wsrpc/sample/canvas/main.go

package main

import (
	"log"
	"net/http"
	"sync"

	"dev.hexasoftware.com/stdio/wsrpc"

	_ "dev.hexasoftware.com/stdio/prettylog"

	"dev.hexasoftware.com/stdio/wsrpc/sample/canvas/canvas"
)

var objlock sync.Mutex

type Point struct {
	x, y int
}

func ClientHandler(ctx *wsrpc.ClientCtx) {
	log.Println("Client connected", ctx.WS.RemoteAddr())
	c := canvas.New(ctx)
	points := []Point{}
	c.OnMouseMove = func(x, y int) {
		objlock.Lock()
		defer objlock.Unlock()
		c.Clear()

		points = append(points, Point{x, y})
		lenPoints := len(points)
		// Test this
		if lenPoints > 2 {
			for i := 1; i < lenPoints; i++ {
				c.Line(points[i-1].x, points[i-1].y,
					points[i].x, points[i].y)

			}
		}
		if lenPoints > 15 { // try 100 drawCalls
			points = points[1:] // remove first
		}
	}

}

func main() {
	var mux = http.NewServeMux()
	wsrpc.RegisterTo(mux, ClientHandler)

	mux.Handle("/", http.FileServer(http.Dir("web")))
	log.Println("Listening :8080")
	http.ListenAndServe(":8080", mux)
}