/*! \page properties Properties
*
+@section what-is-a-property What is a property?
+
+A property is a value used by an object that can be modified or read externally to that object.
+This could be from within DALi or externally by an application.
+
+<h2 class="pg">What is a property used for?</h2>
+
+Properties can be set externally by an application, allowing that application to change the configuration or behaviour of an actor.
+This could include the physical geometry of the actor, or how it is drawn or moves.
+
+Properties can also be read. This feature can be used in conjunction with constraints to allow changes to a property within one actor to cause changes to the property of another actor. For example, an actor following the movement of another separate actor (that it is not a child of).
+
+Properties can be used to expose any useful information or behaviour of an actor.
+Other actor variables that are used to implement this bevahiour, or do not make useful sense from an application developers point of view should not be exposed.
+
+<h2 class="pg">How to implement a property within Dali-core:</h2>
+
+<b>There are two stages:</b>
+
+- Define the properties as an enum in the public-api header file.
+- Define the property details using the pre-defined macros to build up a table of property information.
+
+There are some pre-defined macros designed to help with and standardise the definition of the propery details table per class.
+
+These macros generate an array of property details which allow efficient lookup of flags like "animatable" or "constraint input".
+
+<b>Example: Layer</b>
+
+Within the public-api header file; layer.h:
+
+@code
+ /**
+ * @brief An enumeration of properties belonging to the Layer class.
+ *
+ * Properties additional to Actor.
+ */
+ struct Property
+ {
+ enum
+ {
+ CLIPPING_ENABLE = DEFAULT_DERIVED_ACTOR_PROPERTY_START_INDEX, ///< name "clippingEnable", type bool @SINCE_1_0.0
+ CLIPPING_BOX, ///< name "clippingBox", type Rect<int> @SINCE_1_0.0
+ BEHAVIOR, ///< name "behavior", type String @SINCE_1_0.0
+ };
+ };
+@endcode
+From @ref Dali::Layer::Property
+
+<b>Notes:</b>
+
+- The properties are enumerated within a named struct to give them a namespace.
+- The properties are then refered to as <OBJECT>::%Property::<PROPERTY_NAME>.
+
+Within the internal implementation; <b>layer-impl.cpp</b>:
+
+@code
+namespace // Unnamed namespace
+{
+
+// Properties
+
+// Name Type writable animatable constraint-input enum for index-checking
+DALI_PROPERTY_TABLE_BEGIN
+DALI_PROPERTY( "clippingEnable", BOOLEAN, true, false, true, Dali::Layer::Property::CLIPPING_ENABLE )
+DALI_PROPERTY( "clippingBox", RECTANGLE, true, false, true, Dali::Layer::Property::CLIPPING_BOX )
+DALI_PROPERTY( "behavior", STRING, true, false, false, Dali::Layer::Property::BEHAVIOR )
+DALI_PROPERTY_TABLE_END( DEFAULT_DERIVED_ACTOR_PROPERTY_START_INDEX )
+@endcode
+
+<b>Notes:</b>
+
+- The table lays within an unnamed namespace.
+- The table should be in the same order as the enum.
+- The table should be the only place where the text names of the properties are defined.
+- The information in the table should be used within the classes IsDefaultPropertyWritable / Animatable / ConstraintInput methods for quick lookup.
+- The last entry in the table is optionally used in debug builds for index checking.
+- The parameter to DALI_PROPERTY_TABLE_END should match the start index of the property enumeration.
+
+<br>
+<h2 class="pg">How to implement a property within Dali-toolkit:</h2>
+
+Macros are used to define properties for the following reasons:
+
+- To standardise the way properties are defined.
+- To handle type-registering for properties, signals and actions in one place.
+- To facilitate the posibility of running the code with the type-registry disabled.
+
+Two different macros are provided depending on whether the property is to be an event-side only property or an animatable property.
+
+<b>There are two stages:</b>
+
+- Define the properties as an enum in the public-api header file, along with a definition of the property ranges.
+- Define the property details using the pre-defined macros to perform the type-registering of the properties. This is done for signals and actions also.
+
+<b>Example: ImageView</b>
+
+Source file: <b>image-view.h</b>:
+Note that the “PropertyRange” contents “PROPERTY_START_INDEX” & "ANIMATABLE_PROPERTY_REGISTRATION_START_INDEX" are also used by the macro for order checking.
+
+@code
+ /**
+ * @brief The start and end property ranges for this control.
+ */
+ enum PropertyRange
+ {
+ PROPERTY_START_INDEX = Control::CONTROL_PROPERTY_END_INDEX + 1, ///< @SINCE_1_0.0
+ PROPERTY_END_INDEX = PROPERTY_START_INDEX + 1000, ///< Reserve property indices @SINCE_1_0.0
+
+ ANIMATABLE_PROPERTY_START_INDEX = ANIMATABLE_PROPERTY_REGISTRATION_START_INDEX, ///< @SINCE_1_1.18
+ ANIMATABLE_PROPERTY_END_INDEX = ANIMATABLE_PROPERTY_REGISTRATION_START_INDEX + 1000 ///< Reserve animatable property indices, @SINCE_1_1.18
+ };
+
+ /**
+ * @brief An enumeration of properties belonging to the Button class.
+ */
+ struct Property
+ {
+ enum
+ {
+ // Event side properties
+
+ /**
+ * @DEPRECATED_1_1.16. Use IMAGE instead.
+ * @brief name "resourceUrl", type string
+ * @SINCE_1_0.0
+ */
+ RESOURCE_URL = PROPERTY_START_INDEX,
+ /**
+ * @brief name "image", type string if it is a url, map otherwise
+ * @SINCE_1_0.0
+ */
+ IMAGE,
+ /**
+ * @brief name "preMultipliedAlpha", type Boolean
+ * @SINCE_1_1.18
+ * @pre image must be initialized.
+ */
+ PRE_MULTIPLIED_ALPHA,
+
+ // Animatable properties
+
+ /**
+ * @brief name "pixelArea", type Vector4
+ * @details Pixel area is a relative value with the whole image area as [0.0, 0.0, 1.0, 1.0].
+ * @SINCE_1_0.18
+ */
+ PIXEL_AREA = ANIMATABLE_PROPERTY_START_INDEX,
+ };
+ };
+@endcode
+
+Source file: <b>image-view-impl.cpp</b>, within an unnamed namespace:
+
+@clip{"image-view-impl.cpp",DALI_TYPE_REGISTRATION_BEGIN,DALI_TYPE_REGISTRATION_END}
+
+<b>Notes:</b>
+
+- The “Create” parameter to the begin macro is the function pointer to the creation function.
+- Properties should be in the same order as in the enum.
+- Signals and actions are registered likewise in that order.
+- Properties type-registered using these macros will have their order checked at compile time. If you get an indexing compile error, check the order matches the enum order.
+
+<br>
+<hr>
@section property-indices Property Indices
+The properties are enumerated to give them a unique index. This index can be used to access them.
+The indecies must be unique per flattened derivation heirachy.
+EG:
+- CameraActor derives from Actor. No property indicies in either CameraActor or Actor should collide with each other.
+- ActiveConstraintBase derives from Object. It CAN have property indices that match Actor or CameraActor.
+
+There are some predefined start indecies and ranges that should be used for common cases, these are defined below:
+
+
DALi has a property system and provides several different kinds of properties. The following table
shows the index range of the different properties in place.
-<table>
- <tr> <td><b>Kind</b></td> <td><b>Description</b></td> <td style="text-align:center;"><b>Range</b></td> </tr>
- <tr> <td>Default</td> <td>Properties defined within DALi Core, e.g. Dali::Actor, Dali::ShaderEffect default properties etc.</td> <td style="text-align:center;">0 to 9999999</td> </tr>
- <tr> <td>Registered</td> <td>Properties registered using Dali::PropertyRegistration</td> <td style="text-align:center;">10000000 to 19999999</td> </tr>
- <tr> <td>Control</td> <td>Property range reserved by Dali::Toolkit::Control</td> <td style="text-align:center;">10000000 to 10001000<br>
- \link Dali::Toolkit::Internal::Control::CONTROL_PROPERTY_START_INDEX CONTROL_PROPERTY_START_INDEX\endlink
- to \link Dali::Toolkit::Internal::Control::CONTROL_PROPERTY_END_INDEX CONTROL_PROPERTY_END_INDEX\endlink</td> </tr>
- <tr> <td>Derived Control</td> <td>Property range for control deriving directly from Dali::Toolkit::Control</td> <td style="text-align:center;">10001001 to 19999999</td> </tr>
- <tr> <td>Custom</td> <td>Custom properties added to instance using Dali::Handle::RegisterProperty</td> <td style="text-align:center;">50000000 onwards</td> </tr>
-</table>
+| Kind | Description | Start Index | End Index |
+|:----------------------|:--------------------------------------------------------------------------------------------------|:----------------------------------------------------------------------------------------------------------:|:----------------------------------------------------------------------------------------------------------------------------------:|
+| Default | Properties defined within DALi Core, e.g. Dali::Actor, Dali::ShaderEffect default properties etc. | \link Dali::DEFAULT_OBJECT_PROPERTY_START_INDEX DEFAULT_OBJECT_PROPERTY_START_INDEX\endlink | \link Dali::DEFAULT_PROPERTY_MAX_COUNT DEFAULT_PROPERTY_MAX_COUNT\endlink (9999999) |
+| Registered | Properties registered using Dali::PropertyRegistration | \link Dali::PROPERTY_REGISTRATION_START_INDEX PROPERTY_REGISTRATION_START_INDEX\endlink (10000000) | \link Dali::PROPERTY_REGISTRATION_MAX_INDEX PROPERTY_REGISTRATION_MAX_INDEX\endlink (19999999) |
+| Registered Animatable | Animatable properties registered using Dali::PropertyRegistration | \link Dali::ANIMATABLE_PROPERTY_REGISTRATION_START_INDEX ANIMATABLE_PROPERTY_REGISTRATION_START_INDEX\endlink (20000000) | \link Dali::ANIMATABLE_PROPERTY_REGISTRATION_MAX_INDEX ANIMATABLE_PROPERTY_REGISTRATION_MAX_INDEX\endlink (29999999) |
+| Control | Property range reserved by Dali::Toolkit::Control | \link Dali::Toolkit::Control::CONTROL_PROPERTY_START_INDEX CONTROL_PROPERTY_START_INDEX\endlink (10000000) | \link Dali::Toolkit::Control::CONTROL_PROPERTY_END_INDEX CONTROL_PROPERTY_END_INDEX\endlink (10001000) |
+| Derived Control | Property range for control deriving directly from Dali::Toolkit::Control | 10001001 | \link Dali::PROPERTY_REGISTRATION_MAX_INDEX PROPERTY_REGISTRATION_MAX_INDEX\endlink (19999999) |
+| Custom | Custom properties added to instance using Dali::Handle::RegisterProperty | \link Dali::PROPERTY_CUSTOM_START_INDEX PROPERTY_CUSTOM_START_INDEX\endlink (50000000) | Onwards... |
+
+<br>
+<hr>
+@section property-use-example-cpp Property use example C++
+
+Common uses for properties are constraints and animations.
+
+An application developer can use an existing property, or, if necessary, register their own.
+
+Here is a code example.
+
+This example shows how to register and look-up custom properties.
+An image is added to the screen which changes and a custom property is added to the image-view.
+This value is incremented every time the image is touched and the text-label is updated.
+When touched, the property is looked up by index (as this is much faster than a text lookup of the property name).
+
+Property lookup via index should always be used unless the indicies cannot be known. If the property reader was completely decoupled from the creation, e.g. A custom control with a custom property being used by external application code, then it may be necessary. In this case the application writer should aim to perform the text lookup once at start-up, and cache the property index locally.
+
+@clip{"properties.cpp", // C++ EXAMPLE, // C++ EXAMPLE END}
+
+Once run, a grid of buttons will appear. When a button is pressed, the unique number stored in the property (in this case the index) is displayed at the bottom of the screen.
+
+<br>
+<hr>
+@section property-use-example-js Property use in JavaScript
+
+Note that constraints cannot be used within JavaScript, so below is a simple example that sets one of the default properties; scale:
+
+@code
+var imageView = new dali.Control( "ImageView" );
+
+// by default an actor is anchored to the top-left of it's parent actor
+// change it to the middle
+imageView.parentOrigin = dali.CENTER;
+
+// Set an image view property
+imageView.image = {
+ "rendererType" : "image",
+ "imageUrl" : "images/icon-0.png",
+ "width" : 100,
+ "height" : 100
+};
+
+// add to the stage
+dali.stage.add( imageView );
+@endcode
+
+For a more detailed example see the ShaderEffect example in the JavaScript documentation.
+
+<br>
+<hr>
+@section property-use-example-json Property use in JSON
+
+This is a basic example of a button defined in JSON by setting the default properties.
+
+@code
+{
+ "stage":
+ [
+ {
+ "type": "ImageView",
+ "parentOrigin": "CENTER",
+ "anchorPoint": "CENTER",
+ "position": [0, 0, 0],
+ "image":
+ {
+ "rendererType" : "image",
+ "imageUrl" : "images/icon-0.png",
+ "width" : 100,
+ "height" : 100
+ }
+ }
+ ]
+}
+@endcode
*
*/
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