使用HTML5 Canvas建立一個圖案-html教學-PHP中文網

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使用HTML5 Canvas建立一個圖案

Sep 02, 2023 pm 02:57 PM

使用HTML5 Canvas创建一个图案

使用下列方法透過 HTML5 Canvas 建立圖案：createPattern(image, repetition)− 此方法將使用圖片來建立圖案。第二個參數可以是具有以下值之一的字串：repeat、repeat-x、repeat-y 和 no-repeat。如果指定空字串或 null，則將假定重複。

範例

您可以嘗試執行以下程式碼來了解如何建立一個模式 -

&lt;!DOCTYPE HTML&gt;
&lt;html&gt;
   &lt;head&gt;
      &lt;style&gt;
         #test {
            width:100px;
            height:100px;
            margin: 0px auto;
         }
      &lt;/style&gt;
      &lt;script&gt;
         function drawShape(){
            // get the canvas element using the DOM
            var canvas = document.getElementById(&#39;mycanvas&#39;);
            
            // Make sure we don&#39;t execute when canvas isn&#39;t supported
            if (canvas.getContext){
               // use getContext to use the canvas for drawing
               var ctx = canvas.getContext(&#39;2d&#39;);
                
               // create new image object to use as pattern
               var img = new Image();
               img.src = &#39;images/pattern.jpg&#39;;
               img.onload = function(){
                  // create pattern
                  var ptrn = ctx.createPattern(img,&#39;repeat&#39;);
                  ctx.fillStyle = ptrn;
                  ctx.fillRect(0,0,150,150);
               }
            } else {
               alert(&#39;You need Safari or Firefox 1.5+ to see this demo.&#39;);
            }
         }
      &lt;/script&gt;
   &lt;/head&gt;
   &lt;body id = &quot;test&quot; onload = &quot;drawShape();&quot;&gt;
      &lt;canvas id = &quot;mycanvas&quot;&gt;&lt;/canvas&gt;
   &lt;/body&gt;
&lt;/html&gt;