static Image NormalizeImage(Image image)
{
const int bitsPerComponent = 8;
int components;
uint flags = 0;
byte [] buffer;
switch (image.Format)
{
case ImageFormat.Rgb24:
case ImageFormat.Bgr24:
components = 3;
break;
case ImageFormat.Bgra32:
components = 4;
flags = (uint)CGBitmapFlags.ByteOrder32Little | (uint)CGImageAlphaInfo.First;
break;
case ImageFormat.Rgba32:
components = 4;
flags = (uint)CGImageAlphaInfo.Last;
break;
default:
return(null);
}
switch (image.Format)
{
case ImageFormat.Bgr24:
// FIXME: ugh, CGImage really does not want 24bpp in BGR order...
// No CGBitmapFlags can convince it to do the channel swap unless
// the buffer is 32bpp.
buffer = new byte [image.Data.Length];
Array.Copy(image.Data, buffer, buffer.Length);
for (int i = 0; i < buffer.Length; i += components)
{
var b = buffer [i];
buffer [i] = buffer [i + 2];
buffer [i + 2] = b;
}
break;
default:
buffer = image.Data;
break;
}
using (NativeExceptionHandler.Trap())
return(new CGImage(
image.Width,
image.Height,
bitsPerComponent,
bitsPerComponent * components,
image.Width * components,
CGColorSpace.CreateDeviceRGB(),
(CGBitmapFlags)flags,
new CGDataProvider(buffer),
null,
false,
CGColorRenderingIntent.AbsoluteColorimetric).RemoteRepresentation());
}
public override IDisposable TrapNativeExceptions() => NativeExceptionHandler.Trap();
