Difference between revisions of "Development/Tutorials/Plasma/JavaScript/Animations"

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To make Plasma aware of the animations, create an [Animations] section in the theme's metadata.desktop file. This group must contain mappings between the script name and the animations the script contains. For example:
 
To make Plasma aware of the animations, create an [Animations] section in the theme's metadata.desktop file. This group must contain mappings between the script name and the animations the script contains. For example:
  
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<syntaxhighlight lang="ini">
 
[Animations]
 
[Animations]
 
stockanims.js=ZoomAnimation,PulseAnimation
 
stockanims.js=ZoomAnimation,PulseAnimation
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To make Plasma aware of the animations, create an [Animations] section in the Plasmoid's metadata.desktop file. This group must contain mappings between the script name and the animations the script contains. For example:
 
To make Plasma aware of the animations, create an [Animations] section in the Plasmoid's metadata.desktop file. This group must contain mappings between the script name and the animations the script contains. For example:
  
<code ini>
+
<syntaxhighlight lang="ini">
 
[Animations]
 
[Animations]
 
stockanims.js=ZoomAnimation,PulseAnimation
 
stockanims.js=ZoomAnimation,PulseAnimation

Revision as of 21:36, 29 June 2011

Introduction To Javascript Animations

Plasma builds on top of the QtKinetic animation framework to provide a set of ready-made animations. Starting with KDE Development Platform v4.5, it is also possible to write new animations or mash up existing ones using Javascript. This tutorial describes how Javascript animations are defined, where they are stored and how you can access them from your code.

Writing An Animation

The key components of a Javascript animation are the constructor function, the updateCurrentTime function and the registerAnimation call.

The constructor function is called whenever a new instance of the animation is requested. The name of the function is not critical, but it is used in the registerAnimation call.

The updateCurrentTime function drives the actual animation: it is called whenever an animation frame is to be processed. The current time of the animation is passed in to it as the first parameter.

To let Plasma know that the animation exists, the registerAnimation function must be called from the script's global scope. registerAnimation takes two parameters: the name by which the animation will be identified and the constructor function.

A simple example of a zoom animation:

// constructor function for a zoom animation
function ZoomAnimation() {
    // we could do some set up here
 
    // updateCurrentTime
    this.updateCurrentTime = function(currentTime) {
        var delta = currentTime/this.duration;
        this.target.scale = delta;
    }
}
 
registerAnimation("ZoomAnimation", ZoomAnimation)
</code>
 
== Script Files ==
 
=== In Desktop Themes ===
A [[Projects/Plasma/Theme|Plasma desktop theme]] can include one or more JS scripts in the {{path|animations/}} subdirectory, each of which can contain one or more animations. 
 
To make Plasma aware of the animations, create an [Animations] section in the theme's metadata.desktop file. This group must contain mappings between the script name and the animations the script contains. For example:
 
<syntaxhighlight lang="ini">
[Animations]
stockanims.js=ZoomAnimation,PulseAnimation
rotation.js=RotationAnimation
</code>
 
The above example would associate the file in {{path|animations/stockanim.js}} with the ZoomAnimation and PulseAnimation animations and rotation.js with the RotationAnimation animation. Whenever these animations were requested by name, they would be loaded from the respective script and an Animation object would be returned.
 
Theme inheritance is respected and supported as well, so animations defined in inherited themes as well as the default fallback theme will be available if they are not overridden by an animation of the same name in the theme.
 
Animations with the same name as a value in the Plasma::Animator::Animation enumeration will be automatically mapped as a replacement for the native C++ animation that is usually returned by Plasma::Animator::create().
 
=== In Plasmoids ===
A scripted Plasmoid can include one or more JS scripts in the {{path|contents/animations/}} subdirectory of the package. Each script can contain one or more animations.
 
To make Plasma aware of the animations, create an [Animations] section in the Plasmoid's metadata.desktop file. This group must contain mappings between the script name and the animations the script contains. For example:
 
<syntaxhighlight lang="ini">
[Animations]
stockanims.js=ZoomAnimation,PulseAnimation
rotation.js=RotationAnimation
</code>
 
The above example would associate the file in {{path|contents/animations/stockanim.js}} with the ZoomAnimation and PulseAnimation animations and rotation.js with the RotationAnimation animation. Whenever these animations were requested by name, they would be loaded from the respective script and an Animation object would be returned:
 
<syntaxhighlight lang="javascript">
var button = new PushButton
button.text = i18n("Rotate me!")
var anim = animation("RotationAnimation")
anim.targetWidget = button
button.clicked.connet(anim.start)
</code>
 
=== In Plasma Applications ===
 
== Accessing A Javascript Animation ==
 
=== C++ ===
In the Plasma::Animator class there is a create(const QString &animationName, QObject *parent = 0) method which returns a QAbstractAnimation that can be used like any other. The animationName parameter is the name of the Javascript animation as defined at animation registration. If no such animation is available, a null pointer will be returned.
 
=== Javascript ===
Javascript animations can be retrieved like any other animation: by name using the animation(String) method.
 
== API ==
 
The following API is available to Javascript animations.
 
=== Read-Only Properties ===
 
* ''number'' '''duration''': the time in milliseconds that the animation is set to run
* ''QGraphicsWidget'' '''target''': the item to be animated
 
=== Accessing Other Animations ===
An Animation object can be created by calling the ''Animation'' '''animation(string type)''' function. The ''string'' corresponds to the type of animation, which are listed below.
 
By setting the widgetToAnimate property it can be assigned to animate any QGraphicsWidget desired.
 
==== Enumerations ====
All Animation objects have the following enumerations:
 
===== MovementDirection =====
* '''MoveUp'''
* '''MoveUpRight'''
* '''MoveRight'''
* '''MoveDownRight'''
* '''MoveDown'''
* '''MoveDownLeft'''
* '''MoveLeft'''
* '''MoveUpLeft'''
 
===== Reference =====
The reference point, relative to the target widget, for the animation.
* '''Center'''
* '''Up'''
* '''Down'''
* '''Left'''
* '''Right'''
 
===== State =====
* '''Paused'''
* '''Running'''
* '''Stopped'''
 
==== Common API ====
With the exception of Pause and Property animations, all animations support the following read/write properties: 
 
* ''AnimationDirection'' '''direction''': the direction the animation should play: AnimationForward or AnimationBackward
* ''int'' '''duration''': length of the animation in ms.
* ''EasingCurveType'' '''easingCurveType''': The easing curve to use in the animation
* ''QGraphicsWidget'' '''targetWidget''': the QGraphicsWidget (e.g. a Plasma::Widget) that this animation should operate on
 
==== Animation Groups ====
Animations may be put into groups for convenient sequential or parallel running. Sequential groups, where the animations run one after the other, are handled by the '''AnimationGroup''' class. Parallel aniations, where the animations run simultaneously, are handled the '''ParallelAnimationGroup''' class. 
 
Animations are added to a group by calling '''add(Animation)''' on the group object. Groups may also be added to other groups.
 
==== Animation Types ====
Below is a list of all current animation types and their particular read/write properties:
 
===== Fade =====
* ''number'' '''startOpacity''': the opacity, between 0 and 1, that the target widget starts at when the animation begins
* ''number'' '''targetOpacity''': the opacity, between 0 and 1, that the target widget will be at the end of the animation
 
===== Geometry =====
* ''QRectF'' '''startGeometry''': the geometry that the target widget should start with
* ''QRectF'' '''targetGeometry''': the geometry the target widget will have at the end of the animation
 
===== Grow =====
* ''number'' '''factor''': the factor by which the target widget will grow to by the end of the animation
 
===== Pause =====
* ''number'' '''duration''': the number of milliseconds to pause for
 
===== Property =====
Animates an object (must be a QObject internally, which includes all Plasma Widgets) by manipulating one of its properties. Property animations have the following read/write properties:
 
* ''any'' '''startValue'''
* ''any'' '''endValue'''
* ''ByteArray'' '''propertyName'''
* ''QObject'' '''targetObject'''
* ''number'' '''duration'''
* ''EasingCurve'' '''easingCurve'''
 
===== Pulser ===== 
* ''number'' '''targetScale''': the maximum scale of the pulse-shadow item, relative to the target widget
 
===== Rotate =====
* ''QtAxis'' '''axis''': the axis along which to rotate the item
* ''Reference'' '''reference''': the reference point around which to rotate the target widget
* ''number'' '''angle''': the number of degrees to rotate the item
 
===== RotateStacked =====
* ''MovementDirection'' '''movementDirection''': the direction to rotate the widgets in the stack around
* ''QGraphicsLayoutItem'' '''layout'''
* ''Reference'' '''reference''': the reference point around which to rotate the target widget
* ''QGraphicsWidget'' '''backingWidget''': the widget in the "back" to rotate to the front of the target widget
 
===== Slide ===== 
* ''MovementDirection'' '''movementDirection''': the direction to slide the widget
* ''number'' '''distance''': the distance to slide the widget
 
===== Zoom =====
* ''number'' '''zoom''': the factor by which to zoom the target widget
 
=== QEasingCurve ===
Used to set the progress shape of Animation objects, this class has the following read-only properties:
 
* ''string'' '''toString'''
* ''number'' '''valueForProgress(number progress)''': returns effective progress for the easing curve at progress. While progress must be between 0 and 1, the returned effective progress can be outside those bounds.
 
as well as the following read/write property:
 
* ''EasingCurveType'' '''type''': the shape of this easing curve
 
and the following enumeration:
 
* '''EasingCurveType'''
** Linear
** InQuad
** OutQuad
** InOutQuad
** OutInQuad
** InCubic
** OutCubic
** InOutCubic
** OutInCubic
** InQuart
** OutQuart
** InOutQuart
** OutInQuart
** InQuint
** OutQuint
** InOutQuint
** OutInQuint
** InSize
** OutSine
** InOutSine
** OutInSine
** InExpo
** OutExpo
** InOutExpo
** OutInExpo
** InCirc
** OutCirc
** InOutCirc
** InOutCirc
** OutInCirc
** InElastic
** OutElastic
** InOutElastic
** OutInElastic
** InBack
** OutBack
** InOutBack
** OutInBack
** InBounc
** OutBounce
** InOutBounce
** OutInBounce
** InCurve
** OutCurve
** SineCurve
** CosineCurve

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