title: Take a snapshot part of canvas in javaFX
body: <p>I need to save some part of canvas to image that is from <code>x1 &gt; 0</code> and <code>y1 &gt; 0</code> to some <code>x2 &gt; x1</code> and <code>y2 &gt; y1</code>. What I understand from javaFX API, snapshot must occupy a whole area of node,  like </p>
  
  <pre><code>wim = new WritableImage(((int) width), ((int) height));
  bufferedImage = new BufferedImage((int) width, (int) height, BufferedImage.TYPE_INT_ARGB);
  parameter = new SnapshotParameters();
  parameter.setTransform(new Translate(0, 200));
  </code></pre>
  
  <p>and then </p>
  
  <pre><code>node.snapshot(parameter, wim);
  image = SwingFXUtils.fromFXImage(wim, bufferedImage);
  Graphics2D gd = (Graphics2D) image.getGraphics();
  gd.translate(0,200);
  ImageIO.write(image, "png", file);
  </code></pre>