用JavaScript在畫布上繪制自適應粒子

Question

我想更改這些代碼，以使其具有響應性，並且更改瀏覽器大小不會成為問題

第一個代碼：我需要將此更改為響應式

 var canvasDots = function() { var canvas = document.querySelector('canvas'), ctx = canvas.getContext('2d'), colorDot = '#00bdbf', color = '#00bdbf'; canvas.width = window.innerWidth; canvas.height = window.innerHeight; canvas.style.display = 'block'; ctx.fillStyle = colorDot; ctx.lineWidth = .1; ctx.strokeStyle = color; var mousePosition = { x: 30 * canvas.width / 100, y: 30 * canvas.height / 100 }; var dots = { nb: 350, distance: 60, d_radius: 100, array: [] }; function Dot(){ this.x = Math.random() * canvas.width; this.y = Math.random() * canvas.height; this.vx = -.5 + Math.random(); this.vy = -.5 + Math.random(); this.radius = Math.random(); } Dot.prototype = { create: function(){ ctx.beginPath(); ctx.arc(this.x, this.y, this.radius, 0, Math.PI * 2, false); ctx.fill(); }, animate: function(){ for(i = 0; i < dots.nb; i++){ var dot = dots.array[i]; if(dot.y < 0 || dot.y > canvas.height){ dot.vx = dot.vx; dot.vy = - dot.vy; } else if(dot.x < 0 || dot.x > canvas.width){ dot.vx = - dot.vx; dot.vy = dot.vy; } dot.x += dot.vx; dot.y += dot.vy; } }, line: function(){ for(i = 0; i < dots.nb; i++){ for(j = 0; j < dots.nb; j++){ i_dot = dots.array[i]; j_dot = dots.array[j]; if((i_dot.x - j_dot.x) < dots.distance && (i_dot.y - j_dot.y) < dots.distance && (i_dot.x - j_dot.x) > - dots.distance && (i_dot.y - j_dot.y) > - dots.distance){ if((i_dot.x - mousePosition.x) < dots.d_radius && (i_dot.y - mousePosition.y) < dots.d_radius && (i_dot.x - mousePosition.x) > - dots.d_radius && (i_dot.y - mousePosition.y) > - dots.d_radius){ ctx.beginPath(); ctx.moveTo(i_dot.x, i_dot.y); ctx.lineTo(j_dot.x, j_dot.y); ctx.stroke(); ctx.closePath(); } } } } } }; function createDots(){ ctx.clearRect(0, 0, canvas.width, canvas.height); for(i = 0; i < dots.nb; i++){ dots.array.push(new Dot()); dot = dots.array[i]; dot.create(); } dot.line(); dot.animate(); } window.onmousemove = function(parameter) { mousePosition.x = parameter.pageX; mousePosition.y = parameter.pageY; } mousePosition.x = window.innerWidth / 2; mousePosition.y = window.innerHeight / 2; setInterval(createDots, 1000/30); }; window.onload = function() { canvasDots(); }; 

 html, body { background: #333; } canvas{ position: absolute; width: 100%; height: 100%; top: 0; right: 0; bottom: 0; left: 0; } 

 <canvas></canvas> 

Seconde代碼：我需要將此更改為響應式

 var livePatern = { canvas: null, context: null, cols: 0, rows: 0, colors: [252, 251, 249, 248, 241, 240], triangleColors: [], destColors: [], init: function(){ this.canvas = document.getElementById('canvas'); this.context = this.canvas.getContext('2d'); this.cols = Math.floor(document.body.clientWidth / 24); this.rows = Math.floor(document.body.clientHeight / 24) + 1; this.canvas.width = document.body.clientWidth; this.canvas.height = document.body.clientHeight; this.drawBackground(); this.animate(); }, drawTriangle: function(x, y, color, inverted){ inverted = inverted == undefined ? false : inverted; this.context.beginPath(); this.context.moveTo(x, y); this.context.lineTo(inverted ? x - 22 : x + 22, y + 11); this.context.lineTo(x, y + 22); this.context.fillStyle = "rgb("+color+","+color+","+color+")"; this.context.fill(); this.context.closePath(); }, getColor: function(){ return this.colors[(Math.floor(Math.random() * 6))]; }, drawBackground: function(){ var eq = null; var x = this.cols; var destY = 0; var color, y; while(x--){ eq = x % 2; y = this.rows; while(y--){ destY = Math.round((y-0.5) * 24); this.drawTriangle(x * 24 + 2, eq == 1 ? destY : y * 24, this.getColor()); this.drawTriangle(x * 24, eq == 1 ? destY : y * 24, this.getColor(), true); } } }, animate: function(){ var me = this; var x = Math.floor(Math.random() * this.cols); var y = Math.floor(Math.random() * this.rows); var eq = x % 2; if (eq == 1) { me.drawTriangle(x * 24, Math.round((y-0.5) * 24) , this.getColor(), true); } else { me.drawTriangle(x * 24 + 2, y * 24, this.getColor()); } setTimeout(function(){ me.animate.call(me); }, 10); }, }; !function(){livePatern.init();}() 

 * { margin: 0; padding: 0; min-height: 100%; width: 100%; } html, body { height: 100%; } canvas{ height: 100%; width: 100%; } 

 <canvas id="canvas"></canvas> 

我要使用：

window.onresize = function() {

  ctx.clearRect(0,0,canvas.width, canvas.height);

  //call again function;
}

但是動畫是重復的。

Answer 1

您正在設置加載時畫布的大小，並將其保存到所有即將到來的渲染中。 但是，您可以做類似的事情；

//pseudo code, including only the idea.
windown.onload = function () {

  var canvas = document.querySelector(...),
      context = canvas.getContext('2d');

  Dots.init();

  function prepareCanvas (w, h) {
    //set width and height
    //do more nessessary stuff
  }

  (function loop () {
    var w = window.innerWidth,
        h = window.innerHeight;

     prepareCanvas(w, h);
     Dots.render(context, w, h);


    window.requestAnimationFrame(loop);
  })();
}

因此，基本上，將寬度和高度作為參數添加到render方法中，因此顯示尺寸是否更改無關緊要。

更新，由於評論

緩存尺寸，這種情況不會比您需要的更多。

window.onload = function () {
  var w, h, resized = true;

  window.addEventListener('resize', function () {
    resized = true;
  });

  (function loop() {
    if (resized) {
      //get w, h
      prepareCanvas(w, h);
      resized = false;
    }

     Dots.render(context, w, h);
  })();

}