Question

I have a script that draws an image on a canvas and allows people to draw lines on this image. I want to get the context from elsewhere in the script (i.e. a header that has various jQuery functions). Is this possible?

What I mean is something like:

Header:

saveInfo = function ()
{
   //save all the inputs

   //get the context of the canvas so we can find some properties
}

clearInfo = function ()
{
   //clear the inputs

   //get the context of the canvas so we can clear it and redraw the main image
}

Included File

<script type="text/javascript">
   //this is the script that produces the drawing functionality initially that I already have
</script>

Edit: I realise this may seem obvious so to embellish, whenever someone draws a line on the canvas in the included script I add to a json array called paths. I need to be able to get this in the save section.

Answer 1

var context = document.getElementById("myCanvasId").getContext("2d");

… will work in any place in your script.