gog

gog is a Go Object-oriented 2d drawing library for generative art

Instead of immediate drawing, each shape is a Path{} struct made up of points. The Path has Fill() Stroke() FillStroke() StrokeFill() functions for drawing on the canvas. There is also a DebugDraw() function for Debug purposes that draws all the properties of the Path.

All transformations are applied with reference to the Path.Anchor{} point.

• Path.Translate()
• Path.SetPos()
• Path.Rotate()
• Path.Rotated()
• Path.Scale()

It is possible to write the canvas (Go standard package image surface) as a static PNG file or APNG animation.

package main

import (
	"github.com/setanarut/gog"
	"image/color"
)

func main() {
	c := gog.New(250, 250)
	curve := gog.CubicBezier(100, 95, 50, 300, 190, 88, 140, 200)
	curve.SetPos(c.Center).Scale(gog.P(1.3, 1.3))
	for i := 0; i < 150; i++ {
		c.Clear(color.Gray{30})
		curve.Rotate((gog.Pi * 2) / 150)
		c.DebugDraw(curve)
		c.AppendAnimationFrame()
	}
	c.SaveAPNG("curve_anim.png", 3)
}

Motion path example

rect := gog.Rect(gog.Point{}, 30, 10)
ellipse := gog.Circle(c.Center, 50).Scale(gog.P(1, 0.5))
for _, t := range gog.Linspace(0, 1, 150) {
	c.Clear(gog.Black)
	ellipse.Stroke(c)
	p, a := ellipse.PointAngleAtTime(t)
	rect.SetPos(p).Rotated(a).SetFill(colornames.Yellow).Fill(c)
	c.AppendAnimationFrame()
}

Full code is available in example folder