qwt_dial_needle.cpp

/* -*- 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
{
    if ( d_style == ThinStyle ) {
        drawThinNeedle(painter, palette(), colorGroup,
                       center, length, direction);
    } else {
        drawTriangleNeedle(painter, palette(), colorGroup,
                           center, length, direction);
    }
}

/*!
  Draw a compass needle

  \param painter Painter
  \param palette Palette
  \param colorGroup Color group
  \param center Center, where the needle starts
  \param length Length of the needle
  \param direction Direction
*/
void QwtCompassMagnetNeedle::drawTriangleNeedle(QPainter *painter,
        const QPalette &palette, QPalette::ColorGroup colorGroup,
        const QPoint &center, int length, double direction)
{
    const QBrush darkBrush = palette.brush(colorGroup, QwtPalette::Dark);
    const QBrush lightBrush = palette.brush(colorGroup, QwtPalette::Light);

    QBrush brush;

    const int width = qRound(length / 3.0);
    const int colorOffset =  10;

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

    const QPoint arrowCenter(center.x() + 1, center.y() + 1);

    QwtPolygon pa(3);
    pa.setPoint(0, arrowCenter);
    pa.setPoint(1, qwtDegree2Pos(arrowCenter, length, direction));

    pa.setPoint(2, qwtDegree2Pos(arrowCenter, width / 2, direction + 90.0));

    brush = darkBrush;
    brush.setColor(brush.color().dark(100 + colorOffset));
    painter->setBrush(brush);
    painter->drawPolygon(pa);

    pa.setPoint(2, qwtDegree2Pos(arrowCenter, width / 2, direction - 90.0));

    brush = darkBrush;
    brush.setColor(brush.color().dark(100 - colorOffset));
    painter->setBrush(brush);
    painter->drawPolygon(pa);

    // --

    pa.setPoint(1, qwtDegree2Pos(arrowCenter, length, direction + 180.0));

    pa.setPoint(2, qwtDegree2Pos(arrowCenter, width / 2, direction + 90.0));

    brush = lightBrush;
    brush.setColor(brush.color().dark(100 + colorOffset));
    painter->setBrush(brush);
    painter->drawPolygon(pa);

    pa.setPoint(2, qwtDegree2Pos(arrowCenter, width / 2, direction - 90.0));

    brush = lightBrush;
    brush.setColor(brush.color().dark(100 - colorOffset));
    painter->setBrush(brush);
    painter->drawPolygon(pa);

    painter->restore();
}

/*!
  Draw a compass needle

  \param painter Painter
  \param palette Palette
  \param colorGroup Color group
  \param center Center, where the needle starts
  \param length Length of the needle
  \param direction Direction
*/
void QwtCompassMagnetNeedle::drawThinNeedle(QPainter *painter,
        const QPalette &palette, QPalette::ColorGroup colorGroup,
        const QPoint &center, int length, double direction)
{
    const QBrush darkBrush = palette.brush(colorGroup, QwtPalette::Dark);
    const QBrush lightBrush = palette.brush(colorGroup, QwtPalette::Light);
    const QBrush baseBrush = palette.brush(colorGroup, QwtPalette::Base);

    const int colorOffset = 10;
    const int width = qwtMax(qRound(length / 6.0), 3);

    painter->save();

    const QPoint arrowCenter(center.x() + 1, center.y() + 1);

    drawPointer(painter, darkBrush, colorOffset,
                arrowCenter, length, width, direction);
    drawPointer(painter, lightBrush, -colorOffset,
                arrowCenter, length, width, direction + 180.0);

    drawKnob(painter, arrowCenter, width, baseBrush, true);

    painter->restore();
}

/*!
  Draw a compass needle

  \param painter Painter
  \param brush Brush
  \param colorOffset Color offset
  \param center Center, where the needle starts
  \param length Length of the needle
  \param width Width of the needle
  \param direction Direction
*/
void QwtCompassMagnetNeedle::drawPointer(
    QPainter *painter, const QBrush &brush,
    int colorOffset, const QPoint &center, int length,
    int width, double direction)
{
    painter->save();

    const int peak = qwtMax(qRound(length / 10.0), 5);

    const int knobWidth = width + 8;
    QRect knobRect(0, 0, knobWidth, knobWidth);
    knobRect.moveCenter(center);

    QwtPolygon pa(5);

    pa.setPoint(0, qwtDegree2Pos(center, width / 2, direction + 90.0));
    pa.setPoint(1, center);
    pa.setPoint(2, qwtDegree2Pos(pa.point(1), length - peak, direction));
    pa.setPoint(3, qwtDegree2Pos(center, length, direction));
    pa.setPoint(4, qwtDegree2Pos(pa.point(0), length - peak, direction));

    painter->setPen(Qt::NoPen);

    QBrush darkBrush = brush;
    darkBrush.setColor(darkBrush.color().dark(100 + colorOffset));
    painter->setBrush(darkBrush);
    painter->drawPolygon(pa);
    painter->drawPie(knobRect, qRound(direction * 16), 90 * 16);

    pa.setPoint(0, qwtDegree2Pos(center, width / 2, direction - 90.0));
    pa.setPoint(4, qwtDegree2Pos(pa.point(0), length - peak, direction));

    QBrush lightBrush = brush;
    lightBrush.setColor(lightBrush.color().dark(100 - colorOffset));
    painter->setBrush(lightBrush);
    painter->drawPolygon(pa);
    painter->drawPie(knobRect, qRound(direction * 16), -90 * 16);

    painter->restore();
}

/*!
   Constructor

   \param style Arrow style
   \param light Light color
   \param dark Dark color
*/
QwtCompassWindArrow::QwtCompassWindArrow(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);
    }

    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 QwtCompassWindArrow::draw(QPainter *painter, const QPoint &center,
                               int length, double direction, QPalette::ColorGroup colorGroup) const
{
    if ( d_style == Style1 ) {
        drawStyle1Needle(painter, palette(), colorGroup,
                         center, length, direction);
    } else {
        drawStyle2Needle(painter, palette(), colorGroup,
                         center, length, direction);
    }
}

/*!
  Draw a compass needle

 \param painter Painter
 \param palette Palette
 \param colorGroup colorGroup
 \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
*/
void QwtCompassWindArrow::drawStyle1Needle(QPainter *painter,
        const QPalette &palette, QPalette::ColorGroup colorGroup,
        const QPoint &center, int length, double direction)
{
    const QBrush lightBrush = palette.brush(colorGroup, QwtPalette::Light);

    const double AR1[] = {0, 0.4, 0.3, 1, 0.8, 1, 0.3, 0.4};
    const double AW1[] = {0, -45, -20, -15, 0, 15, 20, 45};

    const QPoint arrowCenter(center.x() + 1, center.y() + 1);

    QwtPolygon pa(8);
    pa.setPoint(0, arrowCenter);
    for (int i=1; i<8; i++) {
        const QPoint p = qwtDegree2Pos(center,
                                       AR1[i] * length, direction + AW1[i]);
        pa.setPoint(i, p);
    }

    painter->save();
    painter->setPen(Qt::NoPen);
    painter->setBrush(lightBrush);
    painter->drawPolygon(pa);
    painter->restore();
}

/*!
  Draw a compass needle

 \param painter Painter
 \param palette Palette
 \param colorGroup colorGroup
 \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
*/
void QwtCompassWindArrow::drawStyle2Needle(QPainter *painter,
        const QPalette &palette, QPalette::ColorGroup colorGroup,
        const QPoint &center, int length, double direction)
{
    const QBrush lightBrush = palette.brush(colorGroup, QwtPalette::Light);
    const QBrush darkBrush = palette.brush(colorGroup, QwtPalette::Dark);

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

    const double angle = 12.0;
    const double ratio = 0.7;

    const QPoint arrowCenter(center.x() + 1, center.y() + 1);

    QwtPolygon pa(3);

    pa.setPoint(0, center);
    pa.setPoint(2, qwtDegree2Pos(arrowCenter, ratio * length, direction));

    pa.setPoint(1, qwtDegree2Pos(arrowCenter, length, direction + angle));
    painter->setBrush(darkBrush);
    painter->drawPolygon(pa);

    pa.setPoint(1, qwtDegree2Pos(arrowCenter, length, direction - angle));
    painter->setBrush(lightBrush);
    painter->drawPolygon(pa);

    painter->restore();
}