Minor A* page improvements #

There are some big things I want to change on my pages, but there are lots of little things too. The big things I keep delaying because they're "big projects" that need a chunk of time. But the small things I've been delaying too, because I keep telling myself I'll do them when I do the big one.

Right now I'm not working on any big projects so I'm tackling some small improvements. This week I improved the path reconstruction diagram on my A* introduction. It looked like this:

Low contrast diagram without end marker

What's wrong with this?

  1. The contrast is too low between the arrows and the background. I had been using a lighter background for "unvisited" nodes and a darker background for "visited" nodes, and I also separately had chosen an arrow color that matched the came_from variable in the example code.
  2. The start node shows the blob icon but the goal node shows no icon. This is inconsistent with other diagrams on the page that show both a start and goal icon.
  3. The tricky bit here is that the arrows point backwards from the goal to the start. It's easy to miss this.

I made some quick changes; it now looks like this:

Higher contrast diagram with start/end markers

  1. I stopped using the darker background to distinguish visited/unvisited because in this diagram everything is visited.
  2. I added a goal icon that matches the other diagrams.
  3. I added goal/start icons to the code to remind the reader that the loop starts from the goal, not the start point, and works backwards.

I think it'd be even better with an arrowhead along the path to show the direction, but I was unable to get something I liked, and I didn't want to spend a lot of time on it, so I abandoned the arrow. Another thing to try would be a small animated dot  •  following the path from the end to the start, color matched with the current variable in the code. That's something I'll consider later.

There are lots of little improvements I'd like to make to my pages, and I would probably be better off making them now instead of waiting until I have time to make bigger updates.

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