Capturing Screen

Question

I am trying to capture (screen shot) a view. For that I am using a piece of code shown below that saves it to my document directory as a PNG image.

UIGraphicsBeginImageContextWithOptions(highlightViewController.fhView.centerView.frame.size, YES, 1.0);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *screenshot = UIGraphicsGetImageFromCurrentImageContext();
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *appFile = [documentsDirectory stringByAppendingPathComponent:@"1.png"];
NSData *imageData = UIImagePNGRepresentation(screenshot);
[imageData writeToFile:appFile atomically:YES];
UIGraphicsEndImageContext();

Question: can I capture part of the view? Because in the above code I can't change the origin (frame). If anyone has other approach to capture a particular part of view please share it.

You want to capture from code only? Or some shortcut can work for you? — Nitish, Sep 15 '11 at 11:20

score 6 · Accepted Answer · edited Jul 01 '17 at 06:06

6

You could crop the image: http://iosdevelopertips.com/graphics/how-to-crop-an-image.html

CGRect rect = CGRectMake(0,0,10,10);
CGImageRef imageRef = CGImageCreateWithImageInRect([screenshot CGImage], rect);
UIImage *croppedScreenshot = [UIImage imageWithCGImage:imageRef]; 
CGImageRelease(imageRef);

edited Jul 01 '17 at 06:06

Cœur

37,241
25
195
267

answered Sep 15 '11 at 11:16

Lenar Hoyt

5,971
6
49
59

Parth Bhatt · Answer 2 · 2012-03-06T04:31:35.207

Try this code. This surely works as I have implemented it in many of my projects:

- (UIImage *)image
{
    if (cachedImage == nil) {
        //YOU CAN CHANGE THE FRAME HERE TO WHATEVER YOU WANT TO CAPTURE
        CGRect imageFrame = CGRectMake(0, 0, 400, 300); 
        UIView *imageView = [[UIView alloc] initWithFrame:imageFrame];
        [imageView setOpaque:YES];
        [imageView setUserInteractionEnabled:NO];

        [self renderInView:imageView withTheme:nil];        

        UIGraphicsBeginImageContext(imageView.bounds.size);
            CGContextRef c = UIGraphicsGetCurrentContext();
            CGContextGetCTM(c);
            CGContextScaleCTM(c, 1, -1);
            CGContextTranslateCTM(c, 0, -imageView.bounds.size.height);
            [imageView.layer renderInContext:c];
            cachedImage = [UIGraphicsGetImageFromCurrentImageContext() retain];

            // rescale graph
            UIImage* bigImage = UIGraphicsGetImageFromCurrentImageContext();
            CGImageRef scaledImage = [self newCGImageFromImage:[bigImage CGImage] scaledToSize:CGSizeMake(100.0f, 75.0f)];
            cachedImage = [[UIImage imageWithCGImage:scaledImage] retain];
            CGImageRelease(scaledImage);
        UIGraphicsEndImageContext();

        [imageView release];
    }

    return cachedImage;
}

I hope this will help you.

score 0 · Answer 3 · answered Sep 15 '11 at 11:23

0

See if you can specify the rect like this and then take screenshot.

CGRect requiredRect = CGRectMake(urView.frame.origin.x, urView.frame.origin.y, urView.bounds.size.width, urView.bounds.size.height);
UIGraphicsBeginImageContext(requiredRect.size);

You can alter the origin and see if it works. If this doesn't work out, you can try cropping the image as mentioned by @mcb

answered Sep 15 '11 at 11:23

visakh7

26,380
8
55
69

Hi, is the question about cropping or capturing. I think it is about capturing image though. May be your perception is different from mine. But Good answer anyways :) – Parth Bhatt Sep 15 '11 at 12:27
@Parth Bhatt: Actually cropping was another option. Thats all. – visakh7 Sep 15 '11 at 12:36
Thanks for your answer i want the screen capture on the view in a particular part. – ajay Sep 15 '11 at 12:52
@ajay: checkout my answer.. I think that is what you are looking for.. Please contact me if you have some doubts..! – Parth Bhatt Sep 15 '11 at 14:59

score 0 · Answer 4 · edited Mar 12 '14 at 10:17

You can use this code

UIGraphicsBeginImageContext(self.view.bounds.size);

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

UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGRect rect;
rect = CGRectMake(250,61 ,410, 255);
CGImageRef imageRef = CGImageCreateWithImageInRect([viewImage CGImage], rect);

UIImage *img = [UIImage imageWithCGImage:imageRef]; 

UIImageWriteToSavedPhotosAlbum(img, nil, nil, nil); 
CGImageRelease(imageRef);

Capturing Screen

4 Answers4

Linked