1658333 - printToPDF produces a file that is small and low-resolution relative to Chrome

Status: RESOLVED WONTFIX

(Remote Protocol :: CDP, defect, P3)

Description

[Maja Frydrychowicz :impossibus (was :maja_zf) (needinfo me)]

Attachment: issue-5671-firefox.pdf

Taking a screenshot of the same document in Chrome and Firefox produces different-quality pdf files: the pdf produced by Chrome has a much larger file size and image resolution. See attached example pdfs, which are the result of running the script from this (unrelated) Puppeteer issue: https://github.com/puppeteer/puppeteer/issues/5671

Snippet:

await page.pdf({
        printBackground: true, 
        fullPage: true,
	path: 'issue-5671.pdf'});

A recent change affecting printToPDF is Bug 1632722, but the PDF quality difference was present before that fix landed.

Comment 1

[Maja Frydrychowicz :impossibus (was :maja_zf) (needinfo me)]

Attachment: issue-5671-chrome.pdf

Comment 2

[Maja Frydrychowicz :impossibus (was :maja_zf) (needinfo me)]

True both with and without headless.

Might be Linux-specific (I've only tried there.)

I can see some differences in file metadata:

• Chrome pdf: format PDF 1.4, producer Skia/PDF m85
• Firefox pdf: format PDF 1.5, producer cairo 1.9.5 (http://cairographics.org)

Comment 3

[Henrik Skupin [:whimboo][⌚️UTC+2] (away 10/03 - 10/13)]

Jonathan, is there any way for us right now to specify the compression of the PDF file as generated by Firefox? I can remember that you are working on a refactoring, so maybe it could be added if not existent yet?

Comment 4

[Jonathan Watt [:jwatt]]

There's no way to do this currently, but bug 1639844 covers the first necessary step to make this possible.

Comment 5

[Henrik Skupin [:whimboo][⌚️UTC+2] (away 10/03 - 10/13)]

Good to know. I will mark it as blocker for now to keep track of activity.

Comment 6

[Jonathan Watt [:jwatt]]

Bug 1662820 increased the default resolution for Windows, and bug 1664258 increased it for other platforms and added the float pref print.default_dpi to make this configurable. (Note float prefs are stored as strings, in case anyone wants to experiment with that.)

Comment 7

[Henrik Skupin [:whimboo][⌚️UTC+2] (away 10/03 - 10/13)]

I'll check if that still reproduces.

Comment 8

[Henrik Skupin [:whimboo][⌚️UTC+2] (away 10/03 - 10/13)]

If it's failing or not anymore, we are not going to fix this bug for CDP.