qwt_dial_needle.cpp

QWT5.01用于Qt开发的二维图形库程序

{
    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();
}