Bug 44594 – [Qt] Add Visibility notification NPAPI for plugins

• Component: Plug-ins
• Status: RESOLVED FIXED

[Girish Ramakrishnan]

There is some discussion on plugin-features to implement a plugin visibility notification to NPAPI. The cases are
- Plug-in instance goes out of sight after page scrolling.
- Plug-in instance comes in sight after page scrolling.
- Plug-in instance goes out of sight after browser window goes background.
- Plug-in instance comes in sight after browser window goes foreground.

See thread about it at:
https://mail.mozilla.org/pipermail/plugin-futures/2010-July/000123.html

Wiki entry:
https://wiki.mozilla.org/NPAPI:VisibilityNotification

The bugzilla:
https://bugzilla.mozilla.org/show_bug.cgi?id=583109

This is probably interesting to all platforms but note that the public flash player does not support it and hence this task is Qt/Maemo5 specific for now.

[Girish Ramakrishnan]

The clipRect parameter of SetWindow is used different on Mac and Linux/Windows.

On Mac, it is used to indicate the position of the plugin. When clipRect is set to 0, it means that it's not visible anymore.

On Linux/Windows, clipRect indicates the clipping rect for the painting operation and is called before every paint(). In the plugin-features thread, Adobe person mentions that clipRect is used only on Mac (https://mail.mozilla.org/pipermail/plugin-futures/2010-July/000125.html). So, I guess Flash doesn't use this value.

Currently, in Qt/WebKit, clipRect is always set to 0 on X11 in Windowless mode. In Windowed mode, we call it with the visibile rect but with a quirk (PluginQuirkDontCallSetWindowMoreThanOnce) wherein the height/width is never changed in the lifetime of the plugin.

[Girish Ramakrishnan]

Created attachment 65453 [details]
Set clipRect correctly on X11

[Kenneth Rohde Christiansen]

Comment on attachment 65453 [details]
Set clipRect correctly on X11

WebCore/plugins/qt/PluginViewQt.cpp:588
 +          // position and clipRect is relative to the Drawable
comments start with capital and ends with . Why is Drawable with a capital d?

The comments could be a bit more explanatory.

[Girish Ramakrishnan]

Created attachment 65545 [details]
Set clipRect correctly on X11

Ok, I have a better patch now that also takes care of setting the clip rect to 0 when the plugin is scrolled out in both windowed and windowless mode.

[WebKit Review Bot]

Attachment 65545 [details] did not pass style-queue:

Failed to run "['WebKitTools/Scripts/check-webkit-style']" exit_code: 1
WebCore/plugins/qt/PluginViewQt.cpp:588:  Tests for true/false, null/non-null, and zero/non-zero should all be done without equality comparisons.  [readability/comparison_to_zero] [5]
Total errors found: 1 in 2 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Girish Ramakrishnan]

Created attachment 65546 [details]
Set clipRect correctly on X11

Fix codings style

[Girish Ramakrishnan]

Landed in r66095

[WebKit Review Bot]

http://trac.webkit.org/changeset/66095 might have broken Qt Linux Release

[Simon Hausmann]

Committed r66097: <http://trac.webkit.org/changeset/66097>

[Simon Hausmann]

Committed r66095: <http://trac.webkit.org/changeset/66095>

[Ademar Reis]

Revision r66095 cherry-picked into qtwebkit-2.1 with commit 4a3c8a09303316623216e38f5dea9e0b3f215a26
Revision r66097 cherry-picked into qtwebkit-2.1 with commit fb2dbc367407000b4a1e7d741e740d8b1417946d