/****************************************************************************
**
** Copyright (C) 2021 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Creator documentation.
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Free Documentation License Usage
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file. Please review the following information to ensure
** the GNU Free Documentation License version 1.3 requirements
** will be met: https://www.gnu.org/licenses/fdl-1.3.html.
**
****************************************************************************/

/*!
    \page qtquick-timeline-view.html
    \previouspage qtquick-transition-editor.html
    \nextpage qtquick-curve-editor.html

    \title Timeline

    You can use the timeline and keyframe based editor in the
    \uicontrol Timeline view to animate the properties of
    \l{glossary_component}{components}. The view is empty until
    you create a timeline.

    \image studio-timeline-empty.png "Empty Timeline view"

    Select the \inlineimage icons/plus.png
    (\uicontrol {Add Timeline}) button to \l{Creating Timelines}
    {create a timeline} and specify settings for it in the
    \uicontrol {Timeline Settings} dialog.

    \image studio-timeline-settings.png "Timeline Settings dialog"

    When you select \uicontrol Close, the \uicontrol Timeline view appears.
    It now displays a \l{Timeline Toolbar}{toolbar} and a ruler but no
    keyframe tracks.

    \image studio-timeline-no-tracks.png "Timeline view without keyframe tracks"

    To animate component properties in the \uicontrol Timeline view, you
    must \l{Setting Keyframe Values}{insert keyframes} for them. In the
    \l Properties view, select \inlineimage icons/action-icon.png
    (\uicontrol Actions) > \uicontrol {Insert Keyframe} for a property that you
    want to animate. A keyframe track is generated for each component that you
    insert keyframes for.

    \image studio-timeline-with-empty-tracks.png "Timeline view with a property"

    You can now select \inlineimage icons/local_record_keyframes.png
    to \l{Setting Keyframe Values}{record changes} in component properties
    while you \l{Navigating in Timeline}{navigate the timeline}.

    The following video shows how to insert keyframes for component properties
    and to animate them in \uicontrol Timeline:

    \youtube V3Po15bNErw

    \if defined(qtdesignstudio)
    To try it yourself, follow the \l{Log In UI - Timeline} tutorial.
    \endif


    For more information about creating timeline animations, see
    \l{Creating Timeline Animations}.

    \section1 Navigating in Timeline

    \image studio-timeline.png "Timeline view"

    You can navigate the timeline in the following ways:

    \list
        \li Drag the playhead (1) to a frame.
        \li Click on the ruler (2) to move to a frame.
        \li Select the \uicontrol {To Start (Home)}, \uicontrol {Previous (,)},
            \uicontrol {Next (.)}, or \uicontrol {To End (End)} buttons (3), or
            use the keyboard shortcuts to move to the first, previous, next, or
            last frame on the timeline.
        \li Enter the number of a frame in the current keyframe field (4) to
            move to that frame.
        \li Select the \uicontrol Previous and \uicontrol Next buttons next to
            a property name on the timeline (5) to move to the previous or next
            keyframe for that property.
    \endlist

    \section1 Zooming in Timeline

    Use the slider on the toolbar to set the zooming level in the
    \uicontrol Timeline view. Select the \inlineimage icons/zoom_small.png
    and \inlineimage icons/zoom_big.png
    buttons to zoom out of or into the view.

    \section1 Setting Keyframe Track Color

    To change the color of a keyframe track, select \uicontrol {Override Color}
    in the context menu, and then select a color in the \l{Picking Colors}
    {color picker}. To reset the color, select \uicontrol {Reset Color}.

    \image studio-timeline-keyframe-track-colors.png "Keyframe track colors in Timeline"

    \section1 Timeline Toolbar

    The \uicontrol Timeline toolbar contains the following buttons and fields.

    \table
    \header
        \li Button/Field
        \li Action
        \li Read More
    \row
        \li \inlineimage icons/animation.png
        \li Opens the \uicontrol {Timeline Settings} dialog for editing
            timeline settings.
        \li \l{Creating Timelines}
    \row
        \li Timeline ID
        \li Displays the ID of the current timeline.
        \li \l{Creating Timelines}
    \row
        \li \inlineimage icons/to_first_frame.png
        \li \uicontrol {To Start (Home)} moves to the first frame on the
            timeline.
        \li \l{Navigating in Timeline}
    \row
        \li \inlineimage icons/back_one_frame.png
        \li \uicontrol {Previous (,)} moves to the previous frame on the
            timeline.
        \li \l{Navigating in Timeline}
    \row
        \li \inlineimage icons/start_playback.png
        \li \uicontrol {Play (Space)} previews the animation.
        \li \l{Viewing the Animation}
    \row
        \li \inlineimage icons/forward_one_frame.png
        \li \uicontrol {Next (.)} moves to the next frame on the timeline.
        \li \l{Navigating in Timeline}
    \row
        \li \inlineimage icons/to_last_frame.png
        \li \uicontrol {To End (End)} moves to the last frame on the timeline.
        \li \l{Navigating in Timeline}
    \row
        \li Current Keyframe
        \li Displays the frame that the playhead is currently on. Enter a
            number in the field to move the playhead to the respective frame.
        \li \l{Navigating in Timeline}
    \row
        \li \inlineimage icons/global_record_keyframes.png
        \li Records changes in keyframe values.
        \li \l {Setting Keyframe Values}
    \row
        \li \inlineimage icons/curve_editor.png
        \li Opens \uicontrol {Easing Curve Editor} for attaching an easing
            curve to the selected transition.
        \li \l{Editing Easing Curves}
    \row
        \li Start Frame
        \li Specifies the first frame of the timeline. Negative values are
            allowed. The difference between the start frame and the end frame
            determines the duration of the animation.
        \li \l{Creating Timelines}
    \row
        \li \inlineimage icons/zoom_small.png
        \li \uicontrol {Zoom Out} (\key Ctrl+-) zooms out of the view.
        \li \l{Zooming in Timeline}
    \row
        \li Slider
        \li Sets the zooming level.
        \li \l{Zooming in Timeline}
    \row
        \li \inlineimage icons/zoom_big.png
        \li \uicontrol {Zoom In} (\key Ctrl++) zooms into the view.
        \li \l{Zooming in Timeline}
    \row
        \li End Frame
        \li Specifies the last frame of the timeline. The difference between
            the start frame and the end frame determines the duration of the
            animation, so if the start frame is 0, the end frame equals the
            duration.
        \li \l{Creating Timelines}
    \row
        \li State Name
        \li Displays the name of the current state.
        \li \l{Binding Animations to States}
    \endtable

    \section1 Keyframe Track Icons

    Each keyframe track can contain the following buttons and markers.

    \table
    \header
        \li Button/Icon
        \li Action
        \li Read More
    \row
        \li \inlineimage icons/previous_keyframe.png
        \li Jumps to the previous frame on the timeline.
        \li \l{Setting Keyframe Values}
    \row
        \li \inlineimage icons/next_keyframe.png
        \li Jumps to the next frame on the timeline.
        \li \l{Setting Keyframe Values}
    \row
        \li \inlineimage icons/local_record_keyframes.png
        \li Records changes in keyframe values for a particular property.
        \li \l {Setting Keyframe Values}
    \target keyframe_marker
    \row
        \li \inlineimage icons/keyframe.png
        \li Indicates the type of easing curve attached to the keyframe.
            When a keyframe track is selected, the keyframe markers on it turn
            gray, and when a keyframe itself is selected, its marker turns
            brown:
            \list
                \li \inlineimage icons/keyframe_linear_active.png
                    - linear easing curve
                \li \inlineimage icons/keyframe_manualbezier_active.png
                    - manually set Bezier curve
                \li \inlineimage icons/keyframe_autobezier_active.png
                    - automatically set Bezier curve
                \li \inlineimage icons/keyframe_lineartobezier_active.png
                    - linear-to-Bezier curve
            \endlist
        \li \l {Editing Easing Curves}
    \endtable

    \section1 Timeline Context Menu

    The following table summarizes the context menu items available for each
    keyframe track for a component, property, or keyframe marker and provides
    links to more information about them.

    \table
    \header
        \li To Learn About
        \li Go To
    \row
        \li Delete All Keyframes
        \li \l{Deleting Keyframes}
    \row
        \li Add Keyframes at Current Frame
        \li \l{Setting Keyframe Values}
    \row
        \li Copy All Keyframes
        \li \l{Copying Keyframes}
    \row
        \li Paste Keyframes
        \li \l{Copying Keyframes}
    \row
        \li Remove Property
        \li \l{Setting Keyframe Values}
    \row
        \li Delete Keyframe
        \li \l{Deleting Keyframes}
    \row
        \li Edit Easing Curve
        \li \l{Editing Easing Curves}
    \row
        \li Edit Keyframe
        \li \l{Editing Keyframe Values}
    \row
        \li Override Color
        \li \l{Setting Keyframe Track Color}
    \row
        \li Reset Color
        \li \l{Setting Keyframe Track Color}
    \endtable
*/
