You say you're having trouble getting from text to draw on the canvas...
Here's an example that reads text input and uses context.fillText
to draw the text on the canvas.
http://jsfiddle.net/m1erickson/4g63H/
Html
<input id="theText" type="text">
<button id="submit">Draw text on canvas</button><br>
<canvas id="canvas" width=300 height=300></canvas>
JavaScript
// canvas related variables
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
$("#submit").click(function () {
var text = $("#theText").val()
ctx.fillText(text, 20, 50);
});
Here's a link on how to use context.drawImage to draw an image on the canvas:
http://www.html5canvastutorials.com/tutorials/html5-canvas-images/