259 lines
7.8 KiB
Vue
259 lines
7.8 KiB
Vue
<template>
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<view>
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<canvas canvas-id="reusableCanvas" :width="currentCanvasWidth" :height="currentCanvasHeight"
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class="offscreen-canvas"></canvas>
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</view>
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</template>
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<script>
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export default {
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name: "textToDotMatrixFor7305",
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props: {
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txts: {
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type: Array,
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default: () => [],
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validator: (value) => value.every(item => typeof item === 'string')
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},
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fontSize: {
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type: Number,
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default: 16,
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validator: (value) => value > 0 && value <= 100
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},
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bgColor: {
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type: String,
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default: "#ffffff"
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},
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color: {
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type: String,
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default: "#000000"
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}
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},
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data() {
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return {
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// 当前Canvas的宽高（动态调整）
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currentCanvasWidth: 0,
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currentCanvasHeight: 0,
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// Canvas上下文（复用）
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ctx: null
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};
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},
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computed: {
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validTxts() {
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return this.txts.filter(line => line.trim() !== '');
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}
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},
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mounted() {
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// 初始化Canvas上下文（只创建一次）
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this.ctx = uni.createCanvasContext('reusableCanvas', this);
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},
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methods: {
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/**
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* 估算单行文本所需的Canvas宽度
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*/
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calcLineWidth(textLine) {
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return textLine.length * this.fontSize;
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},
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/**
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* 清除Canvas内容
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*/
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clearCanvas() {
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// 先清除，再用背景色填充，确保无残留
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this.ctx.clearRect(0, 0, this.currentCanvasWidth, this.currentCanvasHeight);
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this.ctx.setFillStyle(this.bgColor);
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this.ctx.fillRect(0, 0, this.currentCanvasWidth, this.currentCanvasHeight);
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},
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/**
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* 复用单个Canvas处理所有文本行
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*/
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async drawAndGetPixels() {
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// 超采样比例（提高分辨率再降采样，减少模糊）
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const SCALE = 3;
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const PADDING_X = 1 * SCALE; // 左侧预留像素，避免首字裁剪
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let binaryToHex = (binaryArray) => {
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if (!Array.isArray(binaryArray) || binaryArray.length !== 8) {
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throw new Error("输入必须是包含8个元素的二进制数组");
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}
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// 检查每个元素是否为0或1
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if (!binaryArray.every(bit => bit === 0 || bit === 1)) {
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throw new Error("数组元素必须只能是0或1");
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}
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// 将二进制数组转换为十进制数
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let decimalValue = 0;
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for (let i = 0; i < 8; i++) {
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// 计算每个位的权重并累加
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decimalValue += binaryArray[i] * Math.pow(2, 7 - i);
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}
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// 将十进制转换为十六进制字符串，并添加0x前缀
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const hexString = "0x" + decimalValue.toString(16).padStart(2, '0').toUpperCase();
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return hexString;
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}
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let convertCharToMatrix = (drawResult, item) => {
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// 设备端使用13x13点阵渲染
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const charWidth = 13;
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const charHeight = 13;
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const { pixelData, width, height } = drawResult;
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// 将高分辨率像素降采样为13x13的布尔矩阵
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const target = new Array(charWidth * charHeight).fill(0);
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const threshold = 0.5; // 每个小块中超过50%亮色（文字）判为1
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// 确保采样区域严格对齐，从PADDING_X开始，只采样13列
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// 字符实际绘制区域：从PADDING_X开始，宽度为13*SCALE
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const charStartX = PADDING_X;
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const charEndX = PADDING_X + charWidth * SCALE;
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for (let y = 0; y < charHeight; y++) {
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for (let x = 0; x < charWidth; x++) {
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let onCount = 0;
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let total = 0;
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// 采样区域：字符从PADDING_X开始绘制，每列宽度为SCALE
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const startX = PADDING_X + x * SCALE;
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const startY = y * SCALE;
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for (let sy = 0; sy < SCALE; sy++) {
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for (let sx = 0; sx < SCALE; sx++) {
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const px = startX + sx;
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const py = startY + sy;
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// 边界检查：确保不超出Canvas边界，且不超出字符实际绘制区域
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if (px < 0 || py < 0 || px >= width || py >= height) {
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// 边界外视为背景（黑色）
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continue;
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}
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// 额外检查：确保不采样到字符右侧的残留区域
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if (px >= charEndX) {
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// 超出字符区域，视为背景
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continue;
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}
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const idx = (py * width + px) * 4;
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const R = pixelData[idx];
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const G = pixelData[idx + 1];
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const B = pixelData[idx + 2];
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const A = pixelData[idx + 3] || 255;
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// 计算亮度
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const luminance = 0.299 * R + 0.587 * G + 0.114 * B;
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const alpha = A / 255;
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// 背景是黑色，文字是白色，所以判断亮色（>=128）为文字点
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if (luminance >= 128 && alpha > 0.5) onCount++;
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total++;
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}
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}
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// 当亮色占比超过阈值时判为1（至少需要采样到一些像素）
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target[y * charWidth + x] = (total > 0 && onCount / total >= threshold) ? 1 : 0;
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}
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}
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const lowBytes = new Array(charWidth).fill(0);
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const highBytes = new Array(charWidth).fill(0);
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// 按列打包，每列13行分成上下两字节：低字节0-7行（8行），高字节8-12行（5行）
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for (let col = 0; col < charWidth; col++) {
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for (let row = 0; row < charHeight; row++) {
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const pixel = target[row * charWidth + col];
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if (pixel === 1) {
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if (row < 8) {
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// 低字节：0-7行，从低位到高位
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lowBytes[col] |= (1 << row);
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} else {
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// 高字节：8-12行，从低位到高位（使用5位，剩余3位未使用）
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highBytes[col] |= (1 << (row - 8));
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}
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}
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}
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}
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return [...lowBytes, ...highBytes];
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}
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let drawTxt = async (textLine) => {
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let result = {};
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let ctx = this.ctx;
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// 1. 动态调整Canvas尺寸（高分辨率）
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// 设备端使用13x13点阵渲染
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this.currentCanvasWidth = 13 * SCALE + PADDING_X;
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this.currentCanvasHeight = 13 * SCALE;
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// 2. 清空Canvas（绘制背景）
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this.clearCanvas();
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// 3. 设置文字样式（整数像素对齐，顶部基线，避免首字裁剪）
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ctx.setFillStyle(this.color);
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ctx.setTextBaseline('top');
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ctx.setTextAlign('left');
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const fs = Math.max(1, Math.round(this.fontSize)) * SCALE;
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ctx.setFontSize(fs);
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ctx.font = `${fs}px "PingFangBold", "PingFang SC", Arial, sans-serif`;
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// 4. 绘制单个字符（每个字符独立绘制在固定位置）
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// 确保字符始终从PADDING_X开始绘制，Y坐标为0，保证采样一致性
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const charX = PADDING_X;
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const charY = 0;
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ctx.fillText(textLine, charX, charY);
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// 5. 异步绘制并获取像素数据（串行处理避免冲突）
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await new Promise((resolve, reject) => {
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ctx.draw(false, () => {
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uni.canvasGetImageData({
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canvasId: 'reusableCanvas',
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x: 0,
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y: 0,
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width: this.currentCanvasWidth,
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height: this.currentCanvasHeight,
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success: res => {
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result = {
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line: textLine,
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pixelData: res.data,
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width: this.currentCanvasWidth,
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height: this.currentCanvasHeight
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};
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resolve();
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},
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fail: err => {
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// console.error(`处理第${i+1}行失败:`, err);
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reject(err)
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}
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});
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});
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});
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return result;
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}
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let arr = [];
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// 循环处理每行文本
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for (let i = 0; i < this.validTxts.length; i++) {
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let linePixls = [];
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let item = this.validTxts[i];
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// console.log("item=", item);
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for (var j = 0; j < item.length; j++) {
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let char = item[j];
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let result = await drawTxt(char);
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let matrix = convertCharToMatrix(result, item);
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// 调试：打印每个字符的点阵数据
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console.log(`[点阵生成] 字符"${char}" 点阵数据:`, matrix.map(b => '0x' + b.toString(16).padStart(2, '0')).join(' '));
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linePixls.push(matrix);
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}
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// console.log("hexs=", linePixls.join(","));
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arr.push(linePixls);
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}
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return arr;
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}
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}
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};
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</script>
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<style>
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.offscreen-canvas {
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position: fixed;
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left: -9999px;
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top: -9999px;
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}
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</style> |