December 20th, 2007

Colorizing Swing components

One of the rules of good UI design is to use consistent coloring guidelines. One of the many reasons is the accessibility for color-blind users who might not be able to distinguish between light red and light green background for validation indications (reported seven percents of male population of United States can’t distinguish between green and red or see them differently). However, some applications can benefit from using colors to visually distinguish between controls, and one of the users of Substance look-and-feel has recently filed an enhancement to provide support for control colorization (attaching this screenshot as sample of the required UI).

And so, i’ve spent the better portion of the last two weeks on colorization support for the core Swing components. What started out to be an innocent and simple enhancement request turned out to be an excellent opportunity to revisit pretty much the entire Substance codebase, fixing few stray bugs and refactoring some duplicate functionality. This entry shows sample screenshots of colorizing awide variety of core Swing components, with support for SwingX and Flamingo component suites coming in the next release. If you want to play with live demo, click the button below, wait for the application to load, switch to “Colorized” tab, check the “colorize” checkbox and play with the slider (which sets the colorization amount).

And now let’s see some screenshots. Here is a collection of toggle buttons, checkboxes and radio buttons in different states (default, selected, disabled and disabled selected) under Business Black Steel skin:

Now, let’s set the background and foreground colors to some application-specific values and see how these controls look under Metal:

While some states respect the settings (for both background and foreground colors), others don’t. For example, the foreground for disabled is always light gray, the background for selected toggle buttons is always light gray. In addition, the checkmarks for check boxes and radio buttons respect neither custom background nor custom foreground. Let’s try under Windows look-and-feel:

This looks even worse than Metal and much of it is due to the limitations of native look-and-feels as described in this earlier entry. The buttons would be better off ignoring the custom settings at all – disabled foreground text is the same as enabled one, and the background is painted as a rectangular “ghost” border around the buttons.

While Substance hasn’t been much better up until now, the things look different in the latest 4.2dev build. Here are the same controls with 50% colorization:

As you can see, the colors of the original theme are now colorized with the custom background and foreground. The disabled controls still look disabled (colorization is not as strong), and the check marks of radio buttons and check boxes are colorized with the custom foreground colors. In addition, the background of check boxes and radio buttons is not colorized at all. Last but not least, the colorization implementation tries to preserve the brightness levels of the original colors, which results in consistent gradients even for large colorization values.

Let’s see how the same controls look under 25% colorization:

If the application requires more colorization, it can set it to anywhere between 0% and 100%. Here are the same controls under 75% (note that the gradients are still discernible):

Let’s see some other controls being colorized. Here are a few text components:

And a scroll pane with yellow background (propagating to the horizontal scroll bar) and green background on the vertical scroll bar (i still haven’t decided whether the corner should be colorized as well):

What about something a little more complicated such as table? The first row has enabled tables with green and dark green backgrounds, while the second row has the same tables disabled. Note how the background colorization is applied not only to the cells and header cells, but also to the table grid lines:

Another complicated example is a tree. Here, the colorization is applied to the striping, the cells, the tree lines and the tree collapse / expand icons:

Another complicated one is an internal frame. Here is a screenshot of desktop pane with custom blue background with four internal frames, two of them minimized. Note how the custom background of an internal frame is applied to its title pane, the title pane buttons, the frame border and the menu bar (first two apply for the desktop icons as well):

Going back to simpler controls, let’s see some sliders and progress bars:

and compare it with Metal:

The last screenshot shows the colorization of menu items (note how it applies to the text, check marks and the arrow icons):

I’d like to thank Luke Sleeman for creating this enhancement request and providing feedback on the initial implementation. To try it out, run the demo linked above. You can download the latest binaries and sources right here and play with the new SubstanceLookAndFeel.COLORIZATION_FACTOR client property which can be set on UIManager (globally) or on any component (applied to the component and all its children). The value should be a Double in 0.0-1.0 range. All the Substance screenshots in this entry have been taken under JDK 6.0 on Vista, with the Bramble plugin providing native text rendering.

These two features (native text rendering and colorization support) mark the code freeze for new core features in the next Substance release (code-named Memphis). At this point, they have resulted in only 40KB increase in the size of the binary library. The release candidate is scheduled for January 21st, with the release scheduled for February 4th.