1165644 - [e10s] "Tab Preview" addon does not work

Status: RESOLVED INCOMPLETE

(Firefox :: Extension Compatibility, defect)

Description

[tidus098]

Attachment: Browse console when trying with addon

Addon Name: Tab Preview
Version: 0.3

Expected to happen:
When placing the cursor over a tab, show a popup preview

Actually happened:
Shows a blank popup

Comment 1

[Chris Peterson [:cpeterson]]

Ted, it looks like your Tab Preview add-on is not e10s compatible.

Comment 2

[(not currently active) Ted Mielczarek]

I'm not actively maintaining any of my addons, but TBH I'm kind of surprised this doesn't work! The meat of the extension boils down to calling ctx.drawWindow(window, ...) where ctx is a 2d Canvas context, and win is a tabbrowser.contentWindow. I put the source up on GitHub since apparently I didn't have it in VCS anywhere:
https://github.com/luser/tabpreview/blob/master/chrome/content/overlay.js#L227

I just installed it and tried it locally, and the console shows:
TabPreview Error: Argument 1 of CanvasRenderingContext2D.drawWindow does not implement interface Window.

so I guess contentWindow isn't really a Window?

Comment 3

[Mike Conley (:mconley) (:⚙️)]

(In reply to Ted Mielczarek [:ted.mielczarek] from comment #2)
> I'm not actively maintaining any of my addons, but TBH I'm kind of surprised
> this doesn't work! The meat of the extension boils down to calling
> ctx.drawWindow(window, ...) where ctx is a 2d Canvas context, and win is a
> tabbrowser.contentWindow. I put the source up on GitHub since apparently I
> didn't have it in VCS anywhere:
> https://github.com/luser/tabpreview/blob/master/chrome/content/overlay.
> js#L227
> 
> I just installed it and tried it locally, and the console shows:
> TabPreview Error: Argument 1 of CanvasRenderingContext2D.drawWindow does not
> implement interface Window.
> 
> so I guess contentWindow isn't really a Window?

In this case, no, it is not - contentWindow is a CPOW.

I do recall us having problems with tab drag-and-drop thumbnails (which use the same technique, I believe). I just tested, and they still appear to be disabled, so I suspect we haven't solved that problem yet. When we do, you'll probably need to adopt a similar solution.

jimm, I think I recall you working on that tab drag-and-drop thumbnail stuff, but I can't find the bug... do you happen to recall what it is?

Comment 4

[Jim Mathies [:jimm]]

(In reply to Mike Conley (:mconley) - Needinfo me! from comment #3)
> (In reply to Ted Mielczarek [:ted.mielczarek] from comment #2)
> > I'm not actively maintaining any of my addons, but TBH I'm kind of surprised
> > this doesn't work! The meat of the extension boils down to calling
> > ctx.drawWindow(window, ...) where ctx is a 2d Canvas context, and win is a
> > tabbrowser.contentWindow. I put the source up on GitHub since apparently I
> > didn't have it in VCS anywhere:
> > https://github.com/luser/tabpreview/blob/master/chrome/content/overlay.
> > js#L227
> > 
> > I just installed it and tried it locally, and the console shows:
> > TabPreview Error: Argument 1 of CanvasRenderingContext2D.drawWindow does not
> > implement interface Window.
> > 
> > so I guess contentWindow isn't really a Window?
> 
> In this case, no, it is not - contentWindow is a CPOW.
> 
> I do recall us having problems with tab drag-and-drop thumbnails (which use
> the same technique, I believe). I just tested, and they still appear to be
> disabled, so I suspect we haven't solved that problem yet. When we do,
> you'll probably need to adopt a similar solution.
> 
> jimm, I think I recall you working on that tab drag-and-drop thumbnail
> stuff, but I can't find the bug... do you happen to recall what it is?

You can use the async apis in PagerThumbs, should be easy to convert over:

http://mxr.mozilla.org/mozilla-central/source/toolkit/components/thumbnails/PageThumbs.jsm#195

Comment 5

[Jerod Lycett]

Should I mark this as wontfix or leave it open?

Comment 6

[Jorge Villalobos [:jorgev] (he/him)]

Based on comment #2, I think this is WONTFIX.

Comment 7

[Jerod Lycett]

(In reply to Jorge Villalobos [:jorgev] from comment #6)
> Based on comment #2, I think this is WONTFIX.

Just being polite.

Comment 8

[Firefox Bug Husbandry Bot]

With Firefox 57 only WebExtensions are permitted and are, by default, e10s compatible.