/**************************************************************************** ** ** 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 quick-animation-overview.html \previouspage qtquick-motion-design.html \title Introduction to Animation Techniques \QDS supports the following types of animation techniques that are suitable for different purposes: \list \li Common motion design techniques for 2D and 3D \li Screen-to-screen or state-to-state animations \li Data-driven UI logic animations \endlist \section1 Common Motion Design Techniques The following table summarizes common motion design techniques for 2D and 3D and their typical use cases. \table \header \li Technique \li Use Case \row \li \l{Timeline}{Timeline animation} \li Linear interpolation through intermediate values at specified keyframes instead of immediately changing to the target value. \row \li \l{Editing Easing Curves}{Easing curves} attached to keyframes \li Nonlinear interpolation between keyframes to make components appear to pick up speed, slow down, or bounce back at the end of the animation. \row \li \l{Curve Editor}{Animation curves} attached to keyframes \li Complex 3D animations that require several keyframes so it becomes necessary to visualize the value and the interpolation of a keyframe simultaneously. \endtable \section2 Timeline and Keyframe Based Animation Timeline animation is based on \e keyframes. In \QC, keyframes determine the value of the property of a \l{glossary_component}{component} at a certain time. Animating properties enables their values to move through intermediate values instead of immediately changing to the target value. For example, you can set the y position property of a rectangle to 0 at the start of your animation and to 100 at the end of the animation. When the animation is run, the rectangle moves from position 0 to 100 on the y axis. In the middle of the animation, the y property has the value of 50 since keyframes are interpolated linearly by default. \section2 Easing Curves Sometimes you don't want linear movement but would rather like the rectangle to move faster at the beginning and slower at the end of the animation. To achieve this effect, you could insert a large number of keyframes between the start frame and the end frame. To avoid this effort, you can specify \e {easing curves} for nonlinear interpolation between keyframes. The easing curves can make components appear to pick up speed, slow down, or bounce back at the end of the animation. \section2 Animation Curves While easing curves work well for most simple UI animations, more complex 3D animations require several keyframes so it becomes necessary to visualize the value and the interpolation of a keyframe simultaneously. The \l {Curve Editor} visualizes the whole animation of a property at once and shows the effective values of a keyframe together with the interpolation between keyframes. It can also show animations of different properties simultaneously so that you can see the animation for the x position and the animation for the y position side-by-side. \section1 Screen-to-Screen or State-to-State Animations The following table summarizes techniques used for navigating between screens and UI states. \table \header \li Technique \li Use Case \if defined(qtdesignstudio) \row \li \l{Designing Application Flows}{Application flows} \li An interactive prototype that can be clicked through to simulate the user experience of the application. \endif \row \li \l{Transition Editor}{Transitions between states} \li Transitions between different states of the UI using a transition timeline that is based on keyframes. You can apply easing curves to the keyframes. \endtable \if defined(qtdesignstudio) \section2 Application Flows You can design an application in the form of a \e {schematic diagram} that shows all the significant components of the application UI and their interconnections by means of symbols. This results in an interactive prototype that can be clicked through to simulate the user experience of the application. Code is created in the background and can be used as the base of the production version of the application. For more information, see \l{Designing Application Flows}. \endif \section2 Transitions Between States UIs are designed to present different UI configurations in different scenarios, or to modify their appearances in response to user interaction. Often, several changes are made concurrently so that the UI can be seen to be internally changing from one \e state to another. This applies generally to UIs regardless of their complexity. A photo viewer may initially present images in a grid, and when an image is clicked, change to a detailed state where the individual image is expanded and the interface is changed to present new options for image editing. At the other end of the scale, when a button is pressed, it may change to a \e pressed state in which its color and position are modified so that it appears to be pressed down. Any component can change between different states to apply sets of changes that modify the properties of relevant components. Each state can present a different configuration that can, for example: \list \li Show some UI components and hide others. \li Present different available actions to the user. \li Start, stop, or pause animations. \li Execute some script required in the new state. \li Change a property value for a particular component. \li Show a different view. \endlist State changes introduce abrupt motion that you can make visually appealing by using \e transitions. Transitions are animation types that interpolate property changes caused by state changes. In \l {Transition Editor}, you can set the start frame, end frame, and duration for the transition of each property. You can also set an \l{Editing Easing Curves}{easing curve} for each animation and the maximum duration of the whole transition. \section1 Data-Driven UI Logic Animations The following table summarizes techniques used for animating the UI logic by using real or mock data from a backend. \table \header \li Technique \li Use Case \row \li Data-driven timeline animation \li Using real or mock data from a backend to control motion. \row \li Programmatic property animation \li Interpolating property values programmatically to create smooth transitions. \endtable \section2 Data-Driven Timeline Animation You can connect property values to data backends to drive timeline animation. You can fetch data from various sources, such as data models, JavaScript files, and backend services. You can also connect your UI to Simulink to load live data from a Simulink simulation. You can connect these data sources to the current frame of a timeline, creating animation when the backend changes the current frame property. For example, you could connect the speed value from a backend to a tachometer dial in a cluster. As the speed value is increased or decreased from the backend, it moves the needle animation from one end of the timeline to the other. For more information, see \l{Simulating Complex Experiences}. \section2 Programmatic Animation You can control property animation programmatically. Property animations are created by binding \l{Animations}{Animation} components to property values of component instances to gradually change the properties values over time. The property animations apply smooth movement by interpolating values between property value changes. They provide timing controls and enable different interpolations through easing curves. Developers can control the execution of property animations by using the \c start(), \c stop(), \c resume(), \c pause(), \c restart(), and \c complete() functions. You can create instances of preset animation components available in \l Library > \uicontrol Components > \uicontrol {Default Components} > \uicontrol Animation to create \l{Animations}{animations} depending on the type of the property that is to be animated and the behavior that you want. \table \header \li Animation Type \li Use Case \row \li Property animation \li Applying animation when the value of a property changes. Color and number animations are property animation types for specific purposes. \row \li Property action \li Setting non-animated property values during an animation. \row \li Color animation \li Applying animation when a color value changes. \row \li Number animation \li Applying animation when a numerical value changes. \row \li Parallel animation \li Running animations in parallel. \row \li Sequential Animation \li Running animations sequentially. \row \li Pause animation \li Creating a step in a sequential animation where nothing happens for a specified duration. \row \li Script action \li Executing JavaScript during an animation. \endtable \section3 Property Animation and Action A property animation is applied when the value of a property changes. To immediately change a property value during an animation without animating the property change, use a property action instead. This is useful for setting non-animated property values during an animation. For example, you can use a sequential animation that contains two property actions around a number animation to set the value of the opacity property of an \l{Images}{Image} to \c 0.5, animate the width of the image, and then set the opacity back to \c 1. \section3 Color Animation A color animation is a specialized property animation that defines an animation to be applied when a color value changes. For example, you can apply animation to the color property of a \l Rectangle to change its value from its current color to another color over a period of time specified in milliseconds. \section3 Number Animation A number animation is a specialized property animation that defines an animation to be applied when a numerical value changes. For example, you can apply animation to the x property of a \l Rectangle to make it appear to move from its current position on the x axis to another position over a period of time specified in milliseconds. \section3 Parallel and Sequential Animation Animations can run in parallel or in sequence. Parallel animations will play a group of animations at the same time while sequential animations play a group of animations in order, one after the other. For example, a banner component may have several icons or slogans to display, one after the other. The opacity property could change to \c 1.0 denoting an opaque object. Using a sequential animation, the opacity animations will play after the preceding animation finishes, whereas a parallel animation will play the animations at the same time. Once individual animations are placed into a group of parallel or sequential animations, they can no longer be started and stopped independently. The sequential or parallel animations must be started and stopped as a group. \section3 Pause Animation When used in a sequential animation, a pause animation is a step when nothing happens, for a specified duration. For example, you could specify a 500-millisecond animation sequence, with a 100-millisecond pause between two animations. */