add ToBitmapBytes examples code

examples/bitmap-bytes/main.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"bytes"
+	"log"
+
+	"image/jpeg"
+	_ "image/jpeg"
+	"io/ioutil"
+
+	"github.com/go-vgo/robotgo"
+	"golang.org/x/image/bmp"
+)
+
+func main() {
+	bitMap := robotgo.CaptureScreen()
+	defer robotgo.FreeBitmap(bitMap)
+
+	bs := robotgo.ToBitmapBytes(bitMap)
+	img, err := bmp.Decode(bytes.NewReader(bs))
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	b := new(bytes.Buffer)
+	err = jpeg.Encode(b, img, &jpeg.Options{20})
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	log.Println("bytes: ", b.Bytes())
+
+	ioutil.WriteFile("out.jpg", b.Bytes(), 0666)
+}