UIImage from SKTexture - objective-c

Question

How to get UIImage from SKTexture?
I tried to get UIImage from SKTextureAtlas, but it seems not working too:
// p40_prop1 is a part of SKTextureAtlas
UIImage *image = [UIImage imageNamed:#"p40_prop1"];
image is nil.

Answer 1

Starting from iOS 9 it is a piece of cake. SKTexture now has CGImage property, which is of CGImageRef type. So getting image from a texture is just one line now:
let image : UIImage = UIImage(CGImage:texture.CGImage)

Answer 2

This seems to be working for me:
- (UIImage*) imageWithView:(UIView *)view
{
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, 0.0);
[view drawViewHierarchyInRect:view.bounds afterScreenUpdates:YES];
UIImage * img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}
- (UIImage*) imageFromNode:(SKNode*)node
{
SKTexture* tex = [self.scene.view textureFromNode:node];
SKView* view = [[SKView alloc]initWithFrame:CGRectMake(0, 0, tex.size.width, tex.size.height)];
SKScene* scene = [SKScene sceneWithSize:tex.size];
SKSpriteNode* sprite = [SKSpriteNode spriteNodeWithTexture:tex];
sprite.position = CGPointMake( CGRectGetMidX(view.frame), CGRectGetMidY(view.frame) );
[scene addChild:sprite];
[view presentScene:scene];
return [self imageWithView:view];
}
get the SKTexture for your node using the current SKView
make another SKView that is just big enough for your texture
add a SKSpriteNode with the texture into your new scene, placing it in the middle
render the view into a graphics context
Or for those who prefer Swift:
func imageWithView(view : UIView) -> UIImage {
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, 0.0)
view.drawViewHierarchyInRect(view.bounds, afterScreenUpdates: true)
let img = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return img
}
func imageFromNode(node : SKNode) -> UIImage? {
if let tex = self.scene?.view?.textureFromNode(node) {
let view = SKView(frame:CGRectMake(0, 0, tex.size().width, tex.size().height))
let scene = SKScene(size: tex.size())
let sprite = SKSpriteNode(texture: tex)
sprite.position = CGPoint(x: CGRectGetMidX(view.frame), y: CGRectGetMidY(view.frame))
scene.addChild(sprite)
view.presentScene(scene)
return self.imageWithView(view)
}
return nil
}

Answer 3

There is actually a way to get a UIImage out of a SKView in iOS 7.0!
It uses regular UIView APIs to render the view into an ImageContext, then pulls a UIImage out of that. However, this solution is very limited in scope. It draws the SKView into a UIImage, then crops the resulting image to fit a given node's frame. So there must not be anything covering that node you want to snapshot. Also, both the view and scene must be visible on-screen (which is stricter than the usual -[SKView textureFromNode:] method). There may even be further restrictions that I haven't discovered.
Given all that, this procedure was still enough for what I needed, so I thought it was worth sharing.
+(UIImage *)imageFromNode:(SKNode *)node {
SKView *view = node.scene.view;
CGFloat scale = [UIScreen mainScreen].scale;
CGRect nodeFrame = [node calculateAccumulatedFrame];
// render SKView into UIImage
UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, 0.0);
[view drawViewHierarchyInRect:view.bounds afterScreenUpdates:YES];
UIImage *sceneSnapshot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// crop to the requested node (making sure to flip the y-coordinate)
CGFloat originY = sceneSnapshot.size.height*scale - nodeFrame.origin.y*scale - nodeFrame.size.height*scale;
CGRect cropRect = CGRectMake(nodeFrame.origin.x * scale, originY, nodeFrame.size.width*scale, nodeFrame.size.height*scale);
CGImageRef croppedSnapshot = CGImageCreateWithImageInRect(sceneSnapshot.CGImage, cropRect);
UIImage *nodeSnapshot = [UIImage imageWithCGImage:croppedSnapshot];
CGImageRelease(croppedSnapshot);
return nodeSnapshot;
}
I've tested this on the simulator in 3.5" and 4" retina iPhones, retina and non-retina iPads. As for actual devices, it worked on iPhone 4S, iPhone 5S, and iPad 2, all running 7.0.4.

Answer 4

func loadBackground() {
guard let _ = childNode(withName: "background") as! SKSpriteNode? else {
let texture = SKTexture(image: UIImage(named: "stick.jpg")!)
let node = SKSpriteNode(texture: texture)
node.size = texture.size()
node.zPosition = StickHeroGameSceneZposition.backgroundZposition.rawValue
self.physicsWorld.gravity = CGVector(dx: 0, dy: gravity)
addChild(node)
return
}
}

Answer 5

As of iOS 7.0 there's no way to get a UIImage from SKTexture, SKTextureAtlas or the SKView.