text: #ifndef DALI_TOOLKIT_INTERNAL_VISUAL_H
  #define DALI_TOOLKIT_INTERNAL_VISUAL_H
  
  /*
   * Copyright (c) 2021 Samsung Electronics Co., Ltd.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   */
  
  // EXTERNAL INCLUDES
  #include <dali/public-api/animation/animation.h>
  #include <dali/public-api/common/intrusive-ptr.h>
  #include <dali/public-api/images/image-operations.h>
  #include <dali/public-api/object/base-object.h>
  #include <dali/public-api/rendering/renderer.h>
  #include <dali/public-api/rendering/shader.h>
  
  // INTERNAL INCLUDES
  #include <dali-toolkit/devel-api/direction-enums.h>
  #include <dali-toolkit/devel-api/visual-factory/visual-base.h>
  #include <dali-toolkit/devel-api/visual-factory/visual-factory.h>
  #include <dali-toolkit/devel-api/visuals/visual-properties-devel.h>
  #include <dali-toolkit/internal/visuals/transition-data-impl.h>
  #include <dali-toolkit/internal/visuals/visual-factory-cache.h>
  #include <dali-toolkit/public-api/visuals/visual-properties.h>
  
  namespace Dali
  {
  namespace Toolkit
  {
  namespace Internal
  {
  namespace Visual
  {
  class EventObserver;
  
  using FittingMode = DevelVisual::FittingMode;
  
  /**
   * Base class for all Control rendering logic. A control may have multiple visuals.
   *
   * Note: The visual responds to the the Actor::COLOR by blending it with the 'Multiply' operator.
   *
   * The following properties are optional
   *
   * | %Property Name          | Type             |
   * |-------------------------|------------------|
   * | customShader            | MAP              |
   *
   * where custom-shader is a map with the following properties:
   * | %Property Name          | Type             |
   * |-------------------------|------------------|
   * | vertexShader            | STRING           |
   * | fragmentShader          | STRING           |
   * | subdivideGridX          | INT              |
   * | subdivideGridY          | INT              |
   * | shaderHints             | INT              |
   */
  class Base : public BaseObject
  {
  public:
    /**
     * Setting the properties of the visual, this API should only called by the VisualFactory
     * @param[in] propertyMap The properties for the requested Visual object.
     */
    void SetProperties(const Property::Map& propertyMap);
  
    /**
     * @copydoc Toolkit::Visual::Base::SetName
     */
    void SetName(const std::string& name);
  
    /**
     * @copydoc Toolkit::Visual::Base::GetName
     */
    const std::string& GetName() const;
  
    /**
     * @copydoc Toolkit::Visual::Base::SetSize
     */
    void SetTransformAndSize(const Property::Map& transform, Size controlSize);
  
    /**
     * @brief Performs an action on the visual with the given action id and attributes.
     *
     * @param[in] actionId The id of the action to perform this API only takes an Index
     * @param[in] attributes The list of attributes for the action. ( optional for this data structure to have content )
     */
    void DoAction(const Dali::Property::Index actionId, const Dali::Property::Value attributes);
  
    /**
     * @copydoc Toolkit::Visual::Base::GetHeightForWidth
     */
    virtual float GetHeightForWidth(float width);
  
    /**
     * @copydoc Toolkit::Visual::Base::GetWidthForHeight
     */
    virtual float GetWidthForHeight(float height);
  
    /**
     * @copydoc Toolkit::Visual::Base::GetNaturalSize
     */
    virtual void GetNaturalSize(Vector2& naturalSize);
  
    /**
     * @copydoc Toolkit::Visual::Base::SetDepthIndex
     */
    void SetDepthIndex(int index);
  
    /**
     * @copydoc Toolkit::Visual::Base::GetDepthIndex
     */
    int GetDepthIndex() const;
  
    /**
     * @copydoc Toolkit::Visual::Base::SetOnScene
     * @pre Impl->mGeometry must be created before this method is called
     */
    void SetOnScene(Actor& actor);
  
    /**
     * @copydoc Toolkit::Visual::Base::SetOffScene
     */
    void SetOffScene(Actor& actor);
  
    /**
     * @copydoc Toolkit::Visual::Base::CreatePropertyMap
     */
    void CreatePropertyMap(Property::Map& map) const;
  
    /**
     * @brief Create a property map containing per-instance visual properties.
     *
     * This will enable creation of new visuals on control state change with
     * any alternative style properties and the relevant instance properties
     * (e.g. for image visual, the desired size, and for text visual, the actual text).
     * @param[in] map The property map into which to write
     */
    void CreateInstancePropertyMap(Property::Map& map) const;
  
    /**
     * @brief Set whether the Pre-multiplied Alpha Blending is required
     *
     * @param[in] preMultiplied whether alpha is pre-multiplied.
     */
    void EnablePreMultipliedAlpha(bool preMultiplied);
  
    /**
     * @brief Query whether alpha is pre-multiplied.
     *
     * @return True is alpha is pre-multiplied, false otherwise.
     */
    bool IsPreMultipliedAlphaEnabled() const;
  
    /**
     * @brief Sets properties of custom shader
     * @param[in] propertyMap Property map containing the custom shader data
     */
    void SetCustomShader(const Property::Map& propertyMap);
  
    /**
     * @copydoc Toolkit::Visual::Base::SetProperty
     */
    void SetProperty(Dali::Property::Index index, const Dali::Property::Value& propertyValue);
  
    /**
     * @copydoc Toolkit::Visual::Base::GetProperty
     */
    Dali::Property::Value GetProperty(Dali::Property::Index index);
  
    /**
     * Gets currently staged renderer, or an empty handle if not staged
     */
    Renderer GetRenderer();
  
    /**
     * Sets the mix color ( including opacity )  of the visual.
     * @param[in] mixColor The new mix color
     */
    void SetMixColor(const Vector4& color);
  
    /**
     * Sets the mix color of the visual.
     * @param[in] mixColor The new mix color
     */
    void SetMixColor(const Vector3& color);
  
    /**
     * Animate the property if it exists in the visual or renderer.
     *
     * If it's a visual property such as mix color or a transform property,
     * saves the target value to the local data.
     *
     * If the visual isn't staged (i.e. it doesn't have a renderer),
     * then this will not add an animation.
     *
     * If the animator is valid and the transition handle is empty - it will
     * be created.
     *
     * @param[in] transition The animation to create or attach to
     * @param[in] animator The animation parameters of the property.
     */
    void AnimateProperty(Dali::Animation&                    transition,
                         Internal::TransitionData::Animator& animator);
  
    /**
     * @brief Add an observer to watch for when the Visuals have events to notify
     * Currently only supports a single observer
     */
    void AddEventObserver(Visual::EventObserver& observer);
  
    /**
     * @brief Remove an observer
     */
    void RemoveEventObserver(Visual::EventObserver& observer);
  
    /**
     * @brief Called when the visuals resources are loaded / ready
     */
    void ResourceReady(Toolkit::Visual::ResourceStatus resourceStatus);
  
    /**
     * @brief Called when the visuals resources are loaded / ready
     * @return true if ready, false otherwise
     */
    virtual bool IsResourceReady() const;
  
    /**
     * @brief Get the loading state of the visual resource
     * @return Return the loading status (PREPARING, READY and FAILED) of visual resource
     */
    Toolkit::Visual::ResourceStatus GetResourceStatus() const;
  
    /**
     * @brief Get the fitting mode for the visual
     */
    FittingMode GetFittingMode() const;
  
    /**
     * @brief Get the actual Visual Object.
     * @return The actual visual object
     * @note Should be overridden by deriving controls if they are acting as a proxy to other visual objects.
     */
    virtual Base& GetVisualObject();
  
    /**
     * @brief Query whether resources requires to be loaded synchronously.
     * @return Returns true if synchronous resource loading is required, false otherwise.
     */
    bool IsSynchronousLoadingRequired() const;
  
    /**
     * @brief Get the type of this visual.
     *
     * @return The the type of this visual.
     */
    Toolkit::Visual::Type GetType() const;
  
    /**
     * @brief Retrieve the property object associated with the property key.
     *
     * @param[in] key The Property key of the visual.
     * @return The Property object
     */
    Dali::Property GetPropertyObject(Dali::Property::Key key);
  
  protected:
    /**
     * @brief Constructor.
     *
     * @param[in] factoryCache A pointer pointing to the VisualFactoryCache object
     * @param[in] fittingMode The value that determines how the visual should be fit to the view
     * @param[in] type The type of the this visual
     */
    Base(VisualFactoryCache& factoryCache, FittingMode fittingMode, Toolkit::Visual::Type type);
  
    /**
     * @brief A reference counted object may only be deleted by calling Unreference().
     */
    ~Base() override;
  
    /**
     * @brief Second-phase constructor.
     */
    void Initialize();
  
  protected:
    /**
     * @brief Called by Initialize() allowing sub classes to initialize them.
     */
    virtual void OnInitialize() = 0;
  
    /**
     * @brief Called by CreatePropertyMap() allowing sub classes to respond to the CreatePropertyMap event
     *
     * @param[out] map The visual property map.
     */
    virtual void DoCreatePropertyMap(Property::Map& map) const = 0;
  
    /**
     * @brief Called by CreateInstancePropertyMap() allowing derived
     * classes to store instanced data (separate to styled data) that
     * needs copying between visuals on state change.
     *
     * @param[out] map The visual property map
     */
    virtual void DoCreateInstancePropertyMap(Property::Map& map) const = 0;
  
    /**
     * @brief Called by SetProperties() allowing sub classes to set their properties
     *
     * @param[in] propertyMap The properties for the requested Visual object.
     */
    virtual void DoSetProperties(const Property::Map& propertyMap) = 0;
  
    /**
     * @brief Called when transform or control size changes
     * ( Of use to SVG and Text visuals )
     */
    virtual void OnSetTransform() = 0;
  
    /**
     * @brief Called by SetOnScene() allowing sub classes to respond to the SetOnScene event
     *
     * @note The derived class is required to create the renderer, and add it to the actor when all the resources are in place.
     *
     * @param[in] actor The actor applying this visual.
     */
    virtual void DoSetOnScene(Actor& actor) = 0;
  
    /**
     * @brief Called by SetOffScene() allowing sub classes to respond to the SetOffScene event
     *
     * @param[in] actor The actor applying this visual.
     */
    virtual void DoSetOffScene(Actor& actor);
  
    /**
     * @brief Called by DoAction() allowing sub classes to do the given action.
     *
     * @param[in] actionId The action to perform
     * @param[in] attributes The list of attributes for the action. ( optional for this data structure to have content )
     */
    virtual void OnDoAction(const Property::Index actionId, const Property::Value& attributes);
  
    /**
     * @brief Update the shader when some properties are changed.
     */
    virtual void UpdateShader()
    {
    }
  
    /**
     * @brief Generate a shader by the current properties from each sub classes's own shader-generate logic.
     * @param[in] factoryCache The visual factory cache to store the generated shader.
     * @return If the function defined, Generated shader by the current properties. Else, empty shader.
     */
    virtual Dali::Shader GenerateShader() const
    {
      return Dali::Shader();
    }
  
    /**
     * @brief Called by GetPropertyObject() allowing sub classes to respond to the GetPropertyObject event
     * @note The derived class is required to register the given property.
     * @param[in] key The key of the visual's property.
     * @return The Property object
     */
    virtual Dali::Property OnGetPropertyObject(Dali::Property::Key key)
    {
      Handle handle;
      return Dali::Property(handle, Property::INVALID_INDEX);
    }
  
  protected:
    /**
     * @brief Gets the on scene state for this Visual
     *
     * @return Returns true if this Visual is on the scene, false if it is off the scene
     */
    bool IsOnScene() const;
  
    /**
     * @brief Query whether the corners of the visual requires to be rounded.
     *
     * @return Returns true if the rounded corner is required, false otherwise.
     */
    bool IsRoundedCornerRequired() const;
  
    /**
     * @brief Query whether the borderline of the visual requires to be rendered.
     *
     * @return Returns true if the outline is required, false otherwise.
     */
    bool IsBorderlineRequired() const;
  
  private:
    /**
     * Register the mix color uniform on the Renderer and store the property index.
     * Note, this is not used by Color or Primitive Visuals, which will use their
     * own property index.
     */
    void RegisterMixColor();
  
    /**
     * Find the matching property on the renderer or shader. If it's a shader
     * property, register it on the renderer in order to animate it for this
     * visual independently.
     * @param[in] key The key to match.
     * @return the matching index, or INVALID_INDEX if it's not found
     */
    Property::Index GetPropertyIndex(Property::Key key);
  
    /**
     * Set up the transition. If no animation is required, then
     * transition will be untouched.
     *
     * @param[in] transition The transition to use or set up.
     * @param[in] animator The animation data to use
     * @param[in] index The property index on the renderer to animate
     * @param[in] initialValue The optional initial value
     * @param[in] targetValue The target value to use
     */
    void SetupTransition(Dali::Animation&                    transition,
                         Internal::TransitionData::Animator& animator,
                         Property::Index                     index,
                         Property::Value&                    initialValue,
                         Property::Value&                    targetValue);
  
    /**
     * Animate the opacity property - Special handling to
     * ensure that the blend mode is set to ON whilst animating,
     * and set back to AUTO if it's opaque at the end of the
     * animation.
     *
     * @param[in] transition The transition to use or set up.
     * @param[in] animator The animation data to use
     */
    void AnimateOpacityProperty(Dali::Animation&                    transition,
                                Internal::TransitionData::Animator& animator);
  
    /**
     * Animate the renderer property - no special handling
     *
     * @param[in] transition The transition to use or set up.
     * @param[in] animator The animation data to use
     */
    void AnimateRendererProperty(Dali::Animation&                    transition,
                                 Internal::TransitionData::Animator& animator);
  
    /**
     * Animate the mix color property.
     *
     * If the animator is a vec3, then it only animates the color
     * channels without animating the opacity.  If it's a vec4, then it
     * runs 2 animators, one for the the vec3 mixColor, and one for the
     * opacity. (They are separate uniforms in the shader )
     *
     * @param[in] transition The transition to use or set up.
     * @param[in] animator The animation data to use
     */
    void AnimateMixColorProperty(Dali::Animation&                    transition,
                                 Internal::TransitionData::Animator& animator);
  
    // Undefined
    Base(const Visual::Base& visual);
  
    // Undefined
    Base& operator=(const Visual::Base& visual);
  
  protected:
    struct Impl;
    Impl*               mImpl;
    VisualFactoryCache& mFactoryCache;
  };
  
  typedef IntrusivePtr<Base> BasePtr;
  
  } // namespace Visual
  
  } // namespace Internal
  
  inline const Internal::Visual::Base& GetImplementation(const Toolkit::Visual::Base& visualBase)
  {
    DALI_ASSERT_ALWAYS(visualBase && "visual base handle is empty");
  
    const BaseObject& handle = visualBase.GetBaseObject();
  
    return static_cast<const Internal::Visual::Base&>(handle);
  }
  
  inline Internal::Visual::Base& GetImplementation(Toolkit::Visual::Base& visualBase)
  {
    DALI_ASSERT_ALWAYS(visualBase && "visual base handle is empty");
  
    BaseObject& handle = visualBase.GetBaseObject();
  
    return static_cast<Internal::Visual::Base&>(handle);
  }
  
  } // namespace Toolkit
  
  } // namespace Dali
  
  #endif // DALI_TOOLKIT_INTERNAL_VISUAL_H
  