渲染/快照SpriteKit场景到NSImage

Does anyone know how to "snapshot" a complete SKView or SKScene into an NSImage?

有谁知道如何将完整的SKView或SKScene“快照”成NSImage？

We have been able to use the textureFromNode API to create an SKTexture from a node and all its children. But so far we can't figure out a way to extract the image data into say an NSImage. We are building a mixed Cocoa / SpriteKit app where we need to extract small thumbnails of scenes.

我们已经能够使用textureFromNode API从节点及其所有子节点创建SKTexture。但到目前为止，我们无法找到将图像数据提取为NSImage的方法。我们正在构建一个混合的Cocoa / SpriteKit应用程序，我们需要提取场景的小缩略图。

Again, this seems possible on iOS (to get a UIImage) using drawViewHierarchyInRect:

再次，这似乎可以使用drawViewHierarchyInRect在iOS上（获取UIImage）：

UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, NO, scale);
[self drawViewHierarchyInRect:self.bounds afterScreenUpdates:YES];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

But how to do this on Cocoa with NSImage? Help.

但是如何使用NSImage在Cocoa上执行此操作？帮帮我。

4 个解决方案

#1

As of OS X 10.11 (and iOS 9 and tvOS, but we'll ignore those since you're asking about NSImage), SKTexture can export its contents to a CGImageRef. So the textureFromNode approach you mention is now the first step in a working solution:

从OS X 10.11（以及iOS 9和tvOS，但我们将忽略那些因为你询问NSImage），SKTexture可以将其内容导出到CGImageRef。所以你提到的textureFromNode方法现在是工作解决方案的第一步：

SKTexture *texture = [view textureFromNode: view.scene];
NSImage *image = [[NSImage alloc] initWithCGImage: texture.CGImage
                                             size: view.bounds];

Note the size parameter to initWithCGImage: you can pass CGSizeZero there to make the NSImage inherit the pixel size of the CGImage, but since you might be dealing with a Retina Display you probably want the point size, which you can get from the view dimensions.

请注意initWithCGImage的size参数：您可以在那里传递CGSizeZero以使NSImage继承CGImage的像素大小，但由于您可能正在处理Retina显示，您可能需要点大小，您可以从视图维度获得。

#2

There's no direct access to the image data from a SKTexture yet. You can present the node in a offscreen scene and capture the view hierarchy. I use this code in iOS for reference:

目前还无法直接访问SKTexture的图像数据。您可以在屏幕外场景中显示节点并捕获视图层次结构。我在iOS中使用此代码作为参考：

class func imageFromNode(node : SKNode, inScene scene: SKScene) -> UIImage? {
    if let texture = scene.view?.textureFromNode(node) {
        let view = SKView(frame: CGRect(origin: CGPointZero, size: texture.size()))
        view.allowsTransparency = true
        view.backgroundColor = SKColor.clearColor()

        let scene = SKScene(size: view.bounds.size)
        scene.view?.allowsTransparency = true
        scene.backgroundColor = SKColor.clearColor()

        let sprite  = SKSpriteNode(texture: texture)
        sprite.position = CGPoint(x: CGRectGetMidX(view.frame), y: CGRectGetMidY(view.frame))
        scene.addChild(sprite)
        view.presentScene(scene)
        UIGraphicsBeginImageContextWithOptions(view.bounds.size, false, 0.0)
        view.drawViewHierarchyInRect(view.bounds, afterScreenUpdates: true)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }
    return nil
}

#3

Here was my attempt (on OSX) to scoop the underlying rendered image...

这是我尝试（在OSX上）挖掘底层渲染图像...

First, I subclassed SKView and in its drawRect method lazily grabbed an NSBitmapImageRep

首先，我将SKView子类化，并在其drawRect方法中懒洋洋地抓取了一个NSBitmapImageRep

if (![self cache])
    [self setCache:[self bitmapImageRepForCachingDisplayInRect:[self visibleRect]]];

I then set up an NSTimer which would periodically attempt to copy the contents of that cache to a custom thumbnail view:

然后我设置了一个NSTimer，它会定期尝试将该缓存的内容复制到自定义缩略图视图：

MySKView *sv = .....
NSBitmapImageRep *cache = [sv cache];
if (!cache)
    return;

NSRect srcFrame = NSMakeRect(0,0,[sv frame].size.width,[sv frame].size.height);
NSRect thumbFrame = [[self thumbView] frame];
NSRect thumbRect = NSMakeRect(0,0,thumbFrame.size.width,thumbFrame.size.height);
[sv cacheDisplayInRect:srcFrame toBitmapImageRep:cache];
[[self thumbView] lockFocus];
[cache drawInRect:thumbRect
         fromRect:srcFrame
         operation:NSCompositeCopy
         fraction:1.0
   respectFlipped:YES
            hints:nil];
[[self thumbView] unlockFocus];

No dice. All I get in my thumbNail view is black.

没有骰子。我进入thumbNail视图的所有内容都是黑色的。

Likely for the same reason that this is all OpenGL/GPU-based drawing.

可能出于同样的原因，这是所有基于OpenGL / GPU的绘图。

That would lead me in the direction of somehow finding the underlying OpenGL drawing context used by SKView and doing a glReadPixels on that context.

这将导致我以某种方式找到SKView使用的基础OpenGL绘图上下文并在该上下文上执行glReadPixels。

#4

SKView is a UIView subclass, so you should be able to draw the view's layer in a CoreGraphics context, and then get the image from the context.

SKView是一个UIView子类，因此您应该能够在CoreGraphics上下文中绘制视图的图层，然后从上下文中获取图像。

Look at using view.layer.drawInContext.

看看使用view.layer.drawInContext。

#1

SKTexture *texture = [view textureFromNode: view.scene];
NSImage *image = [[NSImage alloc] initWithCGImage: texture.CGImage
                                             size: view.bounds];

#2