I have a map view, which can display a SVG map.
I used to use renderInContext to get the UIImage, however its performance is not ideal and I heard iOS 7 has new APIs to do such things, which is drawViewHierarchyInRect
Now I want to turn this map view into UIImage or a screenshot as UIView by drawViewHierarchyInRect
However,
If I use drawViewHierarchyInRect, no valid UIImage I can get neither, I suspect they are the same reason
The code for snapshotView,
PS: for performance, I don't add _mapView into any views
-(void)drawRect:(CGRect)rect {
UIGraphicsBeginImageContextWithOptions(_mapView.bounds.size, _mapView.opaque, [[UIScreen mainScreen] scale]);
CGContextRef context = UIGraphicsGetCurrentContext();
// [mapView.layer renderInContext:context];
[_mapView drawViewHierarchyInRect:_mapView.bounds afterScreenUpdates:YES];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
self.thumbImageView = [[UIImageView alloc] initWithImage:image];
[self addSubview:self.thumbImageView];
}
Related
I can take snapshots of the whole frame of the UIView with no problem.
Taking part of it cause to a squeezed image.
This is my UIView category method:
- (UIImage *)snapshot:(CGRect)frame
{
UIGraphicsBeginImageContextWithOptions(frame.size, YES, [[UIScreen mainScreen] scale]);
[self drawViewHierarchyInRect:frame afterScreenUpdates:YES];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
And this is the call to this method:
UIImage *img = [self.view snapshot:bottomRectToSnap];
When bottomRectToSnap is a partial frame of the view.
Note:The UIView contains UITableView if that matter.
The code you are applying is fine.
Need to add some logic, whatever part you need to take snap, It should be available on screen and hide rest of part while snapping.
Once snap shot done, remove hide code. So it will not effect to view interface too.
Use the following code.
- (void)captureView:(UIView*)view withFrame:(CGRect)frame{
UIGraphicsBeginImageContext(self.view.bounds.size);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGRect rect = frame;
CGImageRef imageRef = CGImageCreateWithImageInRect([viewImage CGImage], rect);
UIImage *img = [UIImage imageWithCGImage:imageRef];
UIImageWriteToSavedPhotosAlbum(img, nil, nil, nil);
CGImageRelease(imageRef);
}
You can add this code to take the snapshot of particular part..
CGRect cropRect=CGRectMake(0, 0, 100, 100);
CGImageRef imageRef = CGImageCreateWithImageInRect([_galleryimageview.image CGImage], cropRect);
UIImage *cropedImage=[UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
This code crop the part of particular image ...Hope this is helpfull for you..
So, I am taking a screenshot of a subclassed UIView that I save into the device's photo stream.
Problem:
The problem is that I use resizableImageWithCapInsets to add a stretched background to my UIView, but this background gets cut off on the right side and I have no idea why. If someone could help me out it would be highly appreciated.
I add the stretched background to my UIView the following way:
[diagramBase addSubview:[self addTileBackgroundOfSize:diagramBase.frame
andType:#"ipad_diagram_border.png"]];
Which calls this method:
- (UIImageView *) addTileBackgroundOfSize:(CGRect)frame
andType:(NSString *)type
{
frame.origin.x = 0.0f;
frame.origin.y = 0.0f;
UIImageView *backgroundView = [[UIImageView alloc] initWithFrame:frame];
UIImage *image = [UIImage imageNamed:type];
UIEdgeInsets insets = UIEdgeInsetsMake(10.0f, 10.0f, 10.0f, 10.0f);
UIImage *backgroundImage = [image resizableImageWithCapInsets:insets];
backgroundView.image = backgroundImage;
return backgroundView;
}
The actual printscreen is done with this method (RINDiagramView is the name of my subclassed UIView, which I am taking a screenshot of). The rotation is in there because I need the image rotated when I save it, but I commented out that part and that is not what does the background to act weird.
- (UIImage *) createSnapshotOfView:(RINDiagram *) view
{
CGRect rect = [view bounds];
rect.size.height = rect.size.height - 81.0f;
UIGraphicsBeginImageContextWithOptions(rect.size, YES, 0.0f);
CGContextRef context = UIGraphicsGetCurrentContext();
[view.layer renderInContext:context];
UIImage *capturedScreen = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImage *finalImage = [[UIImage alloc] initWithCGImage: capturedScreen.CGImage
scale: 1.0
orientation: UIImageOrientationLeft];
return finalImage;
}
I use Xcode 5.1 and everything is done programmatically (no storyboard and such). The base SDK is iOS 7.1.
If you're doing iOS 7+ you can use the new drawViewHierarchyInRect:afterScreenUpdates: and related methods which Apple says are really performant.
Even if you're targeting iOS 6 you should give it a try to see if you get the same problem.
Try using the correct scale?
UIImage *finalImage = [[UIImage alloc] initWithCGImage: capturedScreen.CGImage
scale: [[UIScreen mainScreen] scale]
orientation: UIImageOrientationLeft];
Use a different UIViewContentMode?
UIViewContentModeScaleToFill -> check if you can see the edges
UIViewContentModeScaleAspectFit -> check if you can see the edges, even if position is incorrect
UIViewContentModeScaleAspectFill -> check for edge right side
The reason you got a right-side cut image is caused by this line
UIImage *finalImage = [[UIImage alloc] initWithCGImage: capturedScreen.CGImage
scale: 1.0
orientation: UIImageOrientationLeft];
You made the image orientation to left, the context will thought the left-side is your top-side.And your size has a minus to the height value, so the result turns to the right-side is cut.
About the rotation, I added some code into your code.Hopes it is helpful.
- (UIImage *) createSnapshotOfView:(UIView *) view
{
CGRect rect = [view bounds];
rect.size.height = rect.size.height - 81.0f;
UIGraphicsBeginImageContextWithOptions(rect.size, YES, 0.0f);
CGContextRef context = UIGraphicsGetCurrentContext();
view.transform = CGAffineTransformMakeRotation(M_PI_2);
[view.layer renderInContext:context];
UIImage *capturedScreen = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImage *finalImage = [[UIImage alloc] initWithCGImage: capturedScreen.CGImage
scale: 1.0
orientation: UIImageOrientationLeft];
view.transform = CGAffineTransformMakeRotation(0);
return finalImage;
}
UIGraphicsBeginImageContext(self.window.bounds.size);
[self.window.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSData * data = UIImagePNGRepresentation(image);
[data writeToFile:#"foo.png" atomically:YES];
for retina display, change the first line into this:
if ([[UIScreen mainScreen] respondsToSelector:#selector(scale)])
UIGraphicsBeginImageContextWithOptions(self.window.bounds.size, NO, [UIScreen mainScreen].scale);
else
UIGraphicsBeginImageContext(self.window.bounds.size);
adjust your size, may you get help..
I am using NinevehGL 3D engine http://nineveh.gl/
I want to get screenshot of OpenGL object. Problem is with below code
-(UIImage *) screenshot
{
// Capture screen here... and cut the appropriate size for saving and uploading
UIGraphicsBeginImageContext([self theNGLView].bounds.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// crop the area you want
CGRect rect;
rect = CGRectMake(0, 10, 300, 300); // whatever you want
CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], rect);
UIImage *img = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
return img;
}
Only background comes in screenshot but not actual NGLView or OpenGL object which is drawn on top of it.
I am using iOS SDK 6.0
tried using
[[self the NGLView].layer renderInContext:UIGraphicsGetCurrentContext()];
?
Please go through this link, you need to download the latest NinevehGL SDK for iPhone5/iOS 6 which is provided in their twitter link.
I have a few UIVies butted edge to edge. THe views completely cover the superView. Looks great in display, but when rendered the adjoining edges are visible, that is to sat a line appears between them. Since the views look perfect in display, I imagine it must be interpolation of the pixels of the views that causes this.
Anyone know how to fix this?
The image below is a render. On the device or simulator the lines would not be visible.
render code
-(void)renderImage {
CGSize renderSize = CGSizeMake(masterView.frame.size.width, masterView.frame.size.height);
UIGraphicsBeginImageContext(renderSize);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGContextConcatCTM(context, [[masterView layer] affineTransform]);
[[masterView layer] renderInContext:UIGraphicsGetCurrentContext()];
renderedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGContextRestoreGState(context);
UIImageWriteToSavedPhotosAlbum(renderedImage, self, #selector(image:didFinishSavingWithError:contextInfo:), nil);
masterView.transform = CGAffineTransformIdentity;
}
Core graphics attempts to anti alias your views. You need to tell it not to do that.
Consider the following example which renders self, a UIView, as a UIImage without anti aliasing:
UIGraphicsBeginImageContextWithOptions(self.bounds.size, YES, [[UIScreen mainScreen] scale]);
CGContextSetAllowsAntialiasing(UIGraphicsGetCurrentContext(), FALSE);
[self.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
try:
UIGraphicsBeginImageContextWithOptions(renderSize, false, [[UIScreen mainScreen] scale]);
instead of:
UIGraphicsBeginImageContext(renderSize);
I am working on an app which will only be in landscape. In that app I have a functionality that is take screenshot of that particular screen. I have implemented this code
UIGraphicsBeginImageContext(self.view.window.bounds.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImageView *imageView = [[UIImageView alloc] init];
imageView.image = UIGraphicsGetImageFromCurrentImageContext();;
imageView.transform = CGAffineTransformMakeRotation(3.0 * M_PI / 2.0);
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(imageView.image, nil, nil, nil);
Using this code I get screen shot of my app in portrait mode. I want it in landscape mode.
Don't add that window. If you add it your context size is wrong.
// Just use self.view.bounds.size is OK
UIGraphicsBeginImageContext(self.view.bounds.size);
Perhaps late, but wrapping it in an UIImageView doesn't actually rotate the image itself.
Here's some code I wrote that creates a rotated image from the full window of your application.
UIWindow *keyWindow = [[UIApplication sharedApplication] keyWindow];
CGRect rect = [keyWindow bounds];
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
[keyWindow.layer renderInContext:context];
UIImage * image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return [[UIImage alloc] initWithCGImage:[image CGImage] scale:1 orientation:UIImageOrientationLeft];
If you want it rotated right, just replace UIImageOrientationLeft with UIImageOrientationRight