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下载软件的网站,想要网站导航推广,济南著名网站建设,成都网站建设培训班fabric.BaseBrush，你可以实现各种绘图工具，例如自由绘图、直线、矩形、圆形等。内置了一些基于 fabric.BaseBrush 的画笔工具，例如： fabric.PencilBrush：自由绘图工具。 fabric.CircleBrush：圆形绘图工具。…

fabric.BaseBrush，你可以实现各种绘图工具，例如自由绘图、直线、矩形、圆形等。

内置了一些基于 fabric.BaseBrush 的画笔工具，例如：
fabric.PencilBrush：自由绘图工具。
fabric.CircleBrush：圆形绘图工具。
fabric.SprayBrush：喷枪工具。
fabric.PatternBrush：图案画笔工具。
自定义的绘图工具，可以通过扩展fabric.BaseBrush 来实现。
fabric.BaseBrush 提供了一些核心方法，用于实现绘图工具的逻辑：
initialize(canvas, options)：初始化画笔工具。
onMouseDown(pointer)：鼠标按下时触发。
onMouseMove(pointer)：鼠标移动时触发。
onMouseUp()：鼠标释放时触发。
createPath(pathData)：创建路径对象（用于自由绘图工具）。
setBrushStyles()：设置画笔样式（颜色、宽度等）。
自定义画笔工具-通过以下属性自定义画笔工具的样式：
color：画笔颜色。
width：画笔宽度。
opacity：画笔透明度。

<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Fabric.js 自定义画笔工具</title><script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/5.2.4/fabric.min.js"></script>
</head><body><canvas id="canvas" width="1920" height="1080" style="border: 1px solid #000;"></canvas><script>// 通过继承 fabric.BaseBrush 实现一个自定义的自由绘图工具// 自定义画笔工具-自由绘图工具可以通过记录鼠标移动的路径来实现。const CustomBrush = fabric.util.createClass(fabric.BaseBrush, {initialize: function (canvas, options) {this.callSuper('initialize', canvas, options);this.points = []; // 存储绘图点},// 鼠标按下时触发onMouseDown: function (pointer) {this.points = [pointer]; // 记录起始点this.setBrushStyles(); // 设置画笔样式},// 鼠标移动时触发onMouseMove: function (pointer) {this.points.push(pointer); // 记录移动点this._render(); // 渲染路径},// 鼠标释放时触发onMouseUp: function () {if (this.points.length > 1) {const path = this.createPath(this.points); // 创建路径对象this.canvas.add(path); // 将路径添加到画布}this.points = []; // 清空点},// 创建路径对象createPath: function (points) {const pathData = points.map((point, index) => {return (index === 0 ? 'M' : 'L') + point.x + ' ' + point.y;}).join(' ');return new fabric.Path(pathData, {stroke: this.color,strokeWidth: this.width,fill: null,selectable: false});},// 渲染路径_render: function () {const ctx = this.canvas.getContext('2d');ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);ctx.beginPath();this.points.forEach((point, index) => {if (index === 0) {ctx.moveTo(point.x, point.y);} else {ctx.lineTo(point.x, point.y);}});ctx.strokeStyle = this.color;ctx.lineWidth = this.width;ctx.stroke();}});// 1.直线工具通过记录起点和终点来绘制直线。// const LineBrush = fabric.util.createClass(fabric.BaseBrush, {//     initialize: function (canvas, options) {//         this.callSuper('initialize', canvas, options);//         this.startPoint = null;//     },//     onMouseDown: function (pointer) {//         this.startPoint = pointer;//         this.setBrushStyles();//     },//     onMouseMove: function (pointer) {//         if (!this.startPoint) return;//         this._render(pointer);//     },//     onMouseUp: function () {//         if (this.startPoint) {//             const line = new fabric.Line([//                 this.startPoint.x, this.startPoint.y,//                 this.endPoint.x, this.endPoint.y//             ], {//                 stroke: this.color,//                 strokeWidth: this.width,//                 selectable: false//             });//             this.canvas.add(line);//         }//         this.startPoint = null;//     },//     _render: function (pointer) {//         const ctx = this.canvas.getContext('2d');//         ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);//         ctx.beginPath();//         ctx.moveTo(this.startPoint.x, this.startPoint.y);//         ctx.lineTo(pointer.x, pointer.y);//         ctx.strokeStyle = this.color;//         ctx.lineWidth = this.width;//         ctx.stroke();//         this.endPoint = pointer;//     }// });// 2.矩形工具通过记录起点和终点来绘制矩形。// const RectBrush = fabric.util.createClass(fabric.BaseBrush, {//     initialize: function (canvas, options) {//         this.callSuper('initialize', canvas, options);//         this.startPoint = null;//     },//     onMouseDown: function (pointer) {//         this.startPoint = pointer;//         this.setBrushStyles();//     },//     onMouseMove: function (pointer) {//         if (!this.startPoint) return;//         this._render(pointer);//     },//     onMouseUp: function () {//         if (this.startPoint) {//             const rect = new fabric.Rect({//                 left: this.startPoint.x,//                 top: this.startPoint.y,//                 width: this.endPoint.x - this.startPoint.x,//                 height: this.endPoint.y - this.startPoint.y,//                 stroke: this.color,//                 strokeWidth: this.width,//                 fill: null,//                 selectable: false//             });//             this.canvas.add(rect);//         }//         this.startPoint = null;//     },//     _render: function (pointer) {//         const ctx = this.canvas.getContext('2d');//         ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);//         ctx.strokeStyle = this.color;//         ctx.lineWidth = this.width;//         ctx.strokeRect(//             this.startPoint.x,//             this.startPoint.y,//             pointer.x - this.startPoint.x,//             pointer.y - this.startPoint.y//         );//         this.endPoint = pointer;//     }// });// 3.圆形工具// const CircleBrush = fabric.util.createClass(fabric.BaseBrush, {//     initialize: function (canvas, options) {//         this.callSuper('initialize', canvas, options);//         this.startPoint = null;//     },//     onMouseDown: function (pointer) {//         this.startPoint = pointer;//         this.setBrushStyles();//     },//     onMouseMove: function (pointer) {//         if (!this.startPoint) return;//         this._render(pointer);//     },//     onMouseUp: function () {//         if (this.startPoint) {//             const radius = Math.sqrt(//                 Math.pow(this.endPoint.x - this.startPoint.x, 2) +//                 Math.pow(this.endPoint.y - this.startPoint.y, 2)//             );//             const circle = new fabric.Circle({//                 left: this.startPoint.x,//                 top: this.startPoint.y,//                 radius: radius,//                 stroke: this.color,//                 strokeWidth: this.width,//                 fill: null,//                 selectable: false//             });//             this.canvas.add(circle);//         }//         this.startPoint = null;//     },//     _render: function (pointer) {//         const ctx = this.canvas.getContext('2d');//         ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);//         ctx.beginPath();//         const radius = Math.sqrt(//             Math.pow(pointer.x - this.startPoint.x, 2) +//             Math.pow(pointer.y - this.startPoint.y, 2)//         );//         ctx.arc(this.startPoint.x, this.startPoint.y, radius, 0, Math.PI * 2);//         ctx.strokeStyle = this.color;//         ctx.lineWidth = this.width;//         ctx.stroke();//         this.endPoint = pointer;//     }// });// 初始化画布const canvas = new fabric.Canvas('canvas');// 使用自定义画笔工具// const customBrush = new CustomBrush(canvas);// canvas.freeDrawingBrush = customBrush; // 设置为当前画笔工具// canvas.freeDrawingBrush.color = 'blue'; // 设置画笔颜色// canvas.freeDrawingBrush.width = 5; // 设置画笔宽度// canvas.isDrawingMode = true; // 启用绘图模式// 一、使用fabric.PencilBrush自定义画笔工具const customBrush = new CustomBrush(canvas);canvas.freeDrawingBrush = new fabric.PencilBrush(canvas);canvas.freeDrawingBrush.color = 'blue'; // 设置画笔颜色canvas.freeDrawingBrush.width = 2; // 设置画笔宽度canvas.isDrawingMode = true; // 启用绘图模式// 二、使用 fabric.CircleBrush（圆形绘图工具）// canvas.freeDrawingBrush = new fabric.CircleBrush(canvas);// canvas.freeDrawingBrush.color = 'red'; // 设置画笔颜色// canvas.freeDrawingBrush.width = 10; // 设置画笔宽度// canvas.isDrawingMode = true; // 启用绘图模式// 1.使用直线工具// const customBrush = new LineBrush(canvas);// canvas.freeDrawingBrush = new fabric.PencilBrush(canvas);// canvas.freeDrawingBrush.color = 'red'; // 设置画笔颜色// canvas.freeDrawingBrush.width = 3; // 设置画笔宽度// canvas.isDrawingMode = true; // 启用绘图模式// 2.矩形工具// const customBrush = new RectBrush(canvas);// canvas.freeDrawingBrush = new fabric.PencilBrush(canvas);// canvas.freeDrawingBrush.color = 'green'; // 设置画笔颜色// canvas.freeDrawingBrush.width = 2; // 设置画笔宽度// canvas.isDrawingMode = true; // 启用绘图模式// 3.圆形工具// canvas.freeDrawingBrush = new CircleBrush(canvas);// canvas.freeDrawingBrush = new fabric.PencilBrush(canvas);// canvas.freeDrawingBrush.color = 'green'; // 设置画笔颜色// canvas.freeDrawingBrush.width = 2; // 设置画笔宽度// canvas.isDrawingMode = true; // 启用绘图模式</script>
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