The latest addition in the Flamingo component suite is support for pluggable resizing policies on the ribbon tasks and ribbon bands. This has been one of the items on the roadmap for version 4.0 (code named Fainnear), and is now available in the latest 4.0dev drop of Flamingo core and 5.1dev drop of Substance Flamingo plugin.

The existing support has been in place for more than two years, but it was quite flaky. It would often happen that making the ribbon progressively smaller resulted in a jarring resizing behavior of individual bands, and recently a bug report was filed on inconsistent layouts that sometimes enter into an infinite re-layout loop. In addition, the resizing decisions were rigid and not configurable by the application code.

This has finally been addressed in the latest 4.0dev drop of the core Flamingo library. The entire layout / resizing layer has been completely revisited, making the code much simpler, more modular, and, more importantly, configurable by the application code. I will talk about the relevant APIs at the end of this entry, but first let me show a few screenshots that illustrate the out-of-the-box resize policies.

The first screenshot shows the progressive collapse of different ribbon bands under the core CollapseFromLast resize sequencing policy. Under this policy, the ribbon bands are being collapsed from right to left. When the currently collapsing band has reached the last step (iconified), the band to its left becomes the next one to be collapsed.

The next screenshot shows the progressive collapse of different ribbon bands under the core RoundRobin resize sequencing policy. Under this policy, the ribbon bands are being collapsed in a cyclic fashion, distributing the collapsed pixels between the different bands. Under this resize sequencing policy, when the ribbon gets shrinked it is still possible for a specific band to have more width – see the transition from step 5 to step 6 below.

When a ribbon band is fully collapsed (iconified), its contents can be shown by clicking on its collapse button. Unlike before, the display state of the popup band contents is controlled by the most permissive resize policy installed on that band. Here is a screenshot of a popup ribbon band under the core Restrictive resize policy that makes the three trailing buttons to be displayed in MEDIUM display state (unlike before where they were shown in BIG state):

As before, the popups can be multi level (a drop-down gallery shown from a collapsed ribbon band). The command button menus work as well:

Command buttons in popup ribbon bands show their rich tooltips:

Note that all screenshots are taken under Ubuntu and the native GTK look-and-feel. This illustrates how the core Flamingo components adapt the currently set look-and-feel.

If you are interested in testing the new resizing policies in your applications, here is a quick introduction (until the formal documentation is ready). All the relevant code is in the org.jvnet.flamingo.ribbon.resize package.

There are two main concepts – resize policy and resize sequencing policy. The resize policy defines a single visual state of the given ribbon band. For every control in the specific ribbon band (command button, gallery etc), the resize policy defines what is its display state. The resize sequencing policy defines which ribbon band will be chosen next when the ribbon is shrinked / expanded.

The base interface for the resize policies is defined in the RibbonBandResizePolicy interface.The new JRibbonBand.setResizePolicies API can be used to install a custom set of resize policies on the specific ribbon band. The CoreRibbonResizePolicies factory provides two core resize policies list – permissive and restrictive. The default permissive list starts with a resize policy that shows all command buttons and ribbon galleries in the BIG display state, fully utilizing the available screen space. The restrictive list starts with a resize policy that respects the associated ribbon element priority set on the specific component – this is what is used in the last three screenshots (where the popup band shows one BIG button and three MEDIUM buttons).

The base interface for the resize sequencing policies is defined in the RibbonBandResizeSequencingPolicy interface. The new RibbonTask.setResizeSequencingPolicy API can be used to install a custom resize sequencing policy on the specific ribbon task. The CoreRibbonResizeSequencingPolicies factory provides two core policies – round robin and collapse from last. Under the default round robin policy, the ribbon bands are being collapsed in a cyclic fashion, distributing the collapsed pixels between the different bands. Under the collapse from last policy, the ribbon bands are being collapsed from right to left.

If your application needs more control over the resizing of the specific ribbon task or ribbon band, you can implement one (or both) of these interfaces and install them with the APIs mentioned above. To see the default round robin resize sequencing policy and permissive resize policy in action, click the WebStart launch button below and play with the application width:

As always, you are more than welcome to leave comments and report bugs on the project issue tracker, mailing lists or forums.