Example 3 : Cantor Dust
First, let’s define our L-System:
The interesting thing about this example is that we need to draw, not only the current generation, but also all the preceding generations too.
So I had to approach things slightly differently, and instead of dealing with a Signal(State), I need a Signal(List(State)):
This signal of List(State) is then passed to the display function (along with the dimension of the window):
We can use rectangle to represent the individual bars, and for my screen 25 pixels seems to be a good height.
For each generation we want to place them some distance apart. That is to say that the state for each generation should have a stepped Y position.
so now, we need to add a drawState function that will take in:
- the width of the window;
- the y position for its rectangles; and
- the state it needs to draw
and return a list of rectangles for that state.
You may remember the following paragraph from Part 2:
So to work out the x positions of the first rectangle for this state, we have this slightly dubious looking line of code:
and the next block of code generates the x positions for all the rectangles:
Running this example in Elm Reactor I can get the demo to gen 8, after that it takes noticeably longer to render and the bars are so thin that they’re barely visible.
Live Demo (here)
Use LEFT and RIGHT arrow keys to evolve/devolve the L-System.
Source Code (here)
Next : Koch Curve
I specialise in rapidly transitioning teams to serverless and building production-ready services on AWS.
Are you struggling with serverless or need guidance on best practices? Do you want someone to review your architecture and help you avoid costly mistakes down the line? Whatever the case, I’m here to help.
Check out my new course, Complete Guide to AWS Step Functions. In this course, we’ll cover everything you need to know to use AWS Step Functions service effectively. Including basic concepts, HTTP and event triggers, activities, callbacks, nested workflows, design patterns and best practices.
Here is a complete list of all my posts on serverless and AWS Lambda. In the meantime, here are a few of my most popular blog posts.
- Lambda optimization tip – enable HTTP keep-alive
- You are thinking about serverless costs all wrong
- Many faced threats to Serverless security
- We can do better than percentile latencies
- I’m afraid you’re thinking about AWS Lambda cold starts all wrong
- Yubl’s road to Serverless
- AWS Lambda – should you have few monolithic functions or many single-purposed functions?
- AWS Lambda – compare coldstart time with different languages, memory and code sizes
- Guys, we’re doing pagination wrong