qwt_scale_draw.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
 *****************************************************************************/

// vim: expandtab

#include <qpen.h>
#include <qpainter.h>
#include "qwt_math.h"
#include "qwt_painter.h"
#include "qwt_polygon.h"
#include "qwt_scale_div.h"
#include "qwt_scale_map.h"
#include "qwt_scale_draw.h"

#if QT_VERSION < 0x040000
#include <qwmatrix.h>
#define QwtMatrix QWMatrix
#else
#include <qmatrix.h>
#define QwtMatrix QMatrix
#endif

class QwtScaleDraw::PrivateData
{
public:
    PrivateData():
        len(0),
        alignment(QwtScaleDraw::BottomScale),
        labelAlignment(0),
        labelRotation(0.0)
    {
    }

    QPoint pos;
    int len;

    Alignment alignment;

#if QT_VERSION < 0x040000
    int labelAlignment;
#else
    Qt::Alignment labelAlignment;
#endif
    double labelRotation;
};

QwtScaleDraw::QwtScaleDraw()
{
    d_data = new QwtScaleDraw::PrivateData;
    setLength(100);
}

QwtScaleDraw::QwtScaleDraw(const QwtScaleDraw &other):
    QwtAbstractScaleDraw(other)
{
    d_data = new QwtScaleDraw::PrivateData(*other.d_data);
}

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

QwtScaleDraw &QwtScaleDraw::operator=(const QwtScaleDraw &other)
{
    *(QwtAbstractScaleDraw*)this = (const QwtAbstractScaleDraw &)other;
    *d_data = *other.d_data;
    return *this;
}

QwtScaleDraw::Alignment QwtScaleDraw::alignment() const 
{
    return d_data->alignment; 
}

void QwtScaleDraw::setAlignment(Alignment align)
{
    d_data->alignment = align;
}

Qt::Orientation QwtScaleDraw::orientation() const
{
    switch(d_data->alignment)
    {
        case TopScale:
        case BottomScale:
            return Qt::Horizontal;
        case LeftScale:
        case RightScale:
        default:
            return Qt::Vertical;
    }
}

void QwtScaleDraw::getBorderDistHint(const QFont &font,
    int &start, int &end ) const
{
    start = 0;
    end = 0;
    
    if ( !hasComponent(QwtAbstractScaleDraw::Labels) )
        return;

    const QwtValueList &ticks = scaleDiv().ticks(QwtScaleDiv::MajorTick);
    if ( ticks.count() == 0 ) 
        return;

    QRect lr = labelRect(font, ticks[0]);

    // find the distance between tick and border
    int off = qwtAbs(map().transform(ticks[0]) - qRound(map().p1()));

    if ( orientation() == Qt::Vertical )
        end = lr.bottom() + 1 - off;
    else
        start = -lr.left() - off;

    const int lastTick = ticks.count() - 1;
    lr = labelRect(font, ticks[lastTick]);

    // find the distance between tick and border
    off = qwtAbs(map().transform(ticks[lastTick]) - qRound(map().p2()));

    if ( orientation() == Qt::Vertical )
        start = -lr.top() - off;
    else
        end = lr.right() + 1 - off;

    // if the distance between tick and border is larger
    // than half of the label width/height, we set to 0

    if ( start < 0 )
        start = 0;
    if ( end < 0 )
        end = 0;
}

int QwtScaleDraw::minLabelDist(const QFont &font) const
{
    if ( !hasComponent(QwtAbstractScaleDraw::Labels) )
        return 0;

    const QwtValueList &ticks = scaleDiv().ticks(QwtScaleDiv::MajorTick);
    if (ticks.count() == 0)
        return 0;

    const QFontMetrics fm(font);

    const bool vertical = (orientation() == Qt::Vertical);

    QRect bRect1;
    QRect bRect2 = labelRect(font, ticks[0]);
    if ( vertical )
    {
        bRect2.setRect(-bRect2.bottom(), 0, bRect2.height(), bRect2.width());
    }
    int maxDist = 0;

    for (uint i = 1; i < (uint)ticks.count(); i++ )
    {
        bRect1 = bRect2;
        bRect2 = labelRect(font, ticks[i]);
        if ( vertical )
        {
            bRect2.setRect(-bRect2.bottom(), 0,
                bRect2.height(), bRect2.width());
        }

        int dist = fm.leading(); // space between the labels
        if ( bRect1.right() > 0 )
            dist += bRect1.right();
        if ( bRect2.left() < 0 )
            dist += -bRect2.left();

        if ( dist > maxDist )
            maxDist = dist;
    }

    double angle = labelRotation() / 180.0 * M_PI;
    if ( vertical )
        angle += M_PI / 2;

    if ( sin(angle) == 0.0 )
        return maxDist;

    const int fmHeight = fm.ascent() - 2; 

    // The distance we need until there is
    // the height of the label font. This height is needed
    // for the neighbour labal.

    int labelDist = (int)(fmHeight / sin(angle) * cos(angle));
    if ( labelDist < 0 )
        labelDist = -labelDist;

    // The cast above floored labelDist. We want to ceil.
    labelDist++; 

    // For text orientations close to the scale orientation 

    if ( labelDist > maxDist )
        labelDist = maxDist;

    // For text orientations close to the opposite of the 
    // scale orientation

    if ( labelDist < fmHeight )
        labelDist = fmHeight;

    return labelDist;
}

int QwtScaleDraw::extent(const QPen &pen, const QFont &font) const
{
    int d = 0;

    if ( hasComponent(QwtAbstractScaleDraw::Labels) )
    {
        if ( orientation() == Qt::Vertical )
            d = maxLabelWidth(font);
        else
            d = maxLabelHeight(font);

        if ( d > 0 )
            d += spacing();
    }

    if ( hasComponent(QwtAbstractScaleDraw::Ticks) )
    {
        d += majTickLength();
    }

    if ( hasComponent(QwtAbstractScaleDraw::Backbone) )
    {
        const int pw = qwtMax( 1, pen.width() );  // penwidth can be zero
        d += pw;
    }

    d = qwtMax(d, minimumExtent());
    return d;
}

int QwtScaleDraw::minLength(const QPen &pen, const QFont &font) const
{
    int startDist, endDist;
    getBorderDistHint(font, startDist, endDist);

    const QwtScaleDiv &sd = scaleDiv();

    const uint minorCount =
        sd.ticks(QwtScaleDiv::MinorTick).count() +
        sd.ticks(QwtScaleDiv::MediumTick).count();
    const uint majorCount =
        sd.ticks(QwtScaleDiv::MajorTick).count();

    int lengthForLabels = 0;
    if ( hasComponent(QwtAbstractScaleDraw::Labels) )
    {
        if ( majorCount >= 2 )
            lengthForLabels = minLabelDist(font) * (majorCount - 1);
    }

    int lengthForTicks = 0;
    if ( hasComponent(QwtAbstractScaleDraw::Ticks) )
    {
        const int pw = qwtMax( 1, pen.width() );  // penwidth can be zero
        lengthForTicks = 2 * (majorCount + minorCount) * pw;
    }

    return startDist + endDist + qwtMax(lengthForLabels, lengthForTicks);
}

QPoint QwtScaleDraw::labelPosition( double value) const
{
    const int tval = map().transform(value);
    int dist = spacing() + 1;
    if ( hasComponent(QwtAbstractScaleDraw::Ticks) )
        dist += majTickLength();

    int px = 0;
    int py = 0;

    switch(alignment())
    {
        case RightScale:
        {
            px = d_data->pos.x() + dist;
            py = tval;
            break;
        }
        case LeftScale:
        {
            px = d_data->pos.x() - dist;
            py = tval;
            break;
        }
        case BottomScale:
        {
            px = tval;
            py = d_data->pos.y() + dist;
            break;
        }
        case TopScale:
        {
            px = tval;
            py = d_data->pos.y() - dist;
            break;
        }
    }

    return QPoint(px, py);
}

void QwtScaleDraw::drawTick(QPainter *painter, double value, int len) const
{
    if ( len <= 0 )
        return;

    int pw2 = qwtMin((int)painter->pen().width(), len) / 2;
    
    QwtScaleMap scaleMap = map();
    const QwtMetricsMap metricsMap = QwtPainter::metricsMap();
    QPoint pos = d_data->pos;

    if ( !metricsMap.isIdentity() )
    {
        /*
           The perfect position of the ticks is important.
           To avoid rounding errors we have to use 
           device coordinates.
         */
        QwtPainter::resetMetricsMap();

        pos = metricsMap.layoutToDevice(pos);
    
        if ( orientation() == Qt::Vertical )
        {
            scaleMap.setPaintInterval(
                metricsMap.layoutToDeviceY((int)scaleMap.p1()),
                metricsMap.layoutToDeviceY((int)scaleMap.p2())
            );
            len = metricsMap.layoutToDeviceX(len);
        }
        else
        {
            scaleMap.setPaintInterval(
                metricsMap.layoutToDeviceX((int)scaleMap.p1()),
                metricsMap.layoutToDeviceX((int)scaleMap.p2())
            );
            len = metricsMap.layoutToDeviceY(len);
        }
    }

    const int tval = scaleMap.transform(value);

    switch(alignment())
    {
        case LeftScale:
        {
#if QT_VERSION < 0x040000
            QwtPainter::drawLine(painter, pos.x() + pw2, tval,
                pos.x() - len - 2 * pw2, tval);
#else
            QwtPainter::drawLine(painter, pos.x() - pw2, tval,
                pos.x() - len, tval);
#endif
            break;
        }

        case RightScale:
        {
#if QT_VERSION < 0x040000
            QwtPainter::drawLine(painter, pos.x(), tval,
                pos.x() + len + pw2, tval);
#else
            QwtPainter::drawLine(painter, pos.x() + pw2, tval,
                pos.x() + len, tval);
#endif
            break;
        }
    
        case BottomScale:
        {
#if QT_VERSION < 0x040000
            QwtPainter::drawLine(painter, tval, pos.y(),
                tval, pos.y() + len + 2 * pw2);
#else
            QwtPainter::drawLine(painter, tval, pos.y() + pw2,
                tval, pos.y() + len);
#endif
            break;
        }

        case TopScale:
        {
#if QT_VERSION < 0x040000
            QwtPainter::drawLine(painter, tval, pos.y() + pw2,
                tval, pos.y() - len - 2 * pw2);
#else
            QwtPainter::drawLine(painter, tval, pos.y() - pw2,
                tval, pos.y() - len);
#endif
            break;
        }
    }
    QwtPainter::setMetricsMap(metricsMap); // restore metrics map
}

void QwtScaleDraw::drawBackbone(QPainter *painter) const
{
    const int bw2 = painter->pen().width() / 2;

    const QPoint &pos = d_data->pos;
    const int len = d_data->len - 1;

    switch(alignment())
    {
        case LeftScale:
            QwtPainter::drawLine(painter, pos.x() - bw2,
                pos.y(), pos.x() - bw2, pos.y() + len );
            break;
        case RightScale:
            QwtPainter::drawLine(painter, pos.x() + bw2,
                pos.y(), pos.x() + bw2, pos.y() + len);
            break;
        case TopScale:
            QwtPainter::drawLine(painter, pos.x(), pos.y() - bw2,
                pos.x() + len, pos.y() - bw2);
            break;
        case BottomScale:
            QwtPainter::drawLine(painter, pos.x(), pos.y() + bw2,
                pos.x() + len, pos.y() + bw2);
            break;
    }
}

void QwtScaleDraw::move(const QPoint &pos)
{
    d_data->pos = pos;
    updateMap();
}

QPoint QwtScaleDraw::pos() const
{
    return d_data->pos;
}

void QwtScaleDraw::setLength(int length)
{
    d_data->len = qwtMax(length, 10);
    updateMap();
}

int QwtScaleDraw::length() const
{
    return d_data->len;
}

void QwtScaleDraw::drawLabel(QPainter *painter, double value) const
{
    QwtText lbl = tickLabel(painter->font(), value);
    if ( lbl.isEmpty() )
        return; 

    const QPoint pos = labelPosition(value);

    QSize labelSize = lbl.textSize(painter->font());
    if ( labelSize.height() % 2 )
        labelSize.setHeight(labelSize.height() + 1);
    
    const QwtMatrix m = labelMatrix( pos, labelSize);

    painter->save();
#if QT_VERSION < 0x040000
    painter->setWorldMatrix(m, true);
#else
    painter->setMatrix(m, true);
#endif

    lbl.draw (painter, QRect(QPoint(0, 0), labelSize) );
    painter->restore();
}

QwtMatrix QwtScaleDraw::labelMatrix( 
    const QPoint &pos, const QSize &size) const
{   
    QwtMatrix m;
    m.translate(pos.x(), pos.y());
    m.rotate(labelRotation());
    
    int flags = labelAlignment();
    if ( flags == 0 )
    {
        switch(alignment())
        {
            case RightScale:
            {
                if ( flags == 0 )
                    flags = Qt::AlignRight | Qt::AlignVCenter;
                break;
            }
            case LeftScale:
            {
                if ( flags == 0 )
                    flags = Qt::AlignLeft | Qt::AlignVCenter;
                break;
            }
            case BottomScale:
            {
                if ( flags == 0 )
                    flags = Qt::AlignHCenter | Qt::AlignBottom;
                break;
            }
            case TopScale:
            {
                if ( flags == 0 )
                    flags = Qt::AlignHCenter | Qt::AlignTop;
                break;
            }
        }
    }

    const int w = size.width();
    const int h = size.height();

    int x, y;
    
    if ( flags & Qt::AlignLeft )
        x = -w;
    else if ( flags & Qt::AlignRight )
        x = -(w % 2); 
    else // Qt::AlignHCenter
        x = -(w / 2);
        
    if ( flags & Qt::AlignTop )
        y =  -h ;
    else if ( flags & Qt::AlignBottom )
        y = -(h % 2); 
    else // Qt::AlignVCenter
        y = -(h/2);
        
    m.translate(x, y);
    
    return m;
}   

QRect QwtScaleDraw::labelRect(const QFont &font, double value) const
{   
    QwtText lbl = tickLabel(font, value);
    if ( lbl.isEmpty() )
        return QRect(0, 0, 0, 0);

    const QPoint pos = labelPosition(value);

    QSize labelSize = lbl.textSize(font);
    if ( labelSize.height() % 2 )
    {
        labelSize.setHeight(labelSize.height() + 1);
    }

    const QwtMatrix m = labelMatrix(pos, labelSize);

#if 0
    QRect br = QwtMetricsMap::translate(m, QRect(QPoint(0, 0), labelSize));
#else
    QwtPolygon pol(4);
    pol.setPoint(0, 0, 0); 
    pol.setPoint(1, 0, labelSize.height() - 1 );
    pol.setPoint(2, labelSize.width() - 1, 0);
    pol.setPoint(3, labelSize.width() - 1, labelSize.height() - 1 );

    pol = QwtMetricsMap::translate(m, pol);
    QRect br = pol.boundingRect();
#endif

#if QT_VERSION < 0x040000
    br.moveBy(-pos.x(), -pos.y());
#else
    br.translate(-pos.x(), -pos.y());
#endif

    return br;
}

QSize QwtScaleDraw::labelSize(const QFont &font, double value) const
{
    return labelRect(font, value).size();
}

void QwtScaleDraw::setLabelRotation(double rotation)
{
    d_data->labelRotation = rotation;
}

double QwtScaleDraw::labelRotation() const
{
    return d_data->labelRotation;
}

#if QT_VERSION < 0x040000
void QwtScaleDraw::setLabelAlignment(int alignment)
#else
void QwtScaleDraw::setLabelAlignment(Qt::Alignment alignment)
#endif
{
    d_data->labelAlignment = alignment;
}   

#if QT_VERSION < 0x040000
int QwtScaleDraw::labelAlignment() const
#else
Qt::Alignment QwtScaleDraw::labelAlignment() const
#endif
{
    return d_data->labelAlignment;
}

int QwtScaleDraw::maxLabelWidth(const QFont &font) const
{
    int maxWidth = 0;

    const QwtValueList &ticks = scaleDiv().ticks(QwtScaleDiv::MajorTick);
    for (uint i = 0; i < (uint)ticks.count(); i++)
    {
        const double v = ticks[i];
        if ( scaleDiv().contains(v) )
        {
            const int w = labelSize(font, ticks[i]).width();
            if ( w > maxWidth )
                maxWidth = w;
        }
    }

    return maxWidth;
}

int QwtScaleDraw::maxLabelHeight(const QFont &font) const
{
    int maxHeight = 0;
    
    const QwtValueList &ticks = scaleDiv().ticks(QwtScaleDiv::MajorTick);
    for (uint i = 0; i < (uint)ticks.count(); i++)
    {
        const double v = ticks[i];
        if ( scaleDiv().contains(v) )
        {
            const int h = labelSize(font, ticks[i]).height();
            if ( h > maxHeight )
                maxHeight = h; 
        }       
    }   
    
    return maxHeight;
}   

void QwtScaleDraw::updateMap()
{
    QwtScaleMap &sm = scaleMap();
    if ( orientation() == Qt::Vertical )
        sm.setPaintInterval(d_data->pos.y() + d_data->len - 1, d_data->pos.y());
    else
        sm.setPaintInterval(d_data->pos.x(), d_data->pos.x() + d_data->len - 1);
}

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