{"id":6165,"date":"2017-05-17T01:09:02","date_gmt":"2017-05-16T17:09:02","guid":{"rendered":"http:\/\/www.zhangxinxu.com\/wordpress\/?p=6165"},"modified":"2017-11-30T17:43:39","modified_gmt":"2017-11-30T09:43:39","slug":"canvas-picture-watermark-synthesis","status":"publish","type":"post","link":"https:\/\/www.zhangxinxu.com\/wordpress\/2017\/05\/canvas-picture-watermark-synthesis\/","title":{"rendered":"\u5c0ftips:\u4f7f\u7528canvas\u5728\u524d\u7aef\u5b9e\u73b0\u56fe\u7247\u6c34\u5370\u5408\u6210"},"content":{"rendered":"

by zhangxinxu<\/a> from http:\/\/www.zhangxinxu.com\/wordpress\/?p=6165<\/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

\u56fe\u7247\u5408\u6210\u6700\u5e38\u89c1\u7684\u9700\u6c42\u6709\u9a8c\u8bc1\u7801\u56fe\u7247\uff0c\u4ea6\u6216\u8005\u56fe\u7247\u52a0\u6c34\u5370\u7b49\uff0c\u8fd9\u79cd\u5b9e\u73b0\u4e00\u822c\u90fd\u662f\u540e\u7aef\u5b9e\u73b0\u7684\u3002<\/p>\n

\u968f\u7740HTML5\u53d1\u5c55\u548c\u73b0\u4ee3\u6d4f\u89c8\u5668\u7684\u5360\u6bd4\u8d8a\u6765\u8d8a\u9ad8\uff0c\u6211\u4eec\u5176\u5b9e\u4e5f\u53ef\u4ee5\u5728\u524d\u7aef\u76f4\u63a5\u8fdb\u884c\u56fe\u7247\u7684\u5408\u6210\u3002\u4f18\u70b9\u5728\u4e8e\uff0c\u54cd\u5e94\u66f4\u5feb\uff0c\u4f53\u9a8c\u66f4\u597d\uff1b\u5982\u679c\u662f\u548c\u6587\u5b57\u8fdb\u884c\u5408\u6210\uff0c\u6211\u4eec\u53ef\u4ee5\u5229\u7528\u5ba2\u6237\u7aef\u5b57\u4f53\uff0c\u89c6\u89c9\u5c55\u73b0\u6548\u679c\u66f4\u4e30\u5bcc\uff1b\u540c\u65f6\u5c55\u793a\u548c\u5408\u6210\u5168\u90e8\u90fd\u662f\u524d\u7aef\u5b8c\u6210\uff0c\u56e0\u6b64\u66f4\u5229\u4e8e\u7ef4\u62a4\u3002<\/p>\n

\u8fd9\u91cc\u901a\u8fc7\u4e3e\u4e2a\u4f8b\u5b50\uff0c\u6f14\u793a\u5982\u4f55\u5728\u524d\u7aef\u5b9e\u73b0\u591a\u4e2a\u56fe\u7247\u5408\u6210\u7684\u6548\u679c\uff0c\u4e3b\u8981\u662f\u501f\u52a9HTML5 canvas<\/code>\u76f8\u5173\u6280\u672f\u3002<\/p>\n

\u4e00\u3001\u4f7f\u7528canvas\u5728\u524d\u7aef\u5b9e\u73b0\u56fe\u7247\u6c34\u5370\u5408\u6210<\/h3>\n

\u5982\u679c\u4ec5\u4ec5\u662f\u666e\u901a\u7684\u5408\u6210\uff0c\u4f8b\u5982\u4e00\u4e2a\u5e95\u56fe\u548c\u4e00\u4e2aPNG\u6c34\u5370\u56fe\u7247\u5408\u6210\uff0c\u76f4\u63a5\u4f7f\u7528canvas<\/code>\u7684drawImage()<\/code>\u65b9\u6cd5\u5373\u53ef\uff0c\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n

context.drawImage(img,x,y);\ncontext.drawImage(img,x,y,width,height);\ncontext.drawImage(img,sx,sy,swidth,sheight,x,y,width,height);<\/pre>\n
\u5404\u4e2a\u53c2\u6570\u793a\u610f\u4e3a\uff1a<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n
\u53c2\u6570<\/th>\n\u63cf\u8ff0<\/th>\n<\/tr>\n
img<\/i><\/td>\n\u7528\u6765\u88ab\u7ed8\u5236\u7684\u56fe\u50cf\u3001\u753b\u5e03\u6216\u89c6\u9891\u3002<\/td>\n<\/tr>\n
sx<\/i><\/td>\n\u53ef\u9009\u3002img\u88ab\u7ed8\u5236\u533a\u57df\u7684\u8d77\u59cb\u5de6\u4e0ax\u5750\u6807\u3002<\/td>\n<\/tr>\n
sy<\/i><\/td>\n\u53ef\u9009\u3002img\u88ab\u7ed8\u5236\u533a\u57df\u7684\u8d77\u59cb\u5de6\u4e0ay\u5750\u6807\u3002<\/td>\n<\/tr>\n
swidth<\/i><\/td>\n\u53ef\u9009\u3002img\u88ab\u7ed8\u5236\u533a\u57df\u7684\u5bbd\u5ea6\uff08\u5982\u679c\u6ca1\u6709\u540e\u9762\u7684width\u6216height\u53c2\u6570\uff0c\u5219\u53ef\u4ee5\u4f38\u5c55\u6216\u7f29\u5c0f\u56fe\u50cf\uff09\u3002<\/td>\n<\/tr>\n
sheight<\/i><\/td>\n\u53ef\u9009\u3002img\u88ab\u7ed8\u5236\u533a\u57df\u7684\u9ad8\u5ea6\uff08\u5982\u679c\u6ca1\u6709\u540e\u9762\u7684width\u6216height\u53c2\u6570\uff0c\u5219\u53ef\u4ee5\u4f38\u5c55\u6216\u7f29\u5c0f\u56fe\u50cf\uff09\u3002<\/td>\n<\/tr>\n
x<\/i><\/td>\n\u753b\u5e03\u4e0a\u653e\u7f6eimg\u7684\u8d77\u59cbx\u5750\u6807\u3002<\/td>\n<\/tr>\n
y<\/i><\/td>\n\u753b\u5e03\u4e0a\u653e\u7f6eimg\u7684\u8d77\u59cby\u5750\u6807\u3002<\/td>\n<\/tr>\n
width<\/i><\/td>\n\u53ef\u9009\u3002\u753b\u5e03\u4e0a\u653e\u7f6eimg\u63d0\u4f9b\u7684\u5bbd\u5ea6\uff08\u53ef\u80fd\u4f1a\u6709\u56fe\u7247\u526a\u88c1\u6548\u679c\uff09\u3002<\/td>\n<\/tr>\n
height<\/i><\/td>\n\u53ef\u9009\u3002\u753b\u5e03\u4e0a\u653e\u7f6eimg\u63d0\u4f9b\u7684\u9ad8\u5ea6\uff08\u53ef\u80fd\u4f1a\u6709\u56fe\u7247\u526a\u88c1\u6548\u679c\uff09\u3002<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u800cPNG\u6c34\u5370\u56fe\u7247\u7684\u5408\u6210\uff0c\u76f4\u63a5\u8fde\u7eed\u5728\u4f7f\u7528drawImage()<\/code>\u628a\u5bf9\u5e94\u7684\u56fe\u7247\u7ed8\u5236\u5230canvas<\/code>\u753b\u5e03\u4e0a\u5c31\u53ef\u4ee5\uff0c\u539f\u7406\u5c31\u662f\u8fd9\u4e48\u7b80\u5355\u3002<\/p>\n
\u6211\u4eec\u76f4\u63a5\u6848\u4f8b\u5427\uff0c\u60a8\u53ef\u4ee5\u72e0\u72e0\u5730\u70b9\u51fb\u8fd9\u91cc\uff1aJS canvas\u6c34\u5370\u56fe\u7247\u5408\u6210demo<\/a><\/p>\n
demo\u9875\u9762\u7684\u529f\u80fd\u5982\u4e0b\uff1a<\/p>\n
    \n
  1. \u9009\u62e9\u81ea\u5df1\u7535\u8111\u4e2d\u7684\u56fe\u7247\uff1b<\/li>\n
  2. \u5408\u6210\uff1b<\/li>\n<\/ol>\n
    \u4f8b\u5982\uff0c\u6211\u4eec\u70b9\u51fb\u201c\u9009\u62e9\u56fe\u7247\u201d\u6309\u94ae\uff0c\u5982\u4e0b\u622a\u56fe\uff1a<\/p>\n
    \"\u9009\u62e9\u56fe\u7247\"<\/p>\n
    \u9009\u62e9\u4e00\u5f20\u5c0f\u4e8e50K\u7684\u56fe\u7247\uff0c\u4f8b\u5982\u8fd9\u5f20\uff1a
    \n\"\u56fe\u7247\u9009\u62e9\u793a\u610f\"<\/p>\n
    \u7ed3\u679c\u53d8\u6210\u8fd9\u6837\u5b50\uff0c\u767d\u8272\u7684YUX\u5b57\u6837\u662f\u540e\u6765\u5408\u6210\u4e0a\u53bb\u7684\uff1a<\/p>\n
    \"\u5408\u6210\u540e\u9884\u89c8\u6548\u679c\u56fe\"<\/p>\n
    \u4e0d\u8981\u7591\u60d1\u4e3a\u4ec0\u4e48\u4e0d\u4f7f\u7528\u8fd9\u5f20\u56fe\u7247\uff1f<\/p>\n
    <\/p>\n
    \u56e0\u4e3a\u56fe\u7247\u6709\u5927\u7247\u6d45\u8272\u533a\u57df\uff0c\u6c34\u5370\u770b\u4e0d\u6e05\u695a\u3002<\/p><\/blockquote>\n
    \u6b64\u65f6\uff0c\u6211\u4eec\u76f4\u63a5\u53f3\u952e\u5c31\u53ef\u4ee5\u4fdd\u5b58\u8fd9\u5f20\u5408\u6210\u7684\u56fe\u7247\u4e86\uff1a
    \n\"\u53f3\u952e\u4fdd\u5b58\u56fe\u7247\u793a\u610f\"<\/p>\n
    \"\u4fdd\u5b58\u5230\u684c\u9762\u7684\u56fe\u7247\u4fe1\u606f\u5c55\u793a\"<\/p>\n
    \u6b64demo\u67093<\/code>\u5904\u9700\u8981\u7279\u522b\u8bf4\u660e\u7684\u6280\u672f\u70b9\uff0c\u4e00\u662f\u672c\u5730\u9009\u62e9\u56fe\u7247\u8f6c\u5316\u6210base64<\/code>\u5730\u5740\uff0c\u76f8\u5173\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
    inputFile.addEventListener('change', function (event) {\n    var reader = new FileReader();\n    var file = event.target.files[0];\n    reader.onload = function(e) {\n      var base64 = e.target.result;\n    };\n    reader.readAsDataURL(file);\n});<\/pre>\n
    \u4e3b\u8981\u662f\u501f\u52a9HTML5 FileReader<\/code>\u8bfb\u53d6\u6587\u4ef6\u7684base64\u4fe1\u606f\uff1b<\/p>\n
    \u4e8c\u662f\u628a\u8fd9\u4e2a\u56fe\u7247\u7684base64\u5730\u5740\u7ed8\u5236\u5230canvas\u753b\u5e03\u4e0a\uff0c\u6838\u5fc3JS\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
    var canvas = document.createElement('canvas');\nvar context = canvas.getContext('2d');\n\n\/\/ \u8fd9\u662f\u4e0a\u4f20\u56fe\u50cf<\/span>\nvar imgUpload = new Image();\nimgUpload.onload = function () {\n    \/\/ \u7ed8\u5236<\/span>\n    context.drawImage(imgUpload, 0, 0, 180, 180);\n};\nimgUpload.src = base64;<\/pre>\n
    \u4e09\u662f\u5728\u5df2\u7ecf\u7ed8\u5236\u597d\u4e86\u672c\u5730\u56fe\u7247\u7684\u753b\u5e03\u4e0a\u7ee7\u7eed\u753b\u6c34\u5370\u56fe\u7247\uff0c\u5e76\u501f\u52a9canvas\u7684toDataURL()<\/code>\u65b9\u6cd5\u628a\u6211\u4eec\u7684canvas<\/code>\u753b\u5e03\u8f6c\u6362\u6210base64<\/code>\u65e0\u635fPNG\u5730\u5740\u3002\u5047\u8bbe\u6c34\u5370\u56fe\u7247DOM\u5bf9\u8c61\u540d\u79f0\u662feleImgCover<\/code>\uff0c\u5219\uff1a<\/p>\n
    \/\/ \u7ed8\u5236<\/span>\ncontext.drawImage(imgUpload, 0, 0, 180, 180);\n\/\/ \u518d\u6b21\u7ed8\u5236\u6c34\u5370<\/span>\ncontext.drawImage(eleImgCover, 0, 0, 180, 180);\n\/\/ \u6b64\u65f6canvas.toDataURL('image\/png')\u7684\u7ed3\u679c\u5c31\u662f\u6700\u7ec8\u5408\u6210\u7684base64\u56fe\u7247\u4fe1\u606f<\/span>\n\nvar finalResult = canvas.toDataURL('image\/png');<\/pre>\n
    \u66f4\u5b8c\u6574\u7684\u4ee3\u7801\u53c2\u89c1demo\u6f14\u793a\u9875\u9762\u3002<\/p>\n
    \u4e09\u3001\u7ed3\u675f\u8bed<\/h3>\n
    \u65b0\u6d6a\u5fae\u535a\u4eca\u5929\u8d22\u62a5\u5f88\u9753\u4e3d\uff0c\u4e00\u5929\u80a1\u4ef7\u6da8\u4e8620%, \u6211\u6574\u4e2a\u4eba\u987f\u65f6\u5c31\u4e0d\u597d\u4e86\uff01<\/p>\n
    \"\u5fae\u535a\u80a1\u4ef7\"<\/p>\n
    \u5012\u4e0d\u662f\u56e0\u4e3a\u6211\u6ca1\u4e70\u5fae\u535a\u7684\u80a1\u7968\uff0c\u800c\u662f\u8ba9\u6211\u5bf9\u4eba\u751f\u4ea7\u751f\u4e86\u6000\u7591\uff0c\u65b0\u6d6a\u5fae\u535a\u4ea7\u54c1\u505a\u7684\u8fd9\u4e48\u5dee\uff0c\u524d\u7aef\u8fd9\u5757\u4f53\u9a8c\u4e5f\u662f\u95ee\u9898\u591a\u591a\uff0c\u6027\u80fd\u4e5f\u4e0d\u548b\u5730\uff0c\u4f46\u662f\u8fd9\u8d5a\u94b1\u80fd\u529b\uff0c\u7528\u6237\u91cf\u6e9c\u5f97\u98de\u8d77\u3002\u8ba9\u6211\u611f\u89c9\uff0c\u524d\u7aef\u6280\u672f\u5b66\u5f97\u518d\u624e\u5b9e\uff0c\u4f53\u9a8c\u505a\u5f97\u518d\u6781\u81f4\u597d\u50cf\u4e5f\u6ca1\u6709\u4ec0\u4e48\u5375\u7528\uff0c\u79ef\u6781\u6027\u53d7\u5230\u4e86\u5f71\u54cd\uff0c\u4e09\u89c2\u4ea7\u751f\u4e86\u52a8\u6447\u3002<\/p>\n
    \u4e0d\u8fc7\uff0c\u5f88\u5feb\u6211\u5c31\u91ca\u7136\u4e86\u3002\u5c31\u597d\u50cf\u4e00\u4e2a\u957f\u5f97\u5f88\u4e0d\u600e\u4e48\u6837\uff0c\u6709\u6ca1\u6709\u4ec0\u4e48\u94b1\u7684\u7537\u7684\uff0c\u5a36\u4e86\u4e2a\u82b1\u4ed9\u5b50\uff0c\u4e0d\u8981\u6000\u7591\u4eba\u751f\uff0c\u6709\u53ef\u80fd\u4eba\u5bb6\u4e0b\u76d8\u5185\u529f\u597d\u5f97\u60ca\u4eba\uff01\u5927\u591a\u6570\u4eba\u4e0b\u76d8\u5185\u529f\u90fd\u662f\u666e\u901a\u6c34\u51c6\uff0c\u6b64\u65f6\u5982\u679c\u5916\u5728\u8fd8\u53c8\u4e0d\u600e\u4e48\u6837\uff0c\u90a3\u5c31\u771f\u7684\u5c31\u60e8\u4e86\uff0c\u5929\u5929\u53ea\u6709\u770b\u522b\u4eba\u6492\u7cd6\uff0c\u81ea\u5df1\u72ec\u81ea\u5403\u72d7\u7cae\u7684\u4efd\u3002<\/p>\n
    \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
    \n\u672c\u6587\u5730\u5740\uff1a    http:\/\/www.zhangxinxu.com\/wordpress\/?p=6165<\/a><\/p>\n
    \uff08\u672c\u7bc7\u5b8c\uff09<\/p>\n","protected":false},"excerpt":{"rendered":"
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