{"id":34133,"date":"2024-11-25T10:40:04","date_gmt":"2024-11-25T02:40:04","guid":{"rendered":"https:\/\/fwq.ai\/blog\/34133\/"},"modified":"2024-11-25T10:40:04","modified_gmt":"2024-11-25T02:40:04","slug":"%e9%80%9a%e8%bf%87%e5%ae%9e%e4%be%8b%e4%ba%86%e8%a7%a3%e4%b8%80%e4%b8%8b%e5%b0%8f%e7%a8%8b%e5%ba%8f%e4%b8%ad%e6%80%8e%e4%b9%88%e5%ae%9e%e7%8e%b0canvas%e6%8b%96%e5%8a%a8%e5%8a%9f%e8%83%bd","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/34133\/","title":{"rendered":"\u901a\u8fc7\u5b9e\u4f8b\u4e86\u89e3\u4e00\u4e0b\u5c0f\u7a0b\u5e8f\u4e2d\u600e\u4e48\u5b9e\u73b0canvas\u62d6\u52a8\u529f\u80fd"},"content":{"rendered":"

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data\u6570\u636e<\/p>\n
\/\/ \u9f20\u6807\u72b6\u6001\nstatusConfig : {\n      idle: 0,       \/\/\u6b63\u5e38\u72b6\u6001\n      Drag_start: 1, \/\/\u62d6\u62fd\u5f00\u59cb\n      Dragging: 2,   \/\/\u62d6\u62fd\u4e2d\n},\n\/\/ canvas \u72b6\u6001\ncanvasInfo : {\n   \/\/ \u5706\u7684\u72b6\u6001\n   status: 0,\n   \/\/ \u9f20\u6807\u5728\u5728\u5706\u5708\u91cc\u4f4d\u7f6e\u653e\u91cc\u5934\n   dragTarget: null,\n   \/\/ \u70b9\u51fb\u5706\u65f6\u7684\u7684\u4f4d\u7f6e\n   lastEvtPos: {x: null, y: null},\n},<\/pre>\n
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handleCanvasStart(e){\n    \/\/ \u83b7\u53d6\u70b9\u51fb\u70b9\u7684\u4f4d\u7f6e\n    const canvasPosition = this.getCanvasPosition(e);\n    \/\/ \u5224\u65ad\u70b9\u51fb\u70b9\u7684\u4f4d\u7f6e\u5728\u4e0d\u5728\u5708\u91cc\uff0c\u5982\u679c\u4e0d\u5728\u8fd4\u56defalse\uff0c \u5728\u8fd4\u56de\u5706\u7684\u4fe1\u606f\n    const circleRef = this.ifInCircle(canvasPosition);\n    const {canvasInfo, statusConfig} = this.data;\n    \/\/ \u5728\u5706\u91cc\u7684\u8bdd\uff0c\u6539\u53d8\u5706\u6b64\u65f6\u7684\u72b6\u6001\u4fe1\u606f\n    if(circleRef){\n      canvasInfo.dragTarget = circleRef;\n      \/\/\u6539\u53d8\u62d6\u52a8\u72b6\u6001 idle -&gt; Drag_start\n      canvasInfo.status = statusConfig.Drag_start;\n      canvasInfo.lastEvtPos = canvasPosition;\n    }\n    this.setData({\n      canvasInfo\n    })\n  },\n\/\/ \u83b7\u53d6\u70b9\u51fb\u70b9\u7684\u4f4d\u7f6e\ngetCanvasPosition(e){\n    return{\n      x: e.changedTouches[0].x,\n      y: e.changedTouches[0].y\n    }\n},\n\n\/\/ \u770b\u70b9\u51fb\u70b9\u51fb\u70b9\u662f\u4e0d\u662f\u5728\u5708\u91cc\nifInCircle(pos){\n    const {circles} = this.data;\n    for( let i = 0 ; i <p>\u624b\u6307\u89e6\u6478\u540e\u79fb\u52a8 , \u91cd\u65b0\u7ed8\u5236\u5706<\/p><pre class=\"brush:js;toolbar:false;\">handleCanvasMove(e){\n    const canvasPosition = this.getCanvasPosition(e);\n    const {canvasInfo, statusConfig, circles} = this.data;\n    \/\/ \u662f\u62d6\u62fd\u5f00\u59cb\u72b6\u6001\uff0c\u6ed1\u52a8\u7684\u5927\u5c0f\u5927\u4e8e5\uff08\u9632\u6296\uff09\n    if( canvasInfo.status === statusConfig.Drag_start &amp;&amp; \n      this.getDistance(canvasPosition, canvasInfo.lastEvtPos) &gt; 5){\n        \/\/ \u6539\u53d8\u62d6\u52a8\u72b6\u6001 Drag_start -&gt;  Dragging\n        canvasInfo.status = statusConfig.Dragging;\n    }else if( canvasInfo.status === statusConfig.Dragging ){\n        canvasInfo.dragTarget.x = canvasPosition.x;\n        canvasInfo.dragTarget.y = canvasPosition.y;\n        \/\/ \u91cd\u65b0\u7ed8\u5236\n        const query = wx.createSelectorQuery()\n        query.select('#myCanvas')\n          .fields({ node: true, size: true })\n          .exec((res) =&gt; {\n            const canvas = res[0].node\n            canvas.width=\"500\";\n            canvas.height=\"600\";\n            const ctx = canvas.getContext('2d')\n            \/\/ \u904d\u5386circles\uff0c\u628a\u5706\u91cd\u65b0\u753b\u4e00\u904d\n            circles.forEach(c =&gt; this.drawCircle(ctx, c.x, c.y, c.r))\n          })\n    }\n\n    this.setData({\n      canvasInfo,\n    })\n  }<\/pre>\n
 \u767b\u5f55\u540e\u590d\u5236 <\/p>\n
\u624b\u6307\u89e6\u6478\u52a8\u4f5c\u7ed3\u675f ,\u6539\u53d8 canvasInfo\u5728\u72b6\u6001\u91cd\u65b0\u53d8\u6210idle<\/p>\n
 handleCanvasEnd(e){\n    const {canvasInfo, statusConfig} = this.data;\n    if( canvasInfo.status === statusConfig.Dragging ){\n    \/\/ \u6539\u53d8\u62d6\u52a8\u72b6\u6001 Dragging -&gt;  idle\n      canvasInfo.status = statusConfig.idle;\n      this.setData({\n        canvasInfo\n      })\n    }\n  }<\/pre>\n
 \u767b\u5f55\u540e\u590d\u5236 <\/p>\n
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