github.com/jwatson-CO-edu/httpcanvas

httpcanvas

write to an html5 canvas using go

The app function starts once a we browser connects to http://host:port/

That request downloads a bit of html and javascript to connect to the server and run commands

Further GET requests causes the output to move to the most recent request.

Example

package main

import (
    "github.com/kbatten/httpcanvas"
    "math"
    "time"
)

func app(context *httpcanvas.Context) {
    centerX := context.Width / 2
    centerY := context.Height / 2

    context.BeginPath()
    context.Arc(centerX, centerY, 70, 0, 2*math.Pi, false)
    context.FillStyle("green")
    context.Fill()

    time.Sleep(5 * time.Second)

    context.LineWidth(5)
    context.StrokeStyle("#003300")
    context.Stroke()
    
    context.ShowFrame()
}

func main() {
    httpcanvas.ListenAndServe(":8080", app)
}