{"id":7769,"date":"2018-07-08T14:22:23","date_gmt":"2018-07-08T06:22:23","guid":{"rendered":"https:\/\/www.zhangxinxu.com\/wordpress\/?p=7769"},"modified":"2018-07-08T19:48:49","modified_gmt":"2018-07-08T11:48:49","slug":"canvas-html-size-css-size","status":"publish","type":"post","link":"https:\/\/www.zhangxinxu.com\/wordpress\/2018\/07\/canvas-html-size-css-size\/","title":{"rendered":"canvas HTML\u5c5e\u6027\u5c3a\u5bf8\u548cCSS\u5c3a\u5bf8\u591a\u4e2a\u7ec6\u8282\u6df1\u5165"},"content":{"rendered":"

by zhangxinxu<\/a> from http:\/\/www.zhangxinxu.com\/wordpress\/?p=7769<\/a>
\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

\u4e00\u3001canvas width\/height HTML\u5c5e\u6027\u503c\u5408\u6cd5\u6027<\/h3>\n

\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528width<\/code>\u548cheight<\/code>\u8fd9\u4e24\u4e2aHTML\u5c5e\u6027\u63a7\u5236<canvas><\/code>\u5143\u7d20\u7684\u5c3a\u5bf8\u3002<\/p>\n

\u4ece\u5b9a\u4e49\u4e0a\u8bb2\uff0c<canvas><\/code>\u5143\u7d20\u7684width<\/code>\u548cheight<\/code>\u6807\u51c6\u5c5e\u6027\u503c\u53ea\u80fd\u662f\u6574\u6570\uff0c\u4f46\u662f\u5b9e\u9645\u4e0a\uff0c\u4f60\u8bbe\u7f6e\u5c0f\u6570\uff0c\u6d4f\u89c8\u5668\u4e0d\u4f1a\u8ba4\u4e3a\u662f\u4e0d\u5408\u6cd5\u7684\u3002\u4f8b\u5982\uff1a<\/p>\n

<canvas height=\"88.888\" style=\"background:green;\"><\/canvas><\/pre>\n
\u5b9e\u65f6\u6548\u679c\u5982\u4e0b\uff1a<\/p>\n
<\/canvas><\/p>\n
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<canvas height=\"88px\" style=\"background:green;\"><\/canvas><\/pre>\n
\u5b9e\u65f6\u6548\u679c\u5982\u4e0b\uff1a<\/p>\n
<\/canvas><\/p>\n
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<canvas height=\"88em\" style=\"background:green;\"><\/canvas><\/pre>\n
\u5b9e\u65f6\u6548\u679c\u5982\u4e0b\uff1a<\/p>\n
<\/canvas><\/p>\n
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\n
\u4f46\u662f\uff0c\u5982\u679c\u8bbe\u7f6e\u7684\u662f\u8d1f\u6570\uff0c\u6216\u8005\u76f4\u63a5\u4e0d\u8bbe\u7f6e\uff0c\u5bf9\u4e8e\u9ad8\u5ea6\uff0c\u5219\u4f1a\u4ee5150<\/code>\u50cf\u7d20\u9ad8\u5ea6\u5448\u73b0\uff1b\u5bf9\u4e8e\u5bbd\u5ea6\uff0c\u5219\u4f1a\u4ee5300<\/code>\u50cf\u7d20\u5bbd\u5ea6\u5448\u73b0\u3002<\/p>\n
\u4f8b\u5982\u4e0b\u9762\u7684height<\/code>\u8d1f\u503c\u4ee5\u53ca\u76f4\u63a5\u4e0d\u8bbe\u7f6ewidth\/height<\/code>\u5c5e\u6027\uff1a<\/p>\n
<canvas height=\"-150\" style=\"background:green;\"><\/canvas>\n<canvas style=\"background:green;\"><\/canvas><\/pre>\n
\u5b9e\u65f6\u6548\u679c\u5982\u4e0b\uff1a<\/p>\n
<\/canvas> <\/canvas><\/p>\n
\u7136\u800c\uff0c\u5728IE\u6d4f\u89c8\u5668\u4e0b\uff0c\u8d1f\u6570\u5c3a\u5bf8\u503c\u4f1a\u88ab\u5f53\u505a0<\/code>\u89e3\u6790\uff0c\u56e0\u6b64\uff0c\u770b\u4e0d\u5230\u5c3a\u5bf8\u3002\u8fd9\u4e2a\u548cChrome\u548cFirefox\u6d4f\u89c8\u5668\u662f\u4e0d\u4e00\u6837\u7684\u3002<\/p>\n
\u4e3a\u4ec0\u4e48\u9ed8\u8ba4\u5c3a\u5bf8\u662f300*150\uff1f<\/h4>\n
\u4e3a\u4ec0\u4e48<canvas><\/code>\u5143\u7d20\u9ed8\u8ba4\u5c3a\u5bf8\u662f300*150<\/code>\uff0c\u800c\u4e0d\u662f\u5176\u4ed6\u5c3a\u5bf8\u7ec4\u5408\u5462\uff1f\u8fd9\u4e2a\u662fCSS\u89c4\u8303\u4e2d\u5b9a\u4e49\u7684\uff0c\u4f5c\u4e3a\u66ff\u6362\u5143\u7d20\uff0c\u9ed8\u8ba4\u7684\u5c3a\u5bf8\u662f300*150<\/code>\uff0c<canvas><\/code>\u5143\u7d20\u5c31\u662f\u66ff\u6362\u5143\u7d20\uff0c\u56e0\u6b64\u9ed8\u8ba4\u5c3a\u5bf8\u662f300*150<\/code>\u3002\u7531\u4e8e<svg><\/code>\u5143\u7d20\u4e5f\u662f\u66ff\u6362\u5143\u7d20\uff0c\u56e0\u6b64\uff0c<svg><\/code>\u9ed8\u8ba4\u7684\u5c3a\u5bf8\u4e5f\u662f300*150\u3002<\/p>\n
canvas\u6ca1\u6709\u5c3a\u5bf8\u8bbe\u7f6e\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7HTML\u5c5e\u6027\u83b7\u53d6\u5417\uff1f<\/h4>\n
\u4f8b\u5982\uff0c\u4e0b\u9762HTML\uff0c\u6ca1\u6709width<\/code>\u548cheight<\/code>\u8bbe\u7f6e\uff0c\u8bf7\u95eecanvas.height<\/code>\u7684\u8fd4\u56de\u503c\u662f\u591a\u5c11\uff1f<\/p>\n
<canvas style=\"background:green;\"><\/canvas><\/pre>\n
console.log(document.querySelector('canvas').height);<\/pre>\n
\u7ed3\u679c\u8fd4\u56de\u503c\u5c31\u662f\u9ed8\u8ba4\u7684150<\/code>\uff0c\u800c\u4e0d\u662fundefined<\/code>\u3002<\/p>\n
\"\u9ad8\u5ea6\u7f3a\u7701\u65f6\u5019\u4f9d\u7136\u80fd\u591f\u83b7\u53d6\"<\/p>\n
\u4e8c\u3001HTML\u5c5e\u6027\u5c3a\u5bf8\u548cCSS\u5c3a\u5bf8\u5173\u7cfb<\/h3>\n
\u4ece\u89c6\u89c9\u8868\u73b0\u4e0a\u800c\u8a00\uff0cCSS\u7684width<\/code>\uff0cheight<\/code>\u5c5e\u6027\u6743\u91cd\u8981\u5927\u4e8e<canvas><\/code>\u5143\u7d20\u7684width<\/code>\uff0cheight<\/code>\u5c5e\u6027\u6743\u91cd\uff0c\u4f8b\u5982\u4e0b\u9762HTML\u4ee3\u7801\uff0c\u6700\u7ec8<canvas><\/code>\u5143\u7d20\u9ad8\u5ea6\u662f88<\/code>\u50cf\u7d20\u3002<\/p>\n
<canvas height=\"150\" style=\"background:green; height:88px;\"><\/canvas><\/pre>\n
\u5b9e\u65f6\u6548\u679c\u5982\u4e0b\uff1a<\/p>\n
<\/canvas><\/p>\n
<canvas><\/code>\u5143\u7d20\u672c\u8d28\u4e0a\u5c31\u662f\u4e00\u4e2a\u56fe\u7247\uff0c\u5176\u5f88\u591a\u6837\u5f0f\u8868\u73b0\u548c<img><\/code>\u5143\u7d20\u662f\u4e00\u81f4\u7684\uff0c\u4f8b\u5982\u8fd9\u91cc\uff0cCSS\u63a7\u5236\u56fe\u7247\u5c3a\u5bf8\u65f6\u5019\uff0c\u5982\u679c\u9ad8\u5ea6\u6216\u5bbd\u5ea6\u7f3a\u7701\uff0c<canvas><\/code>\u5143\u7d20\u4f9d\u7136\u4fdd\u6301\u539f\u59cb\u7684\u9ad8\u5bbd\u6bd4\u4f8b\u3002\u5177\u4f53\u63cf\u8ff0\u4e3a\uff1a<canvas><\/code>\u5143\u7d20\u8fd9\u91cc\u539f\u59cb\u5c3a\u5bf8\u662f300*150<\/code>\uff0cCSS\u8bbe\u7f6e\u4e3a88px<\/code>\uff0c\u6700\u7ec8\u7684\u5bbd\u5ea6\u8868\u73b0\u4e0d\u662f300<\/code>\u800c\u662f\u7b49\u6bd4\u4f8b\u7f29\u653e\u7684176px<\/code>\u3002<\/p>\n
\u4f46\u662f\uff0c\u6df1\u7a76\u4e0b\u6765\uff0c\u548c<img><\/code>\u8fd8\u662f\u6709\u4e00\u70b9\u533a\u522b\uff0c\u5c31\u662f<canvas><\/code>\u7684\u7b49\u6bd4\u4f8b\u7279\u6027\u662f\u5f3a\u5236\u7684\uff0c\u4f1a\u5ffd\u7565HTML\u5c5e\u6027\u7684\u8bbe\u7f6e\uff0c\u4f46<img><\/code>\u4e0d\u4f1a\u8fd9\u6837\u3002\u5bf9\u6bd4\u4e0b\u9762\u7684\u6d4b\u8bd5HTML\uff1a<\/p>\n
<img src=\".\/1.jpg\" width=\"300\" height=\"150\" style=\"height:88px;\">\n<canvas width=\"300\" height=\"150\" style=\"background:green; height:88px;\"><\/canvas>\n<\/pre>\n
 <\/canvas><\/p>\n
\u53ef\u4ee5\u770b\u5230<img><\/code>\u5bbd\u5ea6\u4f9d\u7136\u662f300px<\/code>\uff0c\u5e76\u6ca1\u6709\u4fdd\u6301\u539f\u59cb\u6bd4\u4f8b\uff0c\u8fd9\u5c31\u662f\u548c<img><\/code>\u7684\u533a\u522b\u3002<\/p>\n
Canvas\u7ed8\u5236\u4e0eCSS\u5c3a\u5bf8\u65e0\u5173<\/h4>\n
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<canvas height=\"150\" style=\"background:green; height:88px;\"><\/canvas><\/pre>\n
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var canvas = document.querySelector('canvas');\nvar context = canvas.getContext('2d');\ncontext.fillStyle = 'orange';\ncontext.arc(150, 75, 75, 0, 2 * Math.PI);\ncontext.fill();<\/pre>\n
\u5b9e\u65f6\u6548\u679c\u5982\u4e0b\uff1a<\/p>\n
<\/canvas><\/p>\n