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    <p><code>clearCanvas</code> is working as intended, the issue here is that you are adding five layers to <code>$canvas</code> on each call to <code>render</code>. So, when <code>drawLayers</code> is called, all the layers added to <code>$canvas</code> are drawn; the five updated ones along with all those layers which were added in previous <code>render</code> calls. </p> <p>One way to solve this issue would be to only alter the layers in the <code>render</code> method with <a href="http://calebevans.me/projects/jcanvas/docs/manipulateLayers/" rel="nofollow"><code>setLayer</code></a>, and add them in a method which is called only once, possibly <code>init</code>. </p> <p>So, <code>init</code> becomes:</p> <pre><code>function init() { $canvas = $('canvas'); ctx = document.getElementById("canvas").getContext("2d"); scaleToWindowDimensions(); console.log($canvas); //Adding layers in init //and defining all the //static properties which //won't change on each render $canvas.addLayer({ name: "l0", //Unique name for access visible: true, method: 'drawArc', strokeStyle: "#000", strokeWidth: 1, fillStyle: '#c33', x: middleX, y: middleY, closed: true, radius: 50, // Event bindings mousedown: function (target) { alert('You pushed RED!'); }, mouseup: function (target) { target.fillStyle = '#c33'; }, mouseover: function (target) { target.fillStyle = "#888"; }, mouseout: function (target) { target.fillStyle = "#c33"; } }) .addLayer({ name: "l1", //Unique name for access visible: true, method: "drawText", strokeStyle: "#000", fromCenter: true, strokeWidth: 1, fillStyle: "#333", fontSize: "18pt", fontFamily: "Verdana", x: middleX, y: middleY, text: "Man", data: { "id": 1, "word": "Man" }, mousedown: function (target) { alert($(this).id); } }) .addLayer({ name: "l2", //Unique name for access visible: true, method: 'drawArc', strokeStyle: "#000", strokeWidth: 1, fillStyle: '#d88', x: 500, y: 100, closed: true, radius: 40, // Event bindings mousedown: function (target) { alert('You pushed RED!'); target.fillStyle = '#333'; }, mouseup: function (target) { target.fillStyle = '#d88'; }, mouseover: function (target) { target.fillStyle = "#888"; }, mouseout: function (target) { target.fillStyle = "#d88"; } }) .addLayer({ name: "l3", //Unique name for access visible: true, method: "drawText", strokeStyle: "#000", fromCenter: true, strokeWidth: 1, fillStyle: "#333", fontSize: "16pt", fontFamily: "Verdana", x: 500, y: 100, text: "Men", data: { "id": 2, "word": "Men" }, mousedown: function (target) { alert($(this).id); } }) .addLayer({ name: "l4", //Unique name for access visible: true, method: 'drawLine', strokeStyle: "#222", strokeWidth: 1, x1: middleX, y1: middleY, x2: 500, y2: 100, radius: 40, }); } </code></pre> <p>And <code>render</code> becomes:</p> <pre><code>function render() { if (!isLoaded) { return; } $canvas.clearCanvas(); // ctx.clearRect(0, 0, $canvas.width(), $canvas.height()); //Here, use setLayer to change //properties which are supposed to change //with render //We use the unique name of each layer //set in init to access them. $canvas.setLayer("l0", { x: middleX, y: middleY, }); $canvas.setLayer("l1", { x: middleX, y: middleY }); //Layer l2 and l3 don't //change anything, so they are //not changed with render. $canvas.setLayer("l4", { x1: middleX, y1: middleY }); $canvas.drawLayers(); } </code></pre> <p><strong><a href="http://jsfiddle.net/m3yNH/" rel="nofollow">Working Example</a></strong>.</p>
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    1. POjCanvas's clearCanvas does not seem to work with layers
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    1. POjCanvas's clearCanvas does not seem to work with layers
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    1. COThis makes sense...just so I understand the problem theoretically, what is wrong with my expectation that clearCanvas would clear the existing layers?
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      1. USChris B. Behrens
    2. CO`clearCanvas` is essentially used to clear whole or part of the canvas. The layers are simply objects which facilitate a layer behavior, but do not extend the actual canvas beyond what it is - a 'dumb' pixel array. `clearCanvas` clears what *has been drawn* on this 'dumb' pixel array, but not the actual layer objects added. So, any call to `drawLayers` will iterate through all the layer objects, if any have been added, and draw them in order on this pixel array. You can try, in your example, to call `render` once, layers and all, and then `clearCanvas`.
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