JavaScript canvas2d object method: createPattern()
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The createPattern() method of the JavaScript
DOM object
returned by the getContext("2d")
method applied to the HTML <canvas>
element repeats a specific element in a specific direction (the element can be
an image, video or another canvas
element).
It has the following
syntax with the following parameters.
context.createPattern(image,
repeatspecification)
Parameter
|
Required / Optional
|
Description
|
image
|
Required
|
Element to be used in
pattern
|
repeatspecification
|
Required
|
Parameter that
specifies how repeating is to be carried out. Can take one of these values:
-
repeat: pattern repeats
both horizontally and vertically
-
repeat-x: pattern only
repeats horizontally
-
repeat-y: pattern only
repeats vertically
-
no-repeat: pattern not
repeated
|
EXAMPLE:
HTML USED IN THIS EXAMPLE:
<!DOCTYPE html>
<html> <!-- Copyright (c) Nematrian Limited 2018 -->
<head></head>
<body>
Image we will create a pattern from:<br>
<img id="shape" src="Pictures/Shape2smaller.jpg"><br><br>
This image drawn onto a canvas<br>
<span id="element"></span>
<script>
var x2 = document.createElement("CANVAS");
x2.setAttribute("width", "200");
x2.setAttribute("height", "100");
x2.setAttribute("style", "border: 1px solid black");
var c2 = x2.getContext("2d");
c2.clearRect(0,0,x2.width,x2.height);
var img = document.getElementById("shape");
var pat = c2.createPattern(img,"repeat");
c2.rect(30,10,150,80);
c2.fillStyle = pat;
c2.fill();
document.getElementById("element").appendChild(x2);
</script>
</body>
</html>
|
FUNCTION THAT MAY ASSIST IN TESTING WHETHER FEATURE IS SUPPORTED:
function isSupportedJavaScriptMethodCanvas2dCreatePattern() {
var x = document.createElement("CANVAS"); var c = x.getContext("2d"); return !!c.createPattern;
} |
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