added ToBytes() method and http example

example/example_http.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"log"
+	"math/rand"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/jdxyw/generativeart"
+	"github.com/jdxyw/generativeart/arts"
+	"github.com/jdxyw/generativeart/common"
+)
+
+func main() {
+	address := ":8090"
+	log.Println("Server started at", address)
+
+	// Initialize handlers
+	http.HandleFunc("/", drawHandler)
+	log.Fatal(http.ListenAndServe(address, nil))
+}
+
+// drawHandler is writes a piece of generative art
+// as a response to an http request
+func drawHandler(w http.ResponseWriter, r *http.Request) {
+
+	// Log Requests
+	log.Printf("method=%s path=%s ", r.Method, r.RequestURI)
+
+	// Draw the image to bytes
+	b, err := drawMyBytes()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Set content headers
+	w.Header().Set("Content-Type", "image/jpeg")
+	w.Header().Set("Content-Length", strconv.Itoa(len(b)))
+
+	// Write image to response
+	if _, err = w.Write(b); err != nil {
+		log.Fatal("unable to write image.")
+	}
+}
+
+func drawMyBytes() ([]byte, error) {
+
+	// Generate a new image
+	rand.Seed(time.Now().Unix())
+	c := generativeart.NewCanva(500, 500)
+	c.SetBackground(common.Black)
+	c.FillBackground()
+	c.SetColorSchema(common.DarkRed)
+	c.SetForeground(common.LightPink)
+	c.Draw(arts.NewJanus(10, 0.2))
+
+	// Return the image as []byte
+	return c.ToBytes()
+}

generativeart.go

@@ -1,13 +1,15 @@
 package generativeart
 
 import (
-	"github.com/jdxyw/generativeart/common"
+	"bytes"
 	"image"
 	"image/color"
 	"image/draw"
 	"image/jpeg"
 	"image/png"
 	"os"
+
+	"github.com/jdxyw/generativeart/common"
 )
 
 type Engine interface {
@@ -169,3 +171,13 @@ func (c *Canva) ToJPEG(path string) error {
 
 	return nil
 }
+
+// ToBytes returns the image as a jpeg-encoded []byte
+func (c *Canva) ToBytes() ([]byte, error) {
+	buffer := new(bytes.Buffer)
+	if err := jpeg.Encode(buffer, c.Img(), nil); err != nil {
+		return nil, err
+	}
+
+	return buffer.Bytes(), nil
+}