Save Byte array to Pgn or Jpg-CodePudding

I read a Tiff file, and I want to make a tile and save it to Png or Jpg. I successfully did this process saving in Tif format, as shown in the attached code, defining DO_TIFF. But I cannot do the same in Jpeg or Png format. The program always crashes at the location indicated in the comment. I have read various indications in Internet, but I cannot find my mistake. The code should be selfexplaining. The difference is that I used two dimensional array in the Tif case, while a one dimensional one in the JPEG case.

        private static void MakeTile(string Original,int X,int Y,int W,int H,string TileName)
        {
            using (Tiff input = Tiff.Open(Original, "r"))
            {
                int width = input.GetField(TiffTag.IMAGEWIDTH)[0].ToInt();
                int height = input.GetField(TiffTag.IMAGELENGTH)[0].ToInt();
                int samplesPerPixel = input.GetField(TiffTag.SAMPLESPERPIXEL)[0].ToInt();
                int bitsPerSample = input.GetField(TiffTag.BITSPERSAMPLE)[0].ToInt();
                int photo = input.GetField(TiffTag.PHOTOMETRIC)[0].ToInt();
                Rectangle roi = new Rectangle(X*samplesPerPixel, Y, W * samplesPerPixel, H);

                int scanlineSize = input.ScanlineSize();

                int nz = roi.Width;

                if (roi.Left nz > scanlineSize)
                {
                    nz = scanlineSize-roi.Left;
                }
#if DO_JPEG
                byte[] output = new byte[roi.Height * nz];
#endif

#if DO_TIFF
                byte[][] output = new byte[roi.Height][];
#endif
                byte[] buffer = new byte[scanlineSize];

                W = nz / samplesPerPixel;

                for (int i = roi.Top,k=0; i < roi.Bottom;   i,k  )
                {
                    input.ReadScanline(buffer, i);
#if DO_TIFF
                    output[k] = new byte[nz];
#endif
                    for (int j=0;j<nz;j  )
                    {
#if DO_TIFF
                        output[k][j]= buffer[roi.Left   j];
#endif

#if DO_JPEG
                        output[j k*nz] = buffer[roi.Left j];
#endif
                    }
                }
#if DO_JPEG
                using (Image image = Image.FromStream(new MemoryStream(output)))// error here: Patrameter Not Valid
                {
                    image.Save("output.jpg", ImageFormat.Jpeg);  // Or Png
                }
#endif
#if DO_TIFF
                using (Tiff Foutput = Tiff.Open(TileName, "w"))
                {
                    Foutput.SetField(TiffTag.IMAGEWIDTH, W);
                    Foutput.SetField(TiffTag.IMAGELENGTH, H);
                    Foutput.SetField(TiffTag.SAMPLESPERPIXEL, samplesPerPixel);
                    Foutput.SetField(TiffTag.BITSPERSAMPLE, bitsPerSample);
                    Foutput.SetField(TiffTag.ROWSPERSTRIP, Foutput.DefaultStripSize(0));
                    Foutput.SetField(TiffTag.PHOTOMETRIC, photo);
                    Foutput.SetField(TiffTag.PLANARCONFIG, PlanarConfig.CONTIG);

                    // change orientation of the image
                    // output.SetField(TiffTag.ORIENTATION, Orientation.RIGHTBOT);

                    for (int i = 0; i < H;   i)
                        Foutput.WriteScanline(output[i], i);
                }
#endif
            }

        }
    }

CodePudding user response：

To save the image as a JPEG or PNG, you'll need to use a different method than the one you are using to save it as a TIFF.

One way to do this is to use the System.Drawing.Bitmap class. This class has a constructor that takes an array of bytes as an argument, so you can pass the output array to the constructor to create a Bitmap object. Then, you can use the Save method of the Bitmap class to save the image to a file in JPEG or PNG format.

#if DO_JPEG
  using (var image = new Bitmap(W, H, PixelFormat.Format24bppRgb)) {
  var bmpData = image.LockBits(new Rectangle(0, 0, W, H), 
  ImageLockMode.WriteOnly, image.PixelFormat);

  var ptr = bmpData.Scan0;
  Marshal.Copy(output, 0, ptr, output.Length);
  image.UnlockBits(bmpData);
  image.Save("output.jpg", ImageFormat.Jpeg);
  }
#endif

To save the image as a PNG, you can use the same code but replace ImageFormat.Jpeg with ImageFormat.Png.

Assuming that the output array contains 24-bit RGB data.