Determining when to use disableFontFace

[tristansokol]

I'm running into issues similar to #4244 but am interested in knowing if there is a way to programmatically determine if I should use disableFontFace.

I'm attempting to OCR invoices, and some of them render correctly with disableFontFace:false and others with disableFontFace:true, if you supply a pdf the wrong disableFontFace you end up with a pdf that is void of text, or has boxes as is documented in other issues.

My question is, Is there a way to determine (via the pdfDocument metadata or any other means) if I should use the disableFontFace option when calling .getDocument()?

I have tried getting text content and looking at fonts, but I'm not sure if I can just say "oh this text content seems to be all in Helvetica, so I know that I need to use disableFontFace:true" That information and a list of system fonts seems like the only path forward based on the other issues I've read.

Thank you.

[sayo96]

@timvandermeij is there any update on this?

[tristansokol]

@sayo96 as far as I am aware there is not a way to determine which setting you need, and depending on your pdfs you may need the effects of both setting to correctly render.

[Snuffleupagus]

After PR #12726, rendering of standard fonts should work even with disableFontFace = true set; assuming obviously that the standardFontDataUrl parameter is correctly set when calling getDocument:

pdf.js/src/display/api.js

Lines 168 to 169 in 891f21f

	* @property {string} [standardFontDataUrl] - The URL where the standard font
	* files are located. Include the trailing slash.

Furthermore, it should also be possible to successfully use disableFontFace = false now (i.e. the default value); possibly you may need to manually set useSystemFonts = false in that case (if you're using PDF.js in a browser).