add the dot line

README.md

@@ -4,7 +4,7 @@
 [![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/jdxyw/generativeart/master/LICENSE)
 
 
-generativeart is a `Go` package to generate many kinds of generative art. The code is collecting some excellent generative art (implemented in `R` or `Processing`), and implement them in `Go` again. Currently, it supports the following type.
+`generativeart` is a `Go` package to generate many kinds of generative art. The goal is to collect some excellent generative art (implemented in `R` or `Processing`), and rewrite them in `Go` again. I would paste the original link at the end of this README(If I remember. You can also submit a PR if you found I miss something.). Currently, it supports the following type.
 
 - Maze
 - Julia Set
@@ -15,6 +15,7 @@ generativeart is a `Go` package to generate many kinds of generative art. The co
 - Circle Line
 - Circle Loop
 - Silk Sky
+- Dot Line
 
 For these kinds of art, the package provides as many as parameters to control the appearance. 
 
@@ -115,6 +116,24 @@ func main() {
 
 ![](images/circleloop.png)
 
+### Dot Line
+
+```go
+func main() {
+	rand.Seed(time.Now().Unix())
+	c := generativeart.NewCanva(2080, 2080)
+	c.SetBackground(color.RGBA{230, 230, 230, 255})
+	c.SetLineWidth(10)
+	c.SetIterations(4000)
+	c.SetColorSchema(generativeart.Plasma)
+	c.FillBackground()
+	c.Draw(generativeart.NewDotLine(100, 20, 50, false))
+	c.ToPNG("dotline.png")
+}
+```
+
+![](images/dotline.png)
+
 ### Julia Set
 
 ```go
@@ -226,3 +245,4 @@ Thanks for the following sites and repos, I got lots of ideas, inspiration, code
 - https://github.com/cdr6934/Generative-Processing-Experiments
 - https://github.com/pkd2512/inktober2017
 - http://blog.dragonlab.de/2015/03/generative-art-week-1
+- https://editor.p5js.org/kenekk1/sketches/Ly-5XYvKX

dotLine.go

@@ -0,0 +1,61 @@
+package generativeart
+
+import (
+	"github.com/fogleman/gg"
+	"math/rand"
+)
+
+// TODO: figure out what the meaning of these parameters.
+type dotLine struct {
+	n         int
+	ras       float64
+	canv      float64
+	randColor bool
+}
+
+func NewDotLine(n int, ras, canv float64, randColor bool) *dotLine {
+	return &dotLine{
+		n:         n,
+		ras:       ras,
+		canv:      canv,
+		randColor: randColor,
+	}
+}
+
+func (d *dotLine) Generative(c *canva) {
+	ctex := gg.NewContextForRGBA(c.img)
+
+	ctex.SetLineWidth(c.opts.lineWidth)
+	var dir []int = []int{-1, 1}
+	for i := 0; i < c.opts.nIters; i++ {
+		oldx := rand.Intn(d.n - 1)
+		oldy := rand.Intn(d.n - 1)
+
+		n := rand.Intn(7)
+		if d.randColor {
+			ctex.SetColor(c.opts.colorSchema[rand.Intn(len(c.opts.colorSchema))])
+		} else {
+			ctex.SetRGBA255(RandomRangeInt(222, 255), RandomRangeInt(20, 222), 0, 255)
+		}
+		for j := 0; j < n; j++ {
+			newx := oldx + dir[rand.Intn(2)]
+			newy := oldy + dir[rand.Intn(2)]
+
+			if Distance(float64(newx), float64(newy), float64(d.n/2), float64(d.n/2)) > float64(d.n/2-10) {
+				newx = oldx
+				newy = oldy
+			}
+			if newx == oldx && rand.Intn(3) > 1 {
+				ctex.DrawEllipse(float64(oldx)*d.ras+d.canv, float64(oldy)*d.ras+d.canv, c.opts.lineWidth, c.opts.lineWidth)
+				ctex.Fill()
+				continue
+			}
+			ctex.DrawLine(float64(oldx)*d.ras+d.canv, float64(oldy)*d.ras+d.canv, float64(newx)*d.ras+d.canv, float64(newy)*d.ras+d.canv)
+			oldx = newx
+			oldy = newy
+
+			ctex.Stroke()
+		}
+	}
+
+}

example/example_dotline.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"github.com/jdxyw/generativeart"
+	"image/color"
+	"math/rand"
+	"time"
+)
+
+func main() {
+	rand.Seed(time.Now().Unix())
+	c := generativeart.NewCanva(2080, 2080)
+	c.SetBackground(color.RGBA{230, 230, 230, 255})
+	c.SetLineWidth(10)
+	c.SetIterations(4000)
+	c.SetColorSchema(generativeart.Plasma)
+	c.FillBackground()
+	c.Draw(generativeart.NewDotLine(100, 20, 50, false))
+	c.ToPNG("dotline.png")
+}

utils.go

@@ -3,6 +3,7 @@ package generativeart
 import (
 	"image/color"
 	"math"
+	"math/rand"
 )
 
 type HSV struct {
@@ -113,3 +114,7 @@ func ConvertPolarToPixel(r, theta, xaixs, yaixs float64, h, w int) (int, int) {
 func Distance(x1, y1, x2, y2 float64) float64 {
 	return math.Sqrt(math.Pow(x1-x2, 2.0) + math.Pow(y1-y2, 2.0))
 }
+
+func RandomRangeInt(min, max int) int {
+	return rand.Intn(max-min) + min
+}