Divider that can be dragged, in a dialog QGraphicsView. More...

#include <ViewProfileDivider.h>

Inheritance diagram for ViewProfileDivider:

Collaboration diagram for ViewProfileDivider:

Signals
void	signalMovedLow (double xSceneOther)
	Signal used when divider is dragged and m_isLowerBoundary is true.
void	signalMovedHigh (double xSceneOther)
	Signal used when divider is dragged and m_isLowerBoundary is false.

Public Member Functions
	ViewProfileDivider (QGraphicsScene &scene, QGraphicsView &view, int sceneWidth, int sceneHeight, int yCenter, bool isLowerBoundary)
	Single constructor.
virtual QVariant	itemChange (GraphicsItemChange change, const QVariant &value)
	Intercept changes so divider movement can be restricted to horizontal direction only.
virtual void	mousePressEvent (QGraphicsSceneMouseEvent *event)
	Save paddle position at start of click-and-drag.
void	setX (double x, double xLow, double xHigh)
	Set the position by specifying the new x coordinate.

Detailed Description

Divider that can be dragged, in a dialog QGraphicsView.

Click on the paddle to drag. There are three parts:

Paddle which is the superclass of this class, since we catch its events so dragging works
Divider which is a vertical line
Shaded area that extends from xAnchor to the divider

Definition at line 23 of file ViewProfileDivider.h.

Constructor & Destructor Documentation

◆ ViewProfileDivider()

ViewProfileDivider::ViewProfileDivider	(	QGraphicsScene &	scene,
		QGraphicsView &	view,
		int	sceneWidth,
		int	sceneHeight,
		int	yCenter,
		bool	isLowerBoundary )

Single constructor.

Definition at line 30 of file ViewProfileDivider.cpp.

                                                              :
  QGraphicsRectItem (X_INITIAL,
                     0,
                     PADDLE_WIDTH,
                     PADDLE_HEIGHT),
  m_view (view),
  m_yCenter (yCenter),
  m_divider (nullptr),
  m_shadedArea (nullptr),
  m_sceneWidth (sceneWidth),
  m_sceneHeight (sceneHeight),
  m_isLowerBoundary (isLowerBoundary)
{
  // Initial positions will not appear since they are overridden by setX
 
  // Paddle
  setVisible (true);
  setPen (QPen (DIVIDER_COLOR));
  setBrush (QBrush (QColor (140, 255, 140)));
  setOpacity (1.0);
  scene.addItem (this);
  setFlags (QGraphicsItem::ItemIsMovable |
            QGraphicsItem::ItemSendsGeometryChanges);
  setCursor (Qt::OpenHandCursor);
  setZValue (2.0);
 
  // Arrow on paddle
  m_arrow = new QGraphicsPolygonItem (this);
 
  // Shaded area
  m_shadedArea = new QGraphicsRectItem (X_INITIAL,
                                        0,
                                        0,
                                        sceneHeight - 1);
  m_shadedArea->setOpacity (SHADED_AREA_OPACITY);
  m_shadedArea->setBrush (QBrush (SHADED_AREA_COLOR));
  m_shadedArea->setPen (Qt::NoPen);
  m_shadedArea->setZValue (0.0);
  scene.addItem (m_shadedArea);
 
  // Vertical divider. This is not made a child of the paddle since that will force the divider
  // to always be drawn above the paddle, rather than underneath the paddle as we want. Even setting
  // the z values will not succeed in drawing the divider under the paddle if they are child-parent.
  m_divider = new QGraphicsLineItem (X_INITIAL,
                                     -SLOP,
                                     X_INITIAL,
                                     2 * SLOP + sceneHeight);
  m_divider->setPen (QPen (QBrush (DIVIDER_COLOR), DIVIDER_WIDTH));
  m_divider->setZValue (1.0);
  scene.addItem (m_divider);
}

Member Function Documentation

◆ itemChange()

QVariant ViewProfileDivider::itemChange	(	GraphicsItemChange	change,
		const QVariant &	value )

virtual

Intercept changes so divider movement can be restricted to horizontal direction only.

Definition at line 87 of file ViewProfileDivider.cpp.

{
  if (change == ItemPositionChange && scene ()) {
 
    // Clip x coordinate, in pixel coordinates. Y coordinate stays the same (by setting delta to zero)
    QPointF newPos = QPointF (value.toPointF().x(), 0.0) + m_startDragPos;
    double newX = newPos.x();
    newX = qMax (newX, 0.0);
    newX = qMin (newX, double (m_sceneWidth));
    newPos.setX (newX);
    newPos -= m_startDragPos; // Change from absolute coordinates back to relative coordinates
 
    // Before returning newPos for the paddle, we apply its movement to the divider and shaded area
    m_xScene = newX;
    updateGeometryDivider();
    updateGeometryNonPaddle ();
 
    sendSignalMoved ();
 
    return newPos;
  }
 
  return QGraphicsRectItem::itemChange (change, value);
}

◆ mousePressEvent()

void ViewProfileDivider::mousePressEvent ( QGraphicsSceneMouseEvent * event )

virtual

Save paddle position at start of click-and-drag.

Definition at line 112 of file ViewProfileDivider.cpp.

{
  // Since the cursor position is probably not in the center of the paddle, we save the paddle center
  m_startDragPos = QPointF (rect().x () + rect().width () / 2.0,
                            rect().y () + rect().height () / 2.0);
}

◆ setX()

void ViewProfileDivider::setX	(	double	x,
		double	xLow,
		double	xHigh )

Set the position by specifying the new x coordinate.

Definition at line 128 of file ViewProfileDivider.cpp.

{
  // Convert to screen coordinates
  m_xScene = m_sceneWidth * (x - xLow) / (xHigh - xLow);
  sendSignalMoved ();
 
  updateGeometryPaddle ();
  updateGeometryDivider ();
  updateGeometryNonPaddle ();
 
  // Triangle vertices
  double xLeft = rect().left() + rect().width() / 2.0 - ARROW_WIDTH / 2.0;
  double xRight = rect().left() + rect().width() / 2.0 + ARROW_WIDTH / 2.0;
  double yTop = rect().top() + rect().height() / 2.0 - ARROW_HEIGHT / 2.0;
  double yMiddle = rect().top() + rect().height() / 2.0;
  double yBottom = rect().top() + rect().height() / 2.0 + ARROW_HEIGHT / 2.0;
 
  QPolygonF polygonArrow;
  if (m_isLowerBoundary) {
 
    // Draw arrow pointing to the right
    polygonArrow.push_front (QPointF (xLeft, yTop));
    polygonArrow.push_front (QPointF (xRight, yMiddle));
    polygonArrow.push_front (QPointF (xLeft, yBottom));
 
  } else {
 
    // Draw arrow pointing to the left
    polygonArrow.push_front (QPointF (xRight, yTop));
    polygonArrow.push_front (QPointF (xLeft, yMiddle));
    polygonArrow.push_front (QPointF (xRight, yBottom));
  }
  m_arrow->setPolygon (polygonArrow);
  m_arrow->setPen (QPen (Qt::black));
  m_arrow->setBrush (QBrush (ARROW_COLOR));
}

◆ signalMovedHigh

void ViewProfileDivider::signalMovedHigh ( double xSceneOther )

signal

Signal used when divider is dragged and m_isLowerBoundary is false.

◆ signalMovedLow

void ViewProfileDivider::signalMovedLow ( double xSceneOther )