从quickdraw到quartz 2D的转换

Question

我有一个旧代码，它使用，

Rect r;    
GetPortBounds(some_bitmap,&r);    
PixMapHandle somehandle = GetGWorldPixMap(some_bitmap);
if(LockPixels(somehandle)){
  TPixel *data = (TPixel *) GetPixBaseAddr(somehandle);  
  long row_bytes = GetPixRowBytes(somehandle);  
  // doing something  
  UnlockPixels(somehandle);  
}  

有人能帮我解决quartz 2d中的替换代码吗？

Answer 1

要使用Quartz修改位图，可以使用图像初始化CGContextRef并使用CGContextDraw...例程绘制到该上下文。

(我为NSView子类编写了以下示例代码。这有点低效。如果您使用代码，请将您可以保留在iVars中的内容分开。)

- (void)drawRect:(NSRect)dirtyRect
{
    //Load an image ...
    NSImage* image = [[NSImage alloc] initWithContentsOfFile:@"/Library/Desktop Pictures/Grass Blades.jpg"];
    CGImageRef testImage = [[[image representations] objectAtIndex:0] CGImage];
    [image release];
    CGDataProviderRef dataProvider = CGImageGetDataProvider(testImage);
    //... and retrieve its pixel data
    CFDataRef imageData = CGDataProviderCopyData(dataProvider);
    void* pixels = (void*)CFDataGetBytePtr(imageData);
    CGColorSpaceRef colorspace = CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB);
    //Init a quartz context that uses the pixel data memory as buffer
    CGContextRef drawContext = CGBitmapContextCreate(pixels, CGImageGetWidth(testImage), CGImageGetHeight(testImage), CGImageGetBitsPerComponent(testImage), CGImageGetBytesPerRow(testImage), colorspace, CGImageGetBitmapInfo(testImage));
    CGContextSetRGBFillColor(drawContext, 0.8, 0.8, 0.8, 1.0);
    //Do something with the newly created context
    CGContextFillRect(drawContext, CGRectMake(20.0, 20.0, 200.0, 200.0));    
    CGColorSpaceRelease(colorspace);
    CGImageRef finalImage = CGBitmapContextCreateImage(drawContext);
    //Draw the modified image to the screen
    CGContextDrawImage([[NSGraphicsContext currentContext] graphicsPort], dirtyRect, finalImage);
    CFRelease(imageData);
    CGImageRelease(finalImage);
    CGContextRelease(drawContext);
}