Scalable vector graphics (SVG) is a way to display lines, rectangles, circles, arcs, etc.
The API is a bit wonky, but (1) it is manageable if you look through MDN docs like these and (2) you can attach event listeners to any shapes and lines you create!
module Example exposing (main)
import Svg exposing (..)
import Svg.Attributes exposing (..)
main : Svg msg
main =
svg
[ width "120"
, height "120"
, viewBox "0 0 120 120"
]
[ rect
[ x "10"
, y "10"
, width "100"
, height "100"
, rx "15"
, ry "15"
]
[]
, circle
[ cx "50"
, cy "50"
, r "50"
]
[]
]
I highly recommend consulting the MDN docs on SVG to learn how to draw various shapes!
SVG is great for data visualizations, and I really want people in the Gren community to explore more in that direction! My instinct is that functions like view : data -> Svg msg will be way easier to work with than what is available in other languages. Just give the data! No need to have data and interaction deeply interwoven in complex ways.
If you are interested in writing a data visualization package, I recommend:
- Reading The Visual Display of Quantitative Information by Edward Tufte.
- Learning about designing for color blindness
- Learning about different color spaces, like CIELUV for changing colors without changing the perceived brightness, cubehelix for heatmaps with nice brightness properties, and how to do color conversions in general
In other words, try to learn as much as possible first! Anyone can show dots on a grid, but a great package will build expertise into the API itself, quietly leading people towards better design and accessibility. Ideally it will help people learn the important principles as well, because it is not just about getting data on screen, it is about helping people understand complex information!
This package should only change to account for new SVG tags and attributes.
Just like gren-lang/html, this package is designed to be predictable. Every node takes two arguments (a list of attributes and a list of children) even though in many cases it is possible to do something nicer. So if you want nice helpers for simple shapes (for example) I recommend creating a separate package that builds upon this one.