add domain warp

README.md

@@ -31,6 +31,7 @@
     - [Dot Line](#dot-line)
     - [Ocean Fish](#ocean-fish)
     - [Circle Loop](#circle-loop)
+    - [Domain Warp](#domain-warp)
     - [Circle Noise](#circle-noise)
     - [Color Canva](#color-canva)
     - [Julia Set](#julia-set)
@@ -81,6 +82,7 @@ This package is still working in progress. More types would be added. Welcome an
 - Yarn
 - Black Hole
 - Color Canva
+- Domain Warp
 
 For these kinds of art, the package provides as many parameters to control the appearance.
 
@@ -120,6 +122,7 @@ NewCircleNoise(dotsN, colorMin, colorMax int)
 NewYarn(n int)
 NewBlackHole(circleN int, density, circleGap float64)
 NewColorCanve(seg float64)
+NewDomainWrap(scale, xOffset, yOffset float64, cmap ColorMapping)
 ```
 
 ## Docs
@@ -414,6 +417,31 @@ func main() {
 
 ![](images/circleloop.png)
 
+### Domain Warp
+
+```go
+func cmap(r, m1, m2 float64) color.RGBA {
+ rgb := color.RGBA{
+  uint8(common.Constrain(m1*255*r, 0, 255)),
+  uint8(common.Constrain(r*200, 0, 255)),
+  uint8(common.Constrain(m2*255*r, 70, 255)),
+  255,
+ }
+ return rgb
+}
+
+func main() {
+ rand.Seed(time.Now().Unix())
+ c := generativeart.NewCanva(500, 500)
+ c.SetBackground(common.Black)
+ c.FillBackground()
+ c.Draw(arts.NewDomainWrap(0.01, 4, 8, cmap))
+ c.ToPNG("domainwarp.png")
+}
+```
+
+![](images/domainwarp.png)
+
 ### Circle Noise
 
 ```go

arts/domainwrap.go

@@ -1,35 +1,40 @@
 package arts
 
 import (
-	"github.com/fogleman/gg"
 	"github.com/jdxyw/generativeart"
 	"github.com/jdxyw/generativeart/common"
+	"image/color"
 )
 
+// ColorMapping maps some parameters to color space.
+type ColorMapping func(float64, float64, float64) color.RGBA
+
 type domainWrap struct {
 	noise            *common.PerlinNoise
 	scale            float64
 	xOffset, yOffset float64
+	fn               ColorMapping
 }
 
 // NewDomainWrap returns a domainWrap object.
-func NewDomainWrap(scale, xOffset, yOffset float64) *domainWrap {
+func NewDomainWrap(scale, xOffset, yOffset float64, cmap ColorMapping) *domainWrap {
 	return &domainWrap{
 		scale:   scale,
 		xOffset: xOffset,
 		yOffset: yOffset,
 		noise:   common.NewPerlinNoise(),
+		fn:      cmap,
 	}
 }
 
 // Generative draws a domain warp image.
 // Reference: https://www.iquilezles.org/www/articles/warp/warp.htm
 func (d *domainWrap) Generative(c *generativeart.Canva) {
-	_ = gg.NewContextForRGBA(c.Img())
-
 	for h := 0.0; h < float64(c.Height()); h += 1.0 {
-		for w := 0.0; h < float64(c.Width()); h += 1.0 {
+		for w := 0.0; w < float64(c.Width()); w += 1.0 {
-			_, _, _ = d.pattern(w*d.scale, h*d.scale, d.xOffset, d.yOffset)
+			r, m1, m2 := d.pattern(w*d.scale, h*d.scale, d.xOffset, d.yOffset)
+			rgb := d.fn(r, m1, m2)
+			c.Img().Set(int(w), int(h), rgb)
 		}
 	}
 }

docs/doc.md

@@ -36,6 +36,8 @@
 		- [parameters](#parameters-15)
 	- [Color Canva](#color-canva)
 		- [parameters](#parameters-16)
+	- [Domain Warping](#domain-warping)
+		- [parameters](#parameters-17)
 
 ## Color Circle 2
 
@@ -263,3 +265,20 @@ cc := arts.NewColorCanve(5)
 ```
 
 ![](../images/colorcanva.png)
+
+## Domain Warping
+
+Warping, or domain distortion is a very common technique in computer graphics for generating procedural textures and geometry. It's often used to pinch an object, stretch it, twist it, bend it, make it thicker or apply any deformation you want.
+
+### parameters
+
+- scale: Control the noise generator.
+- xOffset: Control the noise generator.
+- yOffset: Control the noise generator.
+- fn: A function to mapping the `noise` to color.
+
+```go
+d := arts.NewDomainWrap(0.01, 4, 8, cmap)
+```
+
+![](../images/domainwarp.png)

example/example_domainwrap.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"github.com/jdxyw/generativeart"
+	"github.com/jdxyw/generativeart/arts"
+	"github.com/jdxyw/generativeart/common"
+	"image/color"
+	"math/rand"
+	"time"
+)
+
+func cmap(r, m1, m2 float64) color.RGBA {
+	rgb := color.RGBA{
+		uint8(common.Constrain(m1*255*r, 0, 255)),
+		uint8(common.Constrain(r*200, 0, 255)),
+		uint8(common.Constrain(m2*255*r, 70, 255)),
+		255,
+	}
+	return rgb
+}
+
+func main() {
+	rand.Seed(time.Now().Unix())
+	c := generativeart.NewCanva(500, 500)
+	c.SetBackground(common.Black)
+	c.FillBackground()
+	c.Draw(arts.NewDomainWrap(0.01, 4, 8, cmap))
+	c.ToPNG("domainwarp.png")
+}

example/example_julia.go

@@ -20,7 +20,7 @@ func main() {
 	rand.Seed(time.Now().Unix())
 	c := generativeart.NewCanva(500, 500)
 	c.SetIterations(800)
-	c.SetColorSchema(common.Viridis)
+	c.SetColorSchema(common.Citrus)
 	c.FillBackground()
 	c.Draw(arts.NewJulia(julia1, 40, 1.5, 1.5))
 	c.ToPNG("julia.png")