untitled: a trio from https://penrose.ink

.dsl

type Axes
type Function
predicate On(Function, Axes)

.sty

canvas {
    width = 800
    height = 700
}

const {
    scalar axesSize = 350
    scalar arrowheadSize = 0.7
    scalar lineThickness = 1
    color gray = rgba(0.6, 0.6, 0.6, 1)
    color lightBlue = rgba(0.2, 0.4, 0.8, 1)
    color lightGray = rgba(252, 252, 252, 0.015)
    color none = rgba(0, 0, 0, 0)
}

Axes A {
    scalar axisSize = const.axesSize / 2
    vec2 A.origin = (0, 0)
    vec2 o = A.origin
    A.axisColor = const.gray

    A.background = Rectangle {
        center: A.origin
        width: const.axesSize
        height: const.axesSize
        fillColor: const.lightGray
        strokeColor: const.none
    }

    A.xAxis = Line {
        start: (o[0] - axisSize, o[1])
        end: (o[0] + axisSize, o[1])
        strokeWidth: const.lineThickness
        style: "solid"
        strokeColor: A.axisColor
        startArrowhead: true
        endArrowhead: true
        arrowheadSize: const.arrowheadSize * 2
    }

    A.yAxis = Line {
        start: (o[0], o[1] - axisSize)
        end: (o[0], o[1] + axisSize)
        strokeWidth: const.lineThickness
        style: "solid"
        strokeColor: A.axisColor
        startArrowhead: true
        endArrowhead: true
        arrowheadSize: const.arrowheadSize * 2
    }
}

Function f; Axes A
where On(f, A) {
    f.start = (?, ?)
    f.end = (?, ?)

    f.graph = Line {
        start: f.start
        end: f.end
        strokeWidth: 3
        strokeColor: const.lightBlue
        startArrowhead: true
        endArrowhead: true
        arrowheadSize: const.arrowheadSize
    }

    scalar axisSize = const.axesSize / 2
    vec2 o = A.origin
    scalar a = 0.5

    ensure equal((f.start[0] + f.end[0]) / 2, 0)
    ensure equal((f.start[1] + f.end[1]) / 2, 0)
    ensure equal(min(f.start[0], f.start[1]), -axisSize)
    ensure equal(max(f.end[0], f.end[1]), axisSize)
    ensure equal((f.end[1] - f.start[1]) / (f.end[0] - f.start[0]), a)
}

.sub

Axes A
Function f
On(f, A)

metadata.json

{"authorship":{"madeBy":"samestep","name":"untitled","avatar":"https://avatars.githubusercontent.com/u/8246041?v=4"}}