Created
November 12, 2016 03:30
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Canvas putImageData
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| <!DOCTYPE html> | |
| <head> | |
| <title>test</title> | |
| <script type="text/javascript"> | |
| var cvs2,ctx2; | |
| var cvs,ctx; | |
| var cnt = 0; | |
| function render(){ | |
| ctx.fillStyle = "rgb(255,255,255)"; | |
| ctx.fillRect(0,0,400,400); | |
| ctx.drawImage(cvs2,0,0,400,400); | |
| let cx = 200 + Math.cos(cnt*Math.PI/60)*100; | |
| let cy = 200 + Math.sin(cnt*Math.PI/60)*100; | |
| ctx.fillStyle = "rgb(255,128,0)"; | |
| ctx.fillRect(cx-10,390,20,20); | |
| cnt++; | |
| requestAnimationFrame(render); | |
| } | |
| window.onload = ()=>{ | |
| cvs = document.getElementById("canvas"); | |
| ctx = cvs.getContext('2d'); | |
| cvs2 = document.createElement('canvas'); | |
| cvs2.width = 400; | |
| cvs2.height = 400; | |
| ctx2 = cvs2.getContext('2d'); | |
| let img = ctx2.createImageData(400,400); | |
| let data = img.data; | |
| let pos = 0; | |
| for(let j=0;j<400;j++){ | |
| for(let i=0;i<400;i++){ | |
| data[pos++] = i; // R | |
| data[pos++] = j; // G | |
| data[pos++] = 0x7f; // B | |
| data[pos++] = 0x7f; // A | |
| } | |
| } | |
| ctx2.putImageData(img,0,0); | |
| render(); | |
| }; | |
| </script> | |
| </head> | |
| <body style="background:#333;"> | |
| <canvas id="canvas" width=400 height=400></canvas> | |
| <body> |
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