HTML5 Canvas如何實現紋理填充與描邊(Fill And Stroke)
編輯：HTML5詳解
演示Html5 Canvas Fill 與Stroke文字效果，基於Canvas如何實現紋理填充與描邊。
一：顏色填充與描邊
顏色填充可以通過fillStyle來實現，描邊顏色可以通過strokeStyle來實現。簡單示例
如下：
// fill and stroke text
ctx.font = '60pt Calibri';
ctx.lineWidth = 3;
ctx.strokeStyle = 'green';
ctx.strokeText('Hello World!', 20, 100);
ctx.fillStyle = 'red';
ctx.fillText('Hello World!', 20, 100);
二：紋理填充與描邊
Html5 Canvas還支持紋理填充，通過加載一張紋理圖像，然後創建畫筆模式，創建紋理模式的API為ctx.createPattern(imageTexture,"repeat");第二參數支持四個值，分別為”repeat-x”, ”repeat-y”, ”repeat”,”no-repeat”意思是紋理分別沿著X軸，Y軸，XY方向沿重復或者不重復。紋理描邊與填充的代碼如下：
var woodfill = ctx.createPattern(imageTexture,"repeat");
ctx.strokeStyle = woodfill;
ctx.strokeText('Hello World!', 20, 200);
// fill rectangle
ctx.fillStyle = woodfill;
ctx.fillRect(60, 240, 260, 440);
紋理圖片： 
三：運行效果 
代碼：
<!DOCTYPE Html>
<Html>
<head>
<meta http-equiv="X-UA-Compatible" content="Chrome=IE8">
<meta http-equiv="Content-type" content="text/Html;charset=UTF-8">
<title>Canvas Fill And Stroke Text Demo</title>
<link href="default.CSS" rel="stylesheet" />
<script>
var ctx = null; // global variable 2d context
var imageTexture = null;
window.onload = function() {
var canvas = document.getElementById("text_canvas");
console.log(canvas.parentNode.clIEntWidth);
canvas.width = canvas.parentNode.clIEntWidth;
canvas.height = canvas.parentNode.clIEntHeight;
if (!canvas.getContext) {
console.log("Canvas not supported. Please install a Html5 compatible browser.");
return;
}
// get 2D context of canvas and draw rectangel
ctx = canvas.getContext("2d");
ctx.fillStyle="black";
ctx.fillRect(0, 0, canvas.width, canvas.height);
// fill and stroke text
ctx.font = '60pt Calibri';
ctx.lineWidth = 3;
ctx.strokeStyle = 'green';
ctx.strokeText('Hello World!', 20, 100);
ctx.fillStyle = 'red';
ctx.fillText('Hello World!', 20, 100);
// fill and stroke by pattern
imageTexture = document.createElement('img');
imageTexture.src = "../pattern.png";
imageTexture.onload = loaded();
}
function loaded() {
// delay to image loaded
setTimeout(textureFill, 1000/30);
}
function textureFill() {
// var woodfill = ctx.createPattern(imageTexture, "repeat-x");
// var woodfill = ctx.createPattern(imageTexture, "repeat-y");
// var woodfill = ctx.createPattern(imageTexture, "no-repeat");
var woodfill = ctx.createPattern(imageTexture, "repeat");
ctx.strokeStyle = woodfill;
ctx.strokeText('Hello World!', 20, 200);
// fill rectangle
ctx.fillStyle = woodfill;
ctx.fillRect(60, 240, 260, 440);
}
</script>
</head>
<body>
<h1>Html5 Canvas Text Demo - By Gloomy Fish</h1>
<pre>Fill And Stroke</pre>
<div id="my_painter">
<canvas id="text_canvas"></canvas>
</div>
</body>
</Html>
小編推薦
熱門推薦