Ant Based Image Generator

This code works and works well. That said, it is not the prettiest bunch of code I have ever written. It just kind of came together so things could be done a bit more elegantly than they currently were and was never a pre-designed set of code. However, I go back to my opening statement: it works.

I used to have a modular based build system where I had many components that were available for any given client. So if a client came and said that they wanted to allow users to log in, application management, and a forum then I would include those three modules into a properties file for them that would contain all details specific to the client. I would then type a few Ant commands and, Voila!, the site was ready. The system worked great until I started needing to change the look and feel of each module outside of just the general color scheme. Sometimes this meant custom text while others this mean gradients instead of plain colors. So, wanting to stick with my simple to use Ant based build system, I decided to create an imaging system that would allow me to change gradients and other stuff on the fly without affecting the underlying project.

So what I wound up with was an XML based system where you list details about how the system should create the images for a given module. So in order to create a new image I would have an images.xml file in the module directory with entries like this in it:

    <image name="titlebartop" path="/images" format="png">
        <gradientImage width="650"

There is quite a bit of backing code that knows how to draw various types of images – solid color, gradients, text, shapes, or combinations of the previous – as well as how these things should fit together, should you indicate you want an image with combinations of these features. I will let you look into the details yourself but here is one example method for creating the actual gradient image using the Java 2D and AWT packages:

    private BufferedImage drawGradient(int width,
                                       int height,
                                       int gradientStartX,
                                       int gradientStartY,
                                       int gradientEndX,
                                       int gradientEndY,
                                       Color color1,
                                       Color color2) throws Exception {

        BufferedImage bi = new BufferedImage(width,

        GradientPaint gp = new GradientPaint((float) gradientStartX,
                                             (float) gradientStartY,
                                             (float) gradientEndX,
                                             (float) gradientEndY,

        Graphics2D g = (Graphics2D) bi.getGraphics();

        g.fillRect(0, 0, width, height);

        return bi;

I am out of the contracting game (for now at least) so I don’t really use this code anymore as I don’t have a huge need for large sets of like images. I just ran through and created a quick test page (in the images/test) directory with these images and everything but schema validation still works though.

Here is an example of it in action. This image is ugly, no doubt, but it shows the use of gradients and their alignment options, solid color pictures, basic shapes, and text all compiled into a single image. This is one of the actual images generated by the Ant task and is one of the ones displayed in the test.html file. Note that even the text has a gradient on it.

Get it:
Grab the zip file with the source in it here. Note that ALL images found in the test.html file are generated – none are hand made.

Since this is an Ant based system you will need to have Ant on your system to compile the tasks or to run the Ant task.

1. Unzip the package to its destination on your computer.

2. Navigate to the directory in a command shell and type “ant”.

3. Open the ./images directory and you should see image files. You can open the ./images/test/test.html file to see these fancy-schmancy images in action. I just chose some random colors for illustration so it is kind of ugly.

4. Play with the values in the images.xml file then repeat from step 2.

5. If you are going to use this for anything production you’ll want to take a look at the XSD validation – it is currently commented out as it is not working right. It used to work but somewhere over time got broken and I didn’t feel like fixing it for this example. If you are interested in this contact me and I’ll be glad to help.

As always, this code is free to use, distribute, or modify so long as it is not used for financial gain without my consent. Enjoy!

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Jason McDonald

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