From d59705d46e44db6b42c4f6279e2e3b9283f9db76 Mon Sep 17 00:00:00 2001
From: Dmitry Fedotov <dafedotov@gmail.com>
Date: Tue, 25 Mar 2025 20:53:43 +0300
Subject: [PATCH] add color variations

---
 .gitignore       |  2 ++
 barnsley-fern.go | 68 ++++++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 65 insertions(+), 5 deletions(-)

diff --git a/.gitignore b/.gitignore
index 8f6a2e4..c45b969 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,3 @@
 barnsley-fern
+barnsley-fern-go
+barnsley_fern.png
diff --git a/barnsley-fern.go b/barnsley-fern.go
index ff39457..611f7d0 100644
--- a/barnsley-fern.go
+++ b/barnsley-fern.go
@@ -8,6 +8,7 @@ import (
 	"image/png"
 	"math/rand"
 	"os"
+	"time"
 )
 
 func createImage(h, v int) *image.RGBA {
@@ -20,13 +21,61 @@ func createImage(h, v int) *image.RGBA {
 
 func fillBackground(img *image.RGBA, c color.Color) {
 	rect := img.Bounds()
-	for x := 0; x < rect.Max.X; x++ {
-		for y := 0; y < rect.Max.Y; y++ {
+	for x := range rect.Max.X {
+		for y := range rect.Max.Y {
 			img.Set(x, y, c)
 		}
 	}
 }
 
+func newColorFunc(random bool, timed bool, rainbow bool) func(float64, float64) color.Color {
+	return func(x, y float64) color.Color {
+		var (
+			r, g, b, a uint8
+		)
+
+		switch {
+		case random:
+			// n := rand.Intn(3)
+
+			// switch n {
+			// case 0:
+			// 	r = 255
+			// case 1:
+			// 	g = 255
+			// case 2:
+			// 	b = 255
+			// }
+
+			r = uint8(rand.Intn(256))
+			g = uint8(rand.Intn(256))
+			b = uint8(rand.Intn(256))
+			a = 255
+
+		case timed:
+			n := time.Now().Nanosecond() % 256 // Nanosecond returns range [0, 999999999]
+
+			r = uint8((n + 256) % 256)
+			g = uint8((n + 128) % 256)
+			b = uint8(n % 256)
+
+			a = 255
+
+		case rainbow:
+			r = uint8(y * 256)
+			g = uint8(x * 256)
+			b = uint8(((y - x) - min(x, y)) * 256)
+
+			a = 255
+
+		default:
+			r, g, b, a = 0, 153, 0, 255
+		}
+
+		return color.RGBA{r, g, b, a}
+	}
+}
+
 func min(a, b float64) float64 {
 	if a > b {
 		a = b
@@ -34,7 +83,7 @@ func min(a, b float64) float64 {
 	return a
 }
 
-func drawBarnsleyFern(img *image.RGBA, c color.Color, dots int) {
+func drawBarnsleyFern(img *image.RGBA, colorfunc func(float64, float64) color.Color, dots int) {
 	var (
 		x, y, tmpx, tmpy, r, maxy, maxx, scale, yoffset, xoffset float64
 	)
@@ -68,7 +117,10 @@ func drawBarnsleyFern(img *image.RGBA, c color.Color, dots int) {
 		}
 		// рисуем точку
 		x, y = tmpx, tmpy
-		img.Set(int(xoffset+x*scale), int(maxy-yoffset-y*scale), c)
+
+		color := colorfunc(x, y)
+
+		img.Set(int(xoffset+x*scale), int(maxy-yoffset-y*scale), color)
 	}
 }
 
@@ -78,6 +130,9 @@ func main() {
 		h               = flag.Int("h", 1920, "размер картинки по горизонтали")
 		v               = flag.Int("v", 1080, "размер картинки по вертикали")
 		dots            = flag.Int("d", 100000, "сколько точек рисовать")
+		rand            = flag.Bool("rand", false, "использовать случайные цвета")
+		timed           = flag.Bool("timed", false, "привязка к наносекундам времени исполнения")
+		rainbow         = flag.Bool("rainbow", false, "привязка к координатам")
 		img      *image.RGBA
 		f        *os.File
 		err      error
@@ -87,7 +142,10 @@ func main() {
 	img = createImage(*h, *v)
 
 	fillBackground(img, color.White)
-	drawBarnsleyFern(img, color.RGBA{0, 153, 0, 255}, *dots)
+
+	colorfunc := newColorFunc(*rand, *timed, *rainbow)
+
+	drawBarnsleyFern(img, colorfunc, *dots)
 
 	f, err = os.Create(filename)
 	if err != nil {