src/kitemviews/kitemlistgroupheader.cpp

   1 /***************************************************************************
   2  *   Copyright (C) 2011 by Peter Penz <peter.penz19@gmail.com>             *
   3  *                                                                         *
   4  *   Based on the Itemviews NG project from Trolltech Labs:                *
   5  *   http://qt.gitorious.org/qt-labs/itemviews-ng                          *
   6  *                                                                         *
   7  *   This program is free software; you can redistribute it and/or modify  *
   8  *   it under the terms of the GNU General Public License as published by  *
   9  *   the Free Software Foundation; either version 2 of the License, or     *
  10  *   (at your option) any later version.                                   *
  11  *                                                                         *
  12  *   This program is distributed in the hope that it will be useful,       *
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  15  *   GNU General Public License for more details.                          *
  16  *                                                                         *
  17  *   You should have received a copy of the GNU General Public License     *
  18  *   along with this program; if not, write to the                         *
  19  *   Free Software Foundation, Inc.,                                       *
  20  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  21  ***************************************************************************/
  22
  23 #include "kitemlistgroupheader.h"
  24
  25 #include "kitemlistview.h"
  26
  27 #include <QGraphicsSceneResizeEvent>
  28 #include <QPainter>
  29 #include <QStyleOptionGraphicsItem>
  30 #include <KDebug>
  31
  32 KItemListGroupHeader::KItemListGroupHeader(QGraphicsWidget* parent) :
  33     QGraphicsWidget(parent, 0),
  34     m_dirtyCache(true),
  35     m_role(),
  36     m_data(),
  37     m_styleOption(),
  38     m_scrollOrientation(Qt::Vertical),
  39     m_leftBorderCache(0),
  40     m_rightBorderCache(0),
  41     m_outlineColor()
  42 {
  43 }
  44
  45 KItemListGroupHeader::~KItemListGroupHeader()
  46 {
  47     deleteCache();
  48 }
  49
  50 void KItemListGroupHeader::setRole(const QByteArray& role)
  51 {
  52     if (m_role != role) {
  53         const QByteArray previous = m_role;
  54         m_role = role;
  55         update();
  56         roleChanged(role, previous);
  57     }
  58 }
  59
  60 QByteArray KItemListGroupHeader::role() const
  61 {
  62     return m_role;
  63 }
  64
  65 void KItemListGroupHeader::setData(const QVariant& data)
  66 {
  67     if (m_data != data) {
  68         const QVariant previous = m_data;
  69         m_data = data;
  70         update();
  71         dataChanged(data, previous);
  72     }
  73 }
  74
  75 QVariant KItemListGroupHeader::data() const
  76 {
  77     return m_data;
  78 }
  79
  80 void KItemListGroupHeader::setStyleOption(const KItemListStyleOption& option)
  81 {
  82     const KItemListStyleOption previous = m_styleOption;
  83     m_styleOption = option;
  84     m_dirtyCache = true;
  85     styleOptionChanged(option, previous);
  86 }
  87
  88 const KItemListStyleOption& KItemListGroupHeader::styleOption() const
  89 {
  90     return m_styleOption;
  91 }
  92
  93 void KItemListGroupHeader::setScrollOrientation(Qt::Orientation orientation)
  94 {
  95     if (m_scrollOrientation != orientation) {
  96         const Qt::Orientation previous = m_scrollOrientation;
  97         m_scrollOrientation = orientation;
  98         if (orientation == Qt::Vertical) {
  99             m_dirtyCache = true;
 100         } else {
 101             deleteCache();
 102         }
 103         scrollOrientationChanged(orientation, previous);
 104     }
 105 }
 106
 107 Qt::Orientation KItemListGroupHeader::scrollOrientation() const
 108 {
 109     return m_scrollOrientation;
 110 }
 111
 112 void KItemListGroupHeader::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget)
 113 {
 114     Q_UNUSED(option);
 115     Q_UNUSED(widget);
 116
 117     if (m_scrollOrientation == Qt::Horizontal) {
 118         Q_ASSERT(!m_leftBorderCache);
 119         Q_ASSERT(!m_rightBorderCache);
 120         return;
 121     }
 122
 123     if (m_dirtyCache) {
 124         updateCache();
 125     }
 126
 127     const int leftBorderX = m_leftBorderCache->width() + 1;
 128     const int rightBorderX = size().width() - m_rightBorderCache->width() - 2;
 129
 130     painter->setPen(m_outlineColor);
 131     painter->drawLine(leftBorderX, 1, rightBorderX, 1);
 132
 133     painter->drawPixmap(1, 1, *m_leftBorderCache);
 134     painter->drawPixmap(rightBorderX, 1, *m_rightBorderCache);
 135 }
 136
 137 void KItemListGroupHeader::roleChanged(const QByteArray& current, const QByteArray& previous)
 138 {
 139     Q_UNUSED(current);
 140     Q_UNUSED(previous);
 141 }
 142
 143 void KItemListGroupHeader::dataChanged(const QVariant& current, const QVariant& previous)
 144 {
 145     Q_UNUSED(current);
 146     Q_UNUSED(previous);
 147 }
 148
 149 void KItemListGroupHeader::styleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous)
 150 {
 151     Q_UNUSED(current);
 152     Q_UNUSED(previous);
 153 }
 154
 155 void KItemListGroupHeader::scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous)
 156 {
 157     Q_UNUSED(current);
 158     Q_UNUSED(previous);
 159 }
 160
 161 void KItemListGroupHeader::resizeEvent(QGraphicsSceneResizeEvent* event)
 162 {
 163     QGraphicsWidget::resizeEvent(event);
 164     if (event->oldSize().height() != event->newSize().height()) {
 165         m_dirtyCache = true;
 166     }
 167 }
 168
 169 void KItemListGroupHeader::updateCache()
 170 {
 171     Q_ASSERT(m_dirtyCache);
 172
 173     deleteCache();
 174
 175     const int length = qMax(int(size().height() - 1), 1);
 176     m_leftBorderCache = new QPixmap(length, length);
 177     m_leftBorderCache->fill(Qt::transparent);
 178
 179     m_rightBorderCache = new QPixmap(length, length);
 180     m_rightBorderCache->fill(Qt::transparent);
 181
 182     // Calculate the outline color. No alphablending is used for
 183     // performance reasons.
 184     const QColor c1 = m_styleOption.palette.text().color();
 185     const QColor c2 = m_styleOption.palette.background().color();
 186     const int p1 = 35;
 187     const int p2 = 100 - p1;
 188     m_outlineColor = QColor((c1.red()   * p1 + c2.red()   * p2) / 100,
 189                             (c1.green() * p1 + c2.green() * p2) / 100,
 190                             (c1.blue()  * p1 + c2.blue()  * p2) / 100);
 191
 192     // The drawing code is based on the code of DolphinCategoryDrawer from Dolphin 1.7
 193     // Copyright (C) 2007 Rafael Fernández López <ereslibre@kde.org>
 194     {
 195         // Cache the left border as pixmap
 196         QPainter painter(m_leftBorderCache);
 197         painter.setPen(m_outlineColor);
 198
 199         // 1. Draw top horizontal line
 200         painter.drawLine(3, 0, length, 0);
 201
 202         // 2. Draw vertical line with gradient
 203         const QPoint start(0, 3);
 204         QLinearGradient gradient(start, QPoint(0, length));
 205         gradient.setColorAt(0, m_outlineColor);
 206         gradient.setColorAt(1, Qt::transparent);
 207         painter.fillRect(QRect(start, QSize(1, length - start.y())), gradient);
 208
 209         // 3. Draw arc
 210         painter.setRenderHint(QPainter::Antialiasing);
 211         QRectF arc(QPointF(0, 0), QSizeF(4, 4));
 212         arc.translate(0.5, 0.5);
 213         painter.drawArc(arc, 1440, 1440);
 214     }
 215
 216     {
 217         // Cache the right border as pixmap
 218         QPainter painter(m_rightBorderCache);
 219         painter.setPen(m_outlineColor);
 220
 221         // 1. Draw top horizontal line
 222         painter.drawLine(0, 0, length - 3, 0);
 223
 224         // 2. Draw vertical line with gradient
 225         const int right = length - 1;
 226         const QPoint start(right, 3);
 227         QLinearGradient gradient(start, QPoint(right, length));
 228         gradient.setColorAt(0, m_outlineColor);
 229         gradient.setColorAt(1, Qt::transparent);
 230         painter.fillRect(QRect(start, QSize(1, length - start.y())), gradient);
 231
 232         // 3. Draw arc
 233         painter.setRenderHint(QPainter::Antialiasing);
 234         QRectF arc(QPointF(length - 5, 0), QSizeF(4, 4));
 235         arc.translate(0.5, 0.5);
 236         painter.drawArc(arc, 0, 1440);
 237     }
 238
 239     m_dirtyCache = false;
 240 }
 241
 242 void KItemListGroupHeader::deleteCache()
 243 {
 244     delete m_leftBorderCache;
 245     m_leftBorderCache = 0;
 246
 247     delete m_rightBorderCache;
 248     m_rightBorderCache = 0;
 249 }
 250
 251 #include "kitemlistgroupheader.moc"