Also, after two weeks of neglecting intEGA, I actually got some work done. Fortunately, I have a good idea of all the work that has to be done so that's a plus. Basically I have to write out and implement all the event listeners for each shape drawing command. Also, the raster graphics algorithms have to be implemented for drawing these shapes (filled or only the borders, antialiased or not). But that should not be a problem since these algorithms have been around for a long time and it is not my goal to reinvent them.
This evening I set out to get in touch with the project again. That means going through the code and reading the design documents and trying to get back in the mindset I had when I last worked on it. This went well and I continued to implement the event listeners for drawing a line and completed it. The line is still not drawn in the raster only the "perfect" line.
The idea is that the user draws arbitrary shapes on a raster. These shapes are drawn on the raster but also the "perfect" version is drawn with seemingly infinite precision. The goal is to raise the awareness of how the raster based approach modern video boards use affects the drawing of these shapes. This in contrast to a vector based approach. So the problem of having a discrete grid upon which an infinitely thin line should be drawn is shown.
This update's screenshot: