{"id":6646,"date":"2017-12-18T23:11:58","date_gmt":"2017-12-18T15:11:58","guid":{"rendered":"http:\/\/www.zhangxinxu.com\/wordpress\/?p=6646"},"modified":"2017-12-18T23:14:56","modified_gmt":"2017-12-18T15:14:56","slug":"linear-rgb-srgb-js-convert","status":"publish","type":"post","link":"https:\/\/www.zhangxinxu.com\/wordpress\/2017\/12\/linear-rgb-srgb-js-convert\/","title":{"rendered":"\u5c0ftip: \u4e86\u89e3LinearRGB\u548csRGB\u4ee5\u53ca\u4f7f\u7528JS\u76f8\u4e92\u8f6c\u6362"},"content":{"rendered":"<p>by <a href=\"http:\/\/www.zhangxinxu.com\/\">zhangxinxu<\/a> from <a href=\"http:\/\/www.zhangxinxu.com\/wordpress\/?p=6646\">http:\/\/www.zhangxinxu.com\/wordpress\/?p=6646<\/a><br \/>\n\u672c\u6587\u53ef\u5168\u6587\u8f6c\u8f7d\uff0c\u4f46\u9700\u5f97\u5230\u539f\u4f5c\u8005\u4e66\u9762\u8bb8\u53ef\uff0c\u540c\u65f6\u4fdd\u7559\u539f\u4f5c\u8005\u548c\u51fa\u5904\uff0c\u6458\u8981\u5f15\u6d41\u5219\u968f\u610f\u3002<\/p>\n<h3>\u4e00\u3001\u4e86\u89e3LinearRGB\u548csRGB<\/h3>\n<p>LinearRGB\u987e\u540d\u601d\u4e49\u5c31\u662f\u7ebf\u6027RGB\u989c\u8272\u3002<\/p>\n<p>\u5047\u8bbe\u767d\u677f\u7684\u5149\u7ebf\u53cd\u5c04\u7387\u662f100%\uff0c\u9ed1\u677f\u7684\u5149\u7ebf\u53cd\u5c04\u7387\u662f0%\u3002\u5219\u5728\u7ebf\u6027RGB\u7684\u4e16\u754c\u4e2d\uff0c50%\u7070\u8272\u5c31\u662f\u5149\u7ebf\u53cd\u5c04\u7387\u4e3a50%\u7684\u7070\u8272\u3002<\/p>\n<p>\u7136\u800c\uff0c\u4eba\u8fd9\u79cd\u52a8\u7269\uff0c\u5bf9\u4e8e\u771f\u5b9e\u4e16\u754c\u7684\u989c\u8272\u611f\u53d7\uff0c\u5e76\u4e0d\u662f\u7ebf\u6027\u7684\uff0c\u800c\u662f\u66f2\u7ebf\u7684\uff0c\u5982\u4e0b\u56fe\u793a\u610f\uff1a<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/image.zhangxinxu.com\/image\/blog\/201712\/feel-gray.jpg\" width=\"480\" height=\"431\" alt=\"\u4eba\u7c7b\u5fc3\u7406\u611f\u53d7\u4e0e\u771f\u5b9e\u4eae\u5ea6\u5bf9\u6bd4\" class=\"alignnone\" \/><\/p>\n<p>\u6a2a\u5750\u6807\u662f\u771f\u5b9e\u4eae\u5ea6\uff0c\u7eb5\u5750\u6807\u662f\u4eba\u7684\u89c6\u89c9\u611f\u53d7\u3002\u53ef\u4ee5\u770b\u5230\u4eba\u5bf9\u8fd9\u4e2a\u4e16\u754c\u4eae\u5ea6\u7684\u611f\u53d7\u548c\u5b9e\u9645\u7684\u53cd\u5c04\u4eae\u5ea6\u5e76\u4e0d\u662f\u7ebf\u6027\u7684\uff0c\u800c\u662f\u6709\u7740\u5f88\u5927\u5dee\u5f02\u7684\u3002<\/p>\n<p>\u4f3c\u4e4e\u5927\u5bb6\u53cd\u5e94\u5f88\u5e73\u6de1\u561b\uff0c\u6211\u4eec\u5728\u770b\u4e0b\u9762\u8fd9\u4e2a\u4f8b\u5b50\uff0c\u4e0b\u56fe\u662f\u4e00\u4e2a\u4ece\u767d\u8272\u5230\u9ed1\u8272\u7684\u6e10\u53d8\uff0c\u4e8e\u662f\u5f88\u81ea\u7136\u7684\uff0c\u6211\u4eec\u4f1a\u8ba4\u4e3a\u4e2d\u95f4\u7684\u4f4d\u7f6e\u5c31\u662f50\u5ea6\u7070\uff0c\u4e5f\u5c31\u662f\u4fd7\u79f0\u7684\u4e2d\u7070\uff1a<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/image.zhangxinxu.com\/image\/blog\/201712\/white-to-black-s.jpg\" width=\"480\" height=\"143\" alt=\"\u7eaf\u9ed1\u5230\u7eaf\u767d\" class=\"alignnone\" \/><\/p>\n<p>\u7136\u800c\u8fd9\u4ec5\u4ec5\u662f\u6211\u4eec\u7684\u89c6\u89c9\u611f\u53d7\u662f\u4e2d\u7070\uff0c\u5982\u679c\u6211\u4eec\u628a\u8fd9\u4e2a\u7070\u8272\u653e\u5230\u81ea\u7136\u4e16\u754c\u91cc\uff0c\u5176\u7269\u7406\u4eae\u5ea6\u503c\u5927\u7ea6\u5728\u767d\u8272\u5757\u768421%\u5de6\u53f3\uff0c<strong>\u5176\u5b9e\u5df2\u7ecf\u662f\u76f8\u5f53\u9ed1\u4e86<\/strong>\u3002<\/p>\n<p>\u4ece\u8fdb\u5316\u8bba\u4e0a\u8bb2\uff0c\u53ef\u80fd\u4e0e\u4eba\u7c7b\u662f\u65e5\u884c\u6027\u52a8\u7269\u6709\u5173\u3002<\/p>\n<p>\u7531\u4e8e\u4eba\u7c7b\u76f4\u89c9\u5224\u65ad\u9075\u5faa\u773c\u89c1\u4e3a\u5b9e\uff0c\u5982\u679c\u6211\u4eec\u7684\u663e\u793a\u5668\u8bbe\u5907\uff0c\u5168\u90e8\u90fd\u662f\u6309\u7167LinearRGB\u6765\u6e32\u67d3\uff0c\u5219\u4f1a\u548c\u6211\u4eec\u771f\u5b9e\u4e16\u754c\u770b\u5230\u7684\u989c\u8272\u6709\u5dee\u5f02\u3002\u8fd9\u4e2a\u95ee\u9898\u5728\u4ee5\u524d\u662f\u975e\u5e38\u4e25\u91cd\u7684\uff0c\u8001\u7684\u663e\u793a\u5668\u8fd9\u79cd\u7269\u7406\u5668\u4ef6\u663e\u793a\u989c\u8272\u662f\u7ebf\u6027\u7684\uff0c\u7eaf\u767d\u7eaf\u9ed1\uff0c\u7136\u540e\u7ebf\u6027\u8c03\u8282\u4eae\u5ea6\u989c\u8272\u5c31\u51fa\u6765\u7684\u3002\u4f46\u4eba\u7684\u771f\u5b9e\u89c6\u89c9\u786e\u5b9e\u975e\u7ebf\u6027\u7684\uff0c\u8fd9\u5c31\u5bfc\u81f4\u7535\u8111\u770b\u5230\u4e00\u5f20\u670d\u88c5\u56fe\u7247\u662f\u8fd9\u6837\u5b50\u7684\uff0c\u7ed3\u679c\u73b0\u5b9e\u4e16\u754c\u4e70\u56de\u6765\u662f\u53e6\u5916\u4e00\u4e2a\u6837\u5b50\u3002<\/p>\n<p>\u4e3a\u4e86\u8ba9\u6211\u4eec\u7684\u663e\u793a\u5668\u663e\u793a\u7684\u6548\u679c\uff0c\u66f4\u63a5\u8fd1\u4e8e\u6211\u4eec\u771f\u5b9e\u7684\u89c6\u89c9\u611f\u53d7\uff0c\u5fae\u8f6f\u8054\u5408\u7231\u666e\u751f\u3001HP\u60e0\u666e\u91cd\u65b0\u5236\u5b9a\u7684\u4e00\u5957\u975e\u7ebf\u6027\u7684\u5f69\u8272\u8bed\u8a00\u534f\u8bae\uff0c\u5c31\u662f\u8fd9\u91cc\u7684sRGB\u3002\u76ee\u524d\u6211\u4eec\u4f7f\u7528\u7684\u5404\u7c7b\u8bbe\u5907\u663e\u793a\u5668\u989c\u8272\u5168\u90e8\u90fd\u662f\u57fa\u4e8esRGB\u663e\u793a\u7684\u3002<\/p>\n<p>\u597d\u4e86\uff0c\u770b\u6837\u5b50\u73b0\u5728sRGB\u5df2\u7ecf\u4e00\u7edf\u5929\u4e0b\u4e86\uff0c\u90a3\u8fd8\u6709LinearRGB\u7ebf\u6027RGB\u4ec0\u4e48\u4e8b\u60c5\u5462\uff1f<\/p>\n<p>\u90a3\u5c31\u662fLinearRGB\u5728\u56fe\u5f62\u56fe\u50cf\u5904\u7406\u4e0a\u6709\u7740\u5929\u7136\u7684\u4f18\u52bf\u3002<\/p>\n<p>\u56e0\u4e3a\u5176\u989c\u8272\u662f\u7ebf\u6027\u6709\u660e\u663e\u89c4\u5f8b\u7684\uff0c\u5728\u6570\u5b66\u5904\u7406\u4e0a\u5c31\u975e\u5e38\u7b80\u5355\u3002<\/p>\n<p>\u6bd4\u65b9\u8bf4\u4f60\u8ba9\u4e00\u4e2a\u666e\u901a\u56fe\u50cf\u548c\u4e00\u4e2a\u534a\u900f\u660e\u56fe\u50cf\u76f8\u52a0\uff0c\u6216\u8005\u8fdb\u884c2D\u6df7\u5408\u62163D\u9634\u5f71\u6216\u8005\u51e0\u4e4e\u4efb\u4f55\u56fe\u50cf\u5904\u7406\uff0c\u4f60\u80af\u5b9a\u662f\u5f3a\u70c8\u5e0c\u671b\u91c7\u7528\u7684\u662f\u4e00\u4e2a\u7ebf\u6027\u7684\u989c\u8272\u7a7a\u95f4\uff0c\u56e0\u4e3a\u8ba1\u7b97\u8981\u7b80\u5355\u592a\u591a\u4e86\u3002\u4ec0\u4e48\u53cd\u5411\uff0c\u63d0\u4eae\u7b49\u6548\u679c\u90fd\u4e0d\u5728\u8bdd\u4e0b\u3002<\/p>\n<p>\u4e8e\u662f\uff0c\u5728SVG\u6216\u8005webGL\u7b49\u4e0e\u56fe\u5f62\u5904\u7406\u76f8\u5bc6\u5207\u7684\u8bed\u8a00\u9886\u57df\uff0c\u5f88\u591a\u5c5e\u6027\u6216\u8005\u989c\u8272\u5904\u7406\uff0c\u90fd\u662f\u57fa\u4e8eLinearRGB\u6765\u5b9e\u73b0\u7684\u3002<\/p>\n<p>\u4f8b\u5982SVG\u6ee4\u955c\u4e2d\u7684<a href=\"https:\/\/developer.mozilla.org\/en-US\/docs\/Web\/SVG\/Attribute\/color-interpolation-filters\" rel=\"nofollow\" target=\"_blank\">color-interpolation-filters<\/a>\u5c5e\u6027\u5176\u9ed8\u8ba4\u503c\u5c31\u662fLinearRGB\uff0c\u5e76\u4e14Safari\u6d4f\u89c8\u5668\u4ec5\u652f\u6301LinearRGB\u3002<\/p>\n<p>\u8fd9\u5c31\u7ed9\u6211\u4eec\u7684\u5b9e\u9645\u5f00\u53d1\u5e26\u6765\u4e86\u4e00\u5b9a\u7684\u963b\u788d\uff0c\u6bd4\u5982\u8bf4\u5f53\u6211\u4eec\u5bf9\u8bbe\u8ba1\u8f6f\u4ef6\u8fdb\u884c\u505a\u56fe\u7684\u65f6\u5019\uff0c\u6211\u4eec\u7684RGB\u989c\u8272\u7684\u9009\u53d6\u80af\u5b9a\u662f\u57fa\u4e8e\u663e\u793a\u5668\u989c\u8272\uff0c\u4f46\u8fd9\u4e2a\u989c\u8272\u5f80\u5f80\u5728LinearRGB\u90a3\u91cc\u5c31\u4e0d\u51c6\u786e\u4e86\u3002<\/p>\n<p>\u4e3e\u4f8b\u8bf4\u660e\uff1a<\/p>\n<p>sRGB\u4e16\u754c\u4e2d\uff0cRGB\u8272\u503c\u8303\u56f4\u662f0~255\uff0c\u4e2d\u7070\u8272\u5c31\u662f<code>127<\/code>\uff0c\u4f7f\u75280~1\u8303\u56f4\u8868\u793a\u5c31\u662f<code>0.5<\/code>\uff0c\u4f46\u662f\uff0c\u8f6c\u6362\u6210LinearRGB\u5c31\u662f<code>0.214<\/code>\u3002<\/p>\n<p>\u4e5f\u5c31\u662f\u8bf4\u56fe\u50cf\u5904\u7406\u7684\u65f6\u5019\uff0c\u4f60\u4ee5\u4e3a\u4f60\u4f7f\u7528\u4e86\u4e00\u4e2a\u4e2d\u7070\u8272\uff0c\u5b9e\u9645\u4e0a\u4f7f\u7528\u7684\u662f\u4e00\u4e2a\u6df1\u7070\u8272\u3002<\/p>\n<p>\u5982\u4f55\u907f\u514d\u8fd9\u79cd\u95ee\u9898\u5462\uff1f<\/p>\n<p>\u90a3\u5c31\u662f\u6839\u636e\u9700\u8981\u7684\u989c\u8272\u7a7a\u95f4\u8fdb\u884c\u8f6c\u5316\u3002<\/p>\n<h3>\u4e8c\u3001LinearRGB\u548csRGB\u4f7f\u7528JS\u76f8\u4e92\u8f6c\u6362<\/h3>\n<p>\u8fd9\u91cc\u7684\u8f6c\u5316\u4f7f\u75280\u52301\u8303\u56f4\u793a\u610f\u3002<\/p>\n<p>LinearRGB\u8f6c\u6362\u4e3asRGB\uff1a<\/p>\n<pre>\nvar linear = xxx;  <span style=\"color:green;\">\/\/ xxx\u662f0-1\u7684\u6570\u503c<\/span>\nvar s;\nif (linear <= 0.0031308) {\n  s = linear * 12.92;\n} else {\n  s = 1.055 * Math.pow(linear, 1.0\/2.4) - 0.055;\n}<\/pre>\n<p>sRGB\u8f6c\u6362\u4e3aLinearRGB\uff1a<\/p>\n<pre>\nvar s = xxx;    <span style=\"color:green;\">\/\/ xxx\u662f0-1\u7684\u6570\u503c<\/span>\nvar linear;\nif (s <= 0.04045) {\n  linear = s \/ 12.92;\n} else {\n  linear = Math.pow((s + 0.055) \/ 1.055, 2.4);\n}\n<\/pre>\n<p><strong>\u4f7f\u7528\u793a\u610f<\/strong><br \/>\n\u5047\u8bbe\u6211\u4eec\u7684SVG\u7684\u6ee4\u955c\u4f7f\u7528\u7684\u989c\u8272\u7a7a\u95f4\u662fLinearRGB\uff0c\u6211\u4eec\u5e0c\u671b\u989c\u8272\u6700\u540e\u7684\u8ba1\u7b97\u503c\u662f<code>0.5<\/code>\uff0c\u8bf7\u95ee\uff0c\u6211\u4eec\u5e94\u8be5\u8f93\u5165\u7684sRGB\u503c\u662f\u591a\u5c11\uff1f<\/p>\n<p>\u5957\u7528LinearRGB\u8f6c\u6362\u4e3asRGB\u4ee3\u7801\uff0c\u4e8e\u662f\u6709\uff1a<\/p>\n<pre>s = 1.055 * Math.pow(0.5, 1.0\/2.4) - 0.055 = 0.7353569830524495<\/pre>\n<p>\u5982\u679c\u5c06\u5176\u8ba1\u7b97\u503c\u8f6c\u5316\u6210\u5341\u8fdb\u5236\u7684\u989c\u8272\u8868\u793a\uff0c\u5219\u6709\uff1a<\/p>\n<pre>Math.floor(0.7353569830524495 * 256) = 188<\/pre>\n<p>\u4e5f\u5c31\u662f\u663e\u793a\u5668\u4e0a\u7684188\u989c\u8272\u624d\u5bf9\u5e94LinearRGB\u7684<code>0.5<\/code>\u3002<\/p>\n<p>\u4e5f\u5c31\u662f<code>rgba(188,188,188)<\/code>\u624d\u662f\u7ebf\u6027RGB\u4e16\u754c\u7684\u4e2d\u7070\u8272\uff0c\u800c\u4e0d\u662f<code>rgba(127,127,127)<\/code>\u3002<\/p>\n<h3>\u4e09\u3001\u7ed3\u675f\u8bed<\/h3>\n<p>\u641c\u7d22\u4e86\u4e00\u4e0b\uff0c\u4e2d\u6587\u76f8\u5173\u7684\u8d44\u6599\u5176\u5b9e\u5e76\u4e0d\u591a\uff0c\u6240\u4ee5\u672c\u6587\u5185\u5bb9\u8fd8\u662f\u6709\u5fc5\u8981\u7684\uff0c\u867d\u7136\u8bf4\u5185\u5bb9\u6bd4\u8f83\u5c0f\u4f17\uff0c\u53d7\u4f17\u6709\u9650\uff0c\u4f46\u5bf9\u4e8e\u9700\u8981\u7684\u4eba\u8bb2\uff0c\u53ef\u80fd\u5c31\u662f\u96ea\u4e2d\u9001\u70ad\u7684\u91cd\u8981\u8d44\u6599\u4e86\u3002<\/p>\n<p>\u672c\u6587\u4e24\u5f20\u793a\u610f\u56fe\u53c2\u8003\u81ea\u201c\u8272\u5f69\u6821\u6b63\u4e2d\u7684 gamma \u503c\u662f\u4ec0\u4e48\uff1f\u201d\u8fd9\u4e2a\u95ee\u9898\u7684<a href=\"https:\/\/www.zhihu.com\/question\/27467127\/answer\/37555901\" rel=\"nofollow\" target=\"_blank\">\u8fd9\u4e2a\u56de\u7b54<\/a>\uff0c\u8fd9\u91cc\u8868\u793a\u611f\u8c22\u3002<\/p>\n<p>\u672c\u6587\u5185\u5bb9\u4e5f\u662f\u8fb9\u5b66\u4e60\u8fb9\u6574\u7406\u7684\uff0c\u5982\u679c\u6709\u8868\u8ff0\u4e0d\u5bf9\u7684\u5730\u65b9\uff0c\u8bf7\u5927\u529b\u6307\u6b63\uff01<\/p>\n<p><img decoding=\"async\" src=\"http:\/\/image.zhangxinxu.com\/image\/blog\/201611\/14.png\" align=\"absmiddle\"><\/p>\n<p>\u672c\u6587\u4e3a\u539f\u521b\u6587\u7ae0\uff0c\u4f1a\u7ecf\u5e38\u66f4\u65b0\u77e5\u8bc6\u70b9\u4ee5\u53ca\u4fee\u6b63\u4e00\u4e9b\u9519\u8bef\uff0c\u56e0\u6b64\u8f6c\u8f7d\u8bf7\u4fdd\u7559\u539f\u51fa\u5904\uff0c\u65b9\u4fbf\u6eaf\u6e90\uff0c\u907f\u514d\u9648\u65e7\u9519\u8bef\u77e5\u8bc6\u7684\u8bef\u5bfc\uff0c\u540c\u65f6\u6709\u66f4\u597d\u7684\u9605\u8bfb\u4f53\u9a8c\u3002<br \/>\n\u672c\u6587\u5730\u5740\uff1a<a href=\"http:\/\/www.zhangxinxu.com\/wordpress\/?p=6646\">http:\/\/www.zhangxinxu.com\/wordpress\/?p=6646<\/a><\/p>\n<p>\uff08\u672c\u7bc7\u5b8c\uff09<\/p>\n","protected":false},"excerpt":{"rendered":"<p>LinearRGB\u987e\u540d\u601d\u4e49\u5c31\u662f\u7ebf\u6027RGB\u989c\u8272\u3002<\/p>\n<p>\u5047\u8bbe\u767d\u677f\u7684\u5149\u7ebf\u53cd\u5c04\u7387\u662f100%\uff0c\u9ed1\u677f\u7684\u5149\u7ebf\u53cd\u5c04\u7387\u662f0%\u3002\u5219\u5728\u7ebf\u6027RGB\u7684\u4e16\u754c\u4e2d\uff0c50%\u7070\u8272\u5c31\u662f\u5149\u7ebf\u53cd\u5c04\u7387\u4e3a50%\u7684\u7070\u8272\u3002<\/p>\n<p>\u7136\u800c\uff0c\u4eba\u8fd9\u79cd\u52a8\u7269\uff0c\u5bf9\u4e8e\u771f\u5b9e\u4e16\u754c\u7684\u989c\u8272\u611f\u53d7\uff0c\u5e76\u4e0d\u662f\u7ebf\u6027\u7684\uff0c\u800c\u662f\u66f2\u7ebf\u7684\u2026\u2026<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,5],"tags":[1200,337,1199,250,251],"_links":{"self":[{"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/posts\/6646"}],"collection":[{"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/comments?post=6646"}],"version-history":[{"count":0,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/posts\/6646\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/media?parent=6646"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/categories?post=6646"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/tags?post=6646"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}