Add Effects to the right Container!

The Flubber application I described earlier has an old stop-watch style timer with second and minute hands: Making the clock hand move was trivial using value binding and a rotation transform on the hand graphics object: transforms: Rotate { angle: bind (360.0 / 60 * minutes) - 90.0 } Since we are using a binding expression, setting the minutes variable anywhere (and yes, assigning to it!) will cause the hand angle to be recomputed and the graphics updated. Anyway - once we had the clock moving, the first thing we wanted to do was improve the look of the clock by adding a drop shadow. That was trivial; all we had to add was this: effect: DropShadow { offsetX: 5 offsetY: 5 color: Color.BLACK radius: 10 } That looked pretty good: But look what happened when we let the timer run... Where is the light source? What's happening here is that the drop shadow is rotating with the hand. Not what we want. We were all learning JavaFX that day, so we hacked it, using the following code: effect: DropShadow { offsetX: bind Math.sin(Math.toRadians(handAngle + 45)) * 5.0 offsetY: bind Math.cos(Math.toRadians(handAngle + 45)) * 5.0 color: Color.BLACK radius: 10 } Now, the drop shadow offset moves along with the rotation such that the shadow always appears in the right place. It worked, and we moved on. Now that I understand JavaFX and the scenegraph a bit better I realize that this...

Date: April, 07 2009
Url: http://blogs.sun.com/tor/entry/add_effects_to_the_right

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