Canvas is a new feature in HTML5. It can draw various cool effects on the browser. As a front-end developer, do you know how to use canvas to draw graphics? This article will tell you how to use canvas to draw a rectangle and a gradient rectangle. It has certain reference value. Interested friends can refer to it.
The
Example 1: Use canvas to draw a red rectangle. The specific steps are as follows:
Step one: Use document.getElementById() to find the
Second step Step: Use getContext("2d") to create a context object
Step 3: The fillStyle attribute can set the color of the rectangle. In this example, it is set to red; the fillRect(x,y,width,height) method can be used to draw it. A filled rectangle, x represents the X-axis coordinate of the upper left corner of the rectangle, y represents the Y-axis coordinate of the upper left corner of the rectangle, width represents the width of the rectangle, and height represents the height of the rectangle
The complete code is as follows:
<body>
<canvas id="myCanvas" width="200" height="100" style="border:1px solid #000;"></canvas>
</body>
<script type="text/javascript">
var c=document.getElementById("myCanvas");
var ctx=c.getContext("2d");
ctx.fillStyle="#FF0000";
ctx.fillRect(25,10,150,80);
</script>Rendering:
<body>
<canvas id="myCanvas" width="200" height="100" style="border:1px solid #000;"></canvas>
</body>
<script type="text/javascript">
var c=document.getElementById("myCanvas");
var ctx=c.getContext("2d");
// Create gradient
var grd=ctx.createLinearGradient(0,0,200,0);
grd.addColorStop(0,"orange");
grd.addColorStop(1,"red");
// Fill with gradient
ctx.fillStyle=grd;
ctx.fillRect(25,10,150,80);
</script>createLinearGradient(x,y, x1,y1) can create a linear gradient. When using gradient, you must use two or more colors. addColorStop() method indicates color stop, which can be 0 to 1Use fillStyle Set the color of the rectangle, and then use fillRect(x,y,width,height) to draw the rectangleThe effect is as shown in the figure:
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