The translate() function
Summary: The translate() function can be used to adjust the position of the canvas coordinate system
An example of translating by 25px in the X direction and 25px in the Y direction before drawing a rectangle at (0,0) (as well as a grid)
The translate()
function adjusts the coordinate system of the canvas. Normally
the [0, 0] coordinates are in the top left
corner, but by using the translate()
function you can move them to wherever you wish.
To move things back and up the
numbers can be negative. Translating is affected by the use of the save()
and restore()
functions so if necessary you
can save()
, translate()
, restore()
- and the
state of the canvas will be as it was before you saved.
Arguments to the function
- Number of pixels to move in the X direction (can be negative)
- Number of pixels to move in the Y direction (can be negative)
An example
You can use the function like this:
<script>
window.onload = function ()
{
var canvas = document.getElementById("cvs");
var context = canvas.getContext('2d');
// After the translate the [0,0] coordinates will actually be 50 pixels down and 50
// pixels to the right of where they would be normally
context.translate(50, 50);
context.beginPath();
context.moveTo(100, 100);
context.lineTo(200, 200);
context.stroke();
}
</script>