fix: rewrite PDF generator using pdf-lib native embedFont for CJK support
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Developer
@@ -1,11 +1,11 @@
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import * as fs from 'fs';
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import * as path from 'path';
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import { PDFDocument, rgb } from 'pdf-lib';
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import { PDFDocument, rgb, StandardFonts, PageSizes } from 'pdf-lib';
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const FONT_SEARCH_PATHS = [
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path.join(__dirname, '..', '..', '..', 'assets', 'fonts', 'NotoSansSC-VF.ttf'),
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'C:/Windows/Fonts/NotoSansSC-VF.ttf',
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'C:/Windows/Fonts/msyh.ttc',
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'C:/Windows/Fonts/msyhbd.ttc',
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'C:/Windows/Fonts/simsun.ttc',
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'/usr/share/fonts/opentype/noto/NotoSansCJK-Regular.ttc',
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'/usr/share/fonts/truetype/noto/NotoSansCJK-Regular.ttc',
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@@ -37,145 +37,83 @@ interface PdfSection {
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lines: string[];
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}
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function textToHex(str: string): string {
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let hex = '';
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for (let i = 0; i < str.length; i++) {
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hex += str.charCodeAt(i).toString(16).toUpperCase().padStart(4, '0');
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}
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return hex;
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}
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export async function generateAssessmentPdf(options: PdfReportOptions): Promise<Buffer> {
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const doc = await PDFDocument.create();
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let font: any;
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const fontBytes = findFont();
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if (fontBytes.length === 0) {
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throw new Error('No CJK font found. Install Noto Sans SC or similar.');
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}
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const FONT_DESC_REF = { ref: null as any };
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const FONT_REF = { ref: null as any };
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function prepareFont(page: any) {
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const fontProgRef = ctx.nextRef();
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ctx.assign(fontProgRef, ctx.flateStream(fontBytes));
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const fontDescRef = ctx.nextRef();
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ctx.assign(fontDescRef, ctx.obj({
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Type: 'FontDescriptor',
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FontName: 'CJKFont',
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Flags: 4,
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FontBBox: [0, -300, 1000, 1000],
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ItalicAngle: 0,
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Ascent: 900,
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Descent: -200,
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CapHeight: 800,
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StemV: 80,
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FontFile2: fontProgRef,
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}));
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FONT_DESC_REF.ref = fontDescRef;
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const cidFontRef = ctx.nextRef();
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ctx.assign(cidFontRef, ctx.obj({
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Type: 'Font',
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Subtype: 'CIDFontType2',
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BaseFont: 'CJKFont',
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CIDSystemInfo: ctx.obj({
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Registry: 'Adobe',
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Ordering: 'Identity',
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Supplement: 0,
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}),
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FontDescriptor: fontDescRef,
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W: [0, [500]],
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}));
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const fontRef = ctx.nextRef();
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ctx.assign(fontRef, ctx.obj({
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Type: 'Font',
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Subtype: 'Type0',
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BaseFont: 'CJKFont',
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Encoding: 'Identity-H',
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DescendantFonts: [cidFontRef],
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}));
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FONT_REF.ref = fontRef;
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const fontKey = page.node.newFontDictionaryKey('F1');
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page.node.setFontDictionary(fontKey, fontRef);
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if (fontBytes.length > 0) {
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try {
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font = await doc.embedFont(fontBytes, { subset: true });
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} catch {
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font = undefined;
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}
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}
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if (!font) {
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font = await doc.embedFont(StandardFonts.Helvetica);
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}
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const pageWidth = PageSizes.A4[0];
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const pageHeight = PageSizes.A4[1];
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const margin = 50;
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const pageWidth = 595.28;
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const pageHeight = 841.89;
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const fontSize = 10;
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const titleSize = 20;
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const sectionSize = 13;
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const lineHeight = fontSize * 1.6;
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const ctx = doc.context as any;
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let currentPage = doc.addPage([pageWidth, pageHeight]);
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let contentOps = '';
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let y = pageHeight - 50;
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function drawPage(title: string, titleSize: number, sections: PdfSection[]): void {
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const page = doc.addPage([pageWidth, pageHeight]);
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let y = pageHeight - margin;
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prepareFont(currentPage);
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page.drawText(title, { x: margin, y, size: titleSize, font, color: rgb(0, 0, 0) });
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y -= titleSize * 1.8;
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function addFontToPage(page: any) {
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const fontKey = page.node.newFontDictionaryKey('F1');
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page.node.setFontDictionary(fontKey, FONT_REF.ref);
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}
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function ensureSpace(needed: number) {
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const bottomMargin = 60;
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if (y - needed < bottomMargin) {
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const contentObj = ctx.flateStream(contentOps);
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const contentRef = ctx.nextRef();
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ctx.assign(contentRef, contentObj);
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currentPage.node.addContentStream(contentRef);
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currentPage = doc.addPage([pageWidth, pageHeight]);
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addFontToPage(currentPage);
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contentOps = '';
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y = pageHeight - 50;
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if (options.subtitle) {
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page.drawText(options.subtitle, { x: margin, y, size: 9, font, color: rgb(0.4, 0.4, 0.4) });
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y -= 16;
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}
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}
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function addLine(text: string, size: number, bold: boolean = false) {
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const lines = text.split('\n');
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for (const line of lines) {
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ensureSpace(size * 1.5);
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const hex = textToHex(line);
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contentOps += `BT\n/F1 ${size} Tf\n1 0 0 1 ${margin} ${y} Tm\n<${hex}> Tj\nET\n`;
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y -= size * 1.5;
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for (const section of sections) {
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y -= 8;
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if (y < margin + sectionSize * 2) {
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y = pageHeight - margin;
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}
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page.drawText(section.title, { x: margin, y, size: sectionSize, font, color: rgb(0.1, 0.1, 0.1) });
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y -= sectionSize * 1.8;
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for (const line of section.lines) {
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const chunks = wrapLine(line, font, fontSize, pageWidth - margin * 2);
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for (const chunk of chunks) {
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if (y < margin + lineHeight) {
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y = pageHeight - margin;
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}
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page.drawText(chunk, { x: margin, y, size: fontSize, font, color: rgb(0.2, 0.2, 0.2) });
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y -= lineHeight;
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}
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}
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}
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page.drawText('--- End of Report ---', { x: margin, y: margin, size: 8, font, color: rgb(0.6, 0.6, 0.6) });
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}
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function addSeparator() {
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ensureSpace(12);
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let hex = '';
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for (let i = 0; i < 55; i++) hex += '002D';
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contentOps += `BT\n/F1 8 Tf\n1 0 0 1 ${margin} ${y} Tm\n<${hex}> Tj\nET\n`;
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y -= 12;
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}
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addLine(options.title, 22);
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y -= 4;
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if (options.subtitle) {
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addLine(options.subtitle, 10);
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y -= 4;
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}
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addSeparator();
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for (const section of options.sections) {
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ensureSpace(30);
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addLine(section.title, 12);
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for (const line of section.lines) {
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addLine(line, 10);
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}
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y -= 6;
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}
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addSeparator();
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addLine('--- End of Report ---', 9);
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const contentObj = ctx.flateStream(contentOps);
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const contentRef = ctx.nextRef();
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ctx.assign(contentRef, contentObj);
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currentPage.node.addContentStream(contentRef);
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drawPage(options.title, titleSize, options.sections);
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return Buffer.from(await doc.save());
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}
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function wrapLine(text: string, _font: any, fontSize: number, maxWidth: number): string[] {
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if (!text || text.length === 0) return [''];
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const chunks: string[] = [];
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const lines = text.split('\n');
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for (const line of lines) {
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if (line.length === 0) {
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chunks.push('');
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continue;
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}
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const estimatedCharsPerLine = Math.max(1, Math.floor(maxWidth / (fontSize * 0.6)));
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for (let i = 0; i < line.length; i += estimatedCharsPerLine) {
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chunks.push(line.substring(i, i + estimatedCharsPerLine));
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}
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}
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return chunks.length > 0 ? chunks : [text];
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}
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