feat: 文字涂色
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// import { PAPER_SIZE } from './constant';
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import { PAPER_SIZE } from './constant';
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import { getMiniCodeImage } from './utils';
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class TextDrawService {
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canvas: WechatMiniprogram.Canvas;
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ctx: RenderingContext;
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options: Record<string, any>;
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paperSize: PaperSize;
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currentX: number;
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currentY: number;
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constructor(canvas: Canvas, ctx: RenderingContext, options?: Record<string, any>) {
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this.canvas = canvas;
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this.ctx = ctx;
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this.paperSize = 'A4';
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this.options = {
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appName: '涂鸦呀',
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appHint: '涂色|识字|画画|认知',
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title: '找一找 涂 色',
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subTitle: '把相同的文字涂上相同的颜色',
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colors: ['#FF0000', '#FDAF1A', '#0057FC', '#09FF00', '#8D00FF'],
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characters: ['文', '升', '国', '舟', '丹'],
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...options,
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};
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this.currentX = 0;
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this.currentY = 0;
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}
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draw() {
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this.setPaper();
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this.drawHeader();
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this.drawLegend();
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this.drawContent();
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}
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async drawHeader() {
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const { canvas, ctx } = this;
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const { appName, appHint, title, subTitle } = this.options;
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this.currentX = 80;
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this.currentY = 80;
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const titleX = this.currentX + 200 + 48;
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const titleY = 80;
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const image = await getMiniCodeImage(canvas);
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ctx.drawImage(image, 80, 80, 200, 200);
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ctx.font = 'bold 64px "Microsoft Yahei"';
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ctx.fillStyle = '#000';
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ctx.textAlign = 'left';
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ctx.textBaseline = 'top';
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ctx.fillText(appName, titleX, titleY);
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ctx.font = '48px "Microsoft Yahei"';
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ctx.fillStyle = '#666';
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ctx.fillText(appHint, titleX, 186);
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// 绘制分割线
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// ctx.strokeStyle = '#888';
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// ctx.lineWidth = 2;
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// ctx.beginPath();
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// ctx.moveTo(483, 70);
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// ctx.lineTo(483, 70 + 140);
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// ctx.stroke();
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ctx.font = 'bold 64px "Microsoft Yahei"';
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ctx.fillStyle = '#000';
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ctx.fillText(title, 1015, titleY);
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ctx.font = '48px "Microsoft Yahei"';
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ctx.fillStyle = '#666';
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ctx.fillText(subTitle, 1015, 186);
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this.currentY = 304;
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this.drawLine(this.currentY);
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}
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/** 绘制示例
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* 矩形： x、y为左上角
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* 圆形：x、y为圆心
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* 文字：x textAlign 为 start，文本左边缘对齐
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* y textBaseline 为 alphabetic，y 对应字母基线（类似左下角）
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*
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* */
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drawLegend() {
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const { canvas, ctx, options } = this;
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const { colors, characters } = options;
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const radius = 65;
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const rectWidth = 180;
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const rectHeight = 80;
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const startX = 260 + radius; // 圆形的X坐标是圆心
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const startY = 304 + 26 + radius; // 圆形的Y坐标是圆心
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const len = characters.length || 4;
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const canvasWidth = canvas.width;
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/** 计算每个圆之间的间距 俩个60，一个是页面右侧边距，另一个是圆离右边距地边距*/
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const spaceWidth = (canvasWidth - startX * 2) / (len - 1);
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ctx.moveTo(startX, startY);
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colors.forEach((color: string, index: number) => {
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const x = startX + index * spaceWidth;
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const y = startY; // 计算圆的Y坐标
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// 绘制圆
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ctx.strokeStyle = '#000';
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ctx.fillStyle = color;
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ctx.lineWidth = 4;
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ctx.beginPath();
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ctx.arc(x, y, radius, 0, Math.PI * 2);
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ctx.fill();
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ctx.stroke();
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ctx.closePath();
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// 绘制长方形
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ctx.fillStyle = '#fff'; // 长方形背景色
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ctx.strokeStyle = '#000';
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ctx.lineWidth = 4;
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const rectangleX = x - rectWidth / 2; // 从圆形移动一半的长方形的长
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const rectangleY = y + radius + 43; // 从圆形下移一个半径，再加上43的间距
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ctx.strokeRect(rectangleX, rectangleY, rectWidth, rectHeight); // 绘制长方形
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// 绘制字符
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ctx.fillStyle = '#333';
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ctx.font = 'bold 48px "Microsoft Yahei"';
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ctx.textBaseline = 'middle';
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ctx.textAlign = 'center';
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ctx.fillText(
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characters[index],
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rectangleX + rectWidth / 2,
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rectangleY + rectHeight / 2,
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rectWidth,
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);
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});
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this.currentY = 612; // 计算分割线的Y坐标，距离示例图20px
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this.drawLine(this.currentY);
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}
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drawContent() {
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const { canvas, ctx, options } = this;
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const { characters } = options;
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const len = characters.length;
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const rows = 8;
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const radius = 80;
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const fontSize = 72;
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const startY = this.currentY + 62 + radius;
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const startX1 = 310 + radius;
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const startX2 = 200 + radius;
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const canvasWidth = canvas.width;
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const spaceWidthFrist = (canvasWidth - startX1 * 2) / (5 - 1);
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const spaceWidthSecond = (canvasWidth - startX2 * 2) / (6 - 1);
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const spaceHeight = 54;
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ctx.moveTo(startX1, startY);
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for (let i = 0; i < rows; i++) {
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const cols = i % 2 === 0 ? 5 : 6;
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for (let j = 0; j < cols; j++) {
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const y = startY + i * (spaceHeight + radius * 2);
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const x =
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i % 2 === 0 ? startX1 + j * spaceWidthFrist : startX2 + j * spaceWidthSecond;
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const character = characters[Math.floor(Math.random() * len)];
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ctx.fillStyle = '#fff';
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ctx.strokeStyle = '#000';
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ctx.lineWidth = 4;
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ctx.beginPath();
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ctx.arc(x, y, radius, 0, Math.PI * 2);
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ctx.fill();
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ctx.stroke();
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ctx.closePath();
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ctx.fillStyle = '#333';
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ctx.font = `${fontSize}px "Microsoft Yahei"`;
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ctx.textBaseline = 'middle';
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ctx.textAlign = 'center';
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ctx.fillText(character, x, y, radius * 2);
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}
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}
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}
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drawLine(linY: number) {
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const { canvas, ctx } = this;
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ctx.strokeStyle = '#000';
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ctx.lineWidth = 2;
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ctx.beginPath();
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ctx.moveTo(80, linY);
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ctx.lineTo(canvas.width - 80, linY);
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ctx.stroke();
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}
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setPaper() {
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const { ctx, canvas } = this;
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const { pixelRatio: dpr } = wx.getWindowInfo();
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// const { width, height } = { width: 595 * dpr, height: 842 * dpr };
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let { width, height } = PAPER_SIZE[this.paperSize];
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width = width * dpr;
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height = height * dpr;
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canvas.width = width;
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canvas.height = height;
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console.log('width---:', width);
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console.log('height---:', height);
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this.clear();
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ctx.fillStyle = '#fff'; // 设置背景色为白色
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ctx.fillRect(0, 0, width, height);
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}
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clear() {
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const canvas = this.canvas;
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this.ctx.clearRect(0, 0, canvas.width, canvas.height);
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}
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}
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export default TextDrawService;
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