Getting a Canvas Context
The context object from canvas element exposes drawing functions.
HTMLCanvasElement represents the canvas element in the DOM. We can use HTMLCanvasElement to get the context.
The HTMLCanvasElement object:
Member | Description | Returns |
---|---|---|
height | Corresponds to the height attribute | number |
width | Corresponds to the width attribute | number |
getContext(<context>) | Returns a drawing context for the canvas | object |
To get the two-dimensional context object, we request pass the 2d argument to getContext(<context>).
<!DOCTYPE HTML>
<html>
<head>
<title>Example</title>
<style>
canvas {
border: medium double black;
margin: 4px
}
</style>
</head>
<body>
<canvas id="canvas" width="500" height="100">
Your browser doesn't support the <code>canvas</code> element
</canvas>
<script>
var ctx = document.getElementById("canvas").getContext("2d");
ctx.fillRect(10, 10, 50, 50);
</script>
</body>
</html>
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canvas:
- Getting Started with the Canvas Element
- Getting a Canvas Context
- Drawing Rectangles
- Canvas Drawing State
- Setting the Line Join Style
- Using Gradients
- Using Patterns
- Using smaller shapes with an image pattern
- Drawing Images
- Using Video Images
- Using Canvas Images
- Setting the Fill & Stroke Styles
- Saving and Restoring Drawing State
- Drawing Using Paths
- Drawing Arcs
- Drawing Bezier Curves
- Drawing Text
- Using Shadows
- Using Transparency
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