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Postsdbo
PO
 

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    <p>You need to build several abstraction layers to avoid major headache in your code.</p> <p>I just built a small 'Drawer' class which keep the user context, to remember what is he drawing, color, ... and the current list of all drawn things. Then you need some classes to store line, rect, ... data</p> <p>On each move of the mouse, the whole scene gets redrawn, which will works fast enough on most devices/browser i think.</p> <p><a href="http://jsfiddle.net/ZS34V/1/" rel="nofollow">http://jsfiddle.net/ZS34V/1/</a></p> <pre><code>var Drawer = function () { this.currentFigureType = 0 ; // 0 : free draw, 1 : line, // 2 : square, ... this.currentFigure = null ; this.figures = [] ; this.currentColor = 0 ; this.startX = 0 ; this.startY = 0 ; this.lastX = 0 ; this.lastY = 0 ; this.mouseDown = false; } Drawer.prototype.draw = function(ctx) { var figuresArray = this.figures; for (var i=0, len=figuresArray.length; i &lt; len; i++) { figuresArray[i].draw(ctx); } } </code></pre> <p>And now on the mouse up/down/move, we will check the context and act accordingly : start a new figure on mousedown, update it on mousemove, and store it on mouseup.</p> <pre><code>canvas.addEventListener('mousedown', function(e) { myDrawer.startX = e.pageX ; myDrawer.startY = e.pageY ; myDrawer.mouseDown = true ; switch (myDrawer.currentFigureType) { case 0 : break; case 1 : break ; } }, 0); canvas.addEventListener('mouseup', function() { myDrawer.mouseDown = false switch (myDrawer.currentFigureType) { case 0 : break; case 1 : var newLine = new Line(myDrawer.currentColor, myDrawer.startX, myDrawer.startY, myDrawer.lastX, myDrawer.lastY); myDrawer.figures.push(newLine); break ; } }, 0); canvas.addEventListener('mousemove', function(e) { if(!myDrawer.mouseDown) { return } myDrawer.lastX = e.pageX; myDrawer.lastY=e.pageY; ctx.clearRect(0,0,width, height); myDrawer.draw(ctx); switch (myDrawer.currentFigureType) { case 0 : // draw + store point break; case 1 : with(ctx) { console.log('we here'); beginPath(); moveTo(myDrawer.startX, myDrawer.startY); lineTo(e.pageX , e.pageY ); strokeStyle = myDrawer.currentColor; ctx.lineWidth=1; stroke(); } break; } }, 0); </code></pre>
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    1. POCanvas - How to save user input in an object?
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    1. COthx, but your jsfiddle is not containing the code of your answer
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    2. COsorry, it is ok now.
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    3. COthank you very much! interesting solution
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