+float ItemLayout::GetFlickSpeedFactor() const
+{
+ // By default, the speed factor while dragging and swiping is the same.
+ return GetScrollSpeedFactor();
+}
+
+void ItemLayout::ApplyConstraints( Actor& actor, const int itemId, const float durationSeconds, Constrainable scrollPositionObject, const Actor& itemViewActor )
+{
+ // This just implements the default behaviour of constraint application.
+ // Custom layouts can override this function to apply their custom constraints.
+ Dali::Toolkit::ItemView itemView = Dali::Toolkit::ItemView::DownCast( itemViewActor );
+ if(itemView && scrollPositionObject)
+ {
+ ///!ToDo: Remove this once AlphaFunction in itemview is removed
+ if( itemView.GetDefaultAlphaFunction() != Constraint::DEFAULT_ALPHA_FUNCTION )
+ {
+ mAlphaFunction = itemView.GetDefaultAlphaFunction();
+ }
+
+ Property::Index scrollSpeedProperty = itemView.GetPropertyIndex("item-view-scroll-speed");
+ Property::Index scrollPositionProperty = scrollPositionObject.GetPropertyIndex("scroll-position");
+
+ ItemLayout::Vector3Function positionConstraint;
+ if (GetPositionConstraint(itemId, positionConstraint))
+ {
+ WrappedVector3Constraint wrapped(positionConstraint, itemId);
+ Constraint constraint = Constraint::New<Vector3>( Actor::POSITION,
+ Source( scrollPositionObject, scrollPositionProperty ),
+ ParentSource( scrollSpeedProperty ),
+ ParentSource( Actor::SIZE ),
+ wrapped );
+ constraint.SetApplyTime(durationSeconds);
+ constraint.SetAlphaFunction(mAlphaFunction);
+ actor.ApplyConstraint(constraint);
+ }
+
+ ItemLayout::QuaternionFunction rotationConstraint;
+ if (GetRotationConstraint(itemId, rotationConstraint))
+ {
+ WrappedQuaternionConstraint wrapped(rotationConstraint, itemId);
+
+ Constraint constraint = Constraint::New<Quaternion>( Actor::ROTATION,
+ Source( scrollPositionObject, scrollPositionProperty ),
+ ParentSource( scrollSpeedProperty ),
+ ParentSource( Actor::SIZE ),
+ wrapped );
+ constraint.SetApplyTime(durationSeconds);
+ constraint.SetAlphaFunction(mAlphaFunction);
+
+ actor.ApplyConstraint(constraint);
+ }
+
+ ItemLayout::Vector3Function scaleConstraint;
+ if (GetScaleConstraint(itemId, scaleConstraint))
+ {
+ WrappedVector3Constraint wrapped(scaleConstraint, itemId);
+
+ Constraint constraint = Constraint::New<Vector3>( Actor::SCALE,
+ Source( scrollPositionObject, scrollPositionProperty ),
+ ParentSource( scrollSpeedProperty ),
+ ParentSource( Actor::SIZE ),
+ wrapped );
+ constraint.SetApplyTime(durationSeconds);
+ constraint.SetAlphaFunction(mAlphaFunction);
+
+ actor.ApplyConstraint(constraint);
+ }
+
+ ItemLayout::Vector4Function colorConstraint;
+ if (GetColorConstraint(itemId, colorConstraint))
+ {
+ WrappedVector4Constraint wrapped(colorConstraint, itemId);
+
+ Constraint constraint = Constraint::New<Vector4>( Actor::COLOR,
+ Source( scrollPositionObject, scrollPositionProperty ),
+ ParentSource( scrollSpeedProperty ),
+ ParentSource( Actor::SIZE ),
+ wrapped );
+
+ constraint.SetApplyTime(durationSeconds);
+ constraint.SetAlphaFunction(mAlphaFunction);
+
+ // Release color constraints slowly; this allows ItemView to co-exist with ImageActor fade-in
+ constraint.SetRemoveTime(DEFAULT_COLOR_VISIBILITY_REMOVE_TIME);
+ constraint.SetRemoveAction(Dali::Constraint::Discard);
+
+ actor.ApplyConstraint(constraint);
+ }
+
+ ItemLayout::BoolFunction visibilityConstraint;
+ if (GetVisibilityConstraint(itemId, visibilityConstraint))
+ {
+ WrappedBoolConstraint wrapped(visibilityConstraint, itemId);
+
+ Constraint constraint = Constraint::New<bool>( Actor::VISIBLE,
+ Source( scrollPositionObject, scrollPositionProperty ),
+ ParentSource( scrollSpeedProperty ),
+ ParentSource( Actor::SIZE ),
+ wrapped );
+
+ constraint.SetApplyTime(durationSeconds);
+ constraint.SetAlphaFunction(mAlphaFunction);
+
+ // Release visibility constraints the same time as the color constraint
+ constraint.SetRemoveTime(DEFAULT_COLOR_VISIBILITY_REMOVE_TIME);
+ constraint.SetRemoveAction(Dali::Constraint::Discard);
+
+ actor.ApplyConstraint(constraint);
+ }
+ }
+}
+
+Vector3 ItemLayout::GetItemPosition(int itemID, float currentLayoutPosition, const Vector3& layoutSize) const
+{
+ Vector3 itemPosition = Vector3::ZERO;
+
+ ItemLayout::Vector3Function positionConstraint;
+ if (GetPositionConstraint(itemID, positionConstraint))
+ {
+ itemPosition = positionConstraint(Vector3::ZERO, currentLayoutPosition + itemID, 0.0f, layoutSize);
+ }
+
+ return itemPosition;
+}
+
+void ItemLayout::SetAlphaFunction(AlphaFunction func)
+{
+ mAlphaFunction = func;
+}
+
+AlphaFunction ItemLayout::GetAlphaFunction() const
+{
+ return mAlphaFunction;
+}
+
+