import { getCurrentInstance } from "vue";
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import { isEmpty, isString, cloneDeep, isObject } from "lodash-es";
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// 渲染参数
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declare interface RenderOptions {
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x: number;
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y: number;
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height?: number;
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width?: number;
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[key: string]: any;
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}
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// 文本渲染参数
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declare interface TextRenderOptions extends RenderOptions {
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text: string;
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color?: string;
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fontSize?: number;
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textAlign?: "left" | "right" | "center";
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overflow?: "ellipsis";
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lineClamp?: number;
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letterSpace?: number;
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lineHeight?: number;
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}
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// 图片渲染参数
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declare interface ImageRenderOptions extends RenderOptions {
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url: string;
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mode?: "aspectFill" | "aspectFit";
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radius?: number;
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}
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// 块渲染参数
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declare interface DivRenderOptions extends RenderOptions {
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radius?: number;
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backgroundColor?: string;
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border?: {
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width: number;
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color: string;
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};
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}
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// 导出图片参数
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declare interface CreateImageOptins {
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x?: number;
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y?: number;
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width?: number;
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height?: number;
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destWidth?: number;
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destHeight?: number;
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fileType?: "jpg" | "png";
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quality?: number;
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}
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class Canvas {
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ctx: any;
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canvasId: any;
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scope: any;
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renderQuene: any;
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imageQueue: any;
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constructor(canvasId: string) {
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// 绘图上下文
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this.ctx = null;
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// canvas id
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this.canvasId = canvasId;
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// 当前页面作用域
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const { proxy }: any = getCurrentInstance();
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this.scope = proxy;
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// 渲染队列
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this.renderQuene = [];
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// 图片队列
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this.imageQueue = [];
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// 创建画布
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this.create();
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}
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// 创建画布
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create() {
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this.ctx = uni.createCanvasContext(this.canvasId, this.scope);
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return this;
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}
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// 块
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div(options: DivRenderOptions) {
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let render = () => {
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this.divRender(options);
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};
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this.renderQuene.push(render);
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return this;
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}
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// 文本
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text(options: TextRenderOptions) {
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let render = () => {
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this.textRender(options);
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};
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this.renderQuene.push(render);
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return this;
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}
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// 图片
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image(options: ImageRenderOptions) {
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let render = () => {
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this.imageRender(options);
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};
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this.imageQueue.push(options);
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this.renderQuene.push(render);
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return this;
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}
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// 绘画
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draw(save = false) {
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return new Promise((resolve) => {
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let next = () => {
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this.render();
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this.ctx.draw(save, () => {
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resolve(true);
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});
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};
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if (!isEmpty(this.imageQueue)) {
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this.preLoadImage().then(next);
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} else {
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next();
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}
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});
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}
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// 生成图片
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createImage(options?: CreateImageOptins): Promise<string> {
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return new Promise((resolve, reject) => {
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let data = {
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canvasId: this.canvasId,
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...options,
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success: (res: any) => {
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// #ifdef MP-ALIPAY
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resolve(res.apFilePath);
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// #endif
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// #ifndef MP-ALIPAY
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resolve(res.tempFilePath);
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// #endif
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},
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fail: reject,
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};
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// #ifdef MP-ALIPAY
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this.ctx.toTempFilePath(data);
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// #endif
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// #ifndef MP-ALIPAY
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uni.canvasToTempFilePath(data, this.scope);
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// #endif
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});
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}
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// 保存图片
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saveImage(options?: CreateImageOptins) {
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uni.showLoading({
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title: "图片下载中...",
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});
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this.createImage(options).then((path: any) => {
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return new Promise((resolve) => {
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uni.hideLoading();
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uni.saveImageToPhotosAlbum({
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filePath: path,
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success: () => {
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uni.showToast({
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title: "保存图片成功",
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});
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resolve(path);
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},
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fail: (err) => {
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// #ifdef MP-ALIPAY
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uni.showToast({
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title: "保存图片成功",
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});
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// #endif
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// #ifndef MP-ALIPAY
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uni.showToast({
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title: "保存图片失败",
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icon: "none",
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});
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// #endif
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},
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});
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});
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});
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}
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// 预览图片
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previewImage(options?: CreateImageOptins) {
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this.createImage(options).then((url: string | any) => {
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uni.previewImage({
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urls: [url],
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});
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});
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}
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// 下载图片
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downLoadImage(item: any) {
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return new Promise((resolve, reject) => {
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if (!item.url) {
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return reject("url 不能为空");
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}
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// 处理base64
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// #ifdef MP
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if (item.url.indexOf("data:image") >= 0) {
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let extName = item.url.match(/data\:\S+\/(\S+);/);
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if (extName) {
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extName = extName[1];
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}
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const fs = uni.getFileSystemManager();
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const fileName = Date.now() + "." + extName;
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// @ts-ignore
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const filePath = wx.env.USER_DATA_PATH + "/" + fileName;
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return fs.writeFile({
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filePath,
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data: item.url.replace(/^data:\S+\/\S+;base64,/, ""),
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encoding: "base64",
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success: () => {
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item.url = filePath;
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resolve(filePath);
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},
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});
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}
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// #endif
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// 是否网络图片
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const isHttp = item.url.includes("http");
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uni.getImageInfo({
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src: item.url,
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success: (result) => {
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item.sheight = result.height;
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item.swidth = result.width;
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if (isHttp) {
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item.url = result.path;
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}
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resolve(item.url);
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},
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fail: (err) => {
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console.log(err, item.url);
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reject(err);
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},
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});
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return 1;
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});
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}
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// 预加载图片
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async preLoadImage() {
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await Promise.all(this.imageQueue.map(this.downLoadImage));
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}
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// 设置背景颜色
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setBackground(options: any) {
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if (!options) return null;
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let backgroundColor;
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if (!isString(options)) {
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backgroundColor = options;
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}
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if (isString(options.backgroundColor)) {
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backgroundColor = options.backgroundColor;
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}
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if (isObject(options.backgroundColor)) {
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let { startX, startY, endX, endY, gradient } = options.backgroundColor;
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const rgb = this.ctx.createLinearGradient(startX, startY, endX, endY);
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for (let i = 0, l = gradient.length; i < l; i++) {
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rgb.addColorStop(gradient[i].step, gradient[i].color);
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}
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backgroundColor = rgb;
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}
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this.ctx.setFillStyle(backgroundColor);
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return this;
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}
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// 设置边框
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setBorder(options: any) {
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if (!options.border) return this;
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let { x, y, width: w, height: h, border, radius: r } = options;
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if (border.width) {
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this.ctx.setLineWidth(border.width);
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}
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if (border.color) {
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this.ctx.setStrokeStyle(border.color);
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}
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// 偏移距离
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let p = border.width / 2;
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// 是否有圆角
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if (r) {
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this.drawRadiusRoute(x - p, y - p, w + 2 * p, h + 2 * p, r + p);
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this.ctx.stroke();
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} else {
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this.ctx.strokeRect(x - p, y - p, w + 2 * p, h + 2 * p);
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}
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return this;
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}
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// 设置缩放，旋转
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setTransform(options: any) {
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if (options.scale) {
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}
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if (options.rotate) {
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}
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}
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// 带有圆角的路径绘制
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drawRadiusRoute(x: number, y: number, w: number, h: number, r: number) {
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this.ctx.beginPath();
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this.ctx.moveTo(x + r, y, y);
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this.ctx.lineTo(x + w - r, y);
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this.ctx.arc(x + w - r, y + r, r, 1.5 * Math.PI, 0);
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this.ctx.lineTo(x + w, y + h - r);
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this.ctx.arc(x + w - r, y + h - r, r, 0, 0.5 * Math.PI);
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this.ctx.lineTo(x + r, y + h);
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this.ctx.arc(x + r, y + h - r, r, 0.5 * Math.PI, Math.PI);
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this.ctx.lineTo(x, y + r);
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this.ctx.arc(x + r, y + r, r, Math.PI, 1.5 * Math.PI);
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this.ctx.closePath();
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}
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// 裁剪图片
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cropImage(
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mode: "aspectFill" | "aspectFit",
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width: number,
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height: number,
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sWidth: number,
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sHeight: number,
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x: number,
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y: number
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) {
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let cx, cy, cw, ch, sx, sy, sw, sh;
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switch (mode) {
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case "aspectFill":
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if (width <= height) {
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let p = width / sWidth;
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cw = width;
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ch = sHeight * p;
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cx = 0;
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cy = (height - ch) / 2;
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} else {
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let p = height / sHeight;
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cw = sWidth * p;
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ch = height;
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cx = (width - cw) / 2;
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cy = 0;
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}
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break;
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case "aspectFit":
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if (width <= height) {
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let p = height / sHeight;
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sw = width / p;
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sh = sHeight;
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sx = x + (sWidth - sw) / 2;
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sy = y;
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} else {
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let p = width / sWidth;
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sw = sWidth;
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sh = height / p;
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sx = x;
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sy = y + (sHeight - sh) / 2;
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}
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break;
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}
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return { cx, cy, cw, ch, sx, sy, sw, sh };
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}
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// 获取文本内容
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getTextRows({
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text,
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fontSize = 14,
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width = 100,
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lineClamp = 1,
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overflow,
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letterSpace = 0,
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}: any) {
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let arr: any[] = [[]];
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let a = 0;
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for (let i = 0; i < text.length; i++) {
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let b = this.getFontPx(text[i], { fontSize, letterSpace });
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if (a + b > width) {
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a = b;
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arr.push(text[i]);
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} else {
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// 最后一行且设置超出省略号
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if (
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overflow == "ellipsis" &&
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arr.length == lineClamp &&
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a + 3 * this.getFontPx(".", { fontSize, letterSpace }) > width - 5
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) {
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arr[arr.length - 1] += "...";
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break;
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} else {
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a += b;
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arr[arr.length - 1] += text[i];
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}
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}
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}
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return arr;
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}
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// 获取单个字体像素大小
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getFontPx(text: string, { fontSize = 14, letterSpace }: any) {
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if (!text) {
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return fontSize / 2 + fontSize / 14 + letterSpace;
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}
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let ch = text.charCodeAt(0);
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if ((ch >= 0x0001 && ch <= 0x007e) || (0xff60 <= ch && ch <= 0xff9f)) {
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return fontSize / 2 + fontSize / 14 + letterSpace;
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} else {
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return fontSize + letterSpace;
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}
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}
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// 渲染块
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divRender(options: DivRenderOptions) {
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this.ctx.save();
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this.setBackground(options);
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this.setBorder(options);
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this.setTransform(options);
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// 区分是否有圆角采用不同模式渲染
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if (options.radius) {
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let { x, y } = options;
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let w = options.width || 0;
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let h = options.height || 0;
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let r = options.radius || 0;
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// 画路径
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this.drawRadiusRoute(x, y, w, h, r);
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// 填充
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this.ctx.fill();
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} else {
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this.ctx.fillRect(options.x, options.y, options.width, options.height);
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}
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this.ctx.restore();
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}
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// 渲染文本
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textRender(options: TextRenderOptions) {
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let {
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fontSize = 14,
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textAlign,
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width,
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color = "#000000",
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x,
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y,
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letterSpace,
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lineHeight = 14,
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} = options || {};
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this.ctx.save();
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// 设置字体大小
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this.ctx.setFontSize(fontSize);
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// 设置字体颜色
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this.ctx.setFillStyle(color);
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// 获取文本内容
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let rows = this.getTextRows(options);
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// 获取文本行高
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let lh = lineHeight - fontSize;
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// 左偏移
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let offsetLeft = 0;
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// 字体对齐
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if (textAlign && width) {
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this.ctx.textAlign = textAlign;
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switch (textAlign) {
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case "left":
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break;
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case "center":
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offsetLeft = width / 2;
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break;
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case "right":
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offsetLeft = width;
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break;
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}
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}
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// 逐行写入
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for (let i = 0; i < rows.length; i++) {
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let d = offsetLeft;
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if (letterSpace) {
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for (let j = 0; j < rows[i].length; j++) {
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// 写入文字
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this.ctx.fillText(rows[i][j], x + d, (i + 1) * fontSize + y + lh * i);
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// 设置偏移
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d += this.getFontPx(rows[i][j], options);
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}
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} else {
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// 写入文字
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this.ctx.fillText(rows[i], x + offsetLeft, (i + 1) * fontSize + y + lh * i);
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}
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}
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this.ctx.restore();
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}
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// 渲染图片
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imageRender(options: ImageRenderOptions) {
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this.ctx.save();
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if (options.radius) {
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// 画路径
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this.drawRadiusRoute(
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options.x,
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options.y,
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options.width || options.swidth,
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options.height || options.sHeight,
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options.radius
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);
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// 填充
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this.ctx.fill();
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// 裁剪
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this.ctx.clip();
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}
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let temp = cloneDeep(this.imageQueue[0]);
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if (options.mode) {
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let { cx, cy, cw, ch, sx, sy, sw, sh } = this.cropImage(
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options.mode,
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temp.swidth,
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temp.sheight,
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temp.width,
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temp.height,
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temp.x,
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temp.y
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);
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switch (options.mode) {
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case "aspectFit":
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this.ctx.drawImage(temp.url, sx, sy, sw, sh);
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break;
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case "aspectFill":
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this.ctx.drawImage(
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temp.url,
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cx,
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cy,
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cw,
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ch,
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temp.x,
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temp.y,
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temp.width,
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temp.height
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);
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break;
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}
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} else {
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this.ctx.drawImage(
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temp.url,
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temp.x,
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temp.y,
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temp.width || temp.swidth,
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temp.height || temp.sheight
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);
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}
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this.imageQueue.shift();
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this.ctx.restore();
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}
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// 渲染全部
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render() {
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this.renderQuene.forEach((ele: any) => {
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ele();
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});
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}
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}
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export { Canvas };
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