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author | Alexandru Croitor <alexandru.croitor@qt.io> | 2017-04-27 18:06:46 +0200 |
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committer | Jani Heikkinen <jani.heikkinen@qt.io> | 2017-05-08 18:06:41 +0000 |
commit | 7f28424f864523f2b3ea2152d4686683bb03bd88 (patch) | |
tree | e202d15c60246c92e3616c1d8f9f44b6dc91b849 /src/webengine/doc/src | |
parent | 79759e69ccae1c10bbe78fc0f5d5e0711d7462a2 (diff) |
Disable accessibility support on Linux by default
For very big HTML pages, accessibility support can slow down the
loading and rendering of pages due to creation of many AXNodes
for every DOM node, and a lot of serializing and deserializing
between processes. Because accessibility is almost always enabled
on Linux, and there is no way to query if an accessibility feature
was explicitly requested, Qt WebEngine accessibility support on
Linux will be disabled by default.
Users can set the QTWEBENGINE_ENABLE_LINUX_ACCESSIBILITY
environment variable to re-enable accessibility support on Linux.
[ChangeLog][Accessibility][Linux] Accessibility is disabled
by default for Qt WebEngine on Linux.
Task-number: QTBUG-59922
Task-number: QTBUG-54650
Change-Id: Ib0454f6f753043838e4ecf2227d2249afc15a6ef
Reviewed-by: Kai Koehne <kai.koehne@qt.io>
Diffstat (limited to 'src/webengine/doc/src')
-rw-r--r-- | src/webengine/doc/src/qtwebengine-platform-notes.qdoc | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/webengine/doc/src/qtwebengine-platform-notes.qdoc b/src/webengine/doc/src/qtwebengine-platform-notes.qdoc index 06a4a53a9..57e3ce6a8 100644 --- a/src/webengine/doc/src/qtwebengine-platform-notes.qdoc +++ b/src/webengine/doc/src/qtwebengine-platform-notes.qdoc @@ -161,4 +161,24 @@ set to 1 or alternatively the \c{--no-sandbox} command line argument can be passed to the user application executable. + \section1 Accessibility and Performance + + Qt WebEngine enables accessibility support for web pages when the following conditions + are met: + + \list + \li Qt Core is configured and built with accessibility support enabled. + \li The QPA plugin is notified by the operating system that accessibility should be + activated. This happens for example when using a screen reader application on Windows + or VoiceOver on \macos. + \endlist + + Due to some limitations, the Linux QPA plugin almost always reports that accessibility should + be activated. On big HTML pages, this can cause a significant slowdown in rendering speed. + + Because of that, from Qt 5.9 onwards, Qt WebEngine accessibility support is disabled by default + on Linux. + It can be re-enabled by setting the \c QTWEBENGINE_ENABLE_LINUX_ACCESSIBILITY environment + variable to a non-empty value. + */ |