Move to image transform plugins + web server

main.go

@@ -1,25 +1,28 @@
 package main
 
 import (
+	"image"
+	"image/jpeg"
 	"log"
+	"net/http"
 	"os"
 	"path"
 	"plugin"
 )
 
-func loadPlugin(path string) (func(string), error) {
+func loadPlugin(path string) (func(image.Image) image.Image, error) {
 	p, err := plugin.Open(path)
 	if err != nil {
 		return nil, err
 	}
-	sayHello, err := p.Lookup("SayHello")
+	transform, err := p.Lookup("Transform")
 	if err != nil {
 		return nil, err
 	}
-	return sayHello.(func(string)), nil
+	return transform.(func(image.Image) image.Image), nil
 }
 
-func getPlugins(pluginDir string) ([]func(string), error) {
+func getPlugins(pluginDir string) ([]func(image.Image) image.Image, error) {
 	pDir, err := os.Open(pluginDir)
 	if err != nil {
 		return nil, err
@@ -29,7 +32,7 @@ func getPlugins(pluginDir string) ([]func(string), error) {
 		return nil, err
 	}
 
-	var ret []func(string)
+	var ret []func(image.Image) image.Image
 	for _, pFile := range pFiles {
 		if pFile.IsDir() {
 			continue
@@ -45,14 +48,27 @@ func getPlugins(pluginDir string) ([]func(string), error) {
 	return ret, nil
 }
 
-func main() {
-	pluginDir := os.Args[1]
+func handler(w http.ResponseWriter, r *http.Request) {
+	fi, _ := os.Open("lca.jpg")
+	i, _ := jpeg.Decode(fi)
 
-	ps, err := getPlugins(pluginDir)
+	plugins, err := getPlugins(pluginDir)
 	if err != nil {
 		panic(err)
 	}
-	for _, p := range ps {
-		p("Gildas")
+
+	for _, p := range plugins {
+		i = p(i)
 	}
+
+	jpeg.Encode(w, i, nil)
+}
+
+var pluginDir string
+
+func main() {
+	pluginDir = os.Args[1]
+
+	http.HandleFunc("/a.jpg", handler)
+	http.ListenAndServe(":8080", nil)
 }

pluginSrc/grayscale/plugin.go

@@ -0,0 +1,16 @@
+package main
+
+import "image"
+
+// Convert to grayscale image
+func Transform(src image.Image) image.Image {
+	bounds := src.Bounds()
+	w, h := bounds.Max.X, bounds.Max.Y
+	ret := image.NewGray(image.Rectangle{image.Point{0, 0}, image.Point{w, h}})
+	for x := 0; x < w; x++ {
+		for y := 0; y < h; y++ {
+			ret.Set(x, y, src.At(x, y))
+		}
+	}
+	return ret
+}

pluginSrc/plugin/plugin.go

@@ -1,11 +0,0 @@
-package main
-
-import "fmt"
-
-func SayHello(name string) {
-	fmt.Println("HELLO", name)
-}
-
-func main() {
-	fmt.Println("Coucou")
-}

pluginSrc/plugin2/plugin2.go

@@ -1,11 +0,0 @@
-package main
-
-import "fmt"
-
-func SayHello(name string) {
-	fmt.Println("Bonjour, je m'appelle", name)
-}
-
-func main() {
-	fmt.Println("Coucou")
-}

pluginSrc/posterize/plugin.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"image"
+	"image/color"
+)
+
+// Convert to binary image
+func Transform(src image.Image) image.Image {
+	bounds := src.Bounds()
+	w, h := bounds.Max.X, bounds.Max.Y
+	ret := image.NewRGBA(image.Rectangle{image.Point{0, 0}, image.Point{w, h}})
+	for x := 0; x < w; x++ {
+		for y := 0; y < h; y++ {
+			r, g, b, _ := src.At(x, y).RGBA()
+			r, g, b = r/256, g/256, b/256
+			if r < 100 {
+				r = 0
+			} else {
+				r = 255
+			}
+			if g < 100 {
+				g = 0
+			} else {
+				g = 255
+			}
+			if b < 100 {
+				b = 0
+			} else {
+				b = 255
+			}
+			ret.Set(x, y, color.RGBA{uint8(r), uint8(g), uint8(b), 0})
+		}
+	}
+	return ret
+}