Screen capture while backgrounded in iOS 9 [duplicate] - ios

Question

I need to take screenshot of the whole screen including the status bar, I use CARenderServerRenderDisplay to achieve this, it works right on iPad, but wrong at iPhone 6 Plus. As the * marked part in the code, if I set width=screenSize.width*scale and height=screenSize.height*scale, it will cause crash, if I just change them as:width=screenSize.height*scale and height=screenSize.width*scale, it will works, but produce a image like that:
, I've tried much but no reason found, does anyone know that? I hope I've described it clear enough.
- (void)snapshot
{
CGFloat scale = [UIScreen mainScreen].scale;
CGSize screenSize = [UIScreen mainScreen].bounds.size;
//*********** the place where problem appears
size_t width = screenSize.height * scale;
size_t height = screenSize.width * scale;
//***********
size_t bytesPerElement = 4;
OSType pixelFormat = 'ARGB';
size_t bytesPerRow = bytesPerElement * width;
size_t surfaceAllocSize = bytesPerRow * height;
NSDictionary *properties = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES], kIOSurfaceIsGlobal,
[NSNumber numberWithUnsignedLong:bytesPerElement], kIOSurfaceBytesPerElement,
[NSNumber numberWithUnsignedLong:bytesPerRow], kIOSurfaceBytesPerRow,
[NSNumber numberWithUnsignedLong:width], kIOSurfaceWidth,
[NSNumber numberWithUnsignedLong:height], kIOSurfaceHeight,
[NSNumber numberWithUnsignedInt:pixelFormat], kIOSurfacePixelFormat,
[NSNumber numberWithUnsignedLong:surfaceAllocSize], kIOSurfaceAllocSize,
nil];
IOSurfaceRef destSurf = IOSurfaceCreate((__bridge CFDictionaryRef)(properties));
IOSurfaceLock(destSurf, 0, NULL);
CARenderServerRenderDisplay(0, CFSTR("LCD"), destSurf, 0, 0);
IOSurfaceUnlock(destSurf, 0, NULL);
CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, IOSurfaceGetBaseAddress(destSurf), (width * height * 4), NULL);
CGImageRef cgImage = CGImageCreate(width, height, 8,
8*4, IOSurfaceGetBytesPerRow(destSurf),
CGColorSpaceCreateDeviceRGB(), kCGImageAlphaNoneSkipFirst |kCGBitmapByteOrder32Little,
provider, NULL, YES, kCGRenderingIntentDefault);
UIImage *image = [UIImage imageWithCGImage:cgImage];
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
}

Answer 1

If you are on a Jailbroken environment, you can use the private UIImage method _UICreateScreenUIImage:
OBJC_EXTERN UIImage *_UICreateScreenUIImage(void);
// ...
- (void)takeScreenshot {
UIImage *screenImage = _UICreateScreenUIImage();
// do something with your screenshot
}
This method uses CARenderServerRenderDisplay for faster rendering of the entire device screen. It replaces the UICreateScreenImage and UIGetScreenImage methods that were removed in the arm64 version of the iOS 7 SDK.