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unsafe byte GetByte(int offset, IntPtr buffer) { byte* bufferAsBytes = (byte*) buffer; return bufferAsBytes[offset]; } //Listing 2-7 protected CGBitmapContext CreateARGBBitmapContext(CGImage inImage) { var pixelsWide = inImage.Width; var pixelsHigh = inImage.Height; var bitmapBytesPerRow = pixelsWide * 4; var bitmapByteCount = bitmapBytesPerRow * pixelsHigh; //Note implicit colorSpace.Dispose() using(var colorSpace = CGColorSpace.CreateDeviceRGB()) { //Allocate the bitmap and create context var bitmapData = Marshal.AllocHGlobal(bitmapByteCount); //I think this is unnecessary, as I believe Marshal.AllocHGlobal will throw OutOfMemoryException if(bitmapData == IntPtr.Zero) { throw new Exception("Memory not allocated."); } var context = new CGBitmapContext(bitmapData, pixelsWide, pixelsHigh, 8, bitmapBytesPerRow, colorSpace, CGImageAlphaInfo.PremultipliedFirst); if(context == null) { throw new Exception("Context not created"); } return context; } } //Store pixel data as an ARGB Bitmap protected IntPtr RequestImagePixelData(UIImage inImage) { imageSize = inImage.Size; CGBitmapContext ctxt = CreateARGBBitmapContext(inImage.CGImage); var rect = new RectangleF(0.0f, 0.0f, imageSize.Width, imageSize.Height); ctxt.DrawImage(rect, inImage.CGImage); var data = ctxt.Data; return data; }

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