Loading a CGImage or NSImage from a file using a standard image format (jpeg, gif, png et.) is all very simple.
However, I now need to create a CGImage from an array in bytes in memory generated using libfreetype. Its really easy to create OpenGL textures from an array of formatted bytes, and I can see how to create a CGBitmapContext to write to. But I can't seem to find an easy way to create a CGImage from a raw pixel array.
You can create a CGDataProvider, and let CG request the necessary data from your provider, instead of writing to an image buffer.
Here's a very simple example that generates a black CGImage of size 64x64.
CGDataProviderSequentialCallbacks callbacks;
callbacks.getBytes = getBytes;
CGDataProviderRef provider = CGDataProviderCreateSequential(NULL, &callbacks);
CGColorSpaceRef space = CGColorSpaceCreateDeviceRGB();
CGImageRef img = CGImageCreate(64, // width
64, // height
8, // bitsPerComponent
24, // bitsPerPixel
64*3, // bytesPerRow
space, // colorspace
kCGBitmapByteOrderDefault, // bitmapInfo
provider, // CGDataProvider
NULL, // decode array
NO, // shouldInterpolate
kCGRenderingIntentDefault); // intent
CGColorSpaceRelease(space);
CGDataProviderRelease(provider);
// use the created CGImage
CGImageRelease(img);
and getBytes is defined like this:
size_t getBytes(void *info, void *buffer, size_t count) {
memset(buffer, 0x00, count);
return count;
}
of course, you will want to implement the other callbacks (skipForward, rewind, releaseInfo), and use a proper structure or object for info.
For more information, check out the CGImage and CGDataProvider references.