图片数据类型转换 NSImage、CIImage、CGImageRef

将NSImage转换为CIImage

#import 


// convert NSImage to bitmap 


NSImage * myImage  = [self currentImage];

NSData  * tiffData = [myImage TIFFRepresentation];

NSBitmapImageRep * bitmap;

bitmap = [NSBitmapImageRep imageRepWithData:tiffData];

 

// create CIImage from bitmap


CIImage * ciImage = [[CIImage alloc] initWithBitmapImageRep:bitmap];

 

// create affine transform to flip CIImage


NSAffineTransform *affineTransform = [NSAffineTransform transform];

[affineTransform translateXBy:0 yBy:128];

[affineTransform scaleXBy:1 yBy:-1];

 

// create CIFilter with embedded affine transform


CIFilter *transform = [CIFilter filterWithName:@"CIAffineTransform"];

[transform setValue:ciImage forKey:@"inputImage"];

[transform setValue:affineTransform forKey:@"inputTransform"];

 

// get the new CIImage, flipped and ready to serve


CIImage * result = [transform valueForKey:@"outputImage"];

 

// draw to view


[result drawAtPoint: NSMakePoint ( 0,0 )

           fromRect: NSMakeRect  ( 0,0,128,128 )

          operation: NSCompositeSourceOver

           fraction: 1.0];

// cleanup

[ciImage release];

将CGImageRef转换为NSImage *

- (NSImage*) imageFromCGImageRef:(CGImageRef)image

{

    NSRect imageRect = NSMakeRect(0.0, 0.0, 0.0, 0.0);

    CGContextRef imageContext = nil;

    NSImage* newImage = nil;

 


    // Get the image dimensions.

    imageRect.size.height = CGImageGetHeight(image);

    imageRect.size.width = CGImageGetWidth(image);

 

     // Create a new image to receive the Quartz image data.


    newImage = [[[NSImage alloc] initWithSize:imageRect.size] autorelease];

    [newImage lockFocus];

 

    // Get the Quartz context and draw.

    imageContext = (CGContextRef)[[NSGraphicsContext currentContext] graphicsPort];

    CGContextDrawImage(imageContext, *(CGRect*)&imageRect, image);

    [newImage unlockFocus]; 

    return newImage;

}

将NSImage *转换为CGImageRef 

- (CGImageRef)nsImageToCGImageRef:(NSImage*)image;

{

    NSData * imageData = [image TIFFRepresentation];

    CGImageRef imageRef;

    if(imageData)

    {

        CGImageSourceRef imageSource = 

                  CGImageSourceCreateWithData(

                            (CFDataRef)imageData,  NULL);

        imageRef = CGImageSourceCreateImageAtIndex(

                               imageSource, 0, NULL);

    }

    return imageRef;

}

转自：http://www.cocoachina.com/b/?p=11