As described in the previous post, I believe that JavaFX’s layout mechanism is not as good as it could (should) have been. Naturally it is one thing to complain, another to offer improvement suggestions, but the best is to provide alternatives. First there is MigPane, which is a very powerful layout manager, but it is also possible to ‘slap’ on a different API onto existing layout managers. And that is what is being attempted in the JFXtra’s drop-in replacement layout managers. These layout managers extend the existing one, but add a different style.

The basic idea is that instead of writing:

VBox lVBox = new VBox(5.0);
Button b1 = new Button("short");
lVBox.getChildren().add(b1);
VBox.setVgrow(b1, Priority.ALWAYS);

You can write:

VBox lVBox = new VBox(5.0);
lVBox.add(new Button("short"), new VBox.C().vgrow(Priority.ALWAYS));

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After my previous post, praising the properties and binding mechanism, I’d also like to voice an opinion on something on which I think the JavaFX team has dropped the ball.

In the previous post about Agenda control I explained that there were two ways I updated the nodes in Agenda; either I setup binding in the constructor, or I listen to relevant properties and call a relayout() method, setting the appropriate values there. Especially the binding is a powerful feature. No software engineer can deny that the sniplets below don’t have a certain beauty to them.

Adding a rectangle that serves as a dragger at the bottom of an appointment:

durationDragger.xProperty().bind(widthProperty().multiply(0.25)); // 25% offset from the left border
durationDragger.widthProperty().bind(widthProperty().multiply(0.5)); // 50% of the width of the appointment
durationDragger.yProperty().bind(heightProperty().subtract(5)); // 5 pixels from the bottom border
durationDragger.setHeight(3); // 3 pixels high

Making sure the day head and day body line up:

header.getChildren().add(dayHeader);
week.getChrildren().add(dayBody);
dayHeader.xProperty().bind( dayBody.xProperty());
dayHeader.widthProperty().bind( dayBody.widthProperty());

What is important here is that the x,y,w,h values are set directly on the children. The container does not do any layout, it simply draws its childeren where they say they want to be. This is called an ‘absolute’ layout. All other layouts (VBox, HBox, BorderPane, …) do not want you to set the x,y,w,h of the children, their added value is that they’ll calculate and set them for you. (more…)

After getting my feet wet writing the ListPicker and CalendarPicker control in JavaFX for the JFXtras project, I felt it was time to put my aim at something bigger; I always wanted to write a control that does a “Google Calendar”. Even though such a control on the surface seems simple, there are many things that make it a real challenge and fun for a software engineer to create. For example the beauty of how overlapping appointments are rendered. So after a few days where the spare time went into drawings and scribbles on paper, fleshing out how things should be set it up, the coding started. There were a few things I would like to do different from Google’s version.

1. When I plan an appointment, I always forget to look at the whole day events, and often get conflicts because of that. So I wanted a whole day event to have a presence during the whole day.
2. Google only allows for appointments that span a certain amount time. Tasks (which basically only have a single date & time) are not supported. Google has a task feature, but it is not mature enough IMHO in terms of reminders and visibility.

So before diving into how the control is set up, first a quick peek at the state of affairs when writing this blog (tasks are not implemented yet):

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The first post on the JavaFX 2.0 bubblemark created some feedback, most notably an email from the JavaFX engineering team stating in so many words that JavaFX 2.0 has an issue and that is why it per default is not running on full speed. But the remedy should be the magical “-Djavafx.animation.fullspeed=true” option. So without further due the JavaFX bitmap test was run with that option.

So first here is the total view for all 4 tests (the ‘+’ is the fullspeed option):

And the zoomed-in version:

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Oracle has released the revamped JavaFX 2.0 on JavaOne 2011. It’s an interesting step which immediately invokes many questions. What is the target audience for JavaFX? Which technology segment does it aim at? What are the chances it will actually claim a piece of that segment? Is it any good at the segment it is aiming at? Only the future will tell the answers to all the questions. But some can be attempted to be answered today.

First of all a short summary of what I believe JavaFX 2.0 is: JavaFX attempts to be a higher performance graphics framework, with a UI layer on top, able to display different types of media.

• “Higher” means that it is not aiming at high end gaming (for example the recently released Battlefield 3 and Call of Duty Modern Warfare 3), but more at the level of platform games like Mario Bros or the fancier and animated user interfaces that some applications have lately.
• “Graphics framework” indicates that it is not a UI library in its core (like Swing or SWT), but its designed primarily for drawing, manipulating and animating shapes like circles, rectangles and lines.
• “UI layer on top” to note that it does come with a good set of UI controls, that are drawn using the graphics framework and thus can easily be made “fancy”.
• “able to display different types of media” means that there is support for playing audio or video streams.

This kind of framework is commonly known as a RIA, or rich internet application, framework.

Having established the technical intention of JavaFX, the first step would be to see if it is any good at what it’s trying to be. This means bringing out the tame racing driver, aka a common frame of reference. For benchmarking a RIA the unofficial first thing to do is throw the bubblemark test at it. (more…)