Embed font: subset breaks if text contains a dash

[timotheeg]

What were you trying to do?

Embed just a subset of a font into a pdf.

How did you attempt to do it?

I used the property subset:true. If I set subset:false, the documents gets generated correctly, including the dashes character

What actually happened?

The program crashed with message:

/Users/timotheeg/work/signify/backend/node_modules/@pdf-lib/fontkit/dist/fontkit.umd.js:1531
	    if (offset + ext > buf.length) throw new RangeError('Index out of range');
	                                   ^

RangeError: Index out of range
    at checkInt (/Users/timotheeg/work/signify/backend/node_modules/@pdf-lib/fontkit/dist/fontkit.umd.js:1531:43)
    at Uint8Array.writeUInt16BE (/Users/timotheeg/work/signify/backend/node_modules/@pdf-lib/fontkit/dist/fontkit.umd.js:1596:21)
    at TTFSubset._addGlyph (/Users/timotheeg/work/signify/backend/node_modules/@pdf-lib/fontkit/dist/fontkit.umd.js:40914:17)
    at TTFSubset.encode (/Users/timotheeg/work/signify/backend/node_modules/@pdf-lib/fontkit/dist/fontkit.umd.js:40952:13)
    at /Users/timotheeg/work/signify/backend/node_modules/@pdf-lib/fontkit/dist/fontkit.umd.js:40692:14
    at Item.run (/Users/timotheeg/work/signify/backend/node_modules/@pdf-lib/fontkit/dist/fontkit.umd.js:2632:13)
    at Timeout.drainQueue [as _onTimeout] (/Users/timotheeg/work/signify/backend/node_modules/@pdf-lib/fontkit/dist/fontkit.umd.js:2597:35)
    at listOnTimeout (node:internal/timers:564:17)
    at process.processTimers (node:internal/timers:507:7)

What did you expect to happen?

Document generation should succeed and export just the glyphs being used.

How can we reproduce the issue?

const { PDFDocument, rgb } = require('pdf-lib');
const fontkit =  require('@pdf-lib/fontkit');
const fs = require('fs/promises');

(async () => {
    const poppinsRegularFontBytesWeb = await (await fetch('https://fonts.gstatic.com/s/poppins/v20/pxiEyp8kv8JHgFVrJJfecnFHGPc.woff2')).arrayBuffer()
    const docContent = await fs.readFile('./Some_Dummy_PDF.pdf')

    const pdfDoc = await PDFDocument.load(docContent)

    pdfDoc.registerFontkit(fontkit)

    const fontPoppinsRegular = await pdfDoc.embedFont(poppinsRegularFontBytesWeb, {
        customName: 'PoppinsRegular',
        subset: true // set to false to see output with dash
    })

    const pages = pdfDoc.getPages()
    const page = pages[0]

    const textOffsetX = page.getWidth() * 0.1
    const textOffsetY = page.getHeight() * 0.5

    page.drawText('Text with Dash -', { // remove dash and it works, colon, coma, work either way
        x: textOffsetX,
        y: textOffsetY,
        size: 10,
        color: rgb(0, 0, 0),
        font: fontPoppinsRegular,
    })

    const pdfBytes = await pdfDoc.save()

    await fs.writeFile('./out.pdf', pdfBytes);
})();

Some_Dummy_PDF.pdf
out.pdf

Version

1.17.1

What environment are you running pdf-lib in?

Node

Checklist

• My report includes a Short, Self Contained, Correct (Compilable) Example.
• I have attached all PDFs, images, and other files needed to run my SSCCE.

Additional Notes

No response