html5 – 调整窗口大小时防止画布清除

我正在尝试创建一个在Canvas标签中绘制矩形的简单应用程序. Canvas将Canvas调整到全屏,但是当我调整视口大小时,Canvas会清除.我试图阻止它清除,只是保持内部的内容.有任何想法吗？

http://mediajux.com/experiments/canvas/drawing/

谢谢！

/*
      * This is the primary class used for the application
      * @author Alvin Crespo
      */
      var app = (function(){

        var domBod          = document.body;
        var canvas          = null;
        var canvasWidth     = null;
        var canvasHeight     = null;

        return {

          //Runs after the DOM has achieved an onreadystatechange of "complete"
          initApplication: function()
          {
            //setup envrionment variables
            canvas = document.getElementById('canvas') || null;

            //we need to resize the canvas at the start of the app to be the full window
            this.windowResized();

            //only set the canvas height and width if it is not false/null
            if(canvas)
            {
              canvasWidth = canvas.offsetWidth;
              canvasHeight = canvas.offsetHeight;        
            }

            //add window events
            window.onresize = this.windowResized;   

            circles.canvas = canvas;
            circles.canvasWidth = canvasWidth;
            circles.canvasHeight = canvasHeight;
            circles.generateCircles(10);  

            setInterval(function(){
                circles.animateCircles();
            },50);   
          },/**
          * Executes Resizing procedures on the canvas element
          */
          windowResized: function()
          {
            (this.domBod === null) ? 'true' : 'false';
            try{
              console.log(canvas);
              canvas.setAttribute('width',document.body.clientWidth);
              canvas.setAttribute('height',document.body.clientHeight);        
            }catch(e) {
              console.log(e.name + " :: " + e.message);
            }
          },/**
          * Returns the canvas element 
          * @returns canvas
          */
          getCanvas: function()
          {
            return canvas;
          }

        };
      })();

解决方法

我相信,当监听器触发时,您已经实现了屏幕调整大小并重新绘制画布内容的监听器.

原文地址：https://www.jb51.cc/html5/168723.html