diff options
| -rw-r--r-- | src/core/render_widget_host_view_qt.cpp | 21 | ||||
| -rw-r--r-- | src/webengine/doc/src/qtwebengine-platform-notes.qdoc | 20 |
2 files changed, 38 insertions, 3 deletions
diff --git a/src/core/render_widget_host_view_qt.cpp b/src/core/render_widget_host_view_qt.cpp index 6568398a8..72abe04af 100644 --- a/src/core/render_widget_host_view_qt.cpp +++ b/src/core/render_widget_host_view_qt.cpp @@ -237,6 +237,19 @@ private: float dpiScale; }; +bool isAccessibilityEnabled() { + // On Linux accessibility is disabled by default due to performance issues, + // and can be re-enabled by setting the QTWEBENGINE_ENABLE_LINUX_ACCESSIBILITY environment + // variable. For details, see QTBUG-59922. +#ifdef Q_OS_LINUX + static bool accessibility_enabled + = qEnvironmentVariableIsSet("QTWEBENGINE_ENABLE_LINUX_ACCESSIBILITY"); +#else + const bool accessibility_enabled = true; +#endif + return accessibility_enabled; +} + RenderWidgetHostViewQt::RenderWidgetHostViewQt(content::RenderWidgetHost* widget) : m_host(content::RenderWidgetHostImpl::From(widget)) , m_gestureProvider(QtGestureProviderConfig(), this) @@ -260,9 +273,11 @@ RenderWidgetHostViewQt::RenderWidgetHostViewQt(content::RenderWidgetHost* widget { m_host->SetView(this); #ifndef QT_NO_ACCESSIBILITY - QAccessible::installActivationObserver(this); - if (QAccessible::isActive()) - content::BrowserAccessibilityStateImpl::GetInstance()->EnableAccessibility(); + if (isAccessibilityEnabled()) { + QAccessible::installActivationObserver(this); + if (QAccessible::isActive()) + content::BrowserAccessibilityStateImpl::GetInstance()->EnableAccessibility(); + } #endif // QT_NO_ACCESSIBILITY auto* task_runner = base::ThreadTaskRunnerHandle::Get().get(); m_beginFrameSource.reset(new cc::DelayBasedBeginFrameSource( 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. + */ |