qwt_picker.cpp

QWT5.01用于Qt开发的二维图形库程序

/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

#include <qapplication.h>
#include <qevent.h>
#include <qpainter.h>
#include <qframe.h>
#include <qcursor.h>
#include <qbitmap.h>
#include "qwt_math.h"
#include "qwt_painter.h"
#include "qwt_picker_machine.h"
#include "qwt_picker.h"
#if QT_VERSION < 0x040000
#include <qguardedptr.h>
#else
#include <qpointer.h>
#endif

class QwtPicker::PrivateData
{
public:
    class PickerWidget: public QWidget
    {
    public:
        enum Type
        {
            RubberBand,
            Text
        };
        PickerWidget(QwtPicker *, QWidget *, Type);
        virtual void updateMask();

    protected:
        virtual void paintEvent(QPaintEvent *);

        QwtPicker *d_picker;
        Type d_type;
    };

    bool enabled;

    QwtPickerMachine *stateMachine;

    int selectionFlags;
    QwtPicker::ResizeMode resizeMode;

    QwtPicker::RubberBand rubberBand;
    QPen rubberBandPen;

    QwtPicker::DisplayMode trackerMode;
    QPen trackerPen;
    QFont trackerFont;

    QwtPolygon selection;
    bool isActive;
    QPoint labelPosition;

    bool mouseTracking; // used to save previous value

    /*
      On X11 the widget below the picker widgets gets paint events
      with a region that is the bounding rect of the mask, if it is complex.
      In case of (f.e) a CrossRubberBand and a text this creates complete
      repaints of the widget. So we better use two different widgets.
     */
     
#if QT_VERSION < 0x040000
    QGuardedPtr<PickerWidget> rubberBandWidget;
    QGuardedPtr<PickerWidget> trackerWidget;
#else
    QPointer<PickerWidget> rubberBandWidget;
    QPointer<PickerWidget> trackerWidget;
#endif
};

QwtPicker::PrivateData::PickerWidget::PickerWidget(
        QwtPicker *picker, QWidget *parent, Type type):
    QWidget(parent),
    d_picker(picker),
    d_type(type)
{
#if QT_VERSION >= 0x040000
    setAttribute(Qt::WA_TransparentForMouseEvents);
    setAttribute(Qt::WA_NoSystemBackground);
#if 0
    setAttribute(Qt::WA_PaintOnScreen);
#endif
    setFocusPolicy(Qt::NoFocus);
#else
    setBackgroundMode(Qt::NoBackground);
    setFocusPolicy(QWidget::NoFocus);
    setMouseTracking(true);
#endif
    hide();
}

void QwtPicker::PrivateData::PickerWidget::updateMask()
{
    QBitmap bm(width(), height());
    bm.fill(Qt::color0);

    QPainter painter(&bm);

    if ( d_type == RubberBand )
    {
        QPen pen = d_picker->rubberBandPen();
        pen.setColor(Qt::color1);
        painter.setPen(pen);

        d_picker->drawRubberBand(&painter);
    }
    if ( d_type == Text )
    {
        QPen pen = d_picker->trackerPen();
        pen.setColor(Qt::color1);
        painter.setPen(pen);

        d_picker->drawTracker(&painter);
    }

    painter.end();


#if QT_VERSION < 0x040000
    QWidget *w = parentWidget();
    const bool doUpdate = w->isUpdatesEnabled();
    const Qt::BackgroundMode bgMode = w->backgroundMode();
    w->setUpdatesEnabled(false);
    if ( bgMode != Qt::NoBackground )
        w->setBackgroundMode(Qt::NoBackground);
#endif

    const QRegion r(bm);
    setMask(r);

#if QT_VERSION < 0x040000
    if ( bgMode != Qt::NoBackground )
        w->setBackgroundMode(bgMode);

    w->setUpdatesEnabled(doUpdate);
#endif

    setShown(!r.isEmpty());
}

void QwtPicker::PrivateData::PickerWidget::paintEvent(QPaintEvent *e)
{
    QPainter painter(this);

    if ( d_type == RubberBand )
    {
        painter.setClipRegion(e->region());
        painter.setPen(d_picker->rubberBandPen());
        d_picker->drawRubberBand(&painter);
    }

    if ( d_type == Text )
    {
        painter.setClipRegion(e->region());
#if 0
        painter.setPen(d_picker->trackerPen());
        d_picker->drawTracker(&painter);
#else
        painter.fillRect(e->rect(), QBrush(d_picker->trackerPen().color()));
#endif
    }
}

/*!
  Constructor

  Creates an picker that is enabled, but where selection flag
  is set to NoSelection, rubberband and tracker are disabled.
  
  \param parent Parent widget, that will be observed
 */

QwtPicker::QwtPicker(QWidget *parent):
    QObject(parent)
{
    init(parent, NoSelection, NoRubberBand, AlwaysOff);
}

/*!
  Constructor

  \param selectionFlags Or'd value of SelectionType, RectSelectionType and 
                        SelectionMode
  \param rubberBand Rubberband style
  \param trackerMode Tracker mode
  \param parent Parent widget, that will be observed
 */
QwtPicker::QwtPicker(int selectionFlags, RubberBand rubberBand,
        DisplayMode trackerMode, QWidget *parent):
    QObject(parent)
{
    init(parent, selectionFlags, rubberBand, trackerMode);
}

//! Destructor
QwtPicker::~QwtPicker()
{
    setMouseTracking(false);
    delete d_data->stateMachine;
    delete d_data->rubberBandWidget;
    delete d_data->trackerWidget;
    delete d_data;
}

//! Init the picker, used by the constructors
void QwtPicker::init(QWidget *parent, int selectionFlags, 
    RubberBand rubberBand, DisplayMode trackerMode)
{
    d_data = new PrivateData;

    d_data->rubberBandWidget = NULL;
    d_data->trackerWidget = NULL;

    d_data->rubberBand = rubberBand;
    d_data->enabled = false;
    d_data->resizeMode = Stretch;
    d_data->trackerMode = AlwaysOff;
    d_data->isActive = false;
    d_data->labelPosition = QPoint(-1, -1);
    d_data->mouseTracking = false;

    d_data->stateMachine = NULL;
    setSelectionFlags(selectionFlags);

    if ( parent )
    {
#if QT_VERSION >= 0x040000
        if ( parent->focusPolicy() == Qt::NoFocus )
            parent->setFocusPolicy(Qt::WheelFocus);
#else
        if ( parent->focusPolicy() == QWidget::NoFocus )
            parent->setFocusPolicy(QWidget::WheelFocus);
#endif

        d_data->trackerFont = parent->font();
        d_data->mouseTracking = parent->hasMouseTracking();
        setEnabled(true);
    }
    setTrackerMode(trackerMode);
}

/*!
   Set a state machine and delete the previous one
*/
void QwtPicker::setStateMachine(QwtPickerMachine *stateMachine)
{
    if ( d_data->stateMachine != stateMachine )
    {
        if ( isActive() )
            end(false);

        delete d_data->stateMachine;
        d_data->stateMachine = stateMachine;

        if ( d_data->stateMachine )
            d_data->stateMachine->reset();
    }
}

/*!
   Create a state machine depending on the selection flags.

   - PointSelection | ClickSelection\n
     QwtPickerClickPointMachine()
   - PointSelection | DragSelection\n
     QwtPickerDragPointMachine()
   - RectSelection | ClickSelection\n
     QwtPickerClickRectMachine()
   - RectSelection | DragSelection\n
     QwtPickerDragRectMachine()
   - PolygonSelection\n
     QwtPickerPolygonMachine()

   \sa setSelectionFlags()
*/
QwtPickerMachine *QwtPicker::stateMachine(int flags) const
{
    if ( flags & PointSelection )
    {
        if ( flags & ClickSelection )
            return new QwtPickerClickPointMachine;
        else
            return new QwtPickerDragPointMachine;
    }
    if ( flags & RectSelection )
    {
        if ( flags & ClickSelection )
            return new QwtPickerClickRectMachine;
        else
            return new QwtPickerDragRectMachine;
    }
    if ( flags & PolygonSelection )
    {
        return new QwtPickerPolygonMachine();
    }
    return NULL;
}

//! Return the parent widget, where the selection happens
QWidget *QwtPicker::parentWidget()
{
    QObject *obj = parent();
    if ( obj && obj->isWidgetType() )
        return (QWidget *)obj;

    return NULL;
}

//! Return the parent widget, where the selection happens
const QWidget *QwtPicker::parentWidget() const
{
    QObject *obj = parent();
    if ( obj && obj->isWidgetType() )
        return (QWidget *)obj;

    return NULL;
}

/*!
  Set the selection flags

  \param flags Or'd value of SelectionType, RectSelectionType and 
               SelectionMode. The default value is NoSelection.

  \sa selectionFlags(), SelectionType, RectSelectionType, SelectionMode
*/

void QwtPicker::setSelectionFlags(int flags)
{
    d_data->selectionFlags = flags;
    setStateMachine(stateMachine(flags));
}

/*!
  \return Selection flags, an Or'd value of SelectionType, RectSelectionType and
          SelectionMode.
  \sa setSelectionFlags(), SelectionType, RectSelectionType, SelectionMode
*/
int QwtPicker::selectionFlags() const
{
    return d_data->selectionFlags;
}

/*!
  Set the rubberband style 

  \param rubberBand Rubberband style
         The default value is NoRubberBand.

  \sa rubberBand(), RubberBand, setRubberBandPen()
*/
void QwtPicker::setRubberBand(RubberBand rubberBand)
{
    d_data->rubberBand = rubberBand;
}

/*!
  \return Rubberband style
  \sa setRubberBand(), RubberBand, rubberBandPen()
*/
QwtPicker::RubberBand QwtPicker::rubberBand() const
{
    return d_data->rubberBand;
}

/*!
  \brief Set the display mode of the tracker.

  A tracker displays information about current position of
  the cursor as a string. The display mode controls
  if the tracker has to be displayed whenever the observed
  widget has focus and cursor (AlwaysOn), never (AlwaysOff), or
  only when the selection is active (ActiveOnly).
  
  \param mode Tracker display mode

  \warning In case of AlwaysOn, mouseTracking will be enabled
           for the observed widget.
  \sa trackerMode(), DisplayMode
*/

void QwtPicker::setTrackerMode(DisplayMode mode)
{   
    if ( d_data->trackerMode != mode )
    {
        d_data->trackerMode = mode;
        setMouseTracking(d_data->trackerMode == AlwaysOn);
    }
}   

/*!
  \return Tracker display mode
  \sa setTrackerMode(), DisplayMode
*/
QwtPicker::DisplayMode QwtPicker::trackerMode() const
{   
    return d_data->trackerMode;
}   

/*!
  \brief Set the resize mode.

  The resize mode controls what to do with the selected points of an active
  selection when the observed widget is resized.

  Stretch means the points are scaled according to the new
  size, KeepSize means the points remain unchanged.

  The default mode is Stretch.

  \param mode Resize mode
  \sa resizeMode(), ResizeMode
*/
void QwtPicker::setResizeMode(ResizeMode mode)
{
    d_data->resizeMode = mode;
}   

/*!
  \return Resize mode
  \sa setResizeMode(), ResizeMode
*/

QwtPicker::ResizeMode QwtPicker::resizeMode() const
{   
    return d_data->resizeMode;
}

/*!
  \brief En/disable the picker

  When enabled is true an event filter is installed for
  the observed widget, otherwise the event filter is removed.

  \param enabled true or false
  \sa isEnabled(), eventFilter()
*/
void QwtPicker::setEnabled(bool enabled)