commit f9d1395da6e2c1519486c86ffb523cd765c3a09c
Author: Gator <gator@ariona.fr>
Date:   Sun Apr 24 14:24:54 2022 +0200

    initial commit

diff --git a/assets/lavande.jpg b/assets/lavande.jpg
new file mode 100644
index 0000000..5795267
Binary files /dev/null and b/assets/lavande.jpg differ
diff --git a/assets/moutons.jpg b/assets/moutons.jpg
new file mode 100644
index 0000000..a35ade3
Binary files /dev/null and b/assets/moutons.jpg differ
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..8bcb055
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module ariona.fr/git/gator/pixelweaver
+
+go 1.16
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..3c8b2e0
--- /dev/null
+++ b/main.go
@@ -0,0 +1,208 @@
+package main
+
+import (
+	"fmt"
+	"image"
+	"image/color"
+	"image/jpeg"
+	_ "image/jpeg"
+	_ "image/png"
+	"log"
+	"math"
+	"math/rand"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"sync"
+	"time"
+)
+
+// goroutine to blend colors at position (x, y) from two images
+func blendWorker(jobs <-chan blendColorJob, results chan<- blendColorResult, wg *sync.WaitGroup) {
+	defer wg.Done()
+	for j := range jobs {
+		c1 := j.Img1.At(j.X, j.Y)
+		c2 := j.Img2.At(j.X, j.Y)
+		c3 := blendColor(c1, c2)
+		results <- blendColorResult{j.X, j.Y, c3}
+	}
+}
+
+// goroutine to set the new color values at newImage position (x, y)
+func setImageWorker(results <-chan blendColorResult, newImage *image.RGBA, wg *sync.WaitGroup) {
+	defer wg.Done()
+	for r := range results {
+		newImage.Set(r.X, r.Y, r.Color)
+	}
+}
+
+// convert RGBA pixel to grayscale
+func grayscale(pixel color.Color) color.Color {
+	c := color.RGBAModel.Convert(pixel).(color.RGBA)
+	gray := uint8((c.R + c.G + c.B) / 3)
+	return color.RGBA{
+		R: gray,
+		G: gray,
+		B: gray,
+		A: c.A,
+	}
+}
+
+// alpha blending RGBA pixels
+func blend(fc uint8, bc uint8, fa uint8, ba uint8) float64 {
+	// fc : foreground color
+	// bc : background color
+	// fa : foreground alpha
+	// ba : background alpha
+	// all values are alpha-premultiplied
+
+	// darken only
+	return math.Min(float64(fc), float64(bc))
+
+	// fucky fucky fun
+	// return float64((fc * fa) + (bc * (fa * 2)))
+}
+
+// blend two RGBA colors/pixels and returns a new one
+func blendColor(color1 color.Color, color2 color.Color) color.Color {
+	oc1 := color.RGBAModel.Convert(color1).(color.RGBA)
+	oc2 := color.RGBAModel.Convert(color2).(color.RGBA)
+	r := uint8(blend(oc1.R, oc2.R, oc1.A, oc2.A))
+	g := uint8(blend(oc1.G, oc2.G, oc1.A, oc2.A))
+	b := uint8(blend(oc1.B, oc2.B, oc1.A, oc2.A))
+	a := oc1.A + (1-oc1.A)*oc2.A
+	return color.RGBA{
+		R: r, G: g, B: b, A: a,
+	}
+}
+
+// load an image from a file into an Image value
+func loadImage(filename string) image.Image {
+	img, err := os.Open(filename)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer img.Close()
+
+	imgData, _, err := image.Decode(img)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	return imgData
+}
+
+// Walk through a folder recursively and returns a list of image paths
+func getImagesList(path string) []string {
+	var imgs []string
+
+	err := filepath.Walk(path,
+		func(path string, info os.FileInfo, err error) error {
+			ext := strings.ToLower(filepath.Ext(path))
+			if err != nil {
+				return err
+			}
+			if ext == ".jpg" || ext == ".png" {
+				imgs = append(imgs, path)
+			}
+			return nil
+		})
+
+	if err != nil {
+		log.Println(err)
+	}
+
+	return imgs
+}
+
+// Randomly choose x number of image from a given folder
+func getRandomImages(number int) []string {
+	rand.Seed(time.Now().UnixNano())
+	var images []string
+	dir := getImagesList("/home/gator/Photos/")
+	for i := 0; i < number; i++ {
+		index := rand.Intn(len(dir))
+		images = append(images, dir[index])
+	}
+	return images
+}
+
+// creates a new rectangle with the min height and width from both images
+func getDimensions(img1 image.Image, img2 image.Image) image.Rectangle {
+	// get dimensions for both images
+	size1 := img1.Bounds().Size()
+	size2 := img2.Bounds().Size()
+
+	// final image sized from lowest width and height
+	width := int(math.Min(float64(size1.X), float64(size2.X)))
+	height := int(math.Min(float64(size1.Y), float64(size2.Y)))
+
+	// the dimensions, as Points, of the output image
+	upLeft := image.Point{0, 0}
+	lowRight := image.Point{width, height}
+
+	return image.Rectangle{upLeft, lowRight}
+}
+
+type blendColorJob struct {
+	X    int
+	Y    int
+	Img1 image.Image
+	Img2 image.Image
+}
+
+type blendColorResult struct {
+	X     int
+	Y     int
+	Color color.Color
+}
+
+func main() {
+	cpu := runtime.NumCPU()
+	// channels
+	jobs := make(chan blendColorJob, 1)
+	results := make(chan blendColorResult, 1)
+	// waitgroups
+	wgWorker := new(sync.WaitGroup)
+	wgConsumer := new(sync.WaitGroup)
+
+	// get two random images and load them
+	imgs := getRandomImages(2)
+	// imData1 := loadImage("assets/moutons.jpg")
+	// imData2 := loadImage("assets/lavande.jpg")
+	imData1 := loadImage(imgs[0])
+	imData2 := loadImage(imgs[1])
+
+	dimensions := getDimensions(imData1, imData2)
+
+	// output image, ready to receive pixel values
+	outImg := image.NewRGBA(dimensions)
+	out, _ := os.Create("output.jpg")
+	defer out.Close()
+
+	for i := 1; i < cpu; i++ {
+		wgConsumer.Add(1)
+		wgWorker.Add(1)
+		go blendWorker(jobs, results, wgWorker)
+		go setImageWorker(results, outImg, wgConsumer)
+	}
+
+	// blending pixels and assigning them to the output image
+	for x := 0; x < dimensions.Max.X; x++ {
+		for y := 0; y < dimensions.Max.Y; y++ {
+			jobs <- blendColorJob{x, y, imData1, imData2}
+		}
+	}
+	close(jobs)
+
+	// first waitgroup to wait for the results to be ready before closing the channel
+	wgWorker.Wait()
+	close(results)
+
+	// second waitgroup to ensure the encoding doesn't start before the goroutines are done
+	wgConsumer.Wait()
+	fmt.Print("Encoding the image...")
+	jpeg.Encode(out, outImg, nil)
+	fmt.Println(" Done.")
+}