InputHandler C++ Example Documentation.

Task-id: QTRD-2634

Change-Id: I486f210ed9c87079d6bc93ec10ab1f1831254d3f
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@digia.com>

1 files changed, 42 insertions, 2 deletions

diff --git a/examples/custominput/doc/src/custominput.qdoc b/examples/custominput/doc/src/custominput.qdoc
index 69333d96..9bb5607f 100644
--- a/examples/custominput/doc/src/custominput.qdoc
+++ b/examples/custominput/doc/src/custominput.qdoc
@@ -22,9 +22,49 @@
     \ingroup qtdatavisualization_examples
     \brief Implementing custom input handler in a widget application.
 
-    TBD...
+    The Custom Input example shows how to customize the 3D graph controls in a widget application using a custom graph input handler to capture and process mouse events.
+    The code in this example shows also how the camera is controlled by using QPropertyAnimation to animate the camera and item selection
+    is done on mouseover rather than clicking any mouse buttons. Also the code shows how to implement similar zoom with mouse wheel functionality as the default
+    input handler implements.
 
     \image custominput-example.png
 
-    TBD...
+    \section1 Replacing default input handling
+
+    The default input handling mechanism is replaced by setting the active input handler of \l Q3DScatter
+    to \c CustomInputHandler that implements the custom behavior.
+
+    \snippet ../examples/custominput/scatterdatamodifier.cpp 0
+
+    \section1 Implementing custom selection handling
+
+    The on mouseover selection handling is implemented in the \c CustomInputHandler that captures the mouse events.
+    It then stores the last known coordinates to the \l QAbstract3DInputHandler::inputPosition property.
+
+    \snippet ../examples/custominput/custominputhandler.cpp 0
+
+    As the selection is one shot, and is cleared each time a 3D frame is rendered, a timer is setup to retrigger selection so that the selection moves to the item
+    currently under the mouse cursor as the camera animates around the graph even when the mouse cursor is not moving.
+
+    \snippet ../examples/custominput/scatterdatamodifier.cpp 1
+
+    \section1 Implementing custom zoom handling
+
+    The camera has a zoom factor that represents amount of zoom in percentages. In this example the zoom range is limited
+    between 10% and 500%. This range is then divided to four subranges where \c angleDelta is scaled to different amount of zoom change
+    based on the current subrange.
+
+    \snippet ../examples/custominput/custominputhandler.cpp 1
+
+    \section1 Implementing custom camera handling
+
+    The camera is animated to constantly rotate around the graph with two animations. The rotation around the graph is done with
+    a simple QPropertyAnimation that just increments during 20 seconds from 0 degrees to 360 degrees and sets the \l Q3DCamera::xRotation property.
+
+    \snippet ../examples/custominput/scatterdatamodifier.cpp 2
+
+    The camera movement up and down is implemented with a QSequentialAnimationGroup that varies the \l Q3DCamera::yRotation property of the camera
+    from 5 degrees to 45 degrees and back with in and out easing.
+
+    \snippet ../examples/custominput/scatterdatamodifier.cpp 3
 */