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 /*
  * This file is part of the KDE wacomtablet project. For copyright
  * information and license terms see the AUTHORS and COPYING files
  * in the top-level directory of this distribution.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation; either version 2 of
  * the License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #ifndef PRESSURECURVEWIDGET_H
 #define PRESSURECURVEWIDGET_H
 
 // Qt includes
 #include <QColor>
 #include <QPoint>
 #include <QSize>
 #include <QWidget>
 
 class QMouseEvent;
 class QPaintEvent;
 
 namespace Wacom
 {
 /**
  * This widget implements a visual way to adjust the press curve for wacom tablets
  * It shows the beziercurve and two control points to adjust the curve
  * Furthermore if Qt detects the tablet device the pressure is animated
  * as filled area below the curve to give a better feel what the changes to the press curve mean
  * This step is not necessary to change the press curve settings, but a nice visual help.
  * Qt relies on the xorg.conf to detect the tablet correctly because it use hardcoded names for it
  * name them "stylus", "pen", "eraser" to get it working.
  *
  * @see https://doc.qt.io/qt-5/qtabletevent.html
  */
 class PressureCurveWidget : public QWidget
 {
     Q_OBJECT
 
 public:
     /**
      * default constructor
      *
      * @param parent the parent widget that holds this one
      */
     explicit PressureCurveWidget(QWidget *parent = nullptr);
 
     /**
      * Sets the start values for the bezier presscurve via this control points
      *
      * @bug if this widget has no fixed size, the width()/height() return the
      *      the values as specified in the .ui file or when the widget is created
      *      The automatic layout changes took place before somehow and thus
      *      leads to a wrong placement of the control points
      * @param p1 x value of the first point
      * @param p2 y value of the first point
      * @param p3 x value of the second point
      * @param p4 y value of the second point
      */
     void setControlPoints(qreal p1, qreal p2, qreal p3, qreal p4);
 
 protected:
     /**
      * Called whenever the mouse is pressed in the widget
      * Selects the control point if the mouse click was on it
      *
      * @param event the mouse event
      */
     void mousePressEvent(QMouseEvent *event) override;
 
     /**
      * Drags the control points around
      * based on the active selected control point specified in the mousePressEvent
      * the selected control point is moved around and changes the presscurve directly
      *
      * @param event the mouse event
      */
     void mouseMoveEvent(QMouseEvent *event) override;
 
     /**
      * Dragging the controlpoint stopped
      * Resets the selection of the active control point to move around
      *
      * @param event the mouse event
      */
     void mouseReleaseEvent(QMouseEvent *event) override;
 
     /**
      * Changes the position of the controlpoints with the same ratio than the widget resize
      * This way the presscurve stays the same all the time
      *
      * @param event the resize event
      */
     void resizeEvent(QResizeEvent *event) override;
 
     /**
      * If the tablet was detected by Qt this animates the pressure as filled area below the presscurve
      * Qt detects the tablet only if it was configured via the xorg.conf. Otherwise it does not know about it
      * Furthermore the tablet input devices must have the standard names "stylus" and "eraser"
      *
      * @param event the Tablet event
      */
     void tabletEvent(QTabletEvent *event) override;
 
     /**
      * Draws the background grid, controlpoints and the presscurve on the widget
      * Does it with antialias support
      *
      * @param event the paint event
      */
     void paintEvent(QPaintEvent *event) override;
 
     /**
      * Finds the nearest controlpoint the uses clicks on
      * Will be called for mouse and tabletevent and sets m_activePoint
      * with the number of the clicked point.
      *
      * @param pos the position of the mouse/pen click
      */
     void setNearestPoint(const QPointF &pos);
 
     /**
      * Moves both control points according to the user interaction
      * Both points will be changed even if only one is selected
      * The reason lies deep in the Linux Wacom driver that expect the beziercurve
      * to be this way. So point 2 is always point 1 with mirrored x/y coordinates
      *
      * @param pos the new position
      */
     void moveControlPoint(const QPointF &pos);
 
 signals:
     /**
      * This signal will be fired if the position of the control points change
      * Used to inform the parent widget of this change to be able to display the new values
      * Furthermore the changed presscurve will be set via the xsetwacom driver immediately thus
      * allow the user to see the changes in action right now
      *
      * @param points the presscurve points in a format expected by the xsetwacom driver (like "0 100 0 100")
      */
     void controlPointsChanged(const QString &points);
 
 private:
     QPointF m_cP1; /**< Control point 1 */
     QPointF m_cP2; /**< Control point 2 */
     int m_pointSize = 10; /**< Size of the control point */
     int m_activePoint = 0; /**< The point that is dragged around */
     QColor m_pointColor = Qt::red; /**< Color of the points */
     QColor m_curveColor = Qt::black; /**< Color of the curve */
     qreal m_pressure = 0; /**< Buffers the current stylus pressure. (0.0 - 1.0) used to animate the pressure */
     QColor m_pressAreaColor = Qt::blue; /**< Color of the press indication area */
 };
 
 }
 
 #endif // PRESSURECURVEWIDGET_H