我需要幫助優化BGR888傳輸到NSView

Question

這是最好的，我想出了一個24位BGR圖像傳輸到NSView。

我確實通過確保NSWindow主機也具有相同的顏色空間來修剪了大量的CPU時間。

我認爲有4個或5個像素副本怎麼回事：在vImage轉換（必填）

調用CGDataProviderCreateWithData

調用CGImageCreate

創建NSBitmapImageRep位

1. 與drawInRect（必填）

任何人都想要改進它？

任何幫助將不勝感激。

{ 
    // one-time setup code 
    CGColorSpaceRef useColorSpace = nil; 
    int w = 1920; 
    int h = 1080; 
    [theWindow setColorSpace: [NSColorSpace genericRGBColorSpace]]; 
    // setup vImage buffers (not listed here) 
    // srcBuffer is my 24-bit BGR image (malloc-ed to be w*h*3) 
    // dstBuffer is for the resulting 32-bit RGBA image (malloc-ed to be w*h*4) 

    ... 
    // this is called @ 30-60fps 
    if (!useColorSpace) 
     useColorSpace = CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB); 
    vImage_Error err = vImageConvert_BGR888toRGBA8888(srcBuffer, NULL, 0xff, dstBuffer, NO, 0); 

    CGDataProviderRef newProvider = CGDataProviderCreateWithData(NULL,dstBuffer->data,w*h*4,myReleaseProvider); 
    CGImageRef myImageRGBA = CGImageCreate(w, h, 8, 32, w*4, useColorSpace, kCGBitmapByteOrderDefault | kCGImageAlphaLast, newProvider, NULL, false, kCGRenderingIntentDefault); 
    CGDataProviderRelease(newProvider); 
    // store myImageRGBA in an array of frames (using NSObject wrappers) for later access (setNeedsDisplay:) 
    ... 
} 

- (void)drawRect:(NSRect)dirtyRect 
{ 
    // this is called @ 30-60fps 
    CGImageRef storedImage = ...; // retrieve from array 
    NSBitmapImageRep *repImg = [[NSBitmapImageRep alloc] initWithCGImage:storedImage]; 
    CGRect myFrame = CGRectMake(0,0,CGImageGetWidth(storedImage),CGImageGetHeight(storedImage)); 
    [repImg drawInRect:myFrame fromRect:myFrame operation:NSCompositeCopy fraction:1.0 respectFlipped:TRUE hints:nil]; 

    // free image from array (not listed here) 
} 

// this is called when the CGDataProvider is ready to release its data 
void myReleaseProvider (void *info, const void *data, size_t size) 
{ 
    if (data) { 
     free((void *)data); 
     data=nil; 
    } 
} 

Answer 1

使用CGColorSpaceCreateDeviceRGB而不是genericRGB來避免CG內部的顏色空間轉換。使用kCGImageAlphaNoneSkipLast代替kCGImageAlphaLast，因爲我們知道alpha是不透明的，以允許複製而不是混合。

做出這些更改後，在其上運行儀器時間配置文件以顯示時間正在進行將很有用。