[Bug]: Silent print not working on Windows 10 (+solution strategy)

[conteit]

Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a bug report that matches the one I want to file, without success.

Electron Version

25.x.y-29.x.y

What operating system are you using?

Windows

Operating System Version

Windows 10 1809 and newer

What arch are you using?

x64

Last Known Working Electron version

24.8.8

Expected Behavior

I expect to be able to print webpage content on the whole page at the right size, instead This is what happens if printing non silently or with Chromium/Google Chrome.

Actual Behavior

I get everything printed in the center of the page in approx. a 4x5cm area. As reported thoughtfully in issue #39179.

Testcase Gist URL

No response

Additional Information

I know how to fix it, but I lack C++ and project knowledge for presenting a Pull Request.
The print out get shrunk because, if not specified, silent print, prints at 72 DPI. A better approach would be to query the printer for the actual DPI setting required (see GetDeviceCaps(hdc, LOGPIXELSX) and GetDeviceCaps(hdc, LOGPIXELSY) where hdc = CreateDCW(null, <printerName>, null, devmod) and devmod is retrieved from the printer via DocumentPropertiesW call)

I worked around it via print options object and resolved missing information outside electron. By checking electron code you should have everything in place for resolving the information I'm mentioning.

See #39179 for examples and further details.
Would be nice to have the issue back ported at least on 28.x.y.

Hope it helps.

[jkleinsc]

• Closing as duplicate of [Bug]: Silent print was incorrect paper layout with webContents.print, but layout was correct when I use print dailog #39179

[conteit]

@jkleinsc, I've open the issue because the one I'm duplicating was stale. Is there any actual plan to fix this behaviour?

[hothaifadev]

@conteit it's not just a windows 10 issue, i'm using windows 11 and have the same issue.