<template>
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<div class="paint">
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<canvas id="canvas" :width="canvasWidth" :height="canvasHeight"></canvas>
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<!-- 操作按钮 -->
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<ul class="paint-btn">
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<li class="paint-btn-box">
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<button @click="changeDrawMode">
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{{ isDraw ? "框选模式" : "绘图模式" }}
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</button>
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<button @click="clearCanvas">清除</button>
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<button @click="setModelEraser">
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{{ isEraser ? "画笔" : "橡皮擦" }}
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</button>
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<button @click="saveImgData">保存</button>
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</li>
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<li></li>
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<li>
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<label>画笔：</label>
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<select name="" id="" @change="changeBrush" v-model="brush">
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<option
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v-for="(item, index) in modelList"
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:value="item.value"
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:key="index"
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>
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{{ item.name }}
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</option>
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</select>
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</li>
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<li>
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<label>线色：</label>
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<input type="color" v-model="lineColor" @input="changeLineColor" />
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</li>
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<li>
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<label>线宽：</label>
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<input type="range" v-model="lineWidth" @input="changeLineWidth" />
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</li>
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<li>
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<label>阴影色：</label>
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<input type="color" v-model="showColor" @input="changeShowColor" />
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</li>
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<li>
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<label>阴影宽度：</label>
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<input type="range" v-model="showWidth" @input="changeShowWidth" />
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</li>
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<li>
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<label>阴影偏移量：</label>
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<input type="range" v-model="showOffset" @input="changeShowOffset" />
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</li>
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</ul>
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</div>
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</template>
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<script>
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import { fabric } from "fabric-with-erasing";
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export default {
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data() {
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return {
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canvasWidth:window.innerWidth > 450 ? 400 : window.innerWidth - 30,
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backgroundImgUrl: "", // 背景
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isDraw: true, // 绘画、框选模式
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brush: "Pencil", // 画笔类型
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lineColor: "#000",
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lineWidth: 1,
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isEraser: false,
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showColor: "#000", // 阴影色
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showWidth: 0, // 阴影宽度
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showOffset: 0,
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modelList: [
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{
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name: "Pencil",
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value: "Pencil",
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},
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{
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name: "Circle",
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value: "Circle",
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},
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{
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name: "Spray",
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value: "Spray",
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},
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{
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name: "Pattern",
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value: "Pattern",
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},
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{
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name: "hline",
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value: "hline",
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},
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{
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name: "vline",
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value: "vline",
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},
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{
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name: "square",
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value: "square",
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},
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{
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name: "diamond",
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value: "diamond",
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},
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{
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name: "texture",
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value: "texture",
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},
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],
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// 画笔模式
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vLinePatternBrush: null,
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hLinePatternBrush: null,
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squarePatternBrush: null,
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diamondPatternBrush: null,
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texturePatternBrush: null,
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};
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},
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props: {
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imgUrl: {
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type: String,
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default:
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"https://cdn.learnku.com/uploads/images/202206/29/97252/aArKOJpl2A.png!large",
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},
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page: {
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type: Number,
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default: 1,
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},
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canvasHeight: {
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type: Number,
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default: 380,
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},
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},
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mounted() {
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this.init();
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},
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methods: {
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// 初始化画布
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init() {
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this.canvas = new fabric.Canvas(
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(this.container ? this.container : document).querySelector("#canvas"),
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{
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isDrawingMode: true,
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}
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);
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// 设置背景
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this.setBackgroundImage();
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//
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fabric.Object.prototype.transparentCorners = false;
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this.setBrush();
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},
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// 创建各种笔刷
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setBrush() {
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if (fabric.PatternBrush) {
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// 画笔样式
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this.vLinePatternBrush = new fabric.PatternBrush(this.canvas);
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this.vLinePatternBrush.getPatternSrc = () => {
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let patternCanvas =
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fabric[this.container ? this.container : document].createElement(
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"canvas"
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);
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patternCanvas.width = patternCanvas.height = 10;
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let ctx = patternCanvas.getContext("2d");
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ctx.strokeStyle = this.lineColor;
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ctx.lineWidth = 5;
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ctx.beginPath();
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ctx.moveTo(0, 5);
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ctx.lineTo(10, 5);
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ctx.closePath();
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ctx.stroke();
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return patternCanvas;
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};
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this.hLinePatternBrush = new fabric.PatternBrush(this.canvas);
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this.hLinePatternBrush.getPatternSrc = function () {
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let patternCanvas =
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fabric[this.container ? this.container : document].createElement(
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"canvas"
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);
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patternCanvas.width = patternCanvas.height = 10;
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let ctx = patternCanvas.getContext("2d");
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ctx.strokeStyle = this.lineColor;
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ctx.lineWidth = 5;
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ctx.beginPath();
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ctx.moveTo(5, 0);
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ctx.lineTo(5, 10);
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ctx.closePath();
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ctx.stroke();
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return patternCanvas;
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};
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this.squarePatternBrush = new fabric.PatternBrush(this.canvas);
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this.squarePatternBrush.getPatternSrc = function () {
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const squareWidth = 10;
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const squareDistance = 2;
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const patternCanvas =
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fabric[this.container ? this.container : document].createElement(
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"canvas"
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);
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patternCanvas.width = patternCanvas.height =
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squareWidth + squareDistance;
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const ctx = patternCanvas.getContext("2d");
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ctx.fillStyle = this.color;
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ctx.fillRect(0, 0, squareWidth, squareWidth);
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return patternCanvas;
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};
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this.diamondPatternBrush = new fabric.PatternBrush(this.canvas);
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this.diamondPatternBrush.getPatternSrc = function () {
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const squareWidth = 10;
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const squareDistance = 5;
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const patternCanvas =
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fabric[this.container ? this.container : document].createElement(
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"canvas"
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);
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const rect = new fabric.Rect({
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width: squareWidth,
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height: squareWidth,
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angle: 45,
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fill: this.color,
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});
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var canvasWidth = rect.getBoundingRect().width;
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patternCanvas.width = patternCanvas.height =
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canvasWidth + squareDistance;
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rect.set({ left: canvasWidth / 2, top: canvasWidth / 2 });
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var ctx = patternCanvas.getContext("2d");
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rect.render(ctx);
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return patternCanvas;
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};
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const img = new Image();
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this.texturePatternBrush = new fabric.PatternBrush(this.canvas);
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this.texturePatternBrush.source = img;
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}
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},
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// 设置背景图方法
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setBackgroundImage() {
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// 使用fabric的Image.fromURL方法来加载图像
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const oldData = localStorage.getItem(
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this.config.activeBook.name + "-paint-" + this.page
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);
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this.backgroundImgUrl = oldData || this.imgUrl;
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fabric.Image.fromURL(
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this.backgroundImgUrl,
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(img) => {
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// 图像加载完成后，将其设置为画布的背景
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img
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.scale(
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this.canvas.width / img.width,
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this.canvas.height / img.height
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)
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.set({
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left: 0,
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top: 0,
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originX: "left",
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originY: "top",
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});
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// 将图像添加到画布中，并将其放在最底层
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this.canvas.setBackgroundImage(
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img,
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this.canvas.renderAll.bind(this.canvas),
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{
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// 可以设置图像的样式，比如不透明度
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// opacity: 0.5,
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}
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);
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// 渲染画布
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this.canvas.renderAll();
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},
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{
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crossOrigin: "Anonymous", // 如果图像在不同域上，需要设置crossOrigin
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}
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);
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},
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// 绘图 框选 模式切换
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changeDrawMode() {
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this.isDraw = !this.isDraw;
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this.canvas.isDrawingMode = !this.canvas.isDrawingMode;
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},
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// 清空画布
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clearCanvas() {
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this.canvas.clear();
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this.setBackgroundImage();
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},
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// 修改画笔颜色
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changeLineColor(e) {
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let brush = this.canvas.freeDrawingBrush;
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brush.color = e.srcElement.value;
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if (brush.getPatternSrc) {
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brush.source = brush.getPatternSrc.call(brush);
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}
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},
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// 修改画笔粗细
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changeLineWidth(e) {
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this.canvas.freeDrawingBrush.width =
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parseInt(e.srcElement.value, 10) || 1;
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},
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// 画笔样式切换
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changeBrush() {
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if (this.brush == "hline") {
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this.canvas.freeDrawingBrush = this.vLinePatternBrush;
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} else if (this.brush == "vline") {
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this.canvas.freeDrawingBrush = this.hLinePatternBrush;
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} else if (this.brush == "square") {
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this.canvas.freeDrawingBrush = this.squarePatternBrush;
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} else if (this.brush == "diamond") {
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this.canvas.freeDrawingBrush = this.diamondPatternBrush;
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} else if (this.brush == "texture") {
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this.canvas.freeDrawingBrush = this.texturePatternBrush;
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} else {
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this.canvas.freeDrawingBrush = new fabric[this.brush + "Brush"](
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this.canvas
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);
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}
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if (this.canvas.freeDrawingBrush) {
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var brush = this.canvas.freeDrawingBrush;
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brush.color = this.lineColor;
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if (brush.getPatternSrc) {
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brush.source = brush.getPatternSrc.call(brush);
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}
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brush.width = parseInt(this.lineWidth, 10) || 1;
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brush.shadow = new fabric.Shadow({
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blur: parseInt(this.showWidth, 10) || 0,
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offsetX: 0,
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offsetY: 0,
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affectStroke: true,
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color: this.showColor,
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});
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}
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},
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// 橡皮擦
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setModelEraser() {
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this.isEraser = !this.isEraser;
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if (this.isEraser) {
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this.canvas.freeDrawingBrush = new fabric.EraserBrush(this.canvas); // 使用橡皮擦画笔
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this.canvas.freeDrawingBrush.width = this.lineWidth;
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} else {
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this.changeBrush();
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// this.canvas.freeDrawingBrush = new fabric.PencilBrush(this.canvas); // 使用橡皮擦画笔
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// this.canvas.freeDrawingBrush.width = this.lineWidth; // 设置画笔粗细
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}
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},
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// 修改阴影色
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changeShowColor(e) {
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this.canvas.contextContainer.shadowColor = e.srcElement.value;
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},
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// 阴影宽度
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changeShowWidth(e) {
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console.log(this.canvas);
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this.canvas.contextContainer.shadowBlur =
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parseInt(e.srcElement.value, 10) || 0;
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},
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// 阴影偏移量
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changeShowOffset(e) {
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this.canvas.contextContainer.shadowOffsetX =
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parseInt(e.srcElement.value, 10) || 0;
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this.canvas.contextContainer.shadowOffsetY =
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parseInt(e.srcElement.value, 10) || 0;
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},
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// 保存图片
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saveImgData() {
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const imgData = this.canvas.toDataURL({
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format: "png", // 指定输出格式，通常是'png'或'jpeg'
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quality: 0.8, // 仅在输出格式为'jpeg'时有效
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multiplier: 1, // 提高分辨率，可选参数，默认为1
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left: 0, // 裁剪区域的左边界（可选）
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top: 0, // 裁剪区域的上边界（可选）
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width: canvas.width, // 裁剪区域的宽度（可选，默认为画布的宽度）
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height: canvas.height, // 裁剪区域的高度（可选，默认为画布的高度）
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});
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localStorage.setItem(
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this.config.activeBook.name + "-paint-" + this.page,
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imgData
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);
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console.log("本地图", imgData);
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},
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},
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};
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</script>
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<style lang="less" scoped>
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.paint {
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margin-top: 20px;
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display: flex;
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flex-direction: column;
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align-items: center;
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}
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#canvas {
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border: 1px solid #ccc;
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}
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.paint-btn {
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width: 96%;
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margin-top: 40px;
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padding: 20px;
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border: 1px solid #ededed;
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li {
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margin-bottom: 6px;
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}
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}
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.paint-btn-box {
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display: flex;
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justify-content: space-evenly;
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}
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</style>
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