Raster Shapes for Elm

Shapes dont lend themselves well to being rendered on a raster screen. A screen is a grid of pixels, and a curve cant be perfectly represented in a grid of pixels. These functions take the parameters of a shape and return which pixels should be lit up to render that shape.

A line from (0,0) to (9,7), rendered discretely.

  0         9
0 --------------
  | #
  |  ##
  |    #
  |     #
  |      ##
  |        #
7 |         #
  |
  |

RasterShapes is agnostic about how you are rendering. The line function for example, just takes the start and end positions and returns a list of positions. What you do with those positions is up to you.

These functions are implementations of the Bresenham algorithms, mainly the Bresenham line algorithm.

Example

The example file shows how all these functions work, and even does a little rendering of a bunch of pixelated shapes. To get it working just type..

git clone https://github.com/Elm-Canvas/raster-shapes.git
cd raster-shapes
elm package install --yes
elm-reactor

..and then visit localhost:8000/Example.elm.