{"id":258,"date":"2014-11-22T22:13:49","date_gmt":"2014-11-22T14:13:49","guid":{"rendered":"http:\/\/www.hightopo.com\/blog\/?p=258"},"modified":"2014-11-22T22:16:45","modified_gmt":"2014-11-22T14:16:45","slug":"ht-for-web%e5%9f%ba%e4%ba%8ehtml5%e7%9a%84%e5%9b%be%e5%83%8f%e6%93%8d%e4%bd%9c%ef%bc%88%e4%ba%8c%ef%bc%89","status":"publish","type":"post","link":"https:\/\/www.hightopo.com\/blog\/258.html","title":{"rendered":"HT for Web\u57fa\u4e8eHTML5\u7684\u56fe\u50cf\u64cd\u4f5c\uff08\u4e8c\uff09"},"content":{"rendered":"

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\"Screen<\/a><\/p>\n

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\"Screen<\/a><\/p>\n

 <\/p>\n

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\"Screen<\/a><\/p>\n

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\tfunction createColorImage2(image, color) {\r\n\t\tvar width = image.width;\r\n\t\tvar height = image.height;                \r\n\t\tvar canvas = document.createElement('canvas');\r\n\t\tvar context = canvas.getContext( \"2d\" );\r\n\t\tcanvas.width = width;\r\n\t\tcanvas.height = height;\r\n\t\tcontext.fillStyle = color;    \r\n\t\tcontext.fillRect(0, 0, width, height);    \r\n\t\tcontext.globalCompositeOperation = \"multiply\";\r\n\t\tcontext.drawImage(image, 0, 0, width, height);\r\n\t\tcontext.globalCompositeOperation = \"destination-atop\";\r\n\t\tcontext.drawImage(image, 0, 0, width, height);\r\n\t\treturn canvas;\r\n\t};<\/pre>\n
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\ttime = new Date().getTime();\r\n\tfor(var i=0; i<100; i++){\r\n\t\tcreateColorImage1(image, 'red');\r\n\t}\r\n\tconsole.log(new Date().getTime() - time);\r\n\r\n\ttime = new Date().getTime();\r\n\tfor(var i=0; i<100; i++){\r\n\t\tcreateColorImage2(image, 'red');\r\n\t}\r\n\tconsole.log(new Date().getTime() - time);<\/pre>\n
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http:\/\/blogs.msdn.com\/b\/ie\/archive\/2011\/04\/26\/understanding-differences-in-hardware-acceleration-through-paintball.aspx<\/a><\/p>\n
http:\/\/msdn.microsoft.com\/en-us\/hh562071.aspx<\/a><\/p>\n
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\"Screen<\/a><\/p>\n
\u5404\u79cdglobalCompositeOperation\u6548\u679c\u53ef\u53c2\u8003https:\/\/developer.mozilla.org\/en-US\/docs\/Web\/API\/Canvas_API\/Tutorial\/Compositing<\/a>\u00a0\u7684\u8bf4\u660e\uff0c\u6211\u4eec\u91c7\u7528\u201cmultiply\u201d\u548c\u201cdestination-atop\u201d\u8fd9\u4e24\u79cdblending\u6548\u679c\uff0c\u901a\u8fc7\u4ee5\u4e0b\u4e09\u4e2a\u6b65\u9aa4\u5b9e\u73b0:<\/p>\n
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\"Screen<\/a><\/p>\n
 <\/p>\n
3\u3001\u6700\u540e\u4e00\u6b65\u91c7\u7528\u201cdestination-atop\u201d\u7684globalCompositeOperation\u65b9\u5f0f\uff0c\u518d\u6b21drawImage\uff0c\u8fd9\u6b21\u7ed8\u5236\u6548\u679c\u5c06\u4f1a\u62a0\u51fa\u56fe\u7247\u50cf\u7d20\u533a\u57df\uff0c\u5254\u9664\u975e\u56fe\u7247\u90e8\u5206\uff0c\u6700\u7ec8\u8fbe\u5230\u6211\u4eec\u6240\u8981\u7684\u67d3\u8272\u6548\u679c\u56fe\u7247\uff1a<\/p>\n
\"Screen<\/a><\/p>\n
\u6240\u6709\u4ee3\u7801\u5982\u4e0b<\/p>\n
\tfunction createColorImage2(image, color) {\r\n\t\tvar width = image.width;\r\n\t\tvar height = image.height;                \r\n\t\tvar canvas = document.createElement('canvas');\r\n\t\tvar context = canvas.getContext( \"2d\" );\r\n\t\tcanvas.width = width;\r\n\t\tcanvas.height = height;\r\n\t\tcontext.fillStyle = color;    \r\n\t\tcontext.fillRect(0, 0, width, height);    \r\n\t\tcontext.globalCompositeOperation = \"multiply\";\r\n\t\tcontext.drawImage(image, 0, 0, width, height);\r\n\t\tcontext.globalCompositeOperation = \"destination-atop\";\r\n\t\tcontext.drawImage(image, 0, 0, width, height);\r\n\t\treturn canvas;\r\n\t};<\/pre>\n
\u81f3\u6b64\u6211\u4eec\u6709\u4e24\u79cd\u622a\u7136\u4e0d\u540c\u7684\u7ed8\u5236\u65b9\u5f0f\uff0c\u4e24\u8005\u7684\u4ee3\u7801\u91cf\u5dee\u4e0d\u591a\uff0c\u8be5\u9009\u62e9\u8c01\u5462\uff1f\u8ba9\u6211\u4eec\u6d4b\u8bd5\u4e0b\u4e24\u79cd\u5b9e\u73b0\u65b9\u5f0f\u7684\u6027\u80fd:<\/p>\n
\ttime = new Date().getTime();\r\n\tfor(var i=0; i<100; i++){\r\n\t\tcreateColorImage1(image, 'red');\r\n\t}\r\n\tconsole.log(new Date().getTime() - time);\r\n\r\n\ttime = new Date().getTime();\r\n\tfor(var i=0; i<100; i++){\r\n\t\tcreateColorImage2(image, 'red');\r\n\t}\r\n\tconsole.log(new Date().getTime() - time);<\/pre>\n
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http:\/\/blogs.msdn.com\/b\/ie\/archive\/2011\/04\/26\/understanding-differences-in-hardware-acceleration-through-paintball.aspx<\/a><\/p>\n
http:\/\/msdn.microsoft.com\/en-us\/hh562071.aspx<\/a><\/p>\n
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