Thai Font Support

MheePDF supports complex Thai text layout, including proper positioning of vowels and tone marks.

CAUTION

Usage with Thai language must include a custom Thai font (TTF). Standard PDF fonts (like Helvetica, Times) do not contain Thai glyphs or layout tables.

How it works

Behind the scenes, MheePDF uses HarfBuzz (via harfbuzzjs) and opentype.js to shape the text:

1. It parses the TTF font file.
2. It shapes the character clusters (consonants, vowels, tone marks).
3. It places glyphs at the exact coordinates calculated by the shaper, preventing vowel-overlapping and floating tone marks.

Example Usage

Here is how you can render Thai text using a custom TTF font:

import { MheePDF, PDFType0FontObject } from "mheepdf";
import { readFile } from "fs/promises";

// 1. Load your TTF font buffer (e.g. TH Sarabun New)
const fontBuffer = await readFile("./fonts/Sarabun-Regular.ttf");

// 2. Wrap it with PDFType0FontObject
const sarabunFont = new PDFType0FontObject(fontBuffer);

// 3. Initialize MheePDF with the custom font
const pdf = new MheePDF({
  pageSize: MheePDF.A4,
  fonts: [sarabunFont],
  defaultFont: sarabunFont, // Use it as the default font
});

// 4. Add Thai text
pdf.addText("สวัสดีประเทศไทย");
pdf.addText("จัดหน้าอัตโนมัติ เท่ไหมละครับ");
pdf.addText("\n");
pdf.addText("เพื่อที่โลกาภิวัตน์หรือกระแสความเปลี่ยนแปลงด้านต่างๆ...");

// 5. Generate
const pdfBuffer = await pdf.generatePDFcontent();
await Bun.write("test_thai.pdf", pdfBuffer);