add grid and gradient handler

package main

import (

	"image"

	"image/color"

	//	"image/draw"

	"net/http"

)

func grid6X6Handler(w http.ResponseWriter, r *http.Request) {

	m := image.NewRGBA(image.Rect(0, 0, 240, 240))

	drawGrid6X6(m)

	var img image.Image = m

	writeImage(w, &img)

}

func gradientHandler(w http.ResponseWriter, r *http.Request) {

	m := image.NewRGBA(image.Rect(0, 0, 240, 240))

	drawGradient(m)

	var img image.Image = m

	writeImage(w, &img)

}

func drawGrid6X6(m *image.RGBA) {

	size := m.Bounds().Size()

	quad := size.X / 6

	for x := 0; x < size.X; x++ {

		val := ((x / quad) % quad) % 2

		for y := 0; y < size.Y; y++ {

			val2 := ((y / quad) % quad) % 2

			if val+val2 == 1 {

				color := color.RGBA{

					uint8(255),

					uint8(255),

					255,

					255}

				m.Set(x, y, color)

			}

		}

	}

}

func drawGradient(m *image.RGBA) {

	size := m.Bounds().Size()

	for x := 0; x < size.X; x++ {

		for y := 0; y < size.Y; y++ {

			color := color.RGBA{

				uint8(255 * x / size.X),

				uint8(255 * y / size.Y),

				55,

				255}

			m.Set(x, y, color)

		}

	}

}

	r.HandleFunc("/green/?", greenHandler)

	r.HandleFunc("/blue/?", blueHandler)

	r.HandleFunc("/red/?", redHandler)

	r.HandleFunc("/grid/?", grid6X6Handler)

	r.HandleFunc("/gradient/?", gradientHandler)

	r.AddStaticRoute(root)

	log.Println("Listening on " + os.Getenv("PORT"))