add janus and update readme

README.md

@@ -19,6 +19,7 @@
 - Dot Line
 - Swirl
 - Point Ribbon
+- Janus
 
 For these kinds of art, the package provides as many as parameters to control the appearance. 
 
@@ -43,6 +44,7 @@ NewSpiralSquare(squareNum int, rectSide, decay float64, randColor bool)
 NewSwirl(a, b, c, d, xaixs, yaixs float64)
 NewDotLine(n int, ras, canv float64, randColor bool)
 NewPointRibbon(r float64)
+NewJanus(n int, decay float64)
 ```
 
 ## General Options
@@ -138,6 +140,23 @@ func main() {
 }
 ```
 
+### Junas
+
+```go
+func main() {
+	rand.Seed(time.Now().Unix())
+	c := generativeart.NewCanva(500, 500)
+	c.SetBackground(generativeart.Black)
+	c.FillBackground()
+	c.SetColorSchema(generativeart.DarkRed)
+	c.SetForeground(generativeart.LightPink)
+	c.Draw(generativeart.NewJanus(10, 0.2))
+	c.ToPNG("janus.png")
+}
+```
+
+![](images/janus.png)
+
 ![](images/dotline.png)
 
 ### Julia Set
@@ -194,23 +213,6 @@ func main() {
 
 ![](images/pointribbon.png)
 
-### Swirl
-
-```go
-func main() {
-	rand.Seed(time.Now().Unix())
-	c := generativeart.NewCanva(1600, 1600)
-	c.SetBackground(generativeart.Azure)
-	c.FillBackground()
-	c.SetForeground(color.RGBA{113, 3, 0, 180})
-	c.SetIterations(8000000)
-	c.Draw(generativeart.NewSwirl(0.970, -1.899, -1.381, -1.506, 2.0, 2.0))
-	c.ToPNG("swirl.png")
-}
-```
-
-![](images/swirl.png)
-
 ### Circle Line
 
 ```go
@@ -288,3 +290,4 @@ Thanks for the following sites and repos, I got lots of ideas, inspiration, code
 - https://editor.p5js.org/kenekk1/sketches/Ly-5XYvKX
 - http://paulbourke.net/fractals/peterdejong/
 - https://editor.p5js.org/kenekk1/sketches/O44Dln5oo
+- https://openprocessing.org/sketch/1071233

color.go

@@ -45,6 +45,19 @@ var (
 		{13, 13, 13, 255},
 	}
 
+	DarkRed = []color.RGBA{
+		{48, 19, 21, 255},
+		{71, 15, 16, 255},
+		{92, 10, 12, 255},
+		{115, 5, 4, 255},
+		{139, 0, 3, 255},
+		{163, 32, 1, 255},
+		{185, 66, 0, 255},
+		{208, 98, 1, 255},
+		{231, 133, 0, 255},
+		{254, 165, 0, 255},
+	}
+
 	Plasma = []color.RGBA{
 		color.RGBA{0x0c, 0x07, 0x86, 0xff},
 		color.RGBA{0x10, 0x07, 0x87, 0xff},

example/example_janus.go

@@ -0,0 +1,18 @@
+package main
+
+import (
+	"github.com/jdxyw/generativeart"
+	"math/rand"
+	"time"
+)
+
+func main() {
+	rand.Seed(time.Now().Unix())
+	c := generativeart.NewCanva(500, 500)
+	c.SetBackground(generativeart.Black)
+	c.FillBackground()
+	c.SetColorSchema(generativeart.DarkRed)
+	c.SetForeground(generativeart.LightPink)
+	c.Draw(generativeart.NewJanus(10, 0.2))
+	c.ToPNG("janus.png")
+}

example/test.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"github.com/fogleman/gg"
+	"github.com/jdxyw/generativeart"
+	"github.com/llgcode/draw2d/draw2dimg"
+	"image"
+	"math/rand"
+	"time"
+)
+
+func main() {
+	const S = 400
+	rand.Seed(time.Now().Unix())
+	dest := image.NewRGBA(image.Rect(0, 0, 500, 500))
+
+	gc := draw2dimg.NewGraphicContext(dest)
+	gc.SetStrokeColor(generativeart.Orange)
+	gc.BeginPath()
+	gc.MoveTo(100, 100)
+	gc.QuadCurveTo(150, 50, 200, 100)
+	//fmt.Println(gc.LastPoint())
+	//gc.QuadCurveTo(200, 100, 300, 200)
+	gc.QuadCurveTo(250, 250, 200, 400)
+	gc.QuadCurveTo(100, 250, 100, 100)
+	//gc.QuadCurveTo(200, 400, 100, 10)
+	//gc.Close()
+	gc.Stroke()
+
+	ctex := gg.NewContextForRGBA(dest)
+	ctex.SetColor(generativeart.White)
+	//ctex.DrawCircle(100, 100, 5)
+	//ctex.DrawCircle(200, 400, 5)
+	//ctex.DrawCircle(200, 100, 5)
+	//ctex.DrawCircle(300, 200, 5)
+	//ctex.DrawCircle(200, 400, 5)
+	ctex.Fill()
+	//gc.FillStroke()
+
+	draw2dimg.SaveToPngFile("test.png", dest)
+}

go.mod

@@ -4,6 +4,6 @@ go 1.16
 
 require (
 	github.com/fogleman/gg v1.3.0
-	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 // indirect
+	github.com/llgcode/draw2d v0.0.0-20200930101115-bfaf5d914d1e
 	golang.org/x/image v0.0.0-20210220032944-ac19c3e999fb // indirect
 )

go.sum

@@ -1,7 +1,15 @@
 github.com/fogleman/gg v1.3.0 h1:/7zJX8F6AaYQc57WQCyN9cAIz+4bCJGO9B+dyW29am8=
 github.com/fogleman/gg v1.3.0/go.mod h1:R/bRT+9gY/C5z7JzPU0zXsXHKM4/ayA+zqcVNZzPa1k=
+github.com/go-gl/gl v0.0.0-20180407155706-68e253793080/go.mod h1:482civXOzJJCPzJ4ZOX/pwvXBWSnzD4OKMdH4ClKGbk=
+github.com/go-gl/glfw v0.0.0-20180426074136-46a8d530c326/go.mod h1:vR7hzQXu2zJy9AVAgeJqvqgH9Q5CA+iKCZ2gyEVpxRU=
 github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 h1:DACJavvAHhabrF08vX0COfcOBJRhZ8lUbR+ZWIs0Y5g=
 github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0/go.mod h1:E/TSTwGwJL78qG/PmXZO1EjYhfJinVAhrmmHX6Z8B9k=
+github.com/jung-kurt/gofpdf v1.0.0/go.mod h1:7Id9E/uU8ce6rXgefFLlgrJj/GYY22cpxn+r32jIOes=
+github.com/llgcode/draw2d v0.0.0-20200930101115-bfaf5d914d1e h1:YRRazju3DMGuZTSWEj0nE2SCRcK3DW/qdHQ4UQx7sgs=
+github.com/llgcode/draw2d v0.0.0-20200930101115-bfaf5d914d1e/go.mod h1:mVa0dA29Db2S4LVqDYLlsePDzRJLDfdhVZiI15uY0FA=
+github.com/llgcode/ps v0.0.0-20150911083025-f1443b32eedb h1:61ndUreYSlWFeCY44JxDDkngVoI7/1MVhEl98Nm0KOk=
+github.com/llgcode/ps v0.0.0-20150911083025-f1443b32eedb/go.mod h1:1l8ky+Ew27CMX29uG+a2hNOKpeNYEQjjtiALiBlFQbY=
+golang.org/x/image v0.0.0-20180708004352-c73c2afc3b81/go.mod h1:ux5Hcp/YLpHSI86hEcLt0YII63i6oz57MZXIpbrjZUs=
 golang.org/x/image v0.0.0-20210220032944-ac19c3e999fb h1:fqpd0EBDzlHRCjiphRR5Zo/RSWWQlWv34418dnEixWk=
 golang.org/x/image v0.0.0-20210220032944-ac19c3e999fb/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

janus.go

@@ -0,0 +1,56 @@
+package generativeart
+
+import (
+	"github.com/fogleman/gg"
+	"math"
+)
+
+type janus struct {
+	n     int
+	decay float64
+}
+
+// NewJanus returns a janus object
+func NewJanus(n int, decay float64) *janus {
+	return &janus{
+		n:     n,
+		decay: decay,
+	}
+}
+
+// Generative draws a janus image
+// TODO not finished.
+func (j *janus) Generative(c *canva) {
+	ctex := gg.NewContextForRGBA(c.img)
+	//ctex.SetColor(c.opts.foreground)
+	s := 220.0
+	r := 0.3
+
+	for i := 0; i < j.n; i++ {
+		//k := rand.Intn(len(c.opts.colorSchema))
+		k := i
+		ctex.Push()
+		ctex.Translate(float64(c.width/2), float64(c.height/2))
+
+		//theta += rand.Float64()*math.Pi/2
+		theta := RandomRangeFloat64(math.Pi/4, 3*math.Pi/4)
+		x1, y1 := math.Cos(theta)*r, math.Sin(theta)*r
+		x2, y2 := -x1, -y1
+
+		noise := RandomRangeFloat64(-math.Abs(y1), math.Abs(y1))
+		y1 += noise
+		y2 += noise
+
+		//r = r - r*j.decay
+		s = s * 0.836
+		ctex.Scale(s, s)
+		//r = r * 0.836
+		ctex.DrawArc(x1, y1, 1.0, math.Pi*3/2+theta, math.Pi*5/2+theta)
+		ctex.SetColor(c.opts.colorSchema[k])
+		ctex.Fill()
+		ctex.DrawArc(x2, y2, 1.0, math.Pi/2+theta, math.Pi*3/2+theta)
+		ctex.SetColor(c.opts.colorSchema[k])
+		ctex.Fill()
+		ctex.Pop()
+	}
+}

utils.go

@@ -118,3 +118,7 @@ func Distance(x1, y1, x2, y2 float64) float64 {
 func RandomRangeInt(min, max int) int {
 	return rand.Intn(max-min) + min
 }
+
+func RandomRangeFloat64(min, max float64) float64 {
+	return min + rand.Float64()*(max-min)
+}