use - (nullable UIView *)resizableSnapshotViewFromRect:(CGRect)rect afterScreenUpdates:(BOOL)afterUpdates withCapInsets:(UIEdgeInsets) to snapshot from a UIView which contain a AVCaptureVideoPreviewLayer,and then I want to convert the result(UIView *) to UIImage, and display that, but the UIImage is empty all the time.
CGRect frame = CGRectMake(0, 0, 768, 893);
UIView *photo = [self.cameraView resizableSnapshotViewFromRect:frame afterScreenUpdates:YES withCapInsets:UIEdgeInsetsZero];
UIGraphicsBeginImageContextWithOptions(photo.bounds.size, NO, [[UIScreen mainScreen] scale]);
[photo drawViewHierarchyInRect:photo.bounds afterScreenUpdates:YES];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageView * iv = [[UIImageView alloc] initWithImage:image];
[iv setFrame:CGRectMake(0, 0, image.size.width, image.size.height)];
[self addSubview:iv];
CALayer * layer = [iv layer];
layer.borderWidth = 2.0f;
layer.borderColor = [[UIColor orangeColor] CGColor];
Did anyone know why that can not get the right UIImage?
Xcode Version 8.2.1 (8C1002)
MacOS Sierra 10.12.3(16D32)
Deployment Target 9.3
iPad iOS 9.3.5
I don't know the Objective-C-version of this, but try to convert it to Obj-C yourself, and add this code:
let context = UIGraphicsGetCurrentContext()
photo.layer.render(in:context!)
Add it after
[photo drawViewHierarchyInRect:photo.bounds afterScreenUpdates:YES];
but before
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
Use the following method (untested):
- (UIImage *)renderViewToImage:(UIView *)view
{
UIImage* image = nil;
UIGraphicsBeginImageContext(view.bounds.size);
[view.layer renderInContext: UIGraphicsGetCurrentContext()];
image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image
}
And call:
UIImage *img = [self renderViewToImage:photo]
You might want to make it an Category to UIView.
Related
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 want to merge multiple UIImages in iOS.
To do this, I tried to do as below:
UIImage *imageLeft = [UIImage imageNamed:#"ico-left"];
UIImage *imageRight = [UIImage imageNamed:#"ico-right"];
CGSize size = CGSizeMake(imageLeft.size.width + imageRight.size.width, imageLeft.size.height);
UIGraphicsBeginImageContext(size);
[imageLeft drawInRect:CGRectMake(0, 0, imageLeft.size.width, imageLeft.size.height)];
[imageRight drawInRect:CGRectMake(imageLeft.size.width, 0, imageRight.size.width, imageRight.size.height)];
UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, finalImage.size.width, finalImage.size.height)];
imageView.image = finalImage;
[cell.contentView addSubview:imageView];
But I cannot get any image. How can I fix it?
Thanks.
I think you are not adding extension of image (.png) so change your upper two lines by these
UIImage *imageLeft = [UIImage imageNamed:#"ico-left.png"];
UIImage *imageRight = [UIImage imageNamed:#"ico-right.png"];
I am not sure whether this is your problem but you can give it a try. Sometimes it worked for me
NSString *path1 = [[NSBundle mainBundle] pathForResource:#"ico-left" ofType:#"png"];
NSString *path2 = [[NSBundle mainBundle] pathForResource:#"ico-right" ofType:#"png"];
UIImage *imageLeft = [[UIImage alloc] initWithContentsOfFile:path1];
UIImage *imageRight = [[UIImage alloc] initWithContentsOfFile:path2];
Here's the code I use to merge images. (I think I found all or part of it online at some point). Put it in a UIImage category.
// NOTE! this method should only be called from the main thread because of
// UIGraphicsGetImageFromCurrentImageContext();
- (UIImage *)merge:(UIImage *)image atRect:(CGRect)pos overlay:(BOOL)overlay fillColor:(UIColor *)fill
{
UIGraphicsBeginImageContext(self.size);
UIImage *bottom = (overlay)?self:image;
UIImage *top = (overlay)?image:self;
CGRect lf = CGRectMake(0, 0, self.size.width, self.size.height);
CGRect bottomRect = (overlay)?lf:pos;
CGRect topRect = (overlay)?pos:lf;
if (fill){
[fill setFill];
CGContextFillRect (UIGraphicsGetCurrentContext(), topRect);
}
[bottom drawInRect:bottomRect];
[top drawInRect:topRect];
UIImage *destImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return destImage;
}
This is my code..
extern CGImageRef UIGetScreenImage();
CGRect frame = CGRectMake(0, 0, 320, 548);
CGImageRef cgoriginal = UIGetScreenImage();
CGImageRef cgimg = CGImageCreateWithImageInRect(cgoriginal, frame);
UIImage *viewImage = [UIImage imageWithCGImage:cgimg];
CGImageRelease(cgoriginal);
CGImageRelease(cgimg);
It takes screen shot but not full screen. I know this problem in CGRect frame. But I don't know, how to fix that..
Pay attention that UIGetScreenImage is a private API, so it will be rejected. If you want to do something similar you can try to use -renderInContext on the window layer or -drawViewHierchyInRect(only ios7).
This method should be used as a category on UIView:
- (UIImage *) imageByRenderingViewOpaque:(BOOL) yesOrNO {
UIGraphicsBeginImageContextWithOptions(self.bounds.size, yesOrNO, 0);
if ([self respondsToSelector:#selector(drawViewHierarchyInRect:afterScreenUpdates:)]) {
[self drawViewHierarchyInRect:self.bounds afterScreenUpdates:YES];
}
else {
[self.layer renderInContext:UIGraphicsGetCurrentContext()];
}
UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return resultingImage;
}
You have also this method that you can call on UIScree instance - (UIView *)snapshotViewAfterScreenUpdates:(BOOL)afterUpdates, but that will return only a view not an image.
In my application, I want to set the background image on UIView. In the simulator iOS this code works. And on the iPhone black background. Here's the code:
- (void)viewDidLoad
{
[super viewDidLoad];
UIGraphicsBeginImageContext(self.view.frame.size);
[[UIImage imageNamed:#"appBG.png"] drawInRect:self.view.bounds];
UIImage *appbg = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
self.view.backgroundColor = [UIColor colorWithPatternImage:appbg];
}
UPDATE: I decided my problem
its better u will take an ImageView on UIView and set the image to it. Rather than setting the image to UIView.
Try this code:
UIImage* backgroundImage = [UIImage imageNamed:#"appBG.png"];
CALayer* aLayer = [CALayer layer];
CGFloat nativeWidth = CGImageGetWidth(backgroundImage.CGImage);
CGFloat nativeHeight = CGImageGetHeight(backgroundImage.CGImage);
CGRect startFrame = CGRectMake(0.0, 0.0, nativeWidth, nativeHeight);
aLayer.contents = (id)backgroundImage.CGImage;
aLayer.frame = startFrame;
[self.view.layer addSublayer:aLayer];
[aLayer setNeedsDisplay];
Adjust startFrame value according to your requirement.
Try with Replace following line:
[[UIImage imageNamed:#"appBG.png"] drawInRect:self.view.bounds];
With following line:
[[UIImage imageNamed:#"appBG.png"] drawInRect:self.view.frame];
May be the issue of frame or bound.
The following code splits an image into 2. It seems working fine with non-retina devices, however it gives a different output with retina devices. Could someone please help me fix it? Thanks..
My Code
UIImage *img = [UIImage imageNamed:#"apple.png"];
CGSize sz = [img size];
UIGraphicsBeginImageContextWithOptions(CGSizeMake(sz.width/2, sz.height), NO, 0);
[img drawAtPoint:CGPointMake(-sz.width/2, 0)];
UIImage *right = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
rightView = [[[UIImageView alloc] initWithImage:right] autorelease];
rightView.frame = CGRectMake(self.view.frame.size.width/2, 0, self.view.frame.size.width/2, self.view.frame.size.height);
CGImageRef leftRef = CGImageCreateWithImageInRect([img CGImage],CGRectMake(0,0,sz.width/2,sz.height));
UIGraphicsBeginImageContextWithOptions(CGSizeMake(sz.width/2, sz.height), NO, 0);
CGContextRef con = UIGraphicsGetCurrentContext();
CGContextDrawImage(con, CGRectMake(0,0,sz.width/2.0,sz.height), leftRef);
UIImage *left = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImage *rotatedImage = [left imageRotatedByDegrees:180.0];
leftView = [[[UIImageView alloc] initWithImage:rotatedImage] autorelease];
leftView.frame = CGRectMake(0, 0, self.view.frame.size.width/2, self.view.frame.size.height);
leftView.transform = CGAffineTransformMake(-1,0,0,1,0,0);
CGImageRelease(leftRef);
[self.view addSubview:leftView];
[self.view addSubview:rightView];
non-retina
retina
PS: I don't know if this is important but apple.png has a #2x version..
The [-UIImage size] property returns the size in points, not in pixels. You probably need to also call [-UIImage scale] to figure out how the image is scaled.
When you create the left view with
leftView = [[[UIImageView alloc] initWithImage:rotatedImage] autorelease];,
you're not specifying the correct scale. Rather than creating your UIImage this way:
UIImage *left = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImage *rotatedImage = [left imageRotatedByDegrees:180.0];
try creating a CGImageRef and then initializing the UIImage using
[UIImage imageWithCGImage:scale:orientation:]
while specifying the correct scale. There are a number of ways to convert the raw image data from the context to a CGImageRef, or you can use the image you've created and use the CGImage property of UIImage.