qwt_dial_needle.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 <math.h>
#include <qapplication.h>
#include <qpainter.h>
#include "qwt_math.h"
#include "qwt_painter.h"
#include "qwt_polygon.h"
#include "qwt_dial_needle.h"

#if QT_VERSION < 0x040000
typedef QColorGroup QwtPalette;
#else
typedef QPalette QwtPalette;
#endif

//! Constructor
QwtDialNeedle::QwtDialNeedle():
    d_palette(QApplication::palette())
{
}

//! Destructor
QwtDialNeedle::~QwtDialNeedle() 
{
}

/*!
    Sets the palette for the needle.

    \param palette New Palette
*/
void QwtDialNeedle::setPalette(const QPalette &palette) 
{ 
    d_palette = palette; 
}

/*!
  \return the palette of the needle.
*/
const QPalette &QwtDialNeedle::palette() const 
{ 
    return d_palette; 
}

//!  Draw the knob 
void QwtDialNeedle::drawKnob(QPainter *painter,
    const QPoint &pos, int width, const QBrush &brush, bool sunken)
{
    painter->save();

    QRect rect(0, 0, width, width);
    rect.moveCenter(pos);

    painter->setPen(Qt::NoPen);
    painter->setBrush(brush);
    painter->drawEllipse(rect);

    painter->setBrush(Qt::NoBrush);

    const int colorOffset = 20;

    int startAngle = 45;
    if ( sunken )
        startAngle += 180;

    QPen pen;
    pen.setWidth(1);

    pen.setColor(brush.color().dark(100 - colorOffset));
    painter->setPen(pen);
    painter->drawArc(rect, startAngle * 16, 180 * 16);

    pen.setColor(brush.color().dark(100 + colorOffset));
    painter->setPen(pen);
    painter->drawArc(rect, (startAngle + 180) * 16, 180 * 16);

    painter->restore();
}

/*!
  Constructor
*/
QwtDialSimpleNeedle::QwtDialSimpleNeedle(Style style, bool hasKnob, 
        const QColor &mid, const QColor &base):
    d_style(style),
    d_hasKnob(hasKnob),
    d_width(-1)
{
    QPalette palette;
    for ( int i = 0; i < QPalette::NColorGroups; i++ )
    {
        palette.setColor((QPalette::ColorGroup)i,
            QwtPalette::Mid, mid);
        palette.setColor((QPalette::ColorGroup)i,
            QwtPalette::Base, base);
    }

    setPalette(palette);
}

//! Set the width of the needle
void QwtDialSimpleNeedle::setWidth(int width)
{
    d_width = width;
}

/*!
  \return the width of the needle
*/
int QwtDialSimpleNeedle::width() const
{
    return d_width;
}

/*!
 Draw the needle

 \param painter Painter
 \param center Center of the dial, start position for the needle
 \param length Length of the needle
 \param direction Direction of the needle, in degrees counter clockwise
 \param colorGroup Color group, used for painting
*/
void QwtDialSimpleNeedle::draw(QPainter *painter, const QPoint &center,
    int length, double direction, QPalette::ColorGroup colorGroup) const
{
    if ( d_style == Arrow )
    {
        drawArrowNeedle(painter, palette(), colorGroup,
            center, length, d_width, direction, d_hasKnob);
    }
    else
    {
        drawRayNeedle(painter, palette(), colorGroup, 
            center, length, d_width, direction, d_hasKnob); 
    }
}

/*!
  Draw a needle looking like a ray
*/
void QwtDialSimpleNeedle::drawRayNeedle(QPainter *painter, 
    const QPalette &palette, QPalette::ColorGroup colorGroup,
    const QPoint &center, int length, int width, double direction, 
    bool hasKnob)
{
    if ( width <= 0 )
        width = 5;

    direction *= M_PI / 180.0;

    painter->save();

    const QPoint p1(center.x() + 1, center.y() + 2);
    const QPoint p2 = qwtPolar2Pos(p1, length, direction);

    if ( width == 1 )
    {
        const QColor midColor =
            palette.color(colorGroup, QwtPalette::Mid);

        painter->setPen(QPen(midColor, 1));
        painter->drawLine(p1, p2);
    }
    else
    {
        QwtPolygon pa(4);
        pa.setPoint(0, qwtPolar2Pos(p1, width / 2, direction + M_PI_2));
        pa.setPoint(1, qwtPolar2Pos(p2, width / 2, direction + M_PI_2));
        pa.setPoint(2, qwtPolar2Pos(p2, width / 2, direction - M_PI_2));
        pa.setPoint(3, qwtPolar2Pos(p1, width / 2, direction - M_PI_2));

        painter->setPen(Qt::NoPen);
        painter->setBrush(palette.brush(colorGroup, QwtPalette::Mid));
        painter->drawPolygon(pa);
    }
    if ( hasKnob )
    {
        int knobWidth = qwtMax(qRound(width * 0.7), 5);
        if ( knobWidth % 2 == 0 )
            knobWidth++;

        drawKnob(painter, center, knobWidth, 
            palette.brush(colorGroup, QwtPalette::Base), 
            false);
    }

    painter->restore();
}

/*!
  Draw a needle looking like an arrow
*/
void QwtDialSimpleNeedle::drawArrowNeedle(QPainter *painter, 
    const QPalette &palette, QPalette::ColorGroup colorGroup,
    const QPoint &center, int length, int width,
    double direction, bool hasKnob)
{
    direction *= M_PI / 180.0;

    painter->save();

    if ( width <= 0 )
    {
        width = (int)qwtMax(length * 0.06, 9.0);
        if ( width % 2 == 0 )
            width++;
    }

    const int peak = 3;
    const QPoint p1(center.x() + 1, center.y() + 1);
    const QPoint p2 = qwtPolar2Pos(p1, length - peak, direction);
    const QPoint p3 = qwtPolar2Pos(p1, length, direction);

    QwtPolygon pa(5);
    pa.setPoint(0, qwtPolar2Pos(p1, width / 2, direction - M_PI_2));
    pa.setPoint(1, qwtPolar2Pos(p2, 1, direction - M_PI_2));
    pa.setPoint(2, p3);
    pa.setPoint(3, qwtPolar2Pos(p2, 1, direction + M_PI_2));
    pa.setPoint(4, qwtPolar2Pos(p1, width / 2, direction + M_PI_2));

    painter->setPen(Qt::NoPen);
    painter->setBrush(palette.brush(colorGroup, QwtPalette::Mid));
    painter->drawPolygon(pa);

    QwtPolygon shadowPa(3);

    const int colorOffset = 10;

    int i;
    for ( i = 0; i < 3; i++ )
        shadowPa.setPoint(i, pa[i]);

    const QColor midColor = palette.color(colorGroup, QwtPalette::Mid);

    painter->setPen(midColor.dark(100 + colorOffset));
    painter->drawPolyline(shadowPa);

    for ( i = 0; i < 3; i++ )
        shadowPa.setPoint(i, pa[i + 2]);

    painter->setPen(midColor.dark(100 - colorOffset));
    painter->drawPolyline(shadowPa);

    if ( hasKnob )
    {
        drawKnob(painter, center, qRound(width * 1.3), 
            palette.brush(colorGroup, QwtPalette::Base),
            false);
    }

    painter->restore();
}

//! Constructor

QwtCompassMagnetNeedle::QwtCompassMagnetNeedle(Style style,
        const QColor &light, const QColor &dark):
    d_style(style)
{   
    QPalette palette;
    for ( int i = 0; i < QPalette::NColorGroups; i++ )
    {
        palette.setColor((QPalette::ColorGroup)i,
            QwtPalette::Light, light);
        palette.setColor((QPalette::ColorGroup)i,
            QwtPalette::Dark, dark);
        palette.setColor((QPalette::ColorGroup)i,
            QwtPalette::Base, Qt::darkGray);
    }

    setPalette(palette); 
}

/*!
    Draw the needle

    \param painter Painter
    \param center Center of the dial, start position for the needle
    \param length Length of the needle
    \param direction Direction of the needle, in degrees counter clockwise
    \param colorGroup Color group, used for painting
*/
void QwtCompassMagnetNeedle::draw(QPainter *painter, const QPoint &center,
    int length, double direction, QPalette::ColorGroup colorGroup) const