Peter M. Groen / dali-demo

/*
 * Copyright (c) 2022 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.
 *
 */

#include <dali-toolkit/dali-toolkit.h>
#include <dali-toolkit/devel-api/controls/table-view/table-view.h>
#include <dali/dali.h>
#include "generated/bezier-curve-frag.h"
#include "generated/bezier-curve-vert.h"
#include "shared/view.h"

#include <sstream>

using namespace Dali;
using namespace Dali::Toolkit;
using namespace std;

namespace
{
const Vector4     GRID_BACKGROUND_COLOR(0.85f, 0.85f, 0.85f, 1.0f);
const Vector4     CONTROL_POINT1_COLOR(Color::MAGENTA);
const Vector4     CONTROL_POINT2_COLOR(0.0, 0.9, 0.9, 1.0);
const Vector3     CONTROL_POINT1_ORIGIN(-100, 200, 0);
const Vector3     CONTROL_POINT2_ORIGIN(100, -200, 0);
const char* const CIRCLE1_IMAGE(DEMO_IMAGE_DIR "circle1.png");
const char* const CIRCLE2_IMAGE(DEMO_IMAGE_DIR "circle2.png");
const char* const ANIMATION_BACKGROUND(DEMO_IMAGE_DIR "slider-skin.9.png");
const char*       APPLICATION_TITLE("Bezier curve animation");
const float       ANIM_LEFT_FACTOR(0.2f);
const float       ANIM_RIGHT_FACTOR(0.8f);
const int         AXIS_LABEL_POINT_SIZE(7);
const float       AXIS_LINE_SIZE(1.0f);

inline float Clamp(float v, float min, float max)
{
  if(v < min) return min;
  if(v > max) return max;
  return v;
}

struct HandlePositionConstraint
{
  void operator()(Vector3& current, const PropertyInputContainer& inputs)
  {
    Vector3 size(inputs[0]->GetVector3());
    current.x = Clamp(current.x, minRelX * size.x, maxRelX * size.x);
    current.y = Clamp(current.y, minRelY * size.y, maxRelY * size.y);
  }

  float minRelX{0.0f};
  float maxRelX{0.0f};
  float minRelY{0.0f};
  float maxRelY{0.0f};
};

void AnimatingPositionConstraint(Vector3& current, const PropertyInputContainer& inputs)
{
  float   positionFactor(inputs[0]->GetFloat()); // -1 - 2
  Vector3 size(inputs[1]->GetVector3());

  current.x = size.x * (positionFactor - 0.5f); // size * (-1.5 - 1.5)
}

} //unnamed namespace

class BezierCurveExample : public ConnectionTracker
{
public:
  BezierCurveExample(Application& application)
  : mApplication(application),
    mControlPoint1(),
    mControlPoint2(),
    mControlLine1(),
    mControlLine2(),
    mAnimIcon1(),
    mAnimIcon2(),
    mDragActor(),
    mCurve(),
    mCoefficientLabel(),
    mContentLayer(),
    mGrid(),
    mTimer(),
    mDragAnimation(),
    mBezierAnimation(),
    mCurveVertices(),
    mLine1Vertices(),
    mLine2Vertices(),
    mRelativeDragPoint(),
    mLastControlPointPosition1(),
    mLastControlPointPosition2(),
    mPositionFactorIndex(),
    mDuration(2.0f),
    mControlPoint1Id(0.0f),
    mControlPoint2Id(0.0f),
    mControlPointScale(0.5f),
    mControlPointZoomScale(mControlPointScale * 2.0),
    mGoingRight(true)
  {
    // Connect to the Application's Init signal
    mApplication.InitSignal().Connect(this, &BezierCurveExample::Create);
  }

  ~BezierCurveExample()
  {
    // Nothing to do here;
  }

  // The Init signal is received once (only) during the Application lifetime
  void Create(Application& application)
  {
    Window window = mApplication.GetWindow();
    window.KeyEventSignal().Connect(this, &BezierCurveExample::OnKeyEvent);
    const Vector2 windowSize = window.GetSize();
    const bool orientationPortrait = windowSize.width < windowSize.height;

    unsigned int tableViewRows = 5;
    unsigned int tableViewColumns = 1;
    unsigned int rowPositionAdder = 1;
    TableView::CellPosition gridPosition{1,0};

    // Change layout if we're in landscape mode
    if(!orientationPortrait)
    {
      tableViewRows = 4;
      tableViewColumns = 2;
      rowPositionAdder = 0;
      gridPosition = {0,1,4,1};
    }

    CreateBackground(window);

    mControlPointScale     = 0.5f;
    mControlPointZoomScale = mControlPointScale * 2.0f;

    mContentLayer = Layer::New();
    mContentLayer.SetResizePolicy(ResizePolicy::FILL_TO_PARENT, Dimension::ALL_DIMENSIONS);
    mContentLayer.TouchedSignal().Connect(this, &BezierCurveExample::OnTouchLayer);
    mContentLayer.SetProperty(Actor::Property::PARENT_ORIGIN, ParentOrigin::CENTER);
    window.Add(mContentLayer);

    TableView contentLayout = TableView::New(tableViewRows, tableViewColumns);
    contentLayout.SetProperty(Dali::Actor::Property::NAME, "contentLayout");
    contentLayout.SetResizePolicy(ResizePolicy::FILL_TO_PARENT, Dimension::ALL_DIMENSIONS);
    contentLayout.SetCellPadding(Size(30, 30));
    contentLayout.SetProperty(Actor::Property::PARENT_ORIGIN, ParentOrigin::TOP_CENTER);
    contentLayout.SetProperty(Actor::Property::ANCHOR_POINT, AnchorPoint::TOP_CENTER);
    mContentLayer.Add(contentLayout);

    // Create a TextLabel for the application title.
    Toolkit::TextLabel label = Toolkit::TextLabel::New(APPLICATION_TITLE);
    label.SetProperty(Toolkit::TextLabel::Property::HORIZONTAL_ALIGNMENT, "CENTER");
    label.SetProperty(Toolkit::TextLabel::Property::VERTICAL_ALIGNMENT, "CENTER");
    label.SetProperty(Toolkit::TextLabel::Property::TEXT_COLOR, Color::BLACK);
    contentLayout.Add(label);
    contentLayout.SetFitHeight(0);

    mGrid = Control::New();

    mGrid.SetResizePolicy(ResizePolicy::SIZE_RELATIVE_TO_PARENT, Dimension::WIDTH);
    mGrid.SetResizePolicy(ResizePolicy::DIMENSION_DEPENDENCY, Dimension::HEIGHT);

    mGrid.SetProperty(Actor::Property::PARENT_ORIGIN, ParentOrigin::CENTER);
    mGrid.SetProperty(Actor::Property::ANCHOR_POINT, AnchorPoint::CENTER);
    mGrid.SetBackgroundColor(GRID_BACKGROUND_COLOR);

    contentLayout.AddChild(mGrid, gridPosition);
    contentLayout.SetCellAlignment(1, HorizontalAlignment::CENTER, VerticalAlignment::CENTER);
    CreateCubic(mGrid);
    CreateControlPoints(mGrid); // Control points constrained to double height of grid
    CreateAxisLabels(mGrid);

    mCoefficientLabel = TextLabel::New();
    mCoefficientLabel.SetProperty(TextLabel::Property::ENABLE_MARKUP, true);
    mCoefficientLabel.SetProperty(Toolkit::TextLabel::Property::HORIZONTAL_ALIGNMENT, "CENTER");
    mCoefficientLabel.SetProperty(Toolkit::TextLabel::Property::VERTICAL_ALIGNMENT, "CENTER");
    mCoefficientLabel.SetProperty(Actor::Property::PARENT_ORIGIN, ParentOrigin::CENTER);

    contentLayout.Add(mCoefficientLabel);
    SetLabel(Vector2(0, 0), Vector2(1, 1));
    contentLayout.SetCellAlignment(1 + rowPositionAdder, HorizontalAlignment::CENTER, VerticalAlignment::CENTER);
    contentLayout.SetFitHeight(2);

    // Setup Play button and 2 icons to show off current anim and linear anim

    PushButton play = PushButton::New();
    play.SetProperty(Dali::Actor::Property::NAME, "Play");
    play.SetProperty(Actor::Property::PARENT_ORIGIN, ParentOrigin::CENTER);
    play.SetProperty(Button::Property::LABEL, "Play");
    play.ClickedSignal().Connect(this, &BezierCurveExample::OnPlayClicked);

    contentLayout.Add(play);
    contentLayout.SetCellAlignment(2 + rowPositionAdder, HorizontalAlignment::CENTER, VerticalAlignment::CENTER);
    contentLayout.SetFitHeight(2 + rowPositionAdder);

    auto animContainer = Control::New();
    animContainer.SetProperty(Dali::Actor::Property::NAME, "AnimationContainer");
    animContainer.SetProperty(Actor::Property::PARENT_ORIGIN, ParentOrigin::CENTER);
    animContainer.SetResizePolicy(ResizePolicy::FILL_TO_PARENT, Dimension::ALL_DIMENSIONS);

    auto animRail = Control::New();
    animRail.SetProperty(Control::Property::BACKGROUND, Property::Map().Add(Visual::Property::TYPE, Visual::IMAGE).Add(ImageVisual::Property::URL, ANIMATION_BACKGROUND));
    animRail.SetResizePolicy(ResizePolicy::SIZE_RELATIVE_TO_PARENT, Dimension::ALL_DIMENSIONS);
    animRail.SetProperty(Actor::Property::SIZE_MODE_FACTOR, Vector3(0.666f, 0.2f, 1.0f));
    animRail.SetProperty(Actor::Property::PARENT_ORIGIN, ParentOrigin::CENTER);
    animContainer.Add(animRail);

    contentLayout.Add(animContainer);
    contentLayout.SetFixedHeight(3 + rowPositionAdder, 150);

    mAnimIcon1 = ImageView::New(CIRCLE1_IMAGE);
    mAnimIcon1.SetProperty(Actor::Property::PARENT_ORIGIN, ParentOrigin::CENTER);
    mAnimIcon1.SetProperty(Actor::Property::ANCHOR_POINT, AnchorPoint::CENTER);

    // Would like some means of setting and animating position as a percentage of
    // parent size without using constraints, but this will have to suffice for the moment.
    mPositionFactorIndex  = mAnimIcon1.RegisterProperty("positionFactor", ANIM_LEFT_FACTOR); // range: 0-1 (+/- 1)
    Constraint constraint = Constraint::New<Vector3>(mAnimIcon1, Actor::Property::POSITION, AnimatingPositionConstraint);
    constraint.AddSource(Source(mAnimIcon1, mPositionFactorIndex));
    constraint.AddSource(Source(animContainer, Actor::Property::SIZE));
    constraint.Apply();

    animContainer.Add(mAnimIcon1);

    // First UpdateCurve needs to run after size negotiation and after images have loaded
    mGrid.OnRelayoutSignal().Connect(this, &BezierCurveExample::InitialUpdateCurve);

    auto controlPoint1 = Control::DownCast(mControlPoint1);
    if(controlPoint1)
    {
      controlPoint1.ResourceReadySignal().Connect(this, &BezierCurveExample::ControlPointReady);
    }

    auto controlPoint2 = Control::DownCast(mControlPoint2);
    if(controlPoint2)
    {
      controlPoint2.ResourceReadySignal().Connect(this, &BezierCurveExample::ControlPointReady);
    }
  }

  void ControlPointReady(Control control)
  {
    UpdateCurve();
  }

  void InitialUpdateCurve(Actor actor)
  {
    UpdateCurve();
  }

  void CreateBackground(Window window)
  {
    Toolkit::Control background = Dali::Toolkit::Control::New();
    background.SetProperty(Actor::Property::ANCHOR_POINT, Dali::AnchorPoint::CENTER);
    background.SetProperty(Actor::Property::PARENT_ORIGIN, Dali::ParentOrigin::CENTER);
    background.SetResizePolicy(Dali::ResizePolicy::FILL_TO_PARENT, Dali::Dimension::ALL_DIMENSIONS);

    Property::Map map;
    map.Insert(Visual::Property::TYPE, Visual::COLOR);
    map.Insert(ColorVisual::Property::MIX_COLOR, Vector4(253 / 255.0f, 245 / 255.0f, 230 / 255.0f, 1.0f));
    background.SetProperty(Dali::Toolkit::Control::Property::BACKGROUND, map);
    window.Add(background);
  }

  void CreateCubic(Actor parent)
  {
    // Create a mesh to draw the cubic as a single line
    mCurve = Actor::New();
    mCurve.SetResizePolicy(ResizePolicy::FILL_TO_PARENT, Dimension::ALL_DIMENSIONS);
    mCurve.SetProperty(Actor::Property::PARENT_ORIGIN, ParentOrigin::CENTER);

    Shader shader = Shader::New(SHADER_BEZIER_CURVE_VERT, SHADER_BEZIER_CURVE_FRAG);

    Property::Map curveVertexFormat;
    curveVertexFormat["aPosition"] = Property::VECTOR2;
    mCurveVertices                 = VertexBuffer::New(curveVertexFormat);
    Vector2 vertexData[2]          = {Vector2(-0.5f, 0.5f), Vector2(0.5f, -0.5f)};
    mCurveVertices.SetData(vertexData, 2);

    Geometry geometry = Geometry::New();
    geometry.AddVertexBuffer(mCurveVertices);
    geometry.SetType(Geometry::LINE_STRIP);

    Renderer renderer = Renderer::New(geometry, shader);
    mCurve.AddRenderer(renderer);
    parent.Add(mCurve);
  }

  Actor CreateControlPoint(Actor parent, const char* url, Vector3 position)
  {
    Actor actor = ImageView::New(url);
    actor.SetProperty(Actor::Property::SCALE, mControlPointScale);
    actor.SetProperty(Actor::Property::PARENT_ORIGIN, ParentOrigin::CENTER);
    // Curve and line drawing works off current value (i.e. last update frame's value). Need to animate to ensure
    // initial position is baked to both frames before initially drawing the curve.
    auto positionAnimation = Animation::New(0.01f);
    positionAnimation.AnimateTo(Property(actor, Actor::Property::POSITION), position, AlphaFunction::EASE_IN_OUT);
    positionAnimation.Play();
    positionAnimation.FinishedSignal().Connect(this, &BezierCurveExample::OnAnimationFinished);

    // Set up constraints for drag/drop
    Constraint constraint = Constraint::New<Vector3>(actor, Actor::Property::POSITION, HandlePositionConstraint{-0.5, 0.5, -1, 1});
    constraint.AddSource(Source(parent, Actor::Property::SIZE));
    constraint.Apply();

    actor.TouchedSignal().Connect(this, &BezierCurveExample::OnTouchControlPoint);
    return actor;
  }

  Actor CreateControlLine(VertexBuffer vertexBuffer)
  {
    Actor line = Actor::New();
    line.SetResizePolicy(ResizePolicy::FILL_TO_PARENT, Dimension::ALL_DIMENSIONS);
    line.SetProperty(Actor::Property::PARENT_ORIGIN, ParentOrigin::CENTER);

    Shader   shader   = Shader::New(SHADER_BEZIER_CURVE_VERT, SHADER_BEZIER_CURVE_FRAG);
    Geometry geometry = Geometry::New();
    geometry.AddVertexBuffer(vertexBuffer);
    geometry.SetType(Geometry::LINE_STRIP);

    Renderer renderer = Renderer::New(geometry, shader);
    line.AddRenderer(renderer);
    return line;
  }

  void CreateControlPoints(Actor parent)
  {
    mControlPoint1   = CreateControlPoint(parent,
                                        CIRCLE1_IMAGE,
                                        CONTROL_POINT1_ORIGIN);
    mControlPoint1Id = mControlPoint1.GetProperty<int>(Actor::Property::ID);

    mControlPoint2   = CreateControlPoint(parent,
                                        CIRCLE2_IMAGE,
                                        CONTROL_POINT2_ORIGIN);
    mControlPoint2Id = mControlPoint2.GetProperty<int>(Actor::Property::ID);

    Property::Map lineVertexFormat;
    lineVertexFormat["aPosition"] = Property::VECTOR2;
    mLine1Vertices                = VertexBuffer::New(lineVertexFormat);
    mLine2Vertices                = VertexBuffer::New(lineVertexFormat);

    mControlLine1 = CreateControlLine(mLine1Vertices);
    mControlLine2 = CreateControlLine(mLine2Vertices);

    parent.Add(mControlLine1);
    parent.Add(mControlLine2);
    parent.Add(mControlPoint1);
    parent.Add(mControlPoint2);
  }

  void CreateAxisLabels(Actor parent)
  {
    TextLabel progressionLabel = TextLabel::New("Progression");
    progressionLabel.SetProperty(TextLabel::Property::POINT_SIZE, AXIS_LABEL_POINT_SIZE);
    progressionLabel.SetProperty(Actor::Property::ORIENTATION, Quaternion(Radian(Degree(-90.0f)), Vector3::ZAXIS));
    progressionLabel.SetProperty(Actor::Property::ANCHOR_POINT, AnchorPoint::BOTTOM_LEFT);
    progressionLabel.SetProperty(Actor::Property::PARENT_ORIGIN, ParentOrigin::BOTTOM_LEFT);
    CreateLine(progressionLabel, ParentOrigin::BOTTOM_LEFT);

    TextLabel timeLabel = TextLabel::New("Time");
    timeLabel.SetProperty(TextLabel::Property::POINT_SIZE, AXIS_LABEL_POINT_SIZE);
    timeLabel.SetProperty(Actor::Property::ANCHOR_POINT, AnchorPoint::TOP_LEFT);
    timeLabel.SetProperty(Actor::Property::PARENT_ORIGIN, ParentOrigin::BOTTOM_LEFT);
    CreateLine(timeLabel, ParentOrigin::TOP_LEFT);

    parent.Add(progressionLabel);
    parent.Add(timeLabel);
  }

  void CreateLine(Actor parent, const Vector3& parentOrigin)
  {
    Control control = Control::New();
    control.SetProperty(Actor::Property::ANCHOR_POINT, AnchorPoint::TOP_LEFT);
    control.SetProperty(Actor::Property::PARENT_ORIGIN, parentOrigin);
    control.SetResizePolicy(ResizePolicy::FILL_TO_PARENT, Dimension::WIDTH);
    control.SetProperty(Actor::Property::SIZE_HEIGHT, AXIS_LINE_SIZE);
    control.SetBackgroundColor(Color::BLACK);
    parent.Add(control);
  }

  void SetLabel(Vector2 pos1, Vector2 pos2)
  {
    std::ostringstream oss;
    oss.setf(std::ios::fixed, std::ios::floatfield);
    oss.precision(2);
    oss << "( <color value='#971586'>" << pos1.x << ", " << pos1.y << ", </color>";
    oss << "<color value='#e7640d'>" << pos2.x << ", " << pos2.y << "</color>";
    oss << "<color value='black'> )</color>";

    mCoefficientLabel.SetProperty(TextLabel::Property::TEXT, oss.str());
  }

  Vector2 AlignToGrid(Vector3 actorPos, Vector3 gridSize)
  {
    actorPos /= gridSize; // => -0.5 - 0.5
    actorPos.x = Clamp(actorPos.x, -0.5f, 0.5f);
    return Vector2(actorPos.x + 0.5f, 0.5f - actorPos.y);
  }

  void GetControlPoints(Vector2& pt1, Vector2& pt2)
  {
    Vector3 gridSize = mGrid.GetProperty<Vector3>(Actor::Property::SIZE); // Get target value

    pt1 = AlignToGrid(mControlPoint1.GetCurrentProperty<Vector3>(Actor::Property::POSITION), gridSize);
    pt2 = AlignToGrid(mControlPoint2.GetCurrentProperty<Vector3>(Actor::Property::POSITION), gridSize);
  }

  /**
   * @param[in] actor The actor to get the position from
   * @param[out] point The point in the grid in the range -0.5 -> 0.5 in x and y, with y up.
   * @param[out] position The actor position, floored to the nearest pixel
   */
  void GetPoint(Actor actor, Vector2& point, Vector2& position)
  {
    auto gridSize        = mGrid.GetProperty<Vector3>(Actor::Property::SIZE);            // Get target value
    auto currentPosition = actor.GetCurrentProperty<Vector3>(Actor::Property::POSITION); // Get constrained current value

    position = Vector2(floor(currentPosition.x), floor(currentPosition.y));

    point.x = Clamp(position.x / gridSize.x, -0.5f, 0.5f) + 0.5f;
    point.y = 0.5f - position.y / gridSize.y;
  }

  void UpdateCurve()
  {
    Vector2   point1, point2;
    Vector2   position1, position2;
    const int NUMBER_OF_SEGMENTS(40);

    GetPoint(mControlPoint1, point1, position1);
    GetPoint(mControlPoint2, point2, position2);

    if(position1 != mLastControlPointPosition1 ||
       position2 != mLastControlPointPosition2)
    {
      mLastControlPointPosition1 = position1;
      mLastControlPointPosition2 = position2;

      SetLabel(point1, point2);

      Path path = Path::New();
      path.AddPoint(Vector3::ZERO);
      path.AddPoint(Vector3(1.0f, 1.0f, 1.0f));
      path.AddControlPoint(Vector3(point1.x, point1.y, 0));
      path.AddControlPoint(Vector3(point2.x, point2.y, 0));

      Dali::Vector<float> verts;

      verts.Resize(2 * (NUMBER_OF_SEGMENTS + 1)); // 1 more point than segment
      for(int i = 0; i <= NUMBER_OF_SEGMENTS; ++i)
      {
        Vector3 position, tangent;
        path.Sample(i / float(NUMBER_OF_SEGMENTS), position, tangent);
        verts[i * 2]     = position.x - 0.5;
        verts[i * 2 + 1] = 0.5 - position.y;
      }
      mCurveVertices.SetData(&verts[0], NUMBER_OF_SEGMENTS + 1);

      Vector4 line1(-0.5f, 0.5f, point1.x - 0.5f, 0.5f - point1.y);
      mLine1Vertices.SetData(line1.AsFloat(), 2);

      Vector4 line2(0.5f, -0.5f, point2.x - 0.5f, 0.5f - point2.y);
      mLine2Vertices.SetData(line2.AsFloat(), 2);
    }
  }

  bool OnTouchControlPoint(Actor controlPoint, const TouchEvent& event)
  {
    if(event.GetPointCount() > 0)
    {
      if(event.GetState(0) == PointState::DOWN)
      {
        Vector2 screenPoint = event.GetScreenPosition(0);
        mRelativeDragPoint  = screenPoint;
        mRelativeDragPoint -= Vector2(controlPoint.GetCurrentProperty<Vector3>(Actor::Property::POSITION));
        mDragActor     = controlPoint;
        mDragAnimation = Animation::New(0.25f);
        mDragAnimation.AnimateTo(Property(mDragActor, Actor::Property::SCALE), Vector3(mControlPointZoomScale, mControlPointZoomScale, 1.0f), AlphaFunction::EASE_OUT);
        mDragAnimation.Play();
      }
    }
    return false; // Don't mark this as consumed - let the layer get the touch
  }

  bool OnTouchLayer(Actor actor, const TouchEvent& event)
  {
    if(event.GetPointCount() > 0)
    {
      if(mDragActor)
      {
        Vector3 position(event.GetScreenPosition(0));

        mDragActor.SetProperty(Actor::Property::POSITION, position - Vector3(mRelativeDragPoint));

        if(event.GetState(0) == PointState::UP) // Stop dragging
        {
          mDragAnimation = Animation::New(0.25f);
          mDragAnimation.AnimateTo(Property(mDragActor, Actor::Property::SCALE), Vector3(mControlPointScale, mControlPointScale, 1.0f), AlphaFunction::EASE_IN);
          mDragAnimation.FinishedSignal().Connect(this, &BezierCurveExample::OnAnimationFinished);
          mDragAnimation.Play();
          mDragActor.Reset();
        }
      }
      UpdateCurve();
    }
    return false;
  }

  void OnAnimationFinished(Animation& animation)
  {
    UpdateCurve();
  }

  bool OnPlayClicked(Button button)
  {
    if(!mBezierAnimation)
    {
      mBezierAnimation = Animation::New(mDuration);
    }
    mBezierAnimation.Stop();
    mBezierAnimation.Clear();

    float positionFactor = ANIM_LEFT_FACTOR;
    if(mGoingRight)
    {
      positionFactor = ANIM_RIGHT_FACTOR;
      mGoingRight    = false;
    }
    else
    {
      mGoingRight = true;
    }

    Vector2 pt1, pt2;
    GetControlPoints(pt1, pt2);

    mBezierAnimation.AnimateTo(Property(mAnimIcon1, mPositionFactorIndex), positionFactor, AlphaFunction(pt1, pt2));
    mBezierAnimation.Play();
    return true;
  }

  /**
   * Main key event handler
   */
  void OnKeyEvent(const KeyEvent& event)
  {
    if(event.GetState() == KeyEvent::DOWN && (IsKey(event, DALI_KEY_ESCAPE) || IsKey(event, DALI_KEY_BACK)))
    {
      mApplication.Quit();
    }
  }

private:
  Application&    mApplication;
  Actor           mControlPoint1;
  Actor           mControlPoint2;
  Actor           mControlLine1;
  Actor           mControlLine2;
  ImageView       mAnimIcon1;
  ImageView       mAnimIcon2;
  Actor           mDragActor;
  Actor           mCurve;
  TextLabel       mCoefficientLabel;
  Layer           mContentLayer;
  Control         mGrid;
  Timer           mTimer;
  Animation       mDragAnimation;
  Animation       mBezierAnimation;
  VertexBuffer    mCurveVertices;
  VertexBuffer    mLine1Vertices;
  VertexBuffer    mLine2Vertices;
  Vector2         mRelativeDragPoint;
  Vector2         mLastControlPointPosition1;
  Vector2         mLastControlPointPosition2;
  Property::Index mPositionFactorIndex;
  float           mDuration;
  unsigned int    mControlPoint1Id;
  unsigned int    mControlPoint2Id;
  float           mControlPointScale;
  float           mControlPointZoomScale;
  bool            mGoingRight;
};

int DALI_EXPORT_API main(int argc, char** argv)
{
  Application application = Application::New(&argc, &argv);

  BezierCurveExample test(application);
  application.MainLoop();
  return 0;
}