Unwanted ligatures

[zimt28]

I want to use a font from fonts.google.com and am running into an issue.

I've included the font (Nunito) like so:

const nunitoBoldUrl =
  "https://fonts.gstatic.com/s/nunito/v12/XRXW3I6Li01BKofA6sKUYevIWzgPDA.woff2";
const nunitoBoldFontBytes = await fetch(nunitoBoldUrl).then((res) => res.arrayBuffer());

const nunitoBold = await pdfDoc.embedFont(nunitoBoldFontBytes);

This works, with one exception (there might be more, but this is what I could find):

Printing fi adds unwanted spacing after it which shouldn't be there, the Google preview also doesn't show it.

fi ir fir:

I think the font has a special ligature for fi, if I install the font on my system I get the same connected f and i letters, but without the spacing. Is this an issue with pdf-kit or fontkit?

[fobdy]

The same problem for me with "Source Sans Pro" font and "ft"

[fobdy]

We could try to turn off the ligatures if there was access to the low-level fontkit api

font.layout(lineTxt, { liga:false })

Related foliojs/fontkit#170

[zimt28]

@fobdy Which file format are you trying to use?

[fobdy]

@fobdy Which file format are you trying to use?

I'm using .ttf.
Update: the same with .otf
Fonts that are used: https://github.com/adobe-fonts/source-sans-pro/releases/tag/3.006R

[Hopding]

Hello @zimt28 @fobdy! As far as I'm aware this is an issue with fontkit, though I haven't been able to confirm this. If anybody is interested, it is possible to disable ligatures when performing text layout with fontkit (as @fobdy mentioned). You would just need to update the API to pass options here:

pdf-lib/src/core/embedders/CustomFontEmbedder.ts

Lines 52 to 57 in 193e48f

	/**
	* Encode the JavaScript string into this font. (JavaScript encodes strings in
	* Unicode, but embedded fonts use their own custom encodings)
	*/
	encodeText(text: string): PDFHexString {
	const { glyphs } = this.font.layout(text);

I'd be happy to accept a PR if anybody is interested in working on this.

[Hopding]

Version 1.14.0 includes an API that can disable font ligatures (thanks to @hefler!):

pdf-lib/apps/node/tests/test6.ts

Lines 37 to 40 in c957768

	const nunitoNoLigaFont = await pdfDoc.embedFont(fonts.ttf.nunito, {
	subset: true,
	features: { liga: false },
	});

[direnc]

Same problem with Garamond. features: { liga: false } solution is not working, still with spacing .

[ephraimduncan]

Same problem with Caveat, disabling ligatures is not working

[r4dulf]

@ephraimduncan For the Caveat font, setting calt: false solved the problem

 const caveatRegular = await documentProxy.embedFont(caveatFontData, {
    features: { calt: false },
  });