1602410 - Make `window.print()` work with tab-modal printing

Status: RESOLVED FIXED

(Core :: Printing: Setup, task, P1)

Description

[Jonathan Watt [:jwatt]]

(Edited 2020-08-10 to provide a useful summary and up-to-date understanding of what we need.)

We need window.print() to synchronously create the printing static clone document so that pages that do the following have the print only changes in the print output:

makeChangesThatShouldOnlyShowInThePrintOutput();
window.print();
undoChangesThatShouldOnlyShowInThePrintOutput();

However, for the new printing UI we need the static clone to be generated in the browser element contained within the print preview doorhanger that the frontend opens. Obviously at the time that window.print() is called in the content process, the doorhanger isn't open in the parent process though.

To achieve both the above we will need to either:

• create and store the static clone synchronously during the window.print() call, message the parent to start printing, and the pick up and use the stored static clone after the roundprint to the parent to get it to open the doorhanger
• send an IPDL message to the parent process to open the doorhanger UI in window.print(), and either spin an event loop until the parent sends back the browser to clone into, or else use a blocking IPDL message

Comment 1

[Jonathan Watt [:jwatt]]

Attachment: Bug 1602410. Make `window.print()` invoke printing via the parent process using a JSWindowActor. r=Gijs,kmag

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/bc3a104f8b20
Make `window.print()` invoke printing via the parent process using a JSWindowActor. r=Gijs,kmag

Comment 3

[Narcis Beleuzu [:NarcisB]]

Backed out for build bustages on nsGlobalWindowOuter.cpp

Backout link: https://hg.mozilla.org/integration/autoland/rev/aa430c94ca59624d0128da2edd86a1294854a58e
Log link: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=282206995&repo=autoland&lineNumber=42980

Comment 4

[Jonathan Watt [:jwatt]]

Meh. I've mistakenly used JS::NumberValue instead of JS::BooleanValue. Why do normal builds not complain about that?

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/edf3df2adebb
Make `window.print()` invoke printing via the parent process using a JSWindowActor. r=Gijs,kmag

Comment 6

[Cristina Coroiu [:ccoroiu]]

https://hg.mozilla.org/mozilla-central/rev/edf3df2adebb

Comment 7

[Ryan VanderMeulen [:RyanVM]]

Backed out from Beta for suspicion of causing bug 1607671. This bug remains fixed on m-c for 74+.
https://hg.mozilla.org/releases/mozilla-beta/rev/93585cda453f

Comment 8

[Ryan VanderMeulen [:RyanVM]]

This was backed out for 74+ in bug 1607671.
https://hg.mozilla.org/integration/autoland/rev/d7e962f7ca16

Comment 9

[BugBot [:suhaib / :marco/ :calixte]]

There's a r+ patch which didn't land and no activity in this bug for 2 weeks.
:jwatt, could you have a look please?
For more information, please visit auto_nag documentation.

Comment 10

[Chris Peterson [:cpeterson]]

Tracking for Fission Nightly (M6c)

Comment 11

[Jonathan Watt [:jwatt]]

Attachment: Bug 1602410. Make `window.print()` invoke printing via the parent process using a JSWindowActor. WIP

Comment 12

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1602410 - Plumb an "is for printing" boolean through the window.open-ing code-paths.

Stash it in the openWindowInfo, so that eventually the front-end creates
a hidden window.

Comment 13

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1602410 - Centralize printing entry points in nsGlobalWindowOuter, and move cloning out of nsPrintJob.

This of course still needs some work. Things that I know need fixing:

• Make the frontend not create a visible tab for window.print().
  Instead, probably just create a headless / hidden browser.

• Make the print preview stuff work by either not creating a hidden
  browser for that case (creating the print preview UI in the
  window-opening codepath), or swapping frame loaders with the hidden
  window from the print preview UI.

• Make the print preview viewer have an about:printpreview url (because
  it's special-cased in some cases).

• Fix some other print-preview tests (I've fixed the main one).

• Handle print preview settings changes. Right now I could just call
  printPreviewWindow.printPreview() again I guess, and that'd preserve
  behavior (and keep re-cloning clones), so may be worth doing to get
  this landed, but the idea is that eventually to update the print
  preview settings we don't go through window.printPreview() and
  instead go through a new API in the preview window, that just
  re-creates the print job and presentation.

Depends on D87062

Comment 14

[Emilio Cobos Álvarez (:emilio)]

Comment on attachment 9170014 [details]
Bug 1602410 - Centralize printing entry points in nsGlobalWindowOuter, and move cloning out of nsPrintJob.

As noted, some work still needed, but wdyt of something like this?

Comment 15

[Nika Layzell [:nika] (ni? for response)]

Comment on attachment 9170014 [details]
Bug 1602410 - Centralize printing entry points in nsGlobalWindowOuter, and move cloning out of nsPrintJob.

Added some comments on the revision - generally looks good

Comment 16

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1602410 - Make window.print() work with tab-modal printing. r=nika!,jwatt!

Do this by spinning the event loop until we've done the clone for
preview as appropriate.

This should be much less risky than finishing the previous patches
which would still be nice, but realistically landing them for 81 is not
going to happen.

This just returns without doing nothing in a couple cases, like when
there's already another modal dialog or such. That seems acceptable to
me, it's not clear what better way to do would be.

Comment 17

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e650c0acb702
Make window.print() work with tab-modal printing. r=nika,geckoview-reviewers,agi

Comment 18

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/e650c0acb702

Comment 19

[Phabricator Automation]

Comment on attachment 9170014 [details]
Bug 1602410 - Centralize printing entry points in nsGlobalWindowOuter, and move cloning out of nsPrintJob.

Revision D87063 was moved to bug 1636728. Setting attachment 9170014 [details] to obsolete.