UIImage color changing?

Question

hi, how can i change the UIImage's Color through Programming,any help pls?if i send UIImage, its color must be changed ..any help please? if i change rgb color like the following through bitmaphandling it did not work.i have given blackcolor's RGB value like 0,0,0.....

Answer 1

The answer as a question: What if your UIImage contained a rainbow? What would you expect "changing the image's color" to do with such an image?

Answer 2

I think you can create another context with setting there context color to RGB you want to color your picture. Then draw your UIImage into that context and use that context instead of using directly your picture. This is a concept. This way you're creating offscreen buffer with a colored image. I didn't try this in cocoa, only in carbon, but i suppose it will work in the same way.

Answer 3

The RGB data you are operating on is just a copy. After you finish making changes, you need to turn that data back into an image.

I first make a new bitmap:

CGColorSpaceRef space = CGColorSpaceCreateDeviceRGB();
ctx = CGBitmapContextCreate( malloc(dataSize), width, height,
           8, // CGImageGetBitsPerComponent(cgImage),
           bytesPerRow, //CGImageGetBytesPerRow(cgImage),
           space,
           //kCGImageAlphaNoneSkipLast | kCGBitmapByteOrder32Big );
           kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Little);
           //kCGImageAlphaPremultipliedFirst  | kCGBitmapByteOrder32Little);

    CGColorSpaceRelease( space );

// now draw the image into the context
CGRect rect = CGRectMake( 0, 0, CGImageGetWidth(cgImage), CGImageGetHeight(cgImage) );
CGContextDrawImage( ctx, rect, cgImage );

And get the pixels:

pixels = CGBitmapContextGetData( ctx );

Assuming that your pixel data came from pixels = CGBitmapContextGetData( ctx ); then take that context and build a new image from it:

CGImageRef newImg = CGBitmapContextCreateImage(ctx);
[[UIImage imageWithCGImage:newImg] drawInRect:rect];
CGImageRelease(newImg);

Answer 4

Hmmm -- isn't the order of the bytes supposed to be RGBA? You are setting them as ARGB...