JavaScript canvas2d object method: drawImage()
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The drawImage() method of the JavaScript
DOM object
returned by the getContext("2d")
method applied to the HTML <canvas>
element draws an image,
canvas or video onto the canvas.
There are three versions
of the createImageData() method
with the following formats and parameters (the ones with clip parameters
involve pre-clipping of the image):
context.drawImage(image, x, y)
context.drawImage(image, x, y, width,
height)
context.drawImage(image, clipx, clipy,
clipwidth, clipheight, x, y, width, height)
Parameter
|
Required / Optional
|
Description
|
clipheight
|
Optional
|
Clip height
|
clipwidth
|
Optional
|
Clip width
|
clipx
|
Optional
|
Clip x-coordinate
|
clipy
|
Optional
|
Clip y-coordinate
|
height
|
Optional
|
Height of image to use
(potentially stretching or squashing original image)
|
image
|
Required
|
Image / video / canvas
to be inserted
|
width
|
Optional
|
Width of image to use
(potentially stretching or squashing original image)
|
x
|
Required
|
x-coordinate of
upper-left corner
|
y
|
Required
|
y-coordinate of
upper-left corner
|
EXAMPLE:
HTML USED IN THIS EXAMPLE:
<!DOCTYPE html>
<html> <!-- Copyright (c) Nematrian Limited 2018 -->
<head></head>
<body>
Image we will draw:<br>
<img id="shape" src="Pictures/Shape1and2.png"><br><br>
This image drawn onto a canvas<br>
<span id="element"></span>
<script>
var x2 = document.createElement("CANVAS");
x2.setAttribute("width", "250");
x2.setAttribute("height", "110");
x2.setAttribute("style", "border: 1px solid black");
var c2 = x2.getContext("2d");
var img=document.getElementById("shape");
c2.drawImage(img,30,5);
document.getElementById("element").appendChild(x2);
</script>
</body>
</html>
|
FUNCTION THAT MAY ASSIST IN TESTING WHETHER FEATURE IS SUPPORTED:
function isSupportedJavaScriptMethodCanvas2dDrawImage() {
var x = document.createElement("CANVAS"); var c = x.getContext("2d"); return !!c.drawImage;
} |
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