How to implement a gradient background renderer

The Graph2DView allows to set a custom background renderer that implements the BackgroundRenderer - interface.

The following sample code presents a custom BackgroundRenderer implementation, that paints a background using a gradient painter.

/**
 * This BackgroundRenderer implementation paints the background using a gradient painter
 * from blue (top left corner) to white (bottom right corner).
 */
  class GradientBackgroundRenderer implements BackgroundRenderer {
    private Graph2DView view;
    GradientBackgroundRenderer(Graph2DView view) {
      this.view = view;
    }

    public void paint(Graphics2D gfx, int x, int y, int w, int h) {
      final Rectangle visibleRect = view.getVisibleRect();
      //Store old paint
      final Paint oldPaint = gfx.getPaint();

      //Draw a rectangle in the visible area, using the GradientPainter.
      GradientPaint gradientPaint = new GradientPaint(visibleRect.x, visibleRect.y, Color.BLUE,
          visibleRect.x + visibleRect.width, visibleRect.y + visibleRect.height, Color.WHITE);
      gfx.setPaint(gradientPaint);
      gfx.fillRect(visibleRect.x, visibleRect.y, visibleRect.width, visibleRect.height);

      //Reset old paint
      gfx.setPaint(oldPaint);
    }
  }

In order to apply the GradientBackgroundRenderer on the view, please use the method:

Graph2DView.setBackgroundRenderer(BackgroundRenderer renderer)

//view is a Graph2DView instance
view.setBackgroundRenderer(new GradientBackgroundRenderer(view));