degrafa

Andrew Trice had a post over on InsideRIA about using Degrafa as an item renderer within a Data Grid to create a bar chart like effect. His post really helped show just how simple it can be to use Degrafa for visualizing data. In his example he used some RegularRectangles and bound them to the data that was being pulled into a single column to change the width of the rectangle. This was a very simple, yet effective approach and much nicer than looking at a long list of values.

We extended Andrew’s example a bit into another Data Grid example that uses an item renderer with a split bar visualization and optimized the example a little. This example could be extended even further by using Bitmap or Complex fills based on the data, or changing the shape used for the visual. Here’s what it looks like:

While syncing in iTunes I was looking at the indication of how my media was distributed across my iPhone and realized that same visualization could be duplicated using Degrafa. I used a series of different colored RegularRectangles, some VerticalLineRepeaters for the inset markings that dynamically change count depending on the size, some other Rectangles for highlights and shadows, and a RoundedRectangle to mask the area. I also through in a ComplexFill composed of a Solid, Bitmap and Blend fill to create the colored plaid effect. This was really easy to do with binding to change the width, capacity bars, inset marks and colors. Here’s what the example looks like:

UPDATE: Here’s another example that expands upon the bar charts above to create some shape based renderers and a pie chart renderer. The shape renderers were easy to do. They’re masks created with Repeaters. The stars are Polygon Repeaters, the circles are Circle Repeaters, and the squares are Rounded Rectangle Repeaters. The pie chart renderer is just a couple of Elliptical Arcs. See below:

These examples are available on the Degrafa Samples page with View Source enabled.

There’s so much data flying around out there that would be kinda neat to create unique visualizations for using Degrafa. I’ve been checking out COLOURlovers, Echo Nest, FriendFeed and more that would be cool to try and visualize or use in a visualization. Better yet, you could make certain properties accesible to a designer for them to make the visualizations customized to their specifications.

One of the benefits Degrafa offers as part of the framework is the ability to repurpose code to no end. This may be obvious for things like geometry, but if you find yourself writing redundant code for fills and strokes, this tip should help.

Rather than specifying the same common fills and strokes in every MXML file where you’re doing your drawing, you can separate fills and strokes in to their own MXML files. Then, whenever you need to access a fill or stroke, you can add that component to your MXML file and easily access them when appropriate. By doing this, you also have the advantage of code hinting, which makes for quick and easy coding.

As an example, I could make a Fills.mxml file where I specify a fill, like this:

<?xml version=“1.0“ encoding=“utf-8“?>

<GeometryComposition
	xmlns:mx=“http://www.adobe.com/2006/mxml“
	xmlns=“http://www.degrafa.com/2007“
	>

	
	<SolidFill
		id=“grey“
		color=“#666“
		/>

</GeometryComposition>

Then, I can reference that MXML file wherever I’m drawing with Degrafa. For example, the following Circle.mxml code would reference the Fills.mxml:

<?xml version=“1.0“ encoding=“utf-8“?>

<mx:Application
	xmlns:mx=“http://www.adobe.com/2006/mxml“
	layout=“absolute“
	xmlns=“http://www.degrafa.com/2007“
	xmlns:local=“*“>

	<local:Fills
		id=“fills“
		/>

	<GeometryComposition
		graphicsTarget=“{[ surface ]}“
		>
		<Circle
			radius=“100“
			fill=“{fills.grey}“
			/>
	</GeometryComposition>

	<Surface
		id=“surface“
		verticalCenter=“0“
		horizontalCenter=“0“
		/>

</mx:Application>

Those two code samples represent some of the basic methods for cutting down on the amount of code you need to write. I could reference that Fills.mxml in any other component and use the fills defined in that file. You could do the same for strokes as well or make separate MXML files for each type of stroke or fill. It’s up to you. I put together a more evolved example than what was shown above and you can view it here:

View External Fills and Strokes Example
(View Source enabled. Also available on Degrafa Samples page)

Taking This Further

You can expand on this example by making separate Fills and Strokes files for different parts of an application, share those files with other Degrafa users, adjust the structure for what makes most sense for you, etc. One thing that would be interesting is to make a separate Colors class that you can reference from the Fills and Strokes files. Then, when you change the color values in the Colors class the whole scheme of the app could change. Hook that Color class up to a color API like Kuler or COLOURlovers and you could get some really unique opportunities for custom UIs, data visualization, compositions, etc.

We’ve been thinking about a way to grab a color palette using a color API, present a user with a bunch of variations of Fills and Strokes based on that selected palette, allow for selection of which Fills and Strokes the user wants, then write out MXML files with those selections in it. The user could then drop those MXML files into their Flex project and they’re ready to go. It could work the other way too where a user could read an MXML file and be presented with Fill and Stroke swatches of which they can edit and write out a new MXML file.

The more we keep plugging away on Degrafa it seems there are more and more opportunities for creating some really unique tools. Imagine a Fills and Strokes palette that uses the Fills and Strokes MXML files as the model. Who knows what other kinds of things people will come up with as the framework progresses. Any suggestions?

Last week I spoke at the Rocky Mountain Adobe Users Group about Degrafa and someone asked if I would go back and do a full session about the topic. They also asked how I would feel about making it a Connect session for anyone else interested could participate remotely. I thought would be great idea.

There are so many thinks that you can do with Degrafa and it’s evolving every week. Having a Connect Session would enable us to expose a lot of these features to a wider audience as long as there is a demand. So, I’m asking, is there a lot of interest in this? What areas do you have the most trouble/questions with? Any specific topics you’d like to see covered? I could also record the session and post it after the fact.

A lot of people we’ve talked to have been interested in using Degrafa for mapping. Of particular interest was drawing states or regions that incorporate events and data. We put together a proof of concept a while back for EffectiveUI and we’re now making the source available after some clean up and updates to the latest beta release. The sample uses Degrafa to draw the states and for some custom skinning.

There were a number of people on the Degrafa Group asking for the source, so we’ve enable “View Source” on the application. This sample is also available on the Degrafa Samples page.

View The Degrafa Map Sample