如何獲取CGBitmap的像素數據爲Xamarin iOS中的byte []

Question

我有CGBitmap實例（每像素32位），我想要獲取圖像數據在byte[]。

的字節數組應該得到的值ARGB格式，以便前4個字節對應於所述第一像素中的每個alpha，紅色，綠色和藍色值的圖像字節。

非常感謝！

Answer 1

這是一個想法。圖像的UIImage

 CGImage imageRef = image.CGImage; 
     int width = (int)image.Size.Width; 
     int height = (int)image.Size.Height; 
     CGColorSpace colorSpace = CGColorSpace.CreateDeviceRGB(); 
     byte[] rawData = new byte[height * width * 4]; 
     int bytesPerPixel = 4; 
     int bytesPerRow = bytesPerPixel * width; 
     int bitsPerComponent = 8; 
     CGContext context = new CGBitmapContext(rawData, width, height, 
         bitsPerComponent, bytesPerRow, colorSpace, 
         CGBitmapFlags.PremultipliedLast | CGBitmapFlags.ByteOrder32Big); 

     context.DrawImage((CGRect)new CGRect(0, 0, width, height), (CGImage)imageRef);  

     // Now your rawData contains the image data in the RGBA8888 pixel format. 
     int pixelInfo = (width * y + x) * 4; // The image is png 
     //red,green, blue,alpha 
     byte red = rawData[pixelInfo]; 
     byte green = rawData[pixelInfo+1]; 
     byte blue = rawData[pixelInfo+2]; 
     byte alpha = rawData[pixelInfo + 3];