{"id":6594,"date":"2017-12-09T22:20:49","date_gmt":"2017-12-09T14:20:49","guid":{"rendered":"http:\/\/www.zhangxinxu.com\/wordpress\/?p=6594"},"modified":"2019-08-03T15:32:45","modified_gmt":"2019-08-03T07:32:45","slug":"canvas-getimagedata-letter-shape-animation","status":"publish","type":"post","link":"https:\/\/www.zhangxinxu.com\/wordpress\/2017\/12\/canvas-getimagedata-letter-shape-animation\/","title":{"rendered":"canvas\u5b9e\u73b0\u4efb\u610f\u5b57\u7b26\u56fe\u5f62\u7684\u6253\u70b9\u6216\u8fde\u7ebf\u52a8\u753b"},"content":{"rendered":"

by zhangxinxu<\/a> from https:\/\/www.zhangxinxu.com\/wordpress\/?p=6594<\/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\u3001\u52a8\u6001\u5b57\u7b26\u6216\u56fe\u50cf\u7684\u8fde\u7ebf\u52a8\u753b<\/h3>\n

\u9996\u5148\u89c1\u4e0b\u9762gif\u6548\u679c\u622a\u5c4f\uff1a<\/p>\n

\"5\u8fd9\u4e2a\u5b57\u7b26\u8fde\u7ebf\u52a8\u753b\u793a\u610f\"<\/p>\n

\u4e5f\u5c31\u662f\u6211\u5728\u8f93\u5165\u6846\u4e2d\u8f93\u5165\u4e00\u4e2a\u5b57\u7b26'5'<\/code>\uff0c\u7136\u540e\u56de\u8f66\uff0c\u9875\u9762\u4e0a\u5c31\u4f1a\u4ee5\u8fde\u7ebf\u7684\u65b9\u5f0f\u628a\u8fd9\u4e2a\u5b57\u7b26'5'<\/code>\u7ed9\u5448\u73b0\u51fa\u6765\u3002<\/p>\n

\u4e0a\u9762\u6f14\u793a\u6548\u679c\u6709\u5bf9\u5e94\u7684demo\u9875\u9762\uff0c\u60a8\u53ef\u4ee5\u72e0\u72e0\u7684\u70b9\u51fb\u8fd9\u91cc\uff1a\u4efb\u610f\u5b57\u7b26\u56fe\u5f62\u8fde\u7ebf\u751f\u6210\u52a8\u6548demo<\/a><\/p>\n

\u4e0d\u4ec5\u4ec5\u662f\u5b57\u7b26\uff0c\u6211\u4eec\u8fd8\u53ef\u4ee5\u9009\u62e9\u672c\u5730\u56fe\u7247\u8fdb\u884c\u56fe\u5f62\u751f\u6210\u3002<\/p>\n

\u4f8b\u5982\u6709\u4e00\u4e2a\u624b\u6307PNG\u56fe\u6807\u5982\u4e0b\u56fe\u6548\u679c\uff1a<\/p>\n

<\/p>\n

\u5728demo\u9875\u9762\u4e2d\uff0c\u6211\u4eec\u9009\u62e9\u8fd9\u5f20\u56fe\uff1a<\/p>\n

\"\u9009\u62e9\u56fe\u7247\u793a\u610f\"<\/p>\n

\u7136\u540e\u6548\u679c\u4e3a\uff1a<\/p>\n

\"\u9009\u62e9\u624b\u6307\u56fe\u6807\u540e\u7684\u6548\u679c\"<\/p>\n

\u4e0b\u9762\u7b80\u5355\u8bb2\u4e0b\u5b9e\u73b0\u539f\u7406\uff0c\u4ee5\u53ca\u62d3\u5c55\u51fa\u6765\u5176\u5b83\u597d\u73a9\u4e1c\u897f\u3002<\/p>\n

\u4e8c\u3001canvas getImageData\u4e0e\u56fe\u5f62\u4fe1\u606f\u83b7\u53d6<\/h3>\n

\u8fd9\u79cd\u52a8\u6001\u5185\u5bb9\u52a8\u6548\u5b9e\u73b0\u4e3b\u8981\u96be\u70b9\u5728\u4e8e\u5982\u679c\u51c6\u786e\u83b7\u5f97\u56fe\u5f62\u5750\u6807\u3002<\/p>\n

\u5b9e\u73b0\u539f\u7406\u5982\u4e0b\uff1a<\/p>\n

    \n
  1. \u5b57\u7b26\u6216\u56fe\u5f62\u7ed8\u5236\u5728canvas\u4e0a\uff1b<\/li>\n
  2. \u4f7f\u7528getImageData\u65b9\u6cd5\u83b7\u53d6canvas\u6240\u6709\u50cf\u7d20\u70b9\u4fe1\u606f\uff1b<\/li>\n
  3. \u4ee5\u56fa\u5b9a\u95f4\u9699\u904d\u5386\u8fd9\u4e9b\u50cf\u7d20\u70b9\uff0c\u975e\u900f\u660e\u50cf\u7d20\u70b9\u4f4d\u7f6e\u4f5c\u4e3a\u52a8\u6548\u5173\u952e\u70b9\u5750\u6807\uff1b<\/li>\n
  4. \u62ff\u5230\u8fd9\u4e2a\u52a8\u6548\u5173\u952e\u70b9\u5750\u6807\uff0c\u505a\u8fde\u7ebf\u52a8\u753b\u6548\u679c\uff0c\u6216\u8005\u5b9e\u73b0\u5176\u5b83\u6548\u679c\u3002<\/li>\n<\/ol>\n

    \u4ee5\u4e0a\u9762\u7684demo\u4e3a\u4f8b\uff0c\u6211\u4eec\u770b\u4e0b\u4e0a\u97624\u6b65\u539f\u7406\u662f\u5982\u4f55\u8d70\u4e0b\u6765\u7684\u3002<\/p>\n

    1. \u7ed8\u5236<\/h4>\n

    \u5982\u679c\u662f\u5b57\u7b26\uff0c\u4f7f\u7528fillText()<\/code>\u65b9\u6cd5\u628a\u5b57\u7b26\u7ed8\u5236\u5728canvas\u753b\u5e03\u4e0a\uff1b\u5982\u679c\u662f\u56fe\u7247\uff0c\u4f7f\u7528drawImage()<\/code>\u65b9\u6cd5\u628a\u56fe\u7247\u7ed8\u5236\u5728canvas\u753b\u5e03\u4e0a\u3002<\/p>\n

    fillText()<\/code>\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n

    context.fillText(text, x, y, maxWidth);<\/pre>\n
    \u5176\u4e2d\uff0ctext<\/code>\u8868\u793a\u9700\u8981\u7ed8\u5236\u7684\u6587\u672c\u5185\u5bb9\uff0cx, y<\/code>\u4e3a\u6587\u672c\u7ed8\u5236\u7684\u5750\u6807\u4f4d\u7f6e\uff0cmaxWidth<\/code>\u662f\u53ef\u9009\u53c2\u6570\uff0c\u6211\u662f\u8fd9\u6bb5\u6587\u672c\u6240\u5360\u636e\u7684\u6700\u5927\u5bbd\u5ea6\u3002<\/p>\n
    canvas<\/code>\u4e2d\u7684\u6587\u672c\u7ed8\u5236\u548cCSS\/HTML\u4e2d\u7684\u6587\u672c\u5448\u73b0\u6709\u4e0d\u5c11\u533a\u522b\uff0c\u5176\u4e2d\u6700\u5178\u578b\u7684\u533a\u522b\u4e4b\u4e00\u5c31\u662f\u5b83\u4e0d\u4f1a\u81ea\u52a8\u6362\u884c\uff0c\u8fd9\u91cc\u7684maxWidth<\/code>\u5e76\u4e0d\u662f\u8868\u793a\u6587\u672c\u8d85\u8fc7\u8fd9\u4e2a\u5bbd\u5ea6\u4f1a\u81ea\u52a8\u6362\u884c\uff0c\u800c\u662f\u6587\u672c\u4f1a\u81ea\u52a8\u6536\u7f29\u53d8\u7a84\uff0c\u5c31\u50cf\u88ab\u95e8\u6324\u4e86\u4e00\u6837\uff0c\u4fdd\u8bc1\u4e00\u884c\u663e\u793a\u540c\u65f6\u5bbd\u5ea6\u4e0d\u8d85\u8fc7\u8fd9\u4e2a\u9650\u5236\uff08\u4e0b\u56fe\u793a\u610f\uff09\u3002<\/p>\n
    \"canvas\u6587\u672c\u7ed8\u5236\u8d85\u51fa\u5bbd\u5ea6\u663e\u793a\u540e\u6536\u7f29\u6548\u679c\"<\/p>\n
    drawImage()<\/code>\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n
    context.drawImage(img, dx, dy);\r\ncontext.drawImage(img, dx, dy, dWidth, dHeight);\r\ncontext.drawImage(img, sx, sy, sWidth, sHeight, dx, dy, dWidth, dHeight);<\/pre>\n
    \u5177\u4f53\u89e3\u91ca\uff08\u5305\u542b\u5982\u4f55\u672c\u5730\u56fe\u7247\u7ed8\u5236\u5230canvas\u4e0a\uff09\u53ef\u4ee5\u53c2\u89c1\u8fd9\u7bc7\u6587\u7ae0\u201ccanvas\u5b9e\u73b0\u56fe\u7247\u524d\u7aefJS\u538b\u7f29\u5e76\u4e0a\u4f20<\/a>\u201d\u7b2c\u4e09\u6bb5\uff0c\u8fd9\u91cc\u4e0d\u8d58\u8ff0\u3002<\/p>\n
    2. \u50cf\u7d20\u70b9\u4fe1\u606f\u83b7\u53d6<\/h4>\n
    \u8fd9\u91cc\u4e3b\u8981\u4ecb\u7ecd\u4e0bgetImageData()<\/code>\u65b9\u6cd5\uff0c\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n
    context.getImageData(sx, sy, sw, sh);<\/pre>\n
    \u5176\u4e2d\uff0csx, sy<\/code>\u8868\u793a\u4f60\u60f3\u83b7\u53d6\u7684\u50cf\u7d20\u4fe1\u606f\u533a\u57df\u7684\u5de6\u4e0a\u89d2\u5750\u6807\uff0csw, sh<\/code>\u8868\u793a\u4f60\u60f3\u83b7\u53d6\u7684\u50cf\u7d20\u4fe1\u606f\u533a\u57df\u7684\u5bbd\u5ea6\u548c\u9ad8\u5ea6\u3002<\/p>\n
    \u4f8b\u5982\u4e00\u4e2acanvas\u7684\u5c3a\u5bf8\u662f320*320\uff0c\u5219context.getImageData(10, 10, 100, 100)<\/code>\uff0c\u5c31\u662f\u8868\u793a\u83b7\u53d6canvas\u5de6\u4e0a\u89d210px, 10px<\/code>\u5bbd\u5ea6100px<\/code>\u9ad8\u5ea6100px<\/code>\u7684\u77e9\u5f62\u533a\u57df\u7684\u50cf\u7d20\u70b9\u4fe1\u606f\u3002<\/p>\n
    getImageData()<\/code>\u65b9\u6cd5\u8fd4\u56de\u7684\u662f\u4e00\u4e2aImageData<\/code>\u5bf9\u8c61\uff0c\u5305\u62ecwidth<\/code>, height<\/code>\u4ee5\u53cadata<\/code>\u4e09\u4e2a\u5c5e\u6027\u3002\u901a\u5e38\u6211\u4eec\u5bf9\u50cf\u7d20\u70b9\u8fdb\u884c\u5904\u7406\uff0c\u9700\u8981\u7684\u662f\u540e\u9762\u7684data<\/code>\u5c5e\u6027\u3002<\/p>\n
    \u4f8b\u5982\uff1a<\/p>\n
    var imageData = context.getImageData(0, 0, canvas.width, canvas.height);<\/pre>\n
    \u5219imageData.data<\/code>\u5c31\u662f\u6211\u4eec\u9700\u8981\u7684\u50cf\u7d20\u70b9\u4fe1\u606f\u6570\u7ec4\uff0c\u662f\u4e2a\u4e00\u7ef4\u6570\u7ec4\uff0c\u7c7b\u578b\u4e3aUint8ClampedArray<\/code>\uff0cUint\u8868\u793a\u81ea\u7136\u6570\uff0c8<\/code>\u53ef\u4ee5\u7406\u89e3\u4e3a\u6570\u503c\u8303\u56f4\u4e0d\u8d85\u8fc72<\/code>\u76848<\/code>\u6b21\u65b9\uff0c\u4e5f\u5c31\u662f\u4e0d\u8d85\u8fc7256<\/code>\u3002\u6240\u4ee5\u8fd9\u4e2a\u6570\u7ec4\u4e2d\u6240\u6709\u7684\u503c\u8303\u56f4\u90fd\u662f0~255<\/code>\u3002<\/p>\n
    imageData.data<\/code>\u8fd9\u4e2a\u6570\u7ec4\u8868\u793a\u7684\u662f\u50cf\u7d20\u70b9\u7684RGBA\u989c\u8272\u4fe1\u606f\uff0c\u7531\u4e8e\u7c7b\u578b\u4e3a\u4e00\u7ef4\u6570\u7ec4\uff0c\u56e0\u6b64\uff0cRGBA\u989c\u8272\u4fe1\u606f\u88ab\u6309\u987a\u5e8f\u4f5c\u4e3a4\u4e2a\u72ec\u7acb\u7684\u6570\u7ec4\u9879\u4f9d\u6b21\u6392\u5217\u7684\u3002<\/p>\n
    \u52a0\u4e0a\u4e00\u5f20\u56fe\u7247\uff0c\u53ea\u6709\u4e24\u4e2a\u50cf\u7d20\u70b9\uff0c\u5206\u522b\u662f\u7eaf\u9ed1\u8272\u548c\u7eaf\u767d\u8272\uff0c\u4f7f\u7528CSS3\u7684RGBA\u989c\u8272\u8868\u793a\u5c31\u662frgba(0,0,0,1)\u4ee5\u53cargba(255,255,255,1)\uff0c\u5176\u4e2dRGB\u989c\u8272\u548ccanvas\u4e2d\u7684ImageData\u8303\u56f4\u4e00\u81f4\uff0c\u662f0~255<\/code>\uff0c\u4f46\u8fd9\u4e2a\u4e0e\u900f\u660e\u5ea6\u76f8\u5173\u7684A\u9700\u8981\u8f6c\u6362\u4e0b\uff0c0->0<\/code>\uff0c1->255<\/code>\u3002<\/p>\n
    \u6240\u4ee5\uff0c\u5982\u679c\u6211\u4eec\u4f7f\u7528getImageData()<\/code>\u83b7\u53d6\u8fd9\u4e24\u4e2a\u50cf\u7d20\u70b9\u4fe1\u606f\uff0c\u5219imageData.data<\/code>\u6570\u7ec4\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n
    [0,0,0,255,255,255,255,255]<\/pre>\n
    \u51718\u9879\uff0c\u6bcf4\u9879\u8868\u793a\u4e00\u4e2a\u50cf\u7d20\u70b9\u4fe1\u606f\u3002<\/p>\n
    3. \u5173\u952e\u5750\u6807\u83b7\u53d6<\/h4>\n
    \u7b97\u6cd5\u5982\u4e0b\uff0c\u6c34\u5e73\u548c\u5782\u76f4\u65b9\u5411\u5747\u4ee5\u56fa\u5b9a\u95f4\u9699\u53bb\u8bfb\u53d6imageData<\/code>\u50cf\u7d20\u70b9\u4fe1\u606f\uff0c\u5982\u679c\u662f\u5b8c\u5168\u4e0d\u900f\u660e\u7684\u50cf\u7d20\u70b9\uff0c\u5219\u4f5c\u4e3a\u6211\u4eec\u9700\u8981\u7684\u5173\u952e\u5750\u6807\u4fdd\u5b58\u4e0b\u6765\u3002<\/p>\n
    \u76f8\u5173JS\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
    var imgData = context.getImageData(0,0,width,height).data;\r\n\/\/ \u95f4\u9699\u5927\u5c0f\u4e3a13<\/span>\r\nvar gap = 13;\r\nvar pos = [];\r\nvar x = 0, y = 0, index = 0;\r\nfor (var i=0; i<imgData.length; i+=(4*gap)) {\r\n    if (imgData[i+3] == 255) {\r\n        \/\/ \u585e\u5165\u6b64\u65f6\u7684\u5750\u6807<\/span>\r\n        pos.push({\r\n            x: x,\r\n            y: y\r\n        });\r\n    }\r\n    index = Math.floor(i \/ 4);\r\n    x = index % width;\r\n    y = Math.floor(index \/ width);\r\n    if (x >= width - gap) {\r\n        i += gap * 4 * width;\r\n    }\r\n}\r\n\r\n\/\/ pos\u5c31\u662f\u6211\u4eec\u9700\u8981\u7684\u5173\u952e\u70b9\u5750\u6807\u96c6\u5408<\/span><\/pre>\n
    \u8fd9\u91cc\u7684\u95f4\u9699\u5927\u5c0f\u9009\u53d6\u8fd8\u662f\u503c\u5f97\u4e00\u8bf4\u7684\uff0c\u4e5f\u5c31\u662f\u8fd9\u91cc\u7684gap<\/code>\u53d8\u91cf\u503c\u5e94\u8be5\u9009\u591a\u5927\uff0c\u6839\u636e\u7814\u7a76\u548c\u6d4b\u8bd5\u53d1\u73b0\uff0c\u6211\u4eec\u7684\u95f4\u9699\u9009\u53d6\u8d28\u6570\u65f6\u5019\u7684\u5448\u73b0\u6548\u679c\u8981\u597d\u4e00\u4e9b\uff0c13<\/code>\u5c31\u662f\u4e00\u4e2a\u975e\u5e38\u68d2\u7684\u8d28\u6570\u3002<\/p>\n
    4. \u5750\u6807\u4e0e\u52a8\u6548\u5448\u73b0<\/h4>\n
    \u6709\u4e86\u56fa\u5b9a\u95f4\u9694\u7684\u5173\u952e\u70b9\u5750\u6807\uff0c\u4e0b\u9762\u5c31\u662f\u52a8\u6548\u5448\u73b0\u4e86\uff0c\u6b64\u65f6\uff0c\u53ef\u4f9b\u6211\u4eec\u53d1\u6325\u7684\u7a7a\u95f4\u5c31\u5f88\u5927\u4e86\u3002<\/p>\n
    \u4f8b\u5982\uff0c\u6211\u4eec\u53ef\u4ee5\u501f\u52a9SVG\u7684stroke<\/code>\u63cf\u8fb9\u52a8\u753b\u6765\u8f7b\u677e\u5b9e\u73b0\u6211\u4eec\u7684\u8fde\u7ebf\u52a8\u753b\u6548\u679c\u3002<\/p>\n
    \u4e09\u3001SVG\u63cf\u8fb9\u52a8\u753b\u4e0e\u8fde\u7ebf\u52a8\u6548<\/h3>\n
    \u5173\u4e8eSVG\u8def\u5f84\u63cf\u8fb9\u52a8\u753b\u6280\u672f\u53ef\u4ee5\u53c2\u89c1\u6211\u4e4b\u524d\u5199\u7684\u201c\u7eafCSS\u5b9e\u73b0\u5e05\u6c14\u7684SVG\u8def\u5f84\u63cf\u8fb9\u52a8\u753b\u6548\u679c<\/a>\u201d\u4e00\u6587\u3002<\/p>\n
    \u6240\u4ee5\uff0c\u6211\u4eec\u9700\u8981\u70b9CSS\u914d\u5408\uff1a<\/p>\n
    line {\r\n    stroke: rgba(59,166,241,.8);\r\n    stroke-width: .5px;\r\n    transition: stroke-dashoffset 2s ease-in-out;\r\n}<\/pre>\n
    \u7136\u540e\uff0c\u6839\u636e\u5750\u6807\uff0c\u6211\u4eec\u521b\u5efaSVG\u76f4\u7ebf\u5c31\u597d\u4e86\uff0c\u4f7f\u7528<line><\/code>\u5143\u7d20\uff0c\u539f\u7406\u5982\u4e0b\uff08\u4ee5\u4e00\u6839\u7ebf\u793a\u610f\uff09\uff1a<\/p>\n
    var line = document.createElementNS('http:\/\/www.w3.org\/2000\/svg', \"line\");\r\n\/\/ \u8bbe\u7f6e\u8d77\u6b62\u5750\u6807<\/span>\r\nline.setAttribute('x1', x1);\r\nline.setAttribute('y1', y1);\r\nline.setAttribute('x2', x2);\r\nline.setAttribute('y2', y2);\r\n\/\/ \u8bbe\u7f6e\u76f4\u7ebf\u504f\u79fb\u5230\u770b\u4e0d\u89c1<\/span>\r\nline.style.strokeDasharray = distance + \" \" + distance;\r\nline.style.strokeDashoffset = distance;\r\n\r\nsvg.appendChild(line);\r\n\r\n\/\/ \u7136\u540e\u8bbe\u7f6e\u7ebf\u53ef\u4ee5\u770b\u89c1\uff0c\u52a8\u753b\u4ea4\u7ed9CSS3<\/span>\r\nwindow.requestAnimationFrame(function() {\r\n    lines.style.strokeDashoffset = 0;\r\n})\r\n<\/pre>\n
    \u4ee5\u4e0a\u5c31\u662fSVG\u5b9e\u73b0\u8fde\u7ebf\u52a8\u753b\u7684\u539f\u7406\uff0c\u5c31\u8fd9\u6837\u7ed3\u675f\u4e86\uff1f<\/p>\n
    \u7a0d\u7b49\uff0c\u8fd8\u5dee\u4e00\u6b65\uff0c\u90a3\u5c31\u662f\u4e0d\u662f\u6240\u6709\u7684\u70b9\u548c\u70b9\u90fd\u53ef\u4ee5\u4f5c\u4e3a\u7ebf\u8fde\u63a5\uff0c\u4f8b\u5982\uff0c\u5b57\u7b26'5'<\/code>\u7684\u5de6\u4e0a\u89d2\u70b9\u548c\u53f3\u4e0b\u89d2\u70b9\u5c31\u4e0d\u80fd\u8fde\u5728\u4e00\u8d77\uff0c\u5426\u5219\u6548\u679c\u4f1a\u4e71\u5957\u7684\u3002\u6240\u4ee5\u6211\u4eec\u9700\u8981\u5bf9\u4e00\u4e9b\u5750\u6807\u8fdb\u884c\u8fc7\u6ee4\uff0c\u6709\u4e9b\u53ef\u4ee5\u8fde\u7ebf\uff0c\u6709\u4e9b\u4e0d\u884c\uff0c\u5224\u65ad\u7684\u6807\u51c6\u662f\u4e24\u4e2a\u70b9\u4e4b\u95f4\u7684\u8ddd\u79bb\u3002\u5982\u679c\u4e24\u4e2a\u70b9\u4e4b\u95f4\u7684\u8ddd\u79bb\u8d85\u8fc7\u4e00\u5b9a\u7684\u9650\u5236\uff0c\u6211\u4eec\u5c31\u8ba4\u4e3a\u5b83\u5e76\u4e0d\u662f\u6784\u6210\u56fe\u5f62\u6240\u5fc5\u987b\u7684\u8fde\u7ebf\uff0c\u4e8e\u662f\u6574\u6761line<\/code>\u5c31\u820d\u5f03\u6389\u3002<\/p>\n
    \u4f8b\u5982\u672cdemo\u4e2d\uff0c\u6709\u8bbe\u7f6e\uff1a<\/p>\n
    var maxDistance = 31, minDistance = 0;<\/pre>\n
    \u4e5f\u5c31\u662f\u4e24\u4e2a\u70b9\u4e4b\u95f4\u7684\u8ddd\u79bb\uff0c\u5982\u679c\u8d85\u8fc731<\/code>\u50cf\u7d20\uff0c\u5219\u8ba4\u4e3a\u8fd9\u4e24\u4e2a\u70b9\u4e0d\u9002\u5408\u8fde\u7ebf\u3002<\/p>\n
    \u5177\u4f53JS\u4ee3\u7801\u53ef\u4ee5\u53c2\u8003demo\u9875\u9762\u6e90\u4ee3\u7801\u3002<\/p>\n
    \n
    \u867d\u7136\u4f7f\u7528SVG\u5b9e\u73b0\u4efb\u610f\u5b57\u7b26\u56fe\u5f62\u7684\u8fde\u7ebf\u52a8\u753b\u76f8\u5bf9\u7b80\u5355\u4e9b\uff0c\u4f46\u662f\u5728\u5b9e\u9645\u5e94\u7528\u7684\u65f6\u5019\uff0c\u53d1\u73b0\u6709\u4e00\u4e2a\u81f4\u547d\u7684\u95ee\u9898\uff0c\u90a3\u5c31\u662f\u6027\u80fd\u95ee\u9898\uff0c\u5982\u679c\u6211\u4eec\u7684\u8fde\u7ebf\u6570\u76ee\u8d85\u8fc7\u4e24\u767e\uff0c\u751a\u81f3\u66f4\u591a\uff0c\u5219\u5728\u79fb\u52a8\u7aef\uff0c\u5c24\u5176\u4e00\u4e9bAndroid\u8bbe\u5907\uff0c\u80fd\u660e\u663e\u611f\u89c9\u5230\u5361\u987f\u3002<\/p>\n
    \u6240\u4ee5\uff0c\u5b9e\u9645\u5e94\u7528\u7684\u65f6\u5019\uff0c\u8fd8\u662f\u5efa\u8bae\u4f7f\u7528canvas<\/code>\u6280\u672f\u6765\u7ed8\u5236\u6211\u4eec\u7684\u8fde\u7ebf\u3002<\/p>\n
    \u56db\u3001canvas\u4e0e\u52a8\u6001\u5185\u5bb9\u7684\u8fde\u7ebf\u52a8\u753b<\/h3>\n
    \u8fd9\u91cc\u4ecb\u7ecd\u4e00\u4e0b\u5982\u4f55\u4f7f\u7528canvas\u5b9e\u73b0\u6211\u4eec\u7684\u8fde\u7ebf\u52a8\u6548\uff0c\u524d3\u6b65\u539f\u7406\u90fd\u662f\u4e00\u6837\u7684\uff0c\u4e0d\u4e00\u6837\u7684\u662f\u7ebf\u7684\u7ed8\u5236\u3002<\/p>\n
    canvas\u7ed8\u5236\u7ebf\u7684\u76f8\u5173JS\u5982\u4e0b\uff1a<\/p>\n
    context.beginPath();\r\ncontext.moveTo(x1, y1);\r\ncontext.lineTo(x2, y2);\r\ncontext.lineWidth = 0.5;\r\ncontext.strokeStyle = 'rgba(59,166,241,0.5)';\r\ncontext.stroke();<\/pre>\n
    \u7136\u540e\u5957\u7528canvas 2D\u52a8\u6548\u5b9e\u73b0\u7684\u5e38\u7528\u5957\u8def\u5373\u53ef\uff01\u53c2\u89c1\u8fd9\u91cc\uff1a\u201ccanvas 2D\u70ab\u9177\u52a8\u6548\u7684\u5b9e\u73b0\u5957\u8def<\/a>\u201d\u3002<\/p>\n
    \u5982\u679c\u4f60\u6548\u679c\u6025\u7528\uff0c\u6ca1\u65f6\u95f4\u5b66\u4e60\uff0c\u6ca1\u5173\u7cfb\uff0c\u6709\u73b0\u6210\u7684demo\u9875\u9762\u53ef\u4f9b\u53c2\u8003\uff0c\u60a8\u53ef\u4ee5\u72e0\u72e0\u7684\u70b9\u51fb\u8fd9\u91cc\uff1acanvas\u5b9e\u73b0\u4efb\u610f\u56fe\u7247\u548c\u6587\u5b57\u7684\u8fde\u7ebf\u52a8\u753bdemo<\/a><\/p>\n
    \u4f8b\u5982\uff0c\u6211\u8f93\u5165\u4e00\u4e2a\u7231\u5fc3\u5b57\u7b26\uff1a<\/p>\n
    \"canvas\u5b9e\u73b0\u6548\u679c\u622a\u56fe\"<\/p>\n
    \u6027\u80fd\u975e\u5e38\u6d41\u7545\u3002<\/p>\n
    \n
    \u4e0b\u56fe\u662f\u8be5demo\u5730\u5740\u7684\u4e8c\u7ef4\u7801\uff0c\u6709\u5174\u8da3\u53ef\u4ee5\u624b\u673a\u626b\u4e2a\u7801\uff0c\u611f\u53d7\u4e0b\u6027\u80fd\u3002<\/p>\n
    <\/div>\n
    \u4e3a\u4ec0\u4e48\u8981\u9009\u62e9\u8d28\u6570\u5462\uff1f\u56e0\u4e3a\u8d28\u6570\u662f\u4e0d\u80fd\u56e0\u5f0f\u5206\u89e3\u7684\u81ea\u7136\u6570\uff0c\u968f\u7740\u4e0d\u65ad\u5faa\u73af\uff0c\u5176\u201c\u81ea\u7136\u968f\u673a\u6027\u201d\u8981\u6bd4\u975e\u8d28\u6570\u9ad8\uff0c\u8fd9\u79cd\u4ee5\u8d28\u6570\u4f5c\u4e3a\u5faa\u73af\u5468\u671f\u6765\u589e\u52a0\u201c\u81ea\u7136\u968f\u673a\u6027\u201d\u7684\u7b56\u7565\u6709\u4e00\u79cd\u4e13\u95e8\u7684\u79f0\u8c13\uff0c\u53eb\u505a\u201c\u8749\u539f\u5219\u201d\u3002\u6211\u4e4b\u524d\u6709\u4e13\u95e8\u5199\u6587\u7ae0\u4ecb\u7ecd\u8fc7\uff0c\u6709\u5174\u8da3\u53ef\u4ee5\u9605\u8bfb\u4e0b\uff1a\u201c\u8749\u539f\u5219\u201d\u4e0eCSS3\u968f\u673a\u591a\u80cc\u666f\u968f\u673a\u5706\u89d2\u7b49\u6548\u679c<\/a>\u3002<\/p>\n