);
CGRect photoRect = CGRectMake(0, 0, photoSize.width, photoSize.height);
// Add the original photo into the context
[photoImage drawInRect:photoRect];
// Add the sticker image with its upper left corner set to where the user placed it
[stickerImage drawAtPoint:stickerView.frame.origin];
// Get the resulting 'flattened' image
UIImage *flattenedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
The above assumes photoImage and stickerImage are both instances of UIImage and stickerView is a UIView with containing the stickerImage and thus will be able to use the stickerView frame to determine its origin.
If you have multiple stickers, just iterate through the collection.
If you are looking to save an image of your current view then this might help you.
UIGraphicsBeginImageContext(self.scrollView.contentSize);
[self.scrollView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRef imageRef = CGImageCreateWithImageInRect(finalImage.CGImage,
CGRectMake(scrollView.contentOffset.x, scrollView.contentOffset.y,
scrollView.frame.size.width, scrollView.frame.size.height));
UIImage *screenImage = [UIImage imageWithCGImage:imageRef scale:[UIScreen mainScreen].scale orientation:UIImageOrientationUp];
CGImageRelease(imageRef);
I am creating a native app on Xcode 4.3 and deploying to target iOS 5. The app is a basically a greeting card creator. I am having trouble figuring out how to save a portion of the screen from within the app.
What I want to do is this:
I am offering the user a button, that says "e-mail". when they click the button, the app should 'save' their card as an image and then 'paste' that into an email body.
The reason this is different than other answers on this website is that the area I want to save is made up of 4 'elements'. There is a background graphic that is the tilted card background, then there is a text field where users can type a message and then next to that is a picture area where they can choose their own picture to put on the card.
Here is a photo of what I am talking about:
http://marklopezdesigns.com/mydownloadz!/screenshotCard3.png
How do I save a 'composite' high res of these?
And then how do I get that into an email body message?
The reason i am asking how to 'save' it is because I want to be able to offer users another button that says "save to camera roll" and "send as message". I figure if I can understand how to save this high-res to a variable, then I should be off and running.
Thanks in advance for the help.
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Here's the solution below
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...so after a bit of fiddling. Finally got what I wanted. Here's the codebase I have in my method that fires upon touch of the "Save to Album" button:
- (IBAction)savePhoto{
CGRect rect;
rect = CGRectMake(11,50 ,305, 262);
UIView *cardViewer = [[UIView alloc] initWithFrame:rect];
UIGraphicsBeginImageContext(cardViewer.bounds.size);
//make view background transparent
cardViewer.backgroundColor = [UIColor colorWithWhite:0.0 alpha:0.0];
cardViewer.opaque = NO;
//stuff items into a subview for capturing
[self.view addSubview:cardViewer];
[cardViewer addSubview:self.tiltedCard];
[cardViewer addSubview:self.bigCardView];
[cardViewer addSubview:self.cardWords];
[cardViewer addSubview:self.photoView];
[cardViewer.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRef imageRef = CGImageCreateWithImageInRect([viewImage CGImage], rect);
UIImage *img = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
UIImageWriteToSavedPhotosAlbum(img, nil, nil, nil);
//put everything back where it belongs
[self.view addSubview:self.tiltedCard];
[self.view addSubview:self.bigCardView];
[self.view addSubview:self.cardWords];
[self.view addSubview:self.photoView];
[cardViewer removeFromSuperview];
}
To capture just an area of the screen, specify the bounds using CGRectMake.
CGRect rect = CGRectMake(50, 50, 100, 100);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
[self.view.layer renderInContext:context];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
In the example above we are capturing a 100px by 100px region beginning at x:50px and y:50px.
maybe get the picture of the layer by rendering the layer context and grabbing the image, I use this for displaying fancy animations
UIGraphicsBeginImageContext(self.view.bounds.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
To capture just an area of the screen, use the UIView or SubView and just specify the bounds using CGRectMake.
CGRect rect = CGRectMake(10, 10, 200, 200);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
[self.YourView.layer renderInContext:context]; // Make sure here you are using the greetingcardView rather than self.view
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Note: self.view will capture the whole screen so simply render the view wherever.
I am developing an iPhone app in which I am capturing the live video.
I have added the AVCaptureVideoPreviewLayer to the self.view.layer as sublayer.
[self.view.layer addSublayer: self.prevLayer];
On the same self.view I have added an image as subview.
[self.view addSubView:image];
Now what I want is to capture an image from the live video but the image should also come into that picture as it looks on the screen.
I have tried to take the screen shot but it capture only the image and not the live video image.
Can any body please help me on this.
Thanks in advance.
hi this will help you as it works for me
- (void)didTakePicture:(UIImage *)picture
{
UIImage *frm = self.overlayViewController.imgOverlay.image;
NSLog(#"width %f height %f",picture.size.width,picture.size.height);
UIGraphicsBeginImageContext(picture.size);
[picture drawAtPoint:CGPointMake(0,0)];
[frm drawInRect:CGRectMake(0, 0, picture.size.width, picture.size.height)];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSLog(#"view %#",viewImage.debugDescription);
[self.capturedImages addObject:viewImage];
}
I am trying to build a photo frame application on iphone. I made the frame it is transparent in png formate, then by choosing photos and was placed behind the frame layer in the interface builder.
In interface builder they are placed well and fit well. Now my problem is how can i save them into one picture.
Here is the code i have, but the saving part keep crashing.
-(IBAction) saveImage:(id)sender{
imagefront .backgroundColor = [UIColor clearColor]; //This sets your backgroung to transparent.
imagefront.opaque = NO;
[imageView bringSubviewToFront:imagefront];
UIImage *overlappedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(overlappedImage, self, #selector(imageSavedToPhotosAlbum: didFinishSavingWithError: contextInfo:), nil);
}
Imagefront is the photoframe while imageView is the photo.
Thank you.
Your current approach is incorrect. You will need to do this to get the image.
UIGraphicsBeginImageContext(imageView.frame.size);
[imageView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsGetCurrentContext();
This is assuming that imageView has imageFront as its subview as suggested by the code you've posted.
I am saving image in the camera roll using UIImageWriteToSavedPhotosAlbum but always get an black thumbnail even if the picture is correct.
Do you have pointers to address this?
Thanks in advance for your help.
Regards,
I had the same problem. Drawing the image within a UIGraphicsImageContext solves the issue:
CGRect rect = CGRectMake(0,0,100,100);
UIImage *image = ((put here your image));
UIGraphicsBeginImageContext(rect.size);
[image drawInRect:rect];
UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(
result, self, #selector(image:didFinishSavingWithError:contextInfo:),nil);