Method FilterGradient

java/com/tigervnc/rfb/TightDecoder.java:453–500

(ByteBuffer inbuf,
                                    PixelFormat pf, ByteBuffer outbuf,
                                    int stride, Rect r)

  }

  final private void FilterGradient(ByteBuffer inbuf,
                                    PixelFormat pf, ByteBuffer outbuf,
                                    int stride, Rect r)
  {
    int x, y, c;
    byte[] prevRow = new byte[TIGHT_MAX_WIDTH*3];
    byte[] thisRow = new byte[TIGHT_MAX_WIDTH*3];
    ByteBuffer pix = ByteBuffer.allocate(3);
    int[] est = new int[3];

    // Set up shortcut variables
    int rectHeight = r.height();
    int rectWidth = r.width();

    for (y = 0; y < rectHeight; y++) {
      for (x = 0; x < rectWidth; x++) {
        /* First pixel in a row */
        if (x == 0) {
          pf.rgbFromBuffer(pix.duplicate(), (ByteBuffer)inbuf.position(y*rectWidth), 1);
          for (c = 0; c < 3; c++)
            pix.put(c, (byte)(pix.get(c) + prevRow[c]));

          System.arraycopy(pix.array(), 0, thisRow, 0, pix.capacity());
          pf.bufferFromRGB((ByteBuffer)outbuf.duplicate().position(y*stride), pix, 1);
          continue;
        }

        for (c = 0; c < 3; c++) {
          est[c] = prevRow[x*3+c] + pix.get(c) - prevRow[(x-1)*3+c];
          if (est[c] > 0xff) {
            est[c] = 0xff;
          } else if (est[c] < 0) {
            est[c] = 0;
          }
        }

        pf.rgbFromBuffer(pix.duplicate(), (ByteBuffer)inbuf.position(y*rectWidth+x), 1);
        for (c = 0; c < 3; c++)
          pix.put(c, (byte)(pix.get(c) + est[c]));

        System.arraycopy(pix.array(), 0, thisRow, x*3, pix.capacity());

        pf.bufferFromRGB((ByteBuffer)outbuf.duplicate().position(y*stride+x), pix, 1);
      }

      System.arraycopy(thisRow, 0, prevRow, 0, prevRow.length);
    }
  }

  private void FilterPalette8(ByteBuffer palette, int palSize,
                              ByteBuffer inbuf, ByteBuffer outbuf,