markedscrollbar.cpp

/*
    This file is part of Marked Scroll Bar
    Copyright (C) 2009  Freddie Witherden

    Marked Scroll Bar is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    Marked Scroll Bar is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with Marked Scroll Bar.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "markedscrollbar.h"

#include <QPainter>
#include <QStyle>
#include <QStyleOptionSlider>

MarkedScrollBar::MarkedScrollBar(QWidget *parent)
 : QScrollBar(parent), m_isClipped(true)
{
}

void MarkedScrollBar::addMark(int position, const QColor& colour,
                              const QString& identifier)
{
    markData mark = { position, colour, identifier };
    m_marks.append(mark);
}

void MarkedScrollBar::removeMark(int position)
{
    QMutableListIterator<markData> i(m_marks);
    while (i.hasNext())
    {
        if (i.next().pos == position)
        {
            i.remove();
            break;
        }
    }
}

void MarkedScrollBar::removeMark(const QString& identifier)
{
    QMutableListIterator<markData> i(m_marks);
    while (i.hasNext())
    {
        if (i.next().identifier == identifier)
        {
            i.remove();
            break;
        }
    }
}

void MarkedScrollBar::removeAllMarks()
{
    m_marks.clear();
}

void MarkedScrollBar::removeMarksLessThan(int position)
{
    QMutableListIterator<markData> i(m_marks);
    while (i.hasNext())
    {
        int pos = i.next().pos;
        if (pos < position)
        {
            i.remove();
        }
    }
}

void MarkedScrollBar::removeMarksGreaterThan(int position)
{
    QMutableListIterator<markData> i(m_marks);
    while (i.hasNext())
    {
        int pos = i.next().pos;
        if (pos > position)
        {
            i.remove();
        }
    }
}

void MarkedScrollBar::removeMarksBetween(int start, int end)
{
    if (start > end)
    {
        qWarning("MarkedScrollBar::removeMarksBetween: start > end");
    }

    QMutableListIterator<markData> i(m_marks);
    while (i.hasNext())
    {
        int pos = i.next().pos;
        if (pos > start && pos < end)
        {
            i.remove();
        }
    }
}

void MarkedScrollBar::addShade(int startPos, int endPos, const QColor& colour,
                               const QString& identifier)
{
    if (startPos > endPos)
    {
        qWarning("MarkedScrollBar::addShade: bad argument, startPos > endPos");
    }

    shadeData shade = { startPos, endPos, colour, identifier };
    m_shades.append(shade);
}

void MarkedScrollBar::removeShade(const QString &identifier)
{
    QMutableListIterator<shadeData> i(m_shades);
    while (i.hasNext())
    {
        if (i.next().identifier == identifier)
        {
            i.remove();
            break;
        }
    }
}

void MarkedScrollBar::removeAllShades()
{
    m_shades.clear();
}

bool MarkedScrollBar::isClipped() const
{
   return m_isClipped;
}

void MarkedScrollBar::enableClipping(bool clip)
{
   m_isClipped = clip;
}

void MarkedScrollBar::paintEvent(QPaintEvent *event)
{
    // Draw the scrollbar control
    QScrollBar::paintEvent(event);

    // Get the style options for the control
    QStyleOptionSlider styleOption;
    initStyleOption(&styleOption);

    // Get the bounding rectangles of the add/sub pages
    QRect addPage = style()->subControlRect(QStyle::CC_ScrollBar, &styleOption,
                                            QStyle::SC_ScrollBarAddPage, this);
    QRect subPage = style()->subControlRect(QStyle::CC_ScrollBar, &styleOption,
                                            QStyle::SC_ScrollBarSubPage, this);
    QRect slider = style()->subControlRect(QStyle::CC_ScrollBar, &styleOption,
                                           QStyle::SC_ScrollBarSlider, this);


    // Create a painter to do the actual drawing
    QPainter p(this);

    // Clip it so that we do not draw over the slider
   if (isClipped())
   {
      p.setClipRegion(QRegion(addPage) + QRegion(subPage));
   }

    // The scale factor to use
    qreal sf;

    // Scale and translate the painter appropriately
    if (orientation() == Qt::Horizontal)
    {
        p.translate(qMin(subPage.left(), addPage.left()), 0.0);

        sf = (addPage.width() + subPage.width() + slider.width())
           / ((qreal) maximum() - minimum());
    }
    else // if (orientation() == Qt::Vertical)
    {
        p.translate(0.0, qMin(subPage.top(), addPage.top()));

        sf = (addPage.height() + subPage.height() + slider.height())
           / ((qreal) maximum() - minimum());
    }

    foreach (markData mark, m_marks)
    {
        p.setPen(mark.colour);

        if (orientation() == Qt::Horizontal)
        {
            p.drawLine(QPoint(mark.pos * sf, 2),
                       QPoint(mark.pos * sf, slider.height() - 3));
        }
        else if (orientation() == Qt::Vertical)
        {
            p.drawLine(QPoint(2, mark.pos * sf),
                       QPoint(slider.width() - 3, mark.pos * sf));
        }
    }

    foreach (shadeData shade, m_shades)
    {
        QColor penColour = shade.colour;
        QColor brushColour = shade.colour;
        brushColour.setAlphaF(brushColour.alphaF() * 0.45);

        p.setPen(penColour);
        p.setBrush(brushColour);

        if (orientation() == Qt::Horizontal)
        {
            p.drawRect(QRect(QPoint(shade.start * sf, 2),
                             QPoint(shade.end * sf, slider.height() - 4)));

        }
        else if (orientation() == Qt::Vertical)
        {
            p.drawRect(QRect(QPoint(2, shade.start * sf),
                             QPoint(slider.width() - 4, shade.end * sf)));
        }
    }
}

---