240 lines
7.8 KiB
TypeScript
240 lines
7.8 KiB
TypeScript
// 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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radius: 36,
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colors: ['#2196F3', '#FFEB3B', '#FF9800', '#F44336', '#F44336'],
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characters: ['鱼', '鸟', '猫', '狗', '牛'],
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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.setPaper3();
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this.drawHeader();
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// this.drawLegend();
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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 = 60;
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this.currentY = 60;
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const titleX = this.currentX + 140 + 14;
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const titleY = 87;
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const image = await getMiniCodeImage(canvas);
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ctx.drawImage(image, 60, 60, 140, 140);
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ctx.font = 'bold 36px "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 = '24px "Microsoft Yahei"';
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ctx.fillStyle = '#666';
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ctx.fillText(appHint, titleX, 163);
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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 36px "Microsoft Yahei"';
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ctx.fillStyle = '#000';
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ctx.fillText(title, 538, titleY);
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ctx.font = '24px "Microsoft Yahei"';
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ctx.fillStyle = '#666';
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ctx.fillText(subTitle, 538, 163);
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this.drawLegend();
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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, radius } = options;
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const rectWidth = 100;
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const rectHeight = 48;
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const startX = 978;
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const startY = 60 + radius; // 设置起始Y坐标
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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 - 60 - 60 - radius * (len - 1)) / (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 + radius);
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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 = '#333';
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ctx.fillStyle = color;
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ctx.lineWidth = 2;
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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 = '#333';
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ctx.lineWidth = 2;
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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 + 18; // 从圆形下移一个半径，再加上18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 24px "Microsoft Yahei"';
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ctx.textBaseline = 'top';
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ctx.fillText(characters[index], rectangleX + 38, 163);
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});
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this.currentY = 220; // 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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drawLine(linY: number) {
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const { canvas, ctx } = this;
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ctx.strokeStyle = '#333';
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ctx.lineWidth = 2;
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ctx.beginPath();
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ctx.moveTo(20, linY);
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ctx.lineTo(canvas.width - 20, 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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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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setPaper3() {
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const { ctx, canvas } = this;
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const { pixelRatio: dpr } = wx.getWindowInfo();
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// @ts-ignore
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const winWidth = canvas._width;
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// @ts-ignore
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const winHeight = canvas._height; // 容器逻辑尺寸
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// 计算适配后的物理尺寸
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const targetWidth = winWidth * dpr; // 宽度100%适配容器
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const aspectRatio = 842 / 595; // 原图宽高比（示例为A4纸比例）
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let targetHeight = targetWidth * aspectRatio; // 按比例计算高度
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// 判断是否需要裁剪高度
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if (targetHeight > winHeight * dpr) {
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targetHeight = winHeight * dpr; // 若超出容器高度则强制裁剪
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}
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// 设置 Canvas 物理像素
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canvas.width = targetWidth;
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canvas.height = targetHeight;
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console.log('targetWidth---:', targetWidth);
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console.log('targetHeight---:', targetHeight);
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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, targetWidth, targetHeight);
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}
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setPaper2() {
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const { canvas, ctx } = 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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// @ts-ignore
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const winWidth = canvas._width;
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// @ts-ignore
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const winHeight = canvas._height;
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const canvasAspect = width / height; // Canvas 内容的宽高比
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const containerAspect = winHeight / winWidth; // 容器的宽高比
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// 选择缩放比例较小的方向（确保内容完全显示）
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let scaleRatio =
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containerAspect > canvasAspect
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? winWidth / width // 以宽度为基准
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: winHeight / height; // 以高度为基准
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console.log('scaleRatio-----:', scaleRatio);
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const scaledWidth = width * scaleRatio;
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const scaledHeight = height * scaleRatio;
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// 避免超过小程序画布最大限制（4096）
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if (scaledWidth > 4096 || scaledHeight > 4096) {
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scaleRatio *= Math.min(4096 / scaledWidth, 4096 / scaledHeight);
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}
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console.log('scaledWidth-----:', scaledWidth);
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console.log('scaledHeight-----:', scaledHeight);
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canvas.width = scaledWidth;
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canvas.height = scaledHeight;
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ctx.translate((winWidth * dpr) / 2, (winHeight * dpr) / 2);
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ctx.scale(scaleRatio * dpr, scaleRatio * dpr);
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ctx.translate(-width / 2, -height / 2); // 将内容原点移至中心
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// this.canvas.width = width;
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// this.canvas.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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