Development/Tutorials/Plasma4/JavaScript/API: Difference between revisions

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= Introduction to Plasmoids JavaScript API  =
= Introduction to the Plasmoid JavaScript API  =


This document provides an overview/reference of the Simplified JavaScript API for Plasmoids. The "Simplified" refers to the fact that it isn't a full binding to all of Qt or KDE's libraries, but a highly focused set of bindings designed to make writing Plasmoids fast and easy, while remaining powerful.
This document provides an overview/reference of the Simplified JavaScript API for Plasmoids. The "Simplified" refers to the fact that it isn't a full binding to all of Qt or KDE's libraries, but a highly focused set of bindings designed to make writing Plasmoids fast and easy, while remaining powerful.


The API in this documentation covers the JavaScript API as it appears in the KDE Software Compilation as of version 4.4, unless otherwise noted. This API ships as part of the KDE Base Runtime package, so can be relied on being there by any application that is Powered By KDE.
The API in this documentation covers the JavaScript API as it appears in the KDE Software Compilation as of version 4.4 and higher. Changes between versions are noted in the documentation, including when new API functionality was introduced. This API ships as part of the KDE Base Runtime package, so can be relied on being there by any application that is Powered By KDE.


If you have not done so already, please read the [http://websvn.kde.org/trunk/KDE/kdebase/workspace/plasma/design/plasmoids "plasmoid" design document] first.
= Examples and Tutorials =


== What Is A Simplified JavaScript Plasmoid?  ==
Tutorials can be found [[Development/Tutorials/Plasma|in the Plasma tutorials area here on Techbase]] and full, functioning examples can be found in the [https://projects.kde.org/projects/kde/kdeexamples KDE Examples] repository in the {{path|plasma/javascript}} folder.
 
= Using QML =
 
Starting with the KDE Platform 4.7 release, the Plasma team recommends writing your Plasmoids with [http://qt.nokia.com/qtquick/ QtQuick] technologies with the [http://techbase.kde.org/Development/Tutorials/Plasma#QML_Plasmoids Plasma QML integration API].
 
The QML API uses the same API as the Simplified JavaScript API with the exception of User Interface Elements, Animations and Events which are provided instead by QML itself.
 
The benefits of writing your Plasmoid with QML can include faster development with more sophisticated results visually and in its usability as well as much better performance when run in a QML-only Plasma shell such as Plasma Active.
 
= What Is A Simplified JavaScript Plasmoid?  =


This document describes the native Plasma API available to Simplified JavaScript Plasmoids. What makes them "Simplified" is that they do not have access to the entire C++ API in the Plasma, KDE and Qt libraries (let alone things lower in the API stack). This helps ensure that these Plasmoids are more likely to work properly between releases as changes in underlying API don't affect them as well as allowing Plasma to offer stronger security guarantees around them.  
This document describes the native Plasma API available to Simplified JavaScript Plasmoids. What makes them "Simplified" is that they do not have access to the entire C++ API in the Plasma, KDE and Qt libraries (let alone things lower in the API stack). This helps ensure that these Plasmoids are more likely to work properly between releases as changes in underlying API don't affect them as well as allowing Plasma to offer stronger security guarantees around them.  
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What follows is a description of the runtime environment available to a Simplified JavaScript Plasmoid.  
What follows is a description of the runtime environment available to a Simplified JavaScript Plasmoid.  


== QtScript  ==
= QtScript  =


The Simplified JavaScript API is powered by Qt's QtScript system which provides access to a full featured ECMA Script interpreter. If it works in ECMA Script, it will work in a Simplified JavaScript Plasmoid. As an interesting implementation note, QtScript uses the high performance ECMA Script interpreter from WebKit and shares this code with QtWebKit.  
The Simplified JavaScript API is powered by Qt's QtScript system which provides access to a full featured ECMA Script interpreter. If it works in ECMA Script, it will work in a Simplified JavaScript Plasmoid. As an interesting implementation note, QtScript uses the high performance ECMA Script interpreter from WebKit and shares this code with QtWebKit.  


On top of the ECMA Script language, QtScript provides Qt integration features. Probably the most useful one in this context is the use of signals and slots which is Qt's callback mechanism. Signals may be emitted in QtScript by calling the signal method in question, a signal can be connected to a slot by using the connect() method (and disconnected with disconnect()) and any function defined in the Plasmoid may be used as a slot. For example: <code javascript="javascript">
On top of the ECMA Script language, QtScript provides Qt integration features. Probably the most useful one in this context is the use of signals and slots which is Qt's callback mechanism. Signals may be emitted in QtScript by calling the signal method in question, a signal can be connected to a slot by using the connect() method (and disconnected with disconnect()) and any function defined in the Plasmoid may be used as a slot. For example: <syntaxhighlight lang="javascript">
function onClick()
function onClick()
{
{
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button.clicked.connect(onFirstClick)
button.clicked.connect(onFirstClick)
button.clicked()
button.clicked()
</code> This will print out:  
</syntaxhighlight> This will print out:  


<code>
<syntaxhighlight lang="text">
We got clicked!
We got clicked!
First click!
First click!
</code>  
</syntaxhighlight>  


on the console when the Plasmoid starts, and the "We got clicked!" again whenever the button is clicked by the user.
on the console when the Plasmoid starts, and the "We got clicked!" again whenever the button is clicked by the user.
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The object that emitted the signal that caused a slot to be called can be retrieved using the ''QObject'' '''sender''' read-only property of the global '''plasmoid''' object.
The object that emitted the signal that caused a slot to be called can be retrieved using the ''QObject'' '''sender''' read-only property of the global '''plasmoid''' object.


== Events (API v2) ==
= API =
 
Starting in API v2, it is possible register functions as event handlers. To register an event handler, use:
 
* '''addEventListener(String event, Function listener)'''
 
The event parameter is the name of the event (see list at end of section for known events) and the handler parameter is the function that will be called whenever the event occurs. Event names are not case sensitive. An event object will be passed into the handler, and the type and behavior of that object is event specific.
 
Any number of event handlers may be added to a given event, and one handler may be registered to any number of events. The order of execution of event handlers is not guaranteed.
 
To remove an event handler, use:
 
* '''removeEventListener(String event, Function listener)'''
 
The function passed in will no longer be called as a result of the event occurring. Any currently pending calls to the listener are still made, however.
 
If an event handler is registered using addEventListener, then any callback in the global plasmoid object that may be related to the same event will be suppressed. For instance, if an event handler is registered using addEventListener for the paintInterface event, then plasmoid.paintInterface will not be called.
 
=== Input Events (API v2) ===
 
Following are the input events which are recognized on the Plasmoid along with the type of event object passed in to registered event listeners:
 
* HoverEnter: HoverEvent Object
* HoverLeave: HoverEvent Object
* HoverMove: HoverEvent Object
* KeyPress: KeyEvent Object
* KeyRelease: KeyEvent Object
* MouseDoubleClick: MouseEvent Object
* MouseMove: MouseEvent Object
* MousePress: MouseEvent Object
* MouseRelease: MouseEvent Object
* Wheel: WheelEvent Object
 
Example:
 
<code javascript>
// anonymous function as a listener on KeyPress
plasmoid.addEventListener('KeyPress', function(a) { print(a.key) })
 
function output()
{
    print('Hover Event!')
}
 
function hovered(event)
{
    plasmoid.busy = true
    plasmoid.removeEventListener('HoverEnter', output)
}
 
function unhovered(event)
{
    plasmoid.busy = false
}
 
plasmoid.addEventListener('HoverEnter', hovered)
plasmoid.addEventListener('HoverLeave', unhovered)
plasmoid.addEventListener('HoverEnter', output)
plasmoid.addEventListener('HoverLeave', output)
</code>
 
==== HoverEvent (API v2) ====
 
==== KeyEvent (API v2) ====
 
==== MouseEvent (API v2) ====
 
==== WheelEvent (API v2) ====
 
== The Global plasmoid Object  ==
 
There is a global object available to the Plasmoid called, appropriately, "plasmoid". It has a number of useful properties (some of which are read only, but many of which are read/write), functions, constant values and callbacks. Each are enumerated below.
 
=== Callbacks  ===
 
See the section on Events above.
 
There are some events that are generated by Plasma for the Plasmoid. These can often be caught by providing a function assigned to a specific name in the plasmoid object. For instance, to get notified of form factor changes, one would provide a formFactorChanged method as follows: <code javascript="javascript">
plasmoid.formFactorChanged = function() {
 
    print("the form factor has changed to: " + plasmoid.formFactor())
 
}
</code>
 
The following callbacks are used to notify the Plasmoid of changes in its running environment:
 
* '''configChanged()'''
* '''currentActivityChanged()'''
* '''formFactorChanged()'''
* '''immutabilityChanged()'''
* '''locationChanged()'''
* '''sizeChanged()'''
 
Other callbacks include:
* '''dataUpdated(String source, Map[String, Any] data)''': used to pass in DataEngine updates
* '''activate()''': called when the widget is activated by the user, e.g. by a keyboard shortcut. Useful for setting the focus on a specific input widget, for instance. (API v2)
* '''initExtenderItem(Extender extender)''': Called when an Extender shoudl be set up. (API v2)
* '''popupEvent(boolean shown)''': called on PopupApplets when the popup is shown or hidden. (API v2)
 
 
In API v2, all of these callbacks can also be used as events. So, for instance, instead of implementing plasmoid.popupEvent, one could also write:
 
<code javascript>plasmoid.addEventListener('popupEvent', function(shown) { print('shown? ' + shown) } )</code>
 
This would also suppress any calls to plasmoid.popupEvent.
 
Further documentation on these callbacks can be found in the relevant sections below.
 
=== Environment  ===
 
A set of read-only properties (and in most cases notification functions) that tell the Plasmoid about its current environment:
 
* '''apiVersion''': the integer version of the Simlified JavaScript API in the current execution environment; can be used to change behaviour or usage of functions depending on the version number.
 
* '''formFactor''': one of Planar (e.g. on a desktop or in an application main view), Horizontal, Vertical or MediaCenter. When the form factor changes, the plasmoid.formFactorChanged function, if defined in the Plasmoid, is called.
 
* '''size''': the size of the Plasmoid, expressed in QSizeF (explained below). when it changes, plasmoid.sizeChanged() will be called.
 
* '''location''': one of Floating (no specific location), Desktop (on the application's main view are), FullScreen, LeftEdge, RightEdge, TopEdge or ButtomEdge. When the location changes, the plasmoid.locationChanged function, if defined in the Plasmoid, is called.
 
* '''immutable''': this property is set to true when the Plasmoid is set to not be movable or otherwise changeable, and false otherwise. Configuration is still usually allowed in this state. When the immutability changes, the plasmoid.immutabilityChanged function, if defined in the Plasmoid, is called.
 
* '''currentActivity''': the current contextual activity name. When the current activity changes, the plasmoid.currentActivityChanged function, if defined in the Plasmoid, is called.
 
* '''shouldConserveResources''': true if the plasmoid should not be doing anything that would create too much draw on power, e.g. when on a device with low battery power it may be a good idea not to run a computationally expensive but optional animation
 
* '''userConfiguring''': true if the user configuration interface is currently being displayed.
 
=== Properties  ===
A set of read/write properties that allow the Plasmoid to set various visual or functional properties:
 
* ''AspectRatioMode'' '''aspectRatioMode''': defines how to treat the aspect ratio of a Plasmoid when resizing it. See the [[#AspectRatioMode|AspectRatioMode]] documentation for values and their meaning.
 
* ''BackgroundHints'' '''backgroundHints''': defines how the background of the widget is rendered. See the [[#BackgroundHints|BackgroundHints]] documentation for values and their meaning.
 
* ''boolean'' '''busy''': set to true when the Plasmoid is currently processing or waiting for data and the user interface should be blocked while doing so; will generally show a full-Plasmoid animated overlay to denote business
 
=== Geometry  ===
 
Read Only Properties:
 
* ''QRectF'' '''rect''': the current rect of the Plasmoid; note that the top left may be not be the origin point (0,0)
 
 
Functions:
 
* '''resize(width, height)'''
* '''setMinimumSize(width, height)'''
* '''setPreferredSize(width, height)'''
 
=== Painting and Layout  ===
 
To paint directly on to the canvas, a widget may implement the paintInterface function in the plasmoid object:
<code javascript>
    plasmoid.paintInterface = function(painter) { /* painting code goes here*/ }
</code>
See the Painting section below for information about helpful classes and functions that can be used when implementing a paintInterface function.
 
Read/Write Properties:
 
* ''Layout'' '''layout''': the QGraphicsLayout associated with the Plasmoid for laying out top level items; this property is read-write, though the property is not usually set as one can simply do "new LinearLayout" (or one of the other layout classes provided) and it will be automatically associated with the Plasmoid.
 
Functions:
 
* '''update()''': triggers a full repaint of the Plasmoid.
* '''update(QRectF rect)''' triggers a repaint of the rect area of the Plasmoid.
* '''failedToLaunch(bool failed[, string reason])''' sets the launch status of the Plasmoid; if set to true, the script will stop executing and the reason message, if any, will be displayed to the user.
 
=== Access To Packaged Files  ===
 
Functions:
 
* ''string'' '''file(string type[, string fileName])''': returns the path to a file in the Plasmoid package of the given type, optionally with a file name to match, e.g. <code javascript>var path = plasmoid.file("mainscript")</code> or <code javascript>var pm = new QPixmap(plasmoid.file("images", "mypixmap.png"))</code>
 
* ''bool'' '''include(string filename)''': attempts to include the script defined from the package's code directory
 
=== Configuration Data  ===
 
Configuration values can be defined using [Development/Tutorials/Using_KConfig_XT KConfigXt] XML files in the {{path|contents/config/}} directory of the Plasmoid's package. The default file that is looked for and used is {{path|contents/config/main.xml}}.
 
==== Accessing Configuration Data  ====
Read-write properties:
* ''String'' '''activeConfig''': The current active configuration description. For instance, setting it to "foo" would cause the Plasmoid to try and reference the {{path|contents/config/foo.xml}} KConfigXT file. Setting this to an empty string will switch to the main.xml file.
 
Functions:
* ''any'' '''readConfig(String key)''': reads the value from the configuration data for the given key as defined by the currently active configuration.
 
* '''writeConfig(String key, any value) ''': writes a value to the configuration store under the given key
 
==== User Customization  ====
 
User customization can be offered by providing a Qt Designer file called {{path|contents/ui/config.ui}} in the Plasmoid's package.
 
Callbacks:
* '''configChanged()''': callback function called when the configuration is changed external to the Plasmoid, e.g. when the user changes settings in a configuration dialog.
 
== Global Enumerations ==
In the global namespace are a set of useful enumerations that can be used with various classes in the Simplified Javascript Plasmoid API. These include:
 
=== AspectRatioMode ===
* '''IgnoreAspectRatio''': The Plasmoid can be freely resized
* '''KeepAspectRatio''': The Plasmoid keeps a fixed aspect ratio
* '''Square: The Plasmoid is always a square
* '''ConstrainedSquare''': The Plasmoid is no wider (in horizontal formfactors) or no higher (in vertical ones) than a square
* '''FixedSize''': The Plasmoid cannot be resized
 
 
 
=== FormFactor ===
* '''Planar''': The Plasmoid lives in a plane and has two degrees of freedom to grow. Optimize for desktop, laptop or tablet usage: a high resolution screen 1-3 feet distant from the viewer.
* '''MediaCenter''': As with Plasmoid the applet lives in a but the interface should be optimized for medium-to-high resolution screens that 5-15 feet distant from the viewer. Sometimes referred to as a "ten foot interface".
* '''Horizontal''': The Plasmoid is constrained vertically, but can expand horizontally.
* '''Vertical''': The Plasmoid is constrained horizontally, but can expand vertically.
 
=== Location ===
* '''Floating''': Free floating. Neither geometry or z-ordering is described precisely by this value.
* '''Desktop''': On the planar desktop layer, extending acrossthe full screen from edge to edge
* '''FullScreen'''
* '''TopEdge'''
* '''BottomEdge'''
* '''LeftEdge'''
* '''RightEdge'''
 
=== AnimationDirection ===
* '''AnimationForward'''
* '''AnimationBackward'''
 
=== BackgroundHints ===
* '''NoBackground'''
* '''StandardBackground'''
* '''TranslucentBackground'''
* '''DefaultBackground'''
 
=== QtAlignment ===
* QtAlignLeft
* QtAlignRight
* QtAlignHCenter
* QtAlignJustify
* QtAlignTop
* QtAlignBottom
* QtAlignVCenter
 
=== QtAnchorPoint ===
* QtAnchorLeft
* QtAnchorRight
* QtAnchorBottom
* QtAnchorTop
* QtAnchorHorizontalCenter
* QtAnchorVerticalCenter
 
=== QtCorner ===
* QtTopLeftCorner
* QtTopRightCorner
* QtBottomLeftCorner
* QtBottomRightCorner
 
=== enum QtMouseButton ===
* QtNoButton
* QtLeftButton
* QtRightButton
* QtMidButton
* QtXButton1
* QtXButton2
 
=== QtOrientation ===
* QtHorizontal
* QtVertical
 
=== QtScrollBarPolicy ===
* QtScrollBarAsNeeded
* QtScrollBarAlwaysOff
* QtScrollBarAlwaysOn
 
=== QtSizePolicy ===
* QSizePolicyFixed
* QSizePolicyMinimum
* QSizePolicyMaximum
* QSizePolicyPreferred
* QSizePolicyExpanding
* QSizePolicyMinimumExpanding
* QSizePolicyIgnored
 
== User Interface Elements  ==
 
=== Plasma Widgets  ===
 
The Plasma framework provides a set of standard user interface elements such as pushbuttons and checkboxes for use in Plasmoids, and these are available from the Simplified Javascript API as well. These elements follow the Plasma style and other conventions so that widgets blend well both visually and functionally with other Plasma elements.
 
Note that some UI elements have functions that are synonymous with a read-write property. In those cases, the function can serve as a slot and be connected to signals for easy setting of the property.
 
=== DataEngine-Aware UI Elements ===
Some of the UI elements are able to accept data directly from DataEngines. These widgets will have a dataUpdated function and can be passed into the DataEngine::connectSource method successfully.
 
DataEngine-aware UI elements include:
 
* Label
* TextEdit
* Meter
 
=== Common Properties  ===
 
By default, all of the Plasma user interface elements have the following properties:
 
* ''String'' '''objectName'''
* ''number'' '''opacity'''
* ''boolean'' '''enabled'''
* ''boolean'' '''visible'''
* ''QPointF'' '''pos'''
* ''number'' '''x'''
* ''number'' '''y'''
* ''number'' '''z'''
* ''number'' '''rotation'''
* ''number'' '''scale'''
* ''QPointF'' '''transformOriginPoint'''
* ''QPalette'' '''palette'''
* ''QFont'' '''font'''
* ''QSizeF'' '''size'''
* ''QtFocusPolicy'' '''focusPolicy'''
* ''QRectF'' '''geometry'''
 
=== Common Signals  ===
 
* '''opacityChanged()'''
* '''visibleChanged()'''
* '''enabledChanged()'''
* '''xChanged()'''
* '''yChanged()'''
* '''zChanged()'''
* '''rotationChanged()'''
* '''scaleChanged() '''
 
=== UI Element Gallery  ===
 
==== CSS Styleable UI Elements ====
 
Most UI Elements are able to have their appearance adjust using a CSS stylesheet. All of these elements have the following read/write property:
 
*''String'' '''styleSheet''': A CSS stylesheet describing visual properties to apply to the widget; see [http://doc.trolltech.com/4.5/stylesheet.html the Qt Documentation for more information]
 
===== CheckBox =====
Read-write properties:
* ''String'' '''text'''
* ''String'' '''image'''
* ''boolean'' '''checked'''
* '''toggled(bool)'''
 
===== ComboBox =====
Read-write properties:
* ''String'' '''text'''
 
Funtions:
* '''clear()'''
 
Signals:
* '''activated(String)'''
* '''textChanged(String)'''
 
===== Frame =====
Read-write properties:
* ''Shadow'' '''frameShadow'''
* ''String'' '''text'''
* ''String'' '''image'''
 
Enumerations:
* '''Shadow'''
* '''Plain'''
* '''Raised'''
* '''Sunken'''
 
===== GroupBox =====
Read-write properties:
* ''String'' '''text'''
 
===== Label =====
Read-write properties:
* ''String'' '''text'''
* ''String'' '''image'''
* ''number'' '''alignment'''
* ''boolean'' '''hasScaledContents'''
* ''boolean'' '''textIsSelectable''' (since 4.4.1)
* ''boolean'' '''wordWrap''' (API v2)
 
Functions:
* '''dataUpdated(String, Data)'''
 
Signals:
* '''linkActivated(String)''': emitted when a link is clicked; includes the URL of link that is clicked; this is only available when textIsSelectable
* '''linkHovered(String)''': emitted when a link is hovered
 
===== LineEdit =====
Read-write properties:
* ''String'' '''text'''
* ''boolean'' '''clearButtonShown'''
 
Signals:
* '''editingFinished()'''
* '''returnPressed()'''
* '''textEdited(String)'''
* '''textChanged(String)'''
 
===== PushButton =====
Read-write properties:
* ''String'' '''text'''
* ''String'' '''image'''
* ''QAction'' '''action'''
* ''QIcon'' '''icon'''
* ''boolean'' '''checkable'''
* ''boolean'' '''checked'''
* ''boolean'' '''down'''
 
Signals:
* '''pressed()'''
* '''released()'''
* '''clicked()'''
* '''toggled(bool)'''
 
===== RadioButton =====
Read-write properties:
* ''String'' '''text'''
* ''String'' '''image'''
* ''boolean'' '''checked'''
 
Signals:
* '''toggled(bool)'''
 
===== ScrollWidget =====
Read-write properties:
* ''QGraphicsWidget'' '''widget'''
* ''number'' '''horizontalScrollBarPolicy'''
* ''number'' '''verticalScrollBarPolicy'''
* ''QPointF'' '''scrollPosition'''
* ''QSizeF'' '''contentsSize'''
* ''QRectF'' '''viewportGeometry'''
 
Functions:
* '''ensureRectVisible(QRectF)'''
* '''ensureItemVisible(QGraphicsItem)'''
* '''registerAsDragHandle(QGraphicsWidget)'''
* '''unregisterAsDragHandle(QGraphicsWidget)'''
 
===== ScrollBar =====
Read-write properties:
* ''number'' '''singleStep'''
* ''number'' '''pageStep'''
* ''number'' '''value'''
* ''number'' '''minimum'''
* ''number'' '''maximum'''
* ''QtOrientation'' '''setOrientation'''
 
Functions:
* '''setValue(number)'''
* '''setOrientation(QtOrientation)'''
 
Signals:
* '''valueChanged(number)'''
 
===== Slider =====
Read-write properties:
* ''number'' '''maximum'''
* ''number'' '''minimum'''
* ''number'' '''value'''
* ''number'' '''orientation'''
 
Signals:
* '''sliderMoved(number)'''
* '''valueChanged(number)'''
 
Functions:
* '''setMaximum(number)'''
* '''setMinimum(number)'''
* '''setRange(number, number)'''
* '''setValue(number)'''
* '''setOrientation(QtOrientation)'''
 
===== SpinBox =====
Read-write properties:
* ''number'' '''maximum'''
* ''number'' '''minimum'''
* ''number'' '''value'''
 
Functins:
* '''setMaximum(number)'''
* '''setMinimum(number)'''
* '''setRange(number, number)'''
* '''setValue(number)'''
 
Signals:
* '''sliderMoved(number)'''
* '''valueChanged(number)'''
* '''editingFinished()'''
 
===== TabBar =====
Read-write properties:
* ''number'' '''currentIndex'''
* ''number'' '''count'''
* ''boolean'' '''tabBarShown'''
 
Functions:
* '''setCurrentIndex(number)'''
* '''insertTab(number, QIcon,String,QGraphicsLayoutItem)'''
* '''insertTab(number, QIcon,String)'''
* '''insertTab(number, String,QGraphicsLayoutItem)'''
* '''insertTab(number, String)'''
* '''addTab(QIcon,String,QGraphicsLayoutItem)'''
* '''addTab(QIcon,String)'''
* '''addTab(String,QGraphicsLayoutItem)'''
* '''addTab(String)'''
* '''removeTab(number)'''
* '''takeTab(number)'''
* '''tabAt(number)'''
* '''setTabText(number, String)'''
* '''tabText(number)'''
* '''setTabIcon(number, QIcon)'''
* '''tabIcon(number)'''
 
Signals:
* '''currentChanged(number)'''
 
===== TextEdit =====
Read-write properties:
* ''String'' '''text'''
* ''boolean'' '''readOnly'''
 
Functions:
* '''dataUpdated(String, Data)'''
 
Signals:
* '''textChanged()'''
 
===== ToolButton =====
:Read-write properties:
 
* ''''QAction'' '''action''': the action associated with this '''ToolButton'''
* ''''boolean'' '''autoRaise''': whether or not the ToolButton should raise automatically when the user interacts with it'''
* ''''String'' '''image''': path to an icon or image (e.g. in the widget's Package) to show on the ToolButton
* ''''String'' '''text''': the text shown on the ToolButton
 
API v2 adds:
* ''''boolean'' '''down''': whether or not the ToolButton is in the down position (since protocol version 2)
 
:Signals:
* '''clicked()'''
* '''pressed()'''
* '''released()'''
 
===== TreeView =====
Read-write properties:
* ''QAbstractModel'' '''model'''
 
===== VideoWidget =====
Read-writeproperties:
* ''String'' '''url'''
* ''number'' '''currentTime'''
* ''number'' '''totalTime'''
* ''number'' '''remainingTime'''
* ''Controls'' '''usedControls'''
* ''boolean'' '''controlsVisible'''
 
Functions:
* '''play()'''
* '''pause()'''
* '''stop()'''
* '''seek(number)'''
 
Signals:
* '''tick(number)'''
* '''aboutToFinish()'''
* '''nextRequested()'''
* '''previousRequested()'''
 
 
Enumerations:
* Controls
** NoControls
** Play
** Pause
** Stop
** PlayPause
** Previous
** Next
** Progress
** Volume
** OpenFile
** DefaultControls
 
==== Other UI Elements ====
 
===== BusyWidget =====
Read-write properties:
* ''boolean'' '''running'''
* ''String'' '''label'''
 
Signals:
* '''clicked()'''
 
===== FlashingLabel =====
Read-write properties:
* ''boolean'' '''autohide'''
* ''QColor'' '''color'''
* ''number'' '''duration'''
 
Functins:
* '''kill()'''
* '''fadeIn()'''
* '''fadeOut()'''
* '''flash(String, number, QTextOption)'''
* '''flash(String ,number)'''
* '''flash(String)'''
* '''flash(QPixmap, number, QtAlignment)'''
* '''flash(QPixmap, number)'''
* '''flash(QPixmap)'''
 
===== IconWidget =====
Read-write properties:
* ''String'' '''text'''
* ''String'' '''infoText'''
* ''QIcon'' '''icon'''
* ''QColor'' '''textBackgroundColor'''
* ''QSizeF'' '''iconSize'''
* ''String'' '''svg'''
* ''QAction'' '''action'''
* ''QtOrientation'' '''orientation'''
* ''number'' '''numDisplayLines'''
 
Functions:
* '''setPressed(boolean)'''
* '''setUnpressed()'''
* '''setIcon(String)'''
 
Signals:
* '''pressed(bool)'''
* '''clicked()'''
* '''doubleClicked()'''
* '''activated()'''
* '''changed()'''
 
 
===== ItemBackground =====
Read-write properties:
* ''QRectF'' '''target'''
* ''QGraphicsItem'' '''targetItem'''
 
Signals:
* '''appearanceChanged()'''
* '''animationStep(qreal)'''
* '''targetReached(QRectF)'''
* '''targetItemReached(QGraphicsItem)'''
 
===== Meter =====
Read-write properties:
* ''number'' '''minimum'''
* ''number'' '''maximum'''
* ''number'' '''value'''
* ''String'' '''svg'''
* ''MeterType'' '''meterType'''
 
Functions:
* '''dataUpdated(String, Data)'''
 
Enumerations:
* '''MeterType'''
** BarMeterHorizontal
** BarMeterVertical
** AnalogMeter
 
===== Separator =====
Read-write properties:
* ''QtOrientation'' '''orientation'''
 
===== SignalPlotter =====
Read-write properties:
* ''String'' '''title'''
* ''String'' '''unit'''
* ''boolean'' '''useAutoRange'''
* ''number'' '''horizontalScale'''
* ''boolean'' '''showVerticalLines'''
* ''QColor'' '''verticalLinesColor'''
* ''number'' '''verticalLinesDistance'''
* ''boolean'' '''verticalLinesScroll'''
* ''boolean'' '''showHorizontalLines'''
* ''QColor'' '''horizontalLinesColor'''
* ''QColor'' '''fontColor'''
* ''number'' '''horizontalLinesCount'''
* ''boolean'' '''showLabels'''
* ''boolean'' '''showTopBar'''
* ''QColor'' '''backgroundColor'''
* ''String'' '''svgBackground'''
* ''boolean'' '''thinFrame'''
* ''boolean'' '''stackPlots'''
 
===== SvgWidget =====
Read-write properties:
* ''Svg'' '''svg'''
* ''String'' '''elementID'''
 
Signals:
* '''clicked(QtMouseButton)'''
 
===== WebView =====
Read-only properties:
* ''QSizeF'' '''contentsSize'''
* ''QRectF'' '''viewportGeometry'''
 
Read-write properties:
* ''Url'' '''url'''
* ''String'' '''html'''
* ''boolean'' '''dragToScroll'''
* ''QPointF'' '''scrollPosition'''
 
Signals:
* '''loadProgress(number)'''
* '''loadFinished(bool)'''
 
=== Layouts  ===
 
==== LinearLayout ====
* number spacing
* QtOrientation orientation
* function removeAt
* function addStretch
* function setStretchFactor
* function setAlignment
* function insertStretch
* function setItemSpacing
* function setContentsMargins
* function addItem
* function removeItem
* function insertItem
* function toString
 
==== AnchorLayout ====
* number horizontalSpacing
* number verticalSpacing
* function setSpacing
* function removeAt
* function addAnchor
* function anchor
* function addAnchors
* function addCornerAnchors
* function toString
 
==== GridLayout ====
* number horizontalSpacing
* number verticalSpacing
* function rowSpacing
* function setRowSpacing
* function columnSpacing
* function setColumnSpacing
* function rowMinimumHeight
* function setRowMinimumHeight
* function rowPreferredHeight
* function setRowPreferredHeight
* function rowMaximumHeight
* function setRowMaximumHeight
* function rowFixedHeight
* function setRowFixedHeight
* function columnMinimumWidth
* function setColumnMinimumWidth
* function columnPreferredWidth
* function setColumnPreferredWidth
* function columnMaximumWidth
* function setColumnMaximumWidth
* function columnFixedWidth
* function setColumnFixedWidth
* function remoteAt
* function setAlignment
* function setSpacing
* function setContentsMargins
* function addItem
* function toString
 
=== Undocumented Properties and Functions  ===
 
There are a handful of other undocumented properties and functions available to UI elements. These are not supported or guaranteed to exist in future versions however, and as such should not be used or relied upon.
 
== Animations ==
 
=== Creating Animation Objects ===
An Animation object can be retrieved by calling the ''Animation'' '''animation(string type)''' function. The ''string'' corresponds to the type of animation, which are listed below.
 
New Animation objects are associated with (and therefore will animate) the Plasmoid by default. By setting the widgetToAnimate property, however, it can be assigned to animate any QGraphicsWidget desired (e.g. Plasma widgets such as push buttons, sliders, etc) .
 
=== 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
 
== Painting  ==
 
See the "Painting and Layout" section, part of the Global Plasmoid chapter, for information on using these classes within a widget.
 
=== Pixmaps  ===
 
The QPixmap object allows widgets to use pixmaps for painting. Widgets may include pixmaps in various common formats (PNG, JPEG, GIF, etc.) in the contents/images/ directory of the Plasmoid package and load them by passing the name of the file into the pixmap contrustor:
<code javascript>
    var pixmap = new QPixmap("myimage.png")
</code>
In addition to being used as a file load, some objects return or take pixmaps and the QPixmap object facilitates that as well.
 
Read-only properties:
* ''boolean'' '''null''': true if the pixmap is empty
* ''QRectF'' '''rect''': the rect of the pixmap
 
Functions:
* ''QPixmap'' '''scaled(number width, number height);;: returns a scaled version of the pixmap with width and height dimensions.
 
=== Icons ===
 
(Since 4.4.1)
 
The QIcon object provides simple access to icons. They can be constructed using a String or a QPixmap, with the String version either loading a file from disk if given an absolute path (useful for loading icons from the Plasmoid's package) or from the desktop icon theme if given just a name (e.g. "file-open").
 
Read-only properties:
* ''boolean'' '''null''': true if the icon is empty
 
Functions:
* '''addPixmap(QPixmap)''': adds another pixmap to this icon
* '''addFile(String)''': adds another file to this icon
 
=== SVG Images  ===
 
Plasma makes heavy usage of SVG images. More information on this industry standard scalable vector format can be found here:
 
:http://www.w3.org/Graphics/SVG/
 
Free and Open Source Software tools for creating SVGs include Inkscape and Karbon13. Widgets may include their own SVG files in the contents/images/ directdory or may use SVG images that are part of the standard Plasma Desktop Theme as documented here:
 
:http://techbase.kde.org/Projects/Plasma/Theme
 
Two classes are provide: Svg and FrameSvg. Svg allows loading and painting entire SVG documents or individual elements in an SVG document. FrameSvg extends Svg with methods to paint bordered frames from specially crafted SVG documents (see the Plasma Desktop Theme documentation for more information on this).
 
====Svg====
Constructors:
*'''Svg(string fileName)'''': fileName can be a file in the desktop theme or the plasmoid package
 
Read-only properties:
*''QSizeF'' '''size''': the current size of the svg
 
Read-write properties:
* ''boolean'' '''multipleImages''': whether or not the svg contains multiple separate images
* ''string'' '''imagePath''': the file path, including name of the svg
* ''boolean'' '''usingRenderingCache'': whether or not to cache rendered pixmaps; improves performance (at the cost of some disk and memory usage) for SVG data that is repeatedly rendered
 
Functions:
* ''QSizeF'' elementSize(String svgElemen)'''
* ''QRectF'' elementRect(String svgElemen)'''
* ''boolean'' '''hasElement(String svgElement)'''
* '''elementAtPoint(QPoint pos)'''
* ''boolean'' '''isValid()'''
* ''QPixmap'' '''pixmap(String svgElement)''': a pixmap of the element in the svg rendered to the current size
* ''Qixmap'' '''pixmap()''': a pixmap of the entire svg rendered to the current size
* '''paint(QPainter painter, QPointF point)'''
* '''paint(QPainter painter, QPointF point, String svgElement)'''
* '''paint(QPainter painter, number x, number y)'''
* '''paint(QPainter painter, number x, number y, String svgElement)'''
* '''paint(QPainter painter, QRectF destination)'''
* '''paint(QPainter painter, QRectF destination, String svgElement)'''
* '''paint(QPainter painter, number y, number width, number height)'''
* '''paint(QPainter painter, number x, number y, number width, number height, QString svgElement)'''
* '''resize(number width, number height)
* '''resize(QSizeF size)'''
* '''resize()''': resizes the SVG to the document size defined in the SVG itself
 
Signals:
* '''repaintNeeded()''': emitted when the SVG is in need of a repaint, such as when the theme changes and the SVG has reloaded its data
 
====FrameSvg====
Constructors:
* '''FrameSvg(String fileName)''': fileName can be a file in the desktop theme or the plasmoid package
 
Read-only properties:
* ''boolean'' '''multipleImages''': whether or not the svg contains multiple separate images
 
Functions:
* '''setEnabledBorders(EnabledBorders borders)''': sets which borders are enabled when painting
* ''EnabledBorders'' '''enabledBorders()''': the borders which are enabled when painting
* '''resizeFrame(QSizeF size)''': resizes the frame to size
* ''QSizeF'' '''frameSize()''': the size of the current frame
* ''number'' '''marginSize(MarginEdge margin)''': the size of the margin for a given edge
* '''getMargins(number left, number top, number right, number bottom)''': stores the margin values in the variables passed in
* ''QRectF'' '''contentsRect()''': the rect containing the contents, e.g. the size of the SVG minus the space required by the enabled borders
* '''setElementPrefix(Location)''': sets the frame element for the given location if it exists
* '''setElementPrefix(String prefix)''': sets the element prefix
* ''boolean'' '''hasElementPrefix(String prefix)''': returns true if the SVG contains a frame with the given prefix
* ''boolean'' '''hasElementPrefix(Location location)''': true if the SVG contains a frame element for the given location
* '''prefix()'''
* '''mask()'''
* '''setCacheAllRenderedFrames(bool)'''
* '''cacheAllRenderedFrames()'''
* ''QPixmap'' '''framePixmap()''': a pixmap containing the current frame at the current size
* '''paintFrame(QPainter painter)'''
* '''paintFrame(QPainter painter, QPointF target)'''
* '''paintFrame(QPainter painter, QRectF target)'''
* '''paintFrame(QPainter painter, QRectF target, QRectF source)'''
 
Enumerations
* '''EnabledBorder'''
** NoBorder
** TopBorder
** BottomBorder
** LeftBorder
** RightBorder
** AllBorders
 
=== Painting on the Canvas  ===
 
==== QColor ====
 
*Constructors:
**QColor
**QColor(string colorName)
**QColor(number red, number green, number blue, number alpha)
*number red
*number green
*number blue
*number alpha
*boolean valid
 
==== QFont ====
 
*Constructors:
**QFont
**QFont(string fontName)
**QFont(string fontName, number pointSize)
**QFont(string fontName, number pointSize, number weight)
**QFont(string fontName, number pointSize, number weight, boolean italic)
*string key
*string lastResortFamily
*string lastResortFont
*string defaultFamily
*boolean exactMatch
*string toString
*boolean bold
*string family
*boolean fixedPitch
*undefined fromString
*boolean italic
*boolean kerning
*boolean overline
*number pixelSize
*number pointSize
*number pointSizeF
*boolean strikeOut
*number stretch
*boolean underline
*number weight
*function isCopyOf
*function resolve
 
====QPainter ====
* Constructors
** QPainter
** QPainter(object paintDevice): used to start a painter on a specific QWidget; rarely if ever needed in a JavaScript Plasmoid
* object background
* number backgroundMode
* object brush
* undefined setBrush
* object brushOrigin
* undefined clipping
* object clipPath
* object clipRegion
* number compositionMode
* object font
* number layoutDirection
* number opacity
* object pen
* number renderHints
* undefined transform
* object viewport
* boolean viewTransformEnabled
* object window
* object worldMatrix
* object worldTransform
* boolean worldMatrixEnabled
* object combinedMatrix
* object combinedTransform
* boolean active
* function begin
* function end
* function boundingRect
* function drawChord
* function drawConvexPolygon
* function drawArc
* function drawEllipse
* function drawImage
* function drawLine
* function drawLines
* function drawPath
* function drawPicture
* function drawPie
* function drawPixmap
* function drawPoint
* function drawPoints
* function drawPolygon
* function drawPolyline
* function drawRect
* function drawRects
* function drawRoundRect
* function drawText
* function drawTiledPixmap
* function eraseRect
* function fillPath
* function fillRect
* function resetMatrix
* function resetTransform
* function restore
* function rotate
* function save
* function scale
* function setClipRect
* function setRenderHint
* function shear
* function strokePath
* function testRenderHint
* function toString
* function translate
 
==== QPen ====
*Constructors:
**QPen
* object brush
* object color
* number capStyle
* number joinStyle
* number style
* number dashOffset
* number miterLimit
* number width
* boolean solid
* number red
* number green
* number blue
* number alpha
* boolean valid
 
==== QRectF ====
Read-only properites:
* ''boolean'' '''empty''': true if the rectangle's width or height is less than, or equal to, 0; an empty rectangle is also invalid
* ''boolean'' '''null''': true if the rectangle has both the width and the height set to 0; a null rectangle is also empty and not valid
* ''boolean'' '''valid''':  true if the rectangle has a width > 0 and height 0.
 
Read-write properties:
* ''number'' '''left'''
* ''number'' '''top'''
* ''number'' '''bottom'''
* ''number'' '''right'''
* ''number'' '''height'''
* ''number'' '''width'''
* ''number'' '''x'''
* ''number'' '''y'''
 
Constructors:
* '''QRectF'''
* '''QRectF(number x, number y, number width, number height)''': Sets the coordinates of the rectangle's top-left corner to (x, y), and its size to the given width and height.
 
Functions:
* '''adjust(number dx1, number dy1, number dx2, number dy2)''': adds dx1, dy1, dx2 and dy2 respectively to the existing coordinates of the rectangle
* ''QRectF'' '''adjusted(number dx1, number dy1, number dx2, number dy2)''': returns a new QRectF with dx1, dy1, dx2 and dy2 added respectively to the existing coordinates of the rectangle
* '''translate(number dx, number dy)''': translates the rect by dx, dy
* '''setCoords(number x1, number y1, number x2, number y2)''': sets the coordinates of the rectangle's top-left corner to (x1, y1), and the coordinates of its bottom-right corner to (x2, y2).
* '''setRect(number x, number y, number width, number height)''': sets the coordinates of the rectangle's top-left corner to (x, y), and its size to the given width and height.
* ''boolean'' '''contains(number x, number y)''': returns true if the rect contains the point (x, y)
* '''moveBottom(number delta)'': moves the bottom by delta pixels
* '''moveLeft(number delta)''': moves the left by delta pixels
* '''moveRight(number delta)''': moves the right by delta pixels
* '''moveTo(number x, number y)''': moves the top left of the rect to point (x, y)
* '''moveTop(number delta)''': moves the top by delta pixels
 
==== QSizeF ====
 
*Constructors:
**QSizeF
**QSizeF(number width, number height)
*number height
*number width
 
==== QPoint ====
 
Constructors:
* '''QPoint'''
* '''QPoint(number x, number y)'''
 
Read-only properties:
* ''bool'' '''null'''
* ''number'' '''manhattanLength '''
 
Read-write propertie:
* ''number'' '''x '''
* ''number'' '''y'''
 
== Accessing Sources of Data  ==
 
See the [[Development/Tutorials/Plasma/JavaScript/DataEngine|JavaScript Plasmoid DataEngine tutorials]]
 
=== Global Functions to Access DataEngines and Services ===
* dataEngine(string name): returns a DataEngine object
* service(string dataEngineName, string sourceName): returns a ServiceObject, see also DataEngine::serviceForSource
 
=== DataEngine ===
Read-only properties:
* ''Array[String]'' '''sources'''
* ''boolean'' '''valid'''
* ''String'' '''icon'''
* ''String'' '''name'''
 
Signals:
* '''sourceAdded(String sourceName)'''
* '''sourceRemoved(String sourceName)'''
 
Functions:
* '''serviceForSource(String sourceName)'''
* '''connectSource(String sourceName, Object connectTo[, number interval[, IntervalAlignment alignment] ])''': if the object passed in as the object to connect to is the plasmoid object, then the plasmoid.dataUpdated(String source, Map[String, Any] data) callback will be called if it exists
* '''connectAllSources(Object connectTo[, number interval[, IntervalAlignment alignment] ])''': if the object passed in as the object to connect to is the plasmoid object, then the plasmoid.dataUpdated(String source, Map[String, Any] data) callback will be called if it exists
* '''disconnectSource(String sourceName, Object connectedTo)''': if the object passed in as the object to connect to is the plasmoid object, then the plasmoid.dataUpdated(String source, Map[String, Any] data) callback will be called if it exists
* '''Data query(String sourceName)'''
 
The following functions are only of interest to DataEngine reimplementations (e.g. JavaScript DataEngines):
 
* '''scheduleSourcesUpdated()'''
* '''removeSource(String)'''
* '''updateAllSources()'''
* '''forceImmediateUpdateOfAllVisualizations()'''
* '''DataContainer containerForSource(String)'''
 
=== Service ===
* function finished(Plasma::ServiceJob*)
* function operationsChanged()
* function serviceReady(Plasma::Service*)
* function setDestination(QString)
* function destination()
* function operationNames()
* function operationDescription(QString)
* function startOperationCall(KConfigGroup,QObject*)
* function startOperationCall(KConfigGroup)
* function isOperationEnabled(QString)
* function name()
* function associateWidget(QWidget*,QString)
* function disassociateWidget(QWidget*)
* function associateWidget(QGraphicsWidget*,QString)
* function disassociateWidget(QGraphicsWidget*)
* function parametersFromDescription(KConfigGroup)
 
== Other Functions and Classes  ==
=== Print and Debug ===
* '''print(string message)''': prints message to console
* '''debug(string message)''': print message to console if it is running in a KDE debug build
 
=== GraphicsItem ===
This class represents an item on the canvas. Support is only provided so that GraphicsItem objects returned or taken by other objects work. There is no meaningful API provided directly in the JavaScript runtime for these objects and they should not need to be used directly.
 
=== QSizePolicy ===
The QSizePolicy class is a layout attribute describing horizontal and vertical resizing policy. This can be set on any graphics widget that you have using the enums provided for this (QtSizePolicy ), for example:
 
button = new PushButton();
button.sizePolicy = QSizePolicy(QSizePolicyMaximum, QSizePolicyFixed);
 
This is useful when your widgets are being laid out by a layout (specially the anchor layout).
 
* ''QtSizePolicy '' '''horizontalPolicy''': The horizontal component of the size policy.
* ''QtSizePolicy '' '''verticalPolicy''': The vertical component of the size policy.
* ''number'' '''horizontalStretch''': The horizontal stretch factor of the size policy.
* ''number'' '''verticalStretch''': The vertical stretch factor of the size policy.
 
=== IOJob ===
This object is returned by input/output access for asynchronous file and data access (see the section on Extensions for documentation on getUrl). It is used by connecting Javascript functions in your code to the relevant signals.
 
Functions:
* '''kill()'''
* '''suspend()'''
* '''resume()'''
 
Signals:
* '''data(IOJob job, ByteArray data)''': emitted whenever data arrives. If data is empty (data.length == 0) then the transmission has completed.
* '''dataReq(IOJob job, ByteArray data)''': when sending data, this signal is emitted when data is requested; add the data to be sent ot the data member, or leave it empty to signal that the process is complete and there is no more data to send
* '''finished(IOJob job)''': emitted when the transmission has completed
* '''suspended(IOJob job)''': emitted when the job has been suspeneded
* '''resumed(IOJob job)'''
* '''canceled(IOJob job)'''
* '''connected(IOJob job)'''
* '''redirection(IOJob job, Url to)'''
* '''permanentRedirection(IOJob job, Url from, Url to)'''
* '''mimetype(IOJob job, String mimetype)'''
 
=== QTimer ===
Read-write properties:
* ''boolean'' '''active''': true if active, false if not
* ''boolean'' '''singleShot''': true if the timer will fire once when started, false if it will fire repeatedly until stopped
* ''boolean'' '''interval''': the interval in milliseconds that the timer will trigger
 
Functions:
* '''start(int msec)''': starts the timer with msec as the interval
* '''start()''': starts the timer with the default interval
* '''stop()''': stops the timer
 
Signals:
* '''timeout()''': this signal is emitted whenever the timer interval is reached
 
=== Url ===
Represents a local or remote address. To create a new Url (or assign to an existing one), use the following syntax:
 
<code javascript>var url = new Url("http://kde.org")</code>
 
Read-only properties:
* ''string'' '''toString''': the URL as a String object
 
Read-write properties (each representing a portion of the full URL):
* ''string'' '''protocol'''
* ''string'' '''host'''
* ''string'' '''path'''
* ''string'' '''user'''
* ''string'' '''password'''
 
=== ByteArray ===
This class provides an array of bytes. This is often used by data centric objects, such as the Job classes returned by getUrl.
 
Read-only properties:
* ''number'' '''length''': the size of the array (number of bytes)
 
Functions:
* '''chop(number numBytes)''': chops numBytes from the end of the array
* ''bool'' '''equals(ByteArray other)'''
* ''ByteArray '''left(number len)''': return len bytes from the left of the array
* ''ByteArray '''mid(number pos, number len)''': returns an array of bytes starting a post and length len (if len is -1, it returns all remaining bytes)
* ''ByteArray '''remove(number pos, number len)''': removes len bytes starting at index pos from the array and returns it
* ''ByteArray '''right(number len)''': returns len bytes from the right of the array
* ''ByteArray '''simplified()''': returns a byte array that has whitespace removed from the start and the end, and which has each sequence of internal whitespace replaced with a single space
* ''ByteArray '''toBase64()''': returns the array encoded in base64
* ''ByteArray '''toLower()''': returns a lowercased copy of the array
* ''ByteArray '''toUpper()''': returns an uppercased copy of the array
* ''ByteArray '''trimmed()''': returns a copy of the array with whitespace remove from the start and end
* truncate(number pos): truncates the array at index pos
* ''String'' '''toLatin1String()''': returns a Latin1-ized string based on the array
* ''String'' '''valueOf()''': returns the raw data in the array as a string
 
== Extensions  ==
An API extension is a security controlled set of functions and objects that are loaded on demand. These extensions are requested by the widget by listing the required and the optional extensions (if any) it wants loaded in its metadata.desktop file. This way, even prior to the widget being loaded, Plasma can know what it will want.
 
Required extensions are requested using the X-Plasma-RequiredExtensions key, and optional extensions with the X-Plasma-OptionalExtensions. For example:
 
<code ini>
X-Plasma-RequiredExtensions=FileDialog,MyCustomQScriptExtension
X-Plasma-OptionalExtensions=LaunchApp,HTTP
</code>
 
The Simplified Javascript Engine then decides if the widget will actually get that extension or not. Failure to load a required extension will result in script execution being aborted.
 
Each of the built-in extensions provided are described below.
 
=== FileDialog ===
 
Provides access to open and save dialog classes: OpenFileDialog and SaveFileDialog. Both are non-modal and run asynchronously, so the signals must be used. Other than the name difference (and resulting UI variance) the API for each is identical:
 
* Constructors
** '''OpenFileDialog'''
** '''SaveFileDialog'''
* Properties
** Read Only
*** ''array(Url)'' '''urls''': the selected file, as a Url object
*** ''Url'' '''baseUrl''', the current path (minus filename) as a Url
*** ''string '''file''': the selected file, as a string
*** ''array(string)'' '''files''': selected files (plural), as an array of strings
** Read/Write
*** ''Url'' '''url''': the current Url, can be read from when the user is done or assigned before to set the starting path
*** ''string'' '''filter''': a string representing the mimetype filter; e.g. "*.cpp|C++ Source Files\n*.h|Header files" or "*.cpp" or "*.cpp|*h"
*** ''boolean'' '''localOnly''': true to show only local files, false if network locations are Ok as well
*** ''boolean'' '''directoriesOnly''': true to only allow selection of a directory (not a file)
*** ''boolean'' '''existingOnly''': true if only existing files/directories may be selected
* Functions
** '''show()''': when called, the dialog will be shown to the user
* Signals
** '''accepted(FileDialogProxy)'''': emitted when the file dialog has been successfully accepted by the user with one or more files/directories.
** '''finished(FileDialogProxy)''': emitted when the file dialog closes, included when cancelled/closed without being accepted
 
=== LocalIO ===
This extension allows access to local files.
 
Functions:
* ''IOJob'' '''getUrl(Url url)''': attempts to fetch the file using an IOJob
* ''IOJob'' '''getUrl(String url)''': attempts to fetch the file using an IOJob
 
=== NetworkIO ===
This extensions allows access to network addresses.
 
Functions:
* ''IOJob'' '''getUrl(Url url)''': attempts to fetch the file using an IOJob
* ''IOJob'' '''getUrl(String url)''': attempts to fetch the file using an IOJob
 
=== HTTP ===
This extension allows access to data and files via http and https.
 
Functions:
* ''IOJob'' '''getUrl(Url url)''': attempts to fetch the file using an IOJob
* ''IOJob'' '''getUrl(String url)''': attempts to fetch the file using an IOJob
 
=== LaunchApp ===
 
Adds methods to the global plasmoid object that allow launching applications, running commands and opening files and urls.


* ''bool'' '''runApplication(string application[, array files])''' <br>Runs an application by name (can reference an installed .desktop file as well as an executable in the user's $PATH) with an optional array of files. The file array may contain either Urls or strings. Returns true on success, false on failure.
* [[../API-PlasmoidObject|The Global plasmoid Object]]
* ''bool'' '''runCommand(string exe[, array args])''' <br>Runs the executable with the given arguments. Returns true on success, false on failure.
* [[../API-Enumerations|Global Enumerations]]
* ''bool'' '''openUrl([string|Url] url)''': <br>Opens the url in the default application (or asks the user if there is no default application for the file). The url parameter may be either a string or a Url. Returns true on success, false on failure.
* [[../API-Events|Events]]
* [[../API-UIElements|User Interface Elements]]
* [[../API-Animations|Animations]]
* [[../API-Painting|Painting]]
* [[../API-DataEnginesServices|Accessing Sources of Data with DataEngines and Services]]
* [[../API-Print|Printing To Console and Debug Output]]
* [[../API-IOJobs|Asynchronous Input/Output (IO) Jobs]]
* [[../API-Timers|Timers]]
* [[../API-Misc|Utility API and Objects]]
* [[../API-Extensions|Extensions]]
** [[../API-FileDialog|File Dialog]]
** [[../API-LocalIO|Local IO]]
** [[../API-NetworkIO|Network IO]]
** [[../API-HTTP|HTTP]]
** [[../API-LaunchApp|Launching Applications]]
* [[../API-Addons|Custom Addons (Plugins) in Javascript]]

Latest revision as of 23:27, 11 September 2014

Introduction to the Plasmoid JavaScript API

This document provides an overview/reference of the Simplified JavaScript API for Plasmoids. The "Simplified" refers to the fact that it isn't a full binding to all of Qt or KDE's libraries, but a highly focused set of bindings designed to make writing Plasmoids fast and easy, while remaining powerful.

The API in this documentation covers the JavaScript API as it appears in the KDE Software Compilation as of version 4.4 and higher. Changes between versions are noted in the documentation, including when new API functionality was introduced. This API ships as part of the KDE Base Runtime package, so can be relied on being there by any application that is Powered By KDE.

Examples and Tutorials

Tutorials can be found in the Plasma tutorials area here on Techbase and full, functioning examples can be found in the KDE Examples repository in the plasma/javascript folder.

Using QML

Starting with the KDE Platform 4.7 release, the Plasma team recommends writing your Plasmoids with QtQuick technologies with the Plasma QML integration API.

The QML API uses the same API as the Simplified JavaScript API with the exception of User Interface Elements, Animations and Events which are provided instead by QML itself.

The benefits of writing your Plasmoid with QML can include faster development with more sophisticated results visually and in its usability as well as much better performance when run in a QML-only Plasma shell such as Plasma Active.

What Is A Simplified JavaScript Plasmoid?

This document describes the native Plasma API available to Simplified JavaScript Plasmoids. What makes them "Simplified" is that they do not have access to the entire C++ API in the Plasma, KDE and Qt libraries (let alone things lower in the API stack). This helps ensure that these Plasmoids are more likely to work properly between releases as changes in underlying API don't affect them as well as allowing Plasma to offer stronger security guarantees around them.

To denote that this Plasmoid is a Simplified JavaScript widget, ensure that in the metadata.desktop file there is this line:

X-Plasma-API=javascript

What follows is a description of the runtime environment available to a Simplified JavaScript Plasmoid.

QtScript

The Simplified JavaScript API is powered by Qt's QtScript system which provides access to a full featured ECMA Script interpreter. If it works in ECMA Script, it will work in a Simplified JavaScript Plasmoid. As an interesting implementation note, QtScript uses the high performance ECMA Script interpreter from WebKit and shares this code with QtWebKit.

On top of the ECMA Script language, QtScript provides Qt integration features. Probably the most useful one in this context is the use of signals and slots which is Qt's callback mechanism. Signals may be emitted in QtScript by calling the signal method in question, a signal can be connected to a slot by using the connect() method (and disconnected with disconnect()) and any function defined in the Plasmoid may be used as a slot. For example: 

function onClick()
{
    print("We got clicked!")
}

function onFirstClick()
{
    print("First click!")
    button.clicked.disconnect(onFirstClick)
}

button = new PushButton
button.clicked.connect(onClick)
button.clicked.connect(onFirstClick)
button.clicked()

This will print out: 

We got clicked!
First click!

on the console when the Plasmoid starts, and the "We got clicked!" again whenever the button is clicked by the user.

The object that emitted the signal that caused a slot to be called can be retrieved using the QObject sender read-only property of the global plasmoid object.

API

Retrieved from "https://techbase.kde.org/index.php?title=Development/Tutorials/Plasma4/JavaScript/API&oldid=83660"