Created
August 7, 2013 09:36
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Chrome context.arc bug
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| <html> | |
| <head> | |
| <title>chrome arc bug</title> | |
| </head> | |
| <body> | |
| <canvas id="c" width="3000" height="3000"></canvas> | |
| <script type="text/javascript"> | |
| var canvas = document.getElementById('c'); | |
| var ctx = canvas.getContext('2d'); | |
| function myarc(ctx, cx, cy, r) { | |
| var delta = 0.5; | |
| var alpha = 0; | |
| ctx.moveTo(cx + r, cy); | |
| for(; alpha < 360; alpha += delta) { | |
| px = cx + r * Math.cos(alpha*Math.PI/180); | |
| py = cy + r * Math.sin(alpha*Math.PI/180); | |
| ctx.lineTo(px, py); | |
| } | |
| } | |
| ctx.beginPath(); | |
| ctx.strokeStyle = 'black'; | |
| ctx.arc(1000, 1000, 1000, 0, 2*Math.PI, true); | |
| ctx.stroke(); | |
| ctx.beginPath(); | |
| ctx.strokeStyle = 'red'; | |
| myarc(ctx, 1000, 1000, 1000); | |
| ctx.stroke(); | |
| </script> | |
| </body> | |
| </html> |
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bug在哪？