From 22e88504ab61a622fb9bcf38cf54728286f33bce Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=BCri=20Valdmann?= Date: Mon, 7 Oct 2019 12:30:27 +0200 Subject: Move lifecycle docs to features page Also fix incorrect \since versions in QML API docs. Change-Id: I87b5899d4a55832dca2cd251aeb681e4bb2de2a2 Reviewed-by: Leena Miettinen --- .../webengine/lifecycle/doc/src/lifecycle.qdoc | 67 +--------------------- 1 file changed, 2 insertions(+), 65 deletions(-) (limited to 'examples/webengine') diff --git a/examples/webengine/lifecycle/doc/src/lifecycle.qdoc b/examples/webengine/lifecycle/doc/src/lifecycle.qdoc index 4151d0597..d10e617e3 100644 --- a/examples/webengine/lifecycle/doc/src/lifecycle.qdoc +++ b/examples/webengine/lifecycle/doc/src/lifecycle.qdoc @@ -38,6 +38,8 @@ properties of the \l {WebEngineView} can be used to reduce the CPU and memory usage of background tabs in a tabbed browser. + For an overview of the lifecycle feature, see \l {Page Lifecycle API}. + \include examples-run.qdocinc \section1 UI Elements of the Example @@ -53,71 +55,6 @@ window also has a \l {Drawer} for changing settings. The drawer can be opened by clicking the "⋮" button on the tool bar. - \section1 Overview of Lifecycle States - - Each \l {WebEngineView} item can be in one of three \e {lifecycle states}: - active, frozen, or discarded. These states, like the sleep states of a CPU, - control the resource usage of web views. - - The \e {active} state is the normal, unrestricted state of a web view. All - visible web views are always in the active state, as are all web views that - have not yet finished loading. Only invisible, idle web views can be - transitioned to other lifecycle states. - - The \e {frozen} state is a low CPU usage state. In this state, most HTML - task sources are suspended (frozen) and, as a result, most DOM event - processing and JavaScript execution will also be suspended. The web view - must be invisible in order to be frozen as rendering is not possible in this - state. - - The \e {discarded} state is an extreme resource-saving state. In this state, - the browsing context of the web view will be discarded and the corresponding - renderer subprocess shut down. CPU and memory usage in this state is reduced - virtually to zero. On exiting this state the web page will be automatically - reloaded. The process of entering and exiting the discarded state is similar - to serializing the browsing history of the web view and destroying the view, - then creating a new view and restoring its history. - - See also \l {WebEngineView::LifecycleState}. The equivalent in the Widgets - API is \l {QWebEnginePage::LifecycleState}. - - \section2 The \c {lifecycleState} and \c {recommendedState} Properties - - The \l {WebEngineView::}{lifecycleState} property of the \l {WebEngineView} - type is a read-write property that controls the current lifecycle state of - the web view. This property is designed to place as few restrictions as - possible on what states can be transitioned to. For example, it is allowed - to freeze a web view that is currently playing music in the background, - stopping the music. In order to implement a less aggressive resource-saving - strategy that avoids interrupting user-visible background activity, the \l - {WebEngineView::} {recommendedState} property must be used. - - The \l {WebEngineView::}{recommendedState} property of the \l - {WebEngineView} type is a read-only property that calculates a safe limit on - the \l {WebEngineView::}{lifecycleState} property, taking into account the - current activity of the web view. So, in the example of a web view playing - music in the background, the recommended state will be \c {Active} since a - more aggressive state would stop the music. If the application wants to - avoid interrupting background activity, then it should avoid putting the web - view into a more aggressively resource-saving lifecycle state than what's - given by \l {WebEngineView::}{recommendedState}. - - See also \l {WebEngineView::lifecycleState} and \l - {WebEngineView::recommendedState}. The equivalents in the Widgets API are \l - {QWebEnginePage::lifecycleState} and \l {QWebEnginePage::recommendedState}. - - \section2 The Page Lifecycle API - - The \l {WebEngineView::}{lifecycleState} property is connected to the \l - {https://wicg.github.io/page-lifecycle/spec.html}{Page Lifecycle API}, a - work-in-progress extension to the HTML standard that specifies two new DOM - events, \c {freeze} and \c {resume}, and adds a new \c - {Document.wasDiscarded} boolean property. The \c {freeze} and \c {resume} - events are fired when transitioning from the \c {Active} to the \c {Frozen - state}, and vice-versa. The \c {Document.wasDiscarded} property is set to \c - {true} when transition from the \c {Discarded} state to the \c {Active} - state. - \section1 Lifecycle States in the Example The example implements two ways of changing the lifecycle state: manual and -- cgit v1.2.3