Swing / AWT / SWT / JFace: Zooming Swing components in JScrollPane

• schlenzkaa / 300 / Mon, 04 May 2009 03:23:00 GMT / Comments (3)
• In my application i have a JPanel filled with Swing components. I have to zoom this JPanel within a JScrollPane.

  I already wrote a JZoomPane, which has a paint method like

  public void paint(Graphics g) {

  if (zoomFactor != 1) {

  Graphics2D g2 = (Graphics2D)g;

  g2.scale(zoomFactor, zoomFactor);

  }

  super.paint(g);

  }

  There are two problems i don't know how to solve:

  1. To manage the repainting, i know i have to write my own RepaintManager, but i don't know which part i have to customize.

  2. I have to catch the MouseEvents and transform them against the zoom factor. But i can't use the GlassPane because i have to zoom only the part in the JScrollPane and not the rest of the application. I experimented a little bit with JLayeredPanes but couldn't get them to work.

  Could anybody help me or, even better, send me some sample code.

  Thanks,

  Oliver
• Keywords:

  zooming, swing, components, jscrollpane, awt, swt, jface

• http://java.itags.org/java-swing/50410/«« Last Thread - Next Thread »»

• 1. Something like this:

     public void paint(Graphics g) {

     Graphics2D g2 = (Graphics2D)g;

     if (scale != 1.0) {

     AffineTransform af = new AffineTransform();

     af.scale(scale, scale);

     oldTransform = g2d.getTransform();

     g2d.transform(af);

     }

     super.paint(g)

     if (scale != 1) {

     g2d.setTransform(oldTransform);

     }

     }

     and you have to change size of your panel according to new size.

     mouse motion event returns x and y coordinates.

     e.getX();

     e.getY();

     newX=scale*e.getX();

     newY=scale*e.getY();

     best regards

     Stas

     stanislavla | Sat, 07 Jul 2007 16:25:00 GMT |

  2. 1. The problem is not the scaling itself. I get the panel painted in the correct scaled size when it appears for the first time. But when i scroll the panel, the contained components repaint themselves at the original unscaled position in normal size. I think therefore i have to subclass the RepaintManager (somewhere i read something about it).

     2. Scaling the MouseEvents isn't the problem also. The problem is to catch the MouseEvents without using the glasspane, because i only want to scale parts of my application (i.e. the content of the JScrollPane).

     schlenzkaa | Sat, 07 Jul 2007 16:25:00 GMT |

  3. You will need to change the size and locations of your child components when you adjust the scale on your main panel. I have been trying to do this, but currently it has been unsuccessful.

     jon_ixa | Sat, 07 Jul 2007 16:25:00 GMT |