It has been a while since I posted any example code. Was messing with the canvas tag in HTML5 and thought I would post it up.
Thanks to Mark Pilgrim and his wonderful Dive into HTML5 site, I was working through the canvas tag page and put this together (only got as far as the gradient section though). Enjoy:
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| <!DOCTYPE html> | |
| <html lang="en"> | |
| <head> | |
| <meta charset="utf-8" /> | |
| <title>Test Canvas</title> | |
| <!-- get excanvas.js from http://code.google.com/p/explorercanvas/ | |
| Note the test cases and examples. Very cool! --> | |
| <!--[if IE]> | |
| <script src="excanvas.js"></script> | |
| <![endif]--> | |
| </head> | |
| <body> | |
| <header> | |
| <hgroup> | |
| <h1>Testing Canvas Tag</h1> | |
| </hgroup> | |
| </header> | |
| <section> | |
| <h3>Click on the rectangle to draw a square and move the mouse out of the rectangle to clear it.</h3> | |
| <canvas id="a" width="300" height="225" style="border:1px dotted;" onclick="draw_a();return false;" onmouseout="clearRectangle('a');return false;"></canvas> | |
| </section> | |
| <section> | |
| <h3>Click on the rectangle to draw a grid.</h3> | |
| <canvas id="b" width="500" height="375" style="border:1px dotted;" onclick="draw_b();return false;"></canvas> | |
| <h3>Click <a href="#" onclick="clearRectangle('b');return false;">here</a> to clear the grid.</h3> | |
| </section> | |
| <footer> | |
| <p>© 2010 <a href="http://www.markmcfadden.tel">Mark McFadden</a></p> | |
| </footer> | |
| </body> | |
| <script> | |
| function draw_a() | |
| { | |
| var a_canvas = document.getElementById("a"); | |
| //must use "2d". For 2 dimensional perhaps? | |
| var a_context = a_canvas.getContext("2d"); | |
| a_context.fillRect(50, 25, 150, 100); | |
| } | |
| function draw_b() | |
| { | |
| var b_canvas = document.getElementById("b"); | |
| var context = b_canvas.getContext("2d"); | |
| //Draw vertical lines (like etching) | |
| for (var x = 0.5; x < 500; x += 10) { | |
| //moves the "etcher" to the specified starting point | |
| context.moveTo(x, 0); | |
| //etches a line to the specified ending point. | |
| context.lineTo(x, 375); | |
| } | |
| //Draw horizontal lines | |
| for (var y = 0.5; y < 375; y += 10) { | |
| context.moveTo(0, y); | |
| context.lineTo(500, y); | |
| } | |
| //now "ink" the etched lines | |
| context.strokeStyle = "#eee"; | |
| context.stroke(); | |
| //the horizontal arrow | |
| //draw the arrow in a different color ink — black instead of off-white — so start a new path. | |
| context.beginPath(); | |
| context.moveTo(0, 40); | |
| context.lineTo(240, 40); | |
| context.moveTo(260, 40); | |
| context.lineTo(500, 40); | |
| context.moveTo(495, 35); | |
| context.lineTo(500, 40); | |
| context.lineTo(495, 45); | |
| //vertical arrow | |
| //since the vertical arrow is the same color as the horizontal arrow, do not need to start another new path | |
| context.moveTo(60, 0); | |
| context.lineTo(60, 153); | |
| context.moveTo(60, 173); | |
| context.lineTo(60, 375); | |
| context.moveTo(65, 370); | |
| context.lineTo(60, 375); | |
| context.lineTo(55, 370); | |
| context.strokeStyle = "#000"; | |
| context.stroke(); | |
| //text font | |
| context.font = "bold 12px sans-serif"; | |
| //x axis label | |
| context.fillText("x", 248, 43); | |
| //y axis label | |
| context.fillText("y", 58, 165); | |
| //upper left corner text | |
| context.textBaseline = "top"; | |
| context.fillText("( 0 , 0 )", 8, 5); | |
| //lower right corner text | |
| context.textAlign = "right"; | |
| context.textBaseline = "bottom"; | |
| context.fillText("( 500 , 375 )", 492, 370); | |
| } | |
| function clearRectangle (rec) | |
| { | |
| var the_canvas = document.getElementById(rec); | |
| the_canvas.width = the_canvas.width; | |
| } | |
| </script> | |
| </html> |
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