New Parallax control for Java (JavaFX)


Parallax is a visual effect where you combine two layered images moving at different speeds to achieve a sense of depth.

Think about when you’re driving on the road and you see the trees close to you moving fast whereas the trees that are further away will move in the same direction but slower, the result is that you perceive the trees that are moving faster to be closer to you and the others to be further.

If you are a fan of video games you’ve certainly seen this effect before: two images are placed one over the other, the background moves slower, and the foreground, which could be the player’s avatar or the foreground where he stands moves faster.

This is an often used trick in the video games world. It started to be used quite long ago, an example is the Super Mario video game series.

Super Mario game using a parallax effect

This effect has been adopted in the user interface area, where you can see it used on web sites and also some applications.

Parallax on a web site – source:–GIF-Parallax-Building-animation

My goal was to bring this to JavaFX in the form of a control, where you could, through a simple API, add a parallax effect.

Parallax in a ListView

My primary objective was to bring this to the ListView, that is, have a control with an API similar to the ListView where you could set the background image and the list of items just like in the JavaFX ListView.

Implementing ParallaxListView

To have a parallax effect the items in the ListView, that is, the cells, need to scroll at a faster rate than the background image.

This new control will use the JavaFX ListView with a transparent background, layered in front of a background image.

The first challenge is that the scroll of the JavaFX ListView is done through jumps, that is, when you do a scroll action the position will jump from the original position to the end position without going through the intermediate position values. This will break the effect, since there is no movement like in the real world, only a discrete set of positions. In the real world the objects in the foreground move faster through a translation animation, remember this is about mimicking real world phenomenon like the driving example I gave earlier, to give a sense of depth.

So to accomplish this I had to implement my own ListView scrolling as well as the background scrolling, which when scrolling animates through a set of positions. The following is a live capture turned into a GIF of an example application using the ParallaxListView, the live version image quality and animation is better:

ParallaxListView example (image quality and animation worse than live version)

Where to get it

For now you can get it here:

I decided to stick with JavaFX 8 as Java 9 is still relatively new and some folks might have not yet migrated. This way Java 8 and Java 9 programs can use it.

I’m using private API, namely VirtualFlow, but this has turned into public API in JavaFX 9 so it will be easy to migrate the ParallaxListView code.

The test folder has an example of how to use the control. You have to scroll through the mouse wheel to see the effect.

Conclusion and Further Developments

The ParallaxListView can give a nice touch to your application, adding a bit of flair, however don’t overuse this effect.

In the next days I plan to add the following:

  • Add support for scrolling through the Scroll Bar.
  • Add API to change the height of the background image in relation with the foreground
  • Add the ability to specify the orientation of the ParallaxListView: Hoizontal or Vertical
  • Add a documentation page
  • Also provide a general purpose control that lets you specify a background and an arbitrary scrollable foreground control.


Update to FXRibbon (Ribbon for Java)

I’ve updated the Ribbon control and its documentation.

Here’s some of the relevant code changes (you can check the git log history for more details):

  • Cleaned up API
  • Cleaned up code into standard conventional packages
  • Fixed and cleaned up test apps (that also serve as documentation examples)
  • Added gradle build and configuration
  • Other refactors

Here’s the new page for the FXRibbon documentation: here.

Future developments for this library:

  • Add button controls: current javafx buttons don’t provide the best API for the ribbon use case, there’s also an issue where if you have a button with a multi line label, the label won’t be vertically aligned with the rest of the buttons.
  • Add other specialized controls, e.g. Ribbon gallery
  • Fix other issues in the issue tracker.

Update to JMetro implementation and documentation

It’s been too long since my last post! I plan on posting more regularly in the coming future.

Meanwhile, I took the opportunity to re-design this site which was looking pretty bad. Also thought my free open source libraries needed more attention, namely documentation so I’ve started working on that. The first one is going to be JMetro, you can check out the documentation here.

While I was looking over JMetro to write the documentation, I noticed some bugs and also a few aesthetic issues that I fixed:

  • Spinner: remove white background glitch with some style classes
  • List Box: added border around control
  • Slider: Somehow the fix to the slider when in vertical orientation, that fixed the fact that the fill started from the top instead of the bottom got lost. I re-implemented this fix.

Still haven’t had time with the font rendering issue. You can notice poor font rendering in JMetro on Windows with text in big font sizes. This is probably a JavaFX bug/problem because I’ve seen this elsewhere on images in other people’s blog posts and also other applications I’ve worked on.

Javafx on mobile first impressions

I decided to give it a go at testing javafx in an android device. My android device might be considered a low end device, it’s a nexus 4 from LG. The result can be seen below in a video. The quality of the video isn’t the best, I had to scale down the quality because the video was occupying 2GB.

My conclusion is that java/javafx runs with a very good performance in a low end android device with a pretty decent start up time. There were just 2 problems with this test, the first was with a demo which tested multi touch but didn’t run with top notch responsiveness but that might be the demos fault and not an issue with javafx itself. The second problem were dialogs: they aren’t showing up well.

The demo toke about 6 seconds to start which is more than the standard android app but not too much.