Canvas绘制地板

飞翔的鱼

2019-06-21

导语

随着数据中心可视化系统的要求越来越高，2D、3D效果都要求几乎逼真；3D地板，相较于2D，实为更易，只需引擎(如：twaver.js、three.js等),外加一张地板图片，便可实现；本文重点介绍如何使用2D绘制地板、以及如何做出伪3D的地板效果；

先睹为快

Canvas绘制地板

若有所思

看到如上效果，你也许会嘲笑鄙人；这样的效果，一张图片就解决，何以兴师动众，大动干戈；然，若您知道，房间地板的形状、材质参差不齐，如何一张图片能解决，你是否理解了我的所作所为，所思所想呢？

Canvas绘制地板

如你所想，这样给出地板材质和坐标信息，便很容易呈现形形状状的地板了，具体是如何实现的呢？

实验天地

Canvas

HTML5的Canvas标签，应该无需赘言, 若您对此不解，请移步Canvas.

"给我一张Canvas，还你你个精彩世界"；--世界著名学者Canvas

createPattern

The CanvasRenderingContext2D
.createPattern() method of the Canvas 2D API creates a pattern using the specified image (a CanvasImageSource ). It repeats the source in the directions specified by the repetition argument. This method returns a CanvasPattern .

image

CanvasImageSource to be used as image to repeat. It can either be a:
HTMLImageElement
HTMLVideoElement
HTMLCanvasElement
CanvasRenderingContext2D
ImageBitmap
Blob

repetition

DOMString indicating how to repeat the image. Possible values are:
"repeat" (both directions),
"repeat-x" (horizontal only),
"repeat-y" (vertical only), or
"no-repeat" (neither).

If repetition is an empty string ('') or null (but not undefined), repetition will be "repeat".

Example

<canvas id="canvas"></canvas>
</pre>
<pre>
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');

var img = new Image();
img.src = 'https://mdn.mozillademos.org/files/222/Canvas_createpattern.png';
img.onload = function() {
  var pattern = ctx.createPattern(img, 'repeat');
  ctx.fillStyle = pattern;
  ctx.fillRect(0, 0, 400, 400);
};

Canvas绘制地板

是不是非常的简单，正如API所言，可以支持图片、Canvas、Vedio、Blob等等，因此，我们可以在Canvas上自己绘制地板样式，再用于填充，起步完美！

填充Canvas内容

<!DOCTYPE html>
<html>
<head>
    <title></title>
    <script type="text/javascript">
        function init() {
            var canvas = document.getElementById("bg");
            var ctx = canvas.getContext("2d");

            var tile = document.createElement('canvas');
            tile.width = 50;
            tile.height = 50;
            var tileCtx = tile.getContext("2d");
            draw(tileCtx);
            var objPattern = ctx.createPattern(tile, "repeat");
            ctx.rotate(-(Math.PI / 180) * 25);
            ctx.fillStyle = objPattern;
            ctx.fillRect(50, 300,700,400);
        }

        function draw(tileCtx) {
            var translator = new Translator3D({x:0,y:0,width:50,height:50});
            tileCtx.save();
            tileCtx.beginPath();
            tileCtx.strokeStyle = 'rgba(100,100,0,1)';        
            var point  = {x:0,y:25};
            // point = translator.translate(point.x,point.y);
            tileCtx.moveTo(point.x, point.y);
            var point  = {x:50,y:25};
            // point = translator.translate(point.x,point.y);
            tileCtx.lineTo(point.x, point.y);
            var point  = {x:25,y:0};
            // point = translator.translate(point.x,point.y);
            tileCtx.moveTo(point.x, point.y);
            var point  = {x:25,y:50};
            // point = translator.translate(point.x,point.y);
            tileCtx.lineTo(point.x, point.y);
            
            tileCtx.stroke();
            tileCtx.restore();
        }
    </script>
</head>
<body onload="init();">
    <canvas id="bg" width="1000" height="500" ></canvas>
</body>
</html>

Canvas绘制地板