cocoa - 如何将 NSCIImageRep 绘制到 NSView

Question

我在绘制通过 QTKit mCaptureDecompressedVideoOutput 获得的 NSCIImageRep 时遇到问题。

由于我不想使用 OpenGL 绘制图像，因此我尝试子类化 NSView 并在那里绘制图像:

- (void) drawRect:(NSRect)dirtyRect
{
    NSLog(@"DrawInRect");
    CGContextRef myContext = [[NSGraphicsContext currentContext] graphicsPort];

    if (imageRep != nil)
    {
       CGImageRef image = [imageRep CGImageForProposedRect: &dirtyRect context:    [NSGraphicsContext currentContext] hints:nil];
       CGContextDrawImage(myContext, dirtyRect, image);
       CGImageRelease(image);
    }  
}

imageRep是指向我通过mCaptureDecompressedVideoOutput回调获得的CGImageRef的指针

- (void)captureOutput:(QTCaptureOutput *)captureOutput didOutputVideoFrame:(CVImageBufferRef)videoFrame withSampleBuffer:(QTSampleBuffer *)sampleBuffer fromConnection:(QTCaptureConnection *)connection`.

此代码使我的机器崩溃。有什么建议么？

Answer 1

您不需要仅仅通过 CGImageRef 来绘制 NSCIImageRep。只需要它提供一个 CIImage 并绘制它即可:

CIImage* anImage = [yourNSCIImageRep CIImage];
[anImage drawAtPoint:NSZeroPoint
            fromRect:NSRectFromCGRect([anImage extent])
           operation:NSCompositeSourceOver
            fraction:1.0];