From 9bfdaadd36cdb5254d808688aa8485e5a592937d Mon Sep 17 00:00:00 2001 From: Michael Brasser Date: Thu, 7 Jul 2011 13:10:35 +1000 Subject: Document state fast-forwarding. Task-number: QTBUG-16049 Change-Id: Ib64cc8ec9396d426e623481a69f5a4a1b0fe5ec5 Reviewed-on: http://codereview.qt.nokia.com/2370 Reviewed-by: Qt Sanity Bot Reviewed-by: Bea Lam --- doc/src/declarative/qdeclarativestates.qdoc | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'doc/src') diff --git a/doc/src/declarative/qdeclarativestates.qdoc b/doc/src/declarative/qdeclarativestates.qdoc index 55f38c3596..9857894d2b 100644 --- a/doc/src/declarative/qdeclarativestates.qdoc +++ b/doc/src/declarative/qdeclarativestates.qdoc @@ -133,4 +133,26 @@ The \l {declarative/animation/states}{States and Transitions example} demonstrates how to declare a basic set of states and apply animated transitions between them. +\l{Using QML Behaviors with States} explains a common problem when using Behaviors +to animate state changes. + +\section1 State Fast Forwarding + +In order for Transition to correctly animate state changes, it is sometimes necessary +for the engine to fast forward and rewind a state (that is, internally set and unset the state) +before it is finally applied. The process is as follows: + +\list 1 +\o The state is fast forwarded to determine the complete set of end values. +\o The state is rewound. +\o The state is fully applied, with transitions. +\endlist + +In some cases this may cause unintended behavior. For example, a state that changes +a view's \i model or a Loader's \i sourceComponent will set these properties +multiple times (to apply, rewind, and then reapply), which can be relatively expensive. + +State fast forwarding should be considered an implementation detail, +and may change in later versions. + */ -- cgit v1.2.3