qwt_dial.cpp

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/* -*- 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 <math.h>
#include <qpainter.h>
#if QT_VERSION >= 0x040000
#include <qbitmap.h>
#include <qpalette.h>
#endif
#include <qpixmap.h>
#include <qevent.h>
#include "qwt_math.h"
#include "qwt_scale_engine.h"
#include "qwt_scale_map.h"
#include "qwt_paint_buffer.h"
#include "qwt_painter.h"
#include "qwt_dial_needle.h"
#include "qwt_dial.h"

class QwtDial::PrivateData
{
public:
    PrivateData():
        visibleBackground(true),
        frameShadow(Sunken),
        lineWidth(0),
        mode(RotateNeedle),
        direction(Clockwise),
        origin(90.0),
        minScaleArc(0.0),
        maxScaleArc(0.0),
        scaleDraw(0),
        maxMajIntv(36),
        maxMinIntv(10),
        scaleStep(0.0),
        needle(0)
    {
    }

    ~PrivateData()
    {
        delete scaleDraw;
        delete needle;
    }
    bool visibleBackground;
    Shadow frameShadow;
    int lineWidth;

    QwtDial::Mode mode;
    QwtDial::Direction direction;

    double origin;
    double minScaleArc;
    double maxScaleArc;

    QwtDialScaleDraw *scaleDraw;
    int maxMajIntv;
    int maxMinIntv;
    double scaleStep;

    QwtDialNeedle *needle;

    static double previousDir;
};

double QwtDial::PrivateData::previousDir = -1.0;

QwtDialScaleDraw::QwtDialScaleDraw(QwtDial *parent):
    d_parent(parent),
    d_penWidth(1)
{
}

void QwtDialScaleDraw::setPenWidth(uint penWidth)
{
    d_penWidth = penWidth;
}

uint QwtDialScaleDraw::penWidth() const
{
    return d_penWidth;
}

QwtText QwtDialScaleDraw::label(double value) const
{
    if ( d_parent == NULL )
        return QwtRoundScaleDraw::label(value);

    return d_parent->scaleLabel(value);
}

QwtDial::QwtDial(QWidget* parent):
    QwtAbstractSlider(Qt::Horizontal, parent)
{
    initDial();
}

#if QT_VERSION < 0x040000

QwtDial::QwtDial(QWidget* parent, const char *name):
    QwtAbstractSlider(Qt::Horizontal, parent)
{
    setName(name);
    initDial();
}
#endif

void QwtDial::initDial()
{
    d_data = new PrivateData;

#if QT_VERSION < 0x040000
    setWFlags(Qt::WNoAutoErase);
#endif 

#if QT_VERSION >= 0x040000
    using namespace Qt;
#endif
    setFocusPolicy(TabFocus);

    QPalette p = palette();
    for ( int i = 0; i < QPalette::NColorGroups; i++ )
    {
        const QPalette::ColorGroup cg = (QPalette::ColorGroup)i;

        // Base: background color of the circle inside the frame.
        // Foreground: background color of the circle inside the scale

#if QT_VERSION < 0x040000
        p.setColor(cg, QColorGroup::Foreground, 
            p.color(cg, QColorGroup::Base));
#else
        p.setColor(cg, QPalette::Foreground, 
            p.color(cg, QPalette::Base));
#endif
    }
    setPalette(p);

    d_data->scaleDraw = new QwtDialScaleDraw(this);
    d_data->scaleDraw->setRadius(0);

    setScaleArc(0.0, 360.0); // scale as a full circle
    setRange(0.0, 360.0, 1.0, 10); // degrees as deafult
}

QwtDial::~QwtDial() 
{
    delete d_data;
}

void QwtDial::showBackground(bool show)
{
    if ( d_data->visibleBackground != show )
    {
        d_data->visibleBackground = show;
        updateMask();
    }
}

bool QwtDial::hasVisibleBackground() const 
{ 
    return d_data->visibleBackground; 
}

void QwtDial::setFrameShadow(Shadow shadow)
{
    if ( shadow != d_data->frameShadow )
    {
        d_data->frameShadow = shadow;
        if ( lineWidth() > 0 )
            update();
    }
}

QwtDial::Shadow QwtDial::frameShadow() const 
{ 
    return d_data->frameShadow; 
}

void QwtDial::setLineWidth(int lineWidth)
{
    if ( lineWidth < 0 )
        lineWidth = 0;

    if ( d_data->lineWidth != lineWidth )
    {
        d_data->lineWidth = lineWidth;
        update();
    }
}

int QwtDial::lineWidth() const 
{ 
    return d_data->lineWidth; 
}

QRect QwtDial::contentsRect() const
{
    const int lw = lineWidth();

    QRect r = boundingRect();
    if ( lw > 0 )
    {
        r.setRect(r.x() + lw, r.y() + lw, 
            r.width() - 2 * lw, r.height() - 2 * lw);
    }
    return r;
}

QRect QwtDial::boundingRect() const
{
    const int radius = qwtMin(width(), height()) / 2;

    QRect r(0, 0, 2 * radius, 2 * radius);
    r.moveCenter(rect().center());
    return r;
}

QRect QwtDial::scaleContentsRect() const
{
#if QT_VERSION < 0x040000
    const QPen scalePen(colorGroup().text(), 0, Qt::NoPen);
#else
    const QPen scalePen(palette().text(), 0, Qt::NoPen);
#endif

    int scaleDist = 0;
    if ( d_data->scaleDraw )
    {
        scaleDist = d_data->scaleDraw->extent(scalePen, font());
        scaleDist++; // margin
    }

    const QRect rect = contentsRect();
    return QRect(rect.x() + scaleDist, rect.y() + scaleDist,
        rect.width() - 2 * scaleDist, rect.height() - 2 * scaleDist);
}

void QwtDial::setMode(Mode mode)
{   
    if ( mode != d_data->mode )
    {
        d_data->mode = mode;
        update(); 
    }
}       

QwtDial::Mode QwtDial::mode() const
{
    return d_data->mode;
}

void QwtDial::setWrapping(bool wrapping)
{
    setPeriodic(wrapping);
} 

bool QwtDial::wrapping() const
{
    return periodic();
}

void QwtDial::setDirection(Direction direction)
{
    if ( direction != d_data->direction )
    {
        d_data->direction = direction;
        update();
    }
}

QwtDial::Direction QwtDial::direction() const
{
    return d_data->direction;
}

void QwtDial::resizeEvent(QResizeEvent *e)
{
    QWidget::resizeEvent(e);

    if ( !hasVisibleBackground() )
        updateMask();
}

void QwtDial::paintEvent(QPaintEvent *e)
{
    const QRect &ur = e->rect();
    if ( ur.isValid() )
    {
#if QT_VERSION < 0x040000
        QwtPaintBuffer paintBuffer(this, ur);
        QPainter &painter = *paintBuffer.painter();
#else
        QPainter painter(this);
        painter.setRenderHint(QPainter::Antialiasing, true);
#endif

        painter.save();
        drawContents(&painter);
        painter.restore();

        painter.save();
        drawFrame(&painter);
        painter.restore();

        if ( hasFocus() )
            drawFocusIndicator(&painter);
    }
}

void QwtDial::drawFocusIndicator(QPainter *painter) const
{
    if ( !isReadOnly() )
    {
        QRect focusRect = contentsRect();

        const int margin = 2;
        focusRect.setRect( 
            focusRect.x() + margin,
            focusRect.y() + margin,
            focusRect.width() - 2 * margin,
            focusRect.height() - 2 * margin);

#if QT_VERSION < 0x040000
        QColor color = colorGroup().color(QColorGroup::Base);
#else
        QColor color = palette().color(QPalette::Base);
#endif
        if (color.isValid())
        {
            const QColor gray(Qt::gray);

            int h, s, v;
#if QT_VERSION < 0x040000
            color.hsv(&h, &s, &v);
#else
            color.getHsv(&h, &s, &v);
#endif
            color = (v > 128) ? gray.dark(120) : gray.light(120);
        }
        else
            color = Qt::darkGray;

        painter->save();
        painter->setBrush(Qt::NoBrush);
        painter->setPen(QPen(color, 0, Qt::DotLine));
        painter->drawEllipse(focusRect);
        painter->restore();
    }
}

void QwtDial::drawFrame(QPainter *painter)
{
    const int lw = lineWidth();
    const int off = (lw + 1) % 2;

    QRect r = boundingRect();
    r.setRect(r.x() + lw / 2 - off, r.y() + lw / 2 - off,
        r.width() - lw + off + 1, r.height() - lw + off + 1);
#if QT_VERSION >= 0x040000
    r.setX(r.x() + 1);
    r.setY(r.y() + 1);
    r.setWidth(r.width() - 2);
    r.setHeight(r.height() - 2);
#endif

    if ( lw > 0 )
    {
        switch(d_data->frameShadow)
        {
            case QwtDial::Raised:
#if QT_VERSION < 0x040000
                QwtPainter::drawRoundFrame(painter, r, 
                    lw, colorGroup(), false);
#else
                QwtPainter::drawRoundFrame(painter, r, 
                    lw, palette(), false);
#endif
                break;
            case QwtDial::Sunken:
#if QT_VERSION < 0x040000
                QwtPainter::drawRoundFrame(painter, r, 
                    lw, colorGroup(), true);
#else
                QwtPainter::drawRoundFrame(painter, r, 
                    lw, palette(), true);
#endif
                break;
            default: // Plain
            {
                painter->save();
                painter->setPen(QPen(Qt::black, lw));
                painter->setBrush(Qt::NoBrush);
                painter->drawEllipse(r);
                painter->restore();
            }
        }
    }
}

void QwtDial::drawContents(QPainter *painter) const
{
#if QT_VERSION < 0x040000
    if ( backgroundMode() == Qt::NoBackground || 
        colorGroup().brush(QColorGroup::Base) != 
            colorGroup().brush(QColorGroup::Background) )
#else
    if ( testAttribute(Qt::WA_NoSystemBackground) ||
        palette().brush(QPalette::Base) != 
            palette().brush(QPalette::Background) )
#endif
    {

        const QRect br = boundingRect();

        painter->save();
        painter->setPen(Qt::NoPen);

#if QT_VERSION < 0x040000
        painter->setBrush(colorGroup().brush(QColorGroup::Base));
#else
        painter->setBrush(palette().brush(QPalette::Base));
#endif

        painter->drawEllipse(br);
        painter->restore();
    }


    const QRect insideScaleRect = scaleContentsRect();
#if QT_VERSION < 0x040000
    if ( colorGroup().brush(QColorGroup::Foreground) !=
        colorGroup().brush(QColorGroup::Base) )
#else
    if ( palette().brush(QPalette::Foreground) !=
        palette().brush(QPalette::Base) )
#endif
    {
        painter->save();
        painter->setPen(Qt::NoPen);

#if QT_VERSION < 0x040000
        painter->setBrush(colorGroup().brush(QColorGroup::Foreground));
#else
        painter->setBrush(palette().brush(QPalette::Foreground));
#endif

        painter->drawEllipse(insideScaleRect.x() - 1, insideScaleRect.y() - 1,
            insideScaleRect.width(), insideScaleRect.height() );

        painter->restore();
    }

    const QPoint center = insideScaleRect.center();
    const int radius = insideScaleRect.width() / 2;

    painter->save();
    drawScaleContents(painter, center, radius);
    painter->restore();

    double direction = d_data->origin;

    if (isValid())
    {
        direction = d_data->minScaleArc;
        if ( maxValue() > minValue() && d_data->maxScaleArc > d_data->minScaleArc )
        {
            const double ratio = 
                (value() - minValue()) / (maxValue() - minValue());
            direction += ratio * (d_data->maxScaleArc - d_data->minScaleArc);
        }

        if ( d_data->direction == QwtDial::CounterClockwise )
            direction = d_data->maxScaleArc - (direction - d_data->minScaleArc);

        direction += d_data->origin;
        if ( direction >= 360.0 )
            direction -= 360.0;
        else if ( direction < 0.0 )
            direction += 360.0;
    }

    double origin = d_data->origin;
    if ( mode() == RotateScale )
    {
        origin -= direction - d_data->origin;
        direction = d_data->origin;
    }

    painter->save();
    drawScale(painter, center, radius, origin, 
        d_data->minScaleArc, d_data->maxScaleArc);
    painter->restore();

    if ( isValid() )
    {
        QPalette::ColorGroup cg;
        if ( isEnabled() )
            cg = hasFocus() ? QPalette::Active : QPalette::Inactive;
        else
            cg = QPalette::Disabled;

        painter->save();
        drawNeedle(painter, center, radius, direction, cg);
        painter->restore();
    }
}

void QwtDial::drawNeedle(QPainter *painter, const QPoint &center, 
    int radius, double direction, QPalette::ColorGroup cg) const
{
    if ( d_data->needle )
    {
        direction = 360.0 - direction; // counter clockwise
        d_data->needle->draw(painter, center, radius, direction, cg);
    }
}

void QwtDial::drawScale(QPainter *painter, const QPoint &center,
    int radius, double origin, double minArc, double maxArc) const
{
    if ( d_data->scaleDraw == NULL )
        return;

    origin -= 270.0; // hardcoded origin of QwtScaleDraw

    double angle = maxArc - minArc;
    if ( angle > 360.0 )
        angle = ::fmod(angle, 360.0);

    minArc += origin;
    if ( minArc < -360.0 )
        minArc = ::fmod(minArc, 360.0);
    
    maxArc = minArc + angle;
    if ( maxArc > 360.0 )
    {
        // QwtAbstractScaleDraw::setAngleRange accepts only values
        // in the range [-360.0..360.0]
        minArc -= 360.0;
        maxArc -= 360.0;
    }

    if ( d_data->direction == QwtDial::CounterClockwise )
        qSwap(minArc, maxArc);
    
    painter->setFont(font());

    d_data->scaleDraw->setAngleRange(minArc, maxArc);
    d_data->scaleDraw->setRadius(radius);
    d_data->scaleDraw->moveCenter(center);

#if QT_VERSION < 0x040000
    QColorGroup cg = colorGroup();

    const QColor textColor = cg.color(QColorGroup::Text);
    cg.setColor(QColorGroup::Foreground, textColor);
    painter->setPen(QPen(textColor, d_data->scaleDraw->penWidth()));
    
    d_data->scaleDraw->draw(painter, cg);
#else
    QPalette pal = palette();

    const QColor textColor = pal.color(QPalette::Text);
    pal.setColor(QPalette::Foreground, textColor); //ticks, backbone
    
    painter->setPen(QPen(textColor, d_data->scaleDraw->penWidth()));

    d_data->scaleDraw->draw(painter, pal);
#endif
}

void QwtDial::drawScaleContents(QPainter *, 
    const QPoint &, int) const
{
    // empty default implementation
}

void QwtDial::setNeedle(QwtDialNeedle *needle)
{
    if ( needle != d_data->needle )
    {
        if ( d_data->needle )
            delete d_data->needle;

        d_data->needle = needle;
        update();
    }
}

const QwtDialNeedle *QwtDial::needle() const 
{ 
    return d_data->needle; 
}

QwtDialNeedle *QwtDial::needle() 
{ 
    return d_data->needle; 
}

void QwtDial::rangeChange()
{
    updateScale();
}

void QwtDial::updateScale()
{
    if ( d_data->scaleDraw )
    {
        QwtLinearScaleEngine scaleEngine;

        const QwtScaleDiv scaleDiv = scaleEngine.divideScale(
            minValue(), maxValue(), 
            d_data->maxMajIntv, d_data->maxMinIntv, d_data->scaleStep);

        d_data->scaleDraw->setTransformation(scaleEngine.transformation());
        d_data->scaleDraw->setScaleDiv(scaleDiv);
    }
}

QwtDialScaleDraw *QwtDial::scaleDraw() 
{ 
    return d_data->scaleDraw; 
}

const QwtDialScaleDraw *QwtDial::scaleDraw() const 
{ 
    return d_data->scaleDraw; 
}

void QwtDial::setScaleDraw(QwtDialScaleDraw *scaleDraw)
{
    if ( scaleDraw != d_data->scaleDraw )
    {
        if ( d_data->scaleDraw )
            delete d_data->scaleDraw;
    
        d_data->scaleDraw = scaleDraw;
        updateScale();
        update();
    }
}

void QwtDial::setScale(int maxMajIntv, int maxMinIntv, double step)
{
    d_data->maxMajIntv = maxMajIntv;
    d_data->maxMinIntv = maxMinIntv;
    d_data->scaleStep = step;

    updateScale();
}

void QwtDial::setScaleOptions(int options)
{
    if ( options == 0 )
        setScaleDraw(NULL);

    QwtDialScaleDraw *sd = d_data->scaleDraw;
    if ( sd == NULL )
        return;

    sd->enableComponent(QwtAbstractScaleDraw::Backbone, 
        options & ScaleBackbone);

    sd->enableComponent(QwtAbstractScaleDraw::Ticks, 
        options & ScaleTicks);
    
    sd->enableComponent(QwtAbstractScaleDraw::Labels, 
        options & ScaleLabel);
}

void QwtDial::setScaleTicks(int minLen, int medLen, 
    int majLen, int penWidth)
{
    QwtDialScaleDraw *sd = d_data->scaleDraw;
    if ( sd )
    {
        sd->setTickLength(QwtScaleDiv::MinorTick, minLen);
        sd->setTickLength(QwtScaleDiv::MediumTick, medLen);
        sd->setTickLength(QwtScaleDiv::MajorTick, majLen);
        sd->setPenWidth(penWidth);
    }
}

QwtText QwtDial::scaleLabel(double value) const
{
#if 1
    if ( value == -0 )
        value = 0;
#endif

    return QString::number(value);
}

double QwtDial::minScaleArc() const 
{ 
    return d_data->minScaleArc; 
}

double QwtDial::maxScaleArc() const 
{ 
    return d_data->maxScaleArc; 
}

void QwtDial::setOrigin(double origin)
{
    d_data->origin = origin;
    update();
}

double QwtDial::origin() const
{
    return d_data->origin;
}

void QwtDial::setScaleArc(double minArc, double maxArc)
{
    if ( minArc != 360.0 && minArc != -360.0 )
        minArc = fmod(minArc, 360.0);
    if ( maxArc != 360.0 && maxArc != -360.0 )
        maxArc = fmod(maxArc, 360.0);

    d_data->minScaleArc = qwtMin(minArc, maxArc);
    d_data->maxScaleArc = qwtMax(minArc, maxArc);
    if ( d_data->maxScaleArc - d_data->minScaleArc > 360.0 )
        d_data->maxScaleArc = d_data->minScaleArc + 360.0;
    
    update();
}

void QwtDial::valueChange()
{
    update();
    QwtAbstractSlider::valueChange();
}

QSize QwtDial::sizeHint() const
{
    int sh = 0;
    if ( d_data->scaleDraw )
        sh = d_data->scaleDraw->extent( QPen(), font() );

    const int d = 6 * sh + 2 * lineWidth();
    
    return QSize( d, d );
}

QSize QwtDial::minimumSizeHint() const
{   
    int sh = 0;
    if ( d_data->scaleDraw )
        sh = d_data->scaleDraw->extent(QPen(), font() );

    const int d = 3 * sh + 2 * lineWidth();
    
    return QSize( d, d );
}

static double line2Radians(const QPoint &p1, const QPoint &p2)
{
    const QPoint p = p2 - p1;

    double angle;
    if ( p.x() == 0 )
        angle = ( p.y() <= 0 ) ? M_PI_2 : 3 * M_PI_2;
    else
    {
        angle = atan(double(-p.y()) / double(p.x()));
        if ( p.x() < 0 )
            angle += M_PI;
        if ( angle < 0.0 )
            angle += 2 * M_PI;
    }
    return 360.0 - angle * 180.0 / M_PI;
}

double QwtDial::getValue(const QPoint &pos)
{
    if ( d_data->maxScaleArc == d_data->minScaleArc || maxValue() == minValue() )
        return minValue();

    double dir = line2Radians(rect().center(), pos) - d_data->origin;
    if ( dir < 0.0 )
        dir += 360.0;

    if ( mode() == RotateScale )
        dir = 360.0 - dir;

    // The position might be in the area that is outside the scale arc.
    // We need the range of the scale if it was a complete circle.

    const double completeCircle = 360.0 / (d_data->maxScaleArc - d_data->minScaleArc) 
        * (maxValue() - minValue());

    double posValue = minValue() + completeCircle * dir / 360.0;

    if ( scrollMode() == ScrMouse )
    {
        if ( d_data->previousDir >= 0.0 ) // valid direction
        {
            // We have to find out whether the mouse is moving
            // clock or counter clockwise

            bool clockWise = false;

            const double angle = dir - d_data->previousDir;
            if ( (angle >= 0.0 && angle <= 180.0) || angle < -180.0 )
                clockWise = true;

            if ( clockWise )
            {
                if ( dir < d_data->previousDir && mouseOffset() > 0.0 )
                {
                    // We passed 360 -> 0
                    setMouseOffset(mouseOffset() - completeCircle);
                }

                if ( wrapping() )
                {
                    if ( posValue - mouseOffset() > maxValue() )
                    {
                        // We passed maxValue and the value will be set
                        // to minValue. We have to adjust the mouseOffset.

                        setMouseOffset(posValue - minValue());
                    }
                }
                else
                {
                    if ( posValue - mouseOffset() > maxValue() ||
                        value() == maxValue() )
                    {
                        // We fix the value at maxValue by adjusting
                        // the mouse offset.

                        setMouseOffset(posValue - maxValue());
                    }
                }
            }
            else
            {
                if ( dir > d_data->previousDir && mouseOffset() < 0.0 )
                {
                    // We passed 0 -> 360 
                    setMouseOffset(mouseOffset() + completeCircle);    
                }

                if ( wrapping() )
                {
                    if ( posValue - mouseOffset() < minValue() )
                    {
                        // We passed minValue and the value will be set
                        // to maxValue. We have to adjust the mouseOffset.

                        setMouseOffset(posValue - maxValue());
                    }
                }
                else
                {
                    if ( posValue - mouseOffset() < minValue() ||
                        value() == minValue() )
                    {
                        // We fix the value at minValue by adjusting
                        // the mouse offset.

                        setMouseOffset(posValue - minValue());
                    }
                }
            }
        }
        d_data->previousDir = dir;
    }

    return posValue;
}

void QwtDial::getScrollMode(const QPoint &pos, int &scrollMode, int &direction)
{
    direction = 0;
    scrollMode = ScrNone;

    const QRegion region(contentsRect(), QRegion::Ellipse);
    if ( region.contains(pos) && pos != rect().center() )
    {
        scrollMode = ScrMouse;
        d_data->previousDir = -1.0;
    }
}

void QwtDial::keyPressEvent(QKeyEvent *event)
{
    if ( isReadOnly() )
    {
        event->ignore();
        return;
    }

    if ( !isValid() )
        return;

    double previous = prevValue();
    switch ( event->key() )
    {
        case Qt::Key_Down:
        case Qt::Key_Left:
            QwtDoubleRange::incValue(-1);
            break;
#if QT_VERSION < 0x040000
        case Qt::Key_Prior:
#else
        case Qt::Key_PageUp:
#endif
            QwtDoubleRange::incValue(-pageSize());
            break;
        case Qt::Key_Home:
            setValue(minValue());
            break;

        case Qt::Key_Up:
        case Qt::Key_Right:
            QwtDoubleRange::incValue(1);
            break;
#if QT_VERSION < 0x040000
        case Qt::Key_Next:
#else
        case Qt::Key_PageDown:
#endif
            QwtDoubleRange::incValue(pageSize());
            break;
        case Qt::Key_End:
            setValue(maxValue());
            break;
        default:;
            event->ignore();
    }

    if (value() != previous)
        emit sliderMoved(value());
}

void QwtDial::updateMask()
{
    if ( d_data->visibleBackground )
        clearMask();
    else
        setMask(QRegion(boundingRect(), QRegion::Ellipse));
}