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     delete m_leftBorderCache;
  48     delete m_rightBorderCache;
  49 }
  50
  51 void KItemListGroupHeader::setRole(const QByteArray& role)
  52 {
  53     if (m_role != role) {
  54         const QByteArray previous = m_role;
  55         m_role = role;
  56         update();
  57         roleChanged(role, previous);
  58     }
  59 }
  60
  61 QByteArray KItemListGroupHeader::role() const
  62 {
  63     return m_role;
  64 }
  65
  66 void KItemListGroupHeader::setData(const QVariant& data)
  67 {
  68     if (m_data != data) {
  69         const QVariant previous = m_data;
  70         m_data = data;
  71         update();
  72         dataChanged(data, previous);
  73     }
  74 }
  75
  76 QVariant KItemListGroupHeader::data() const
  77 {
  78     return m_data;
  79 }
  80
  81 void KItemListGroupHeader::setStyleOption(const KItemListStyleOption& option)
  82 {
  83     const KItemListStyleOption previous = m_styleOption;
  84     m_styleOption = option;
  85     m_dirtyCache = true;
  86     styleOptionChanged(option, previous);
  87 }
  88
  89 const KItemListStyleOption& KItemListGroupHeader::styleOption() const
  90 {
  91     return m_styleOption;
  92 }
  93
  94 void KItemListGroupHeader::setScrollOrientation(Qt::Orientation orientation)
  95 {
  96     if (m_scrollOrientation != orientation) {
  97         const Qt::Orientation previous = m_scrollOrientation;
  98         m_scrollOrientation = orientation;
  99         m_dirtyCache = true;
 100         scrollOrientationChanged(orientation, previous);
 101     }
 102 }
 103
 104 Qt::Orientation KItemListGroupHeader::scrollOrientation() const
 105 {
 106     return m_scrollOrientation;
 107 }
 108
 109 void KItemListGroupHeader::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget)
 110 {
 111     if (m_dirtyCache) {
 112         updateCache();
 113     }
 114
 115     Q_UNUSED(option);
 116     Q_UNUSED(widget);
 117
 118     const int leftBorderX = m_leftBorderCache->width() + 1;
 119     const int rightBorderX = size().width() - m_rightBorderCache->width() - 2;
 120
 121     painter->setPen(m_outlineColor);
 122     painter->drawLine(leftBorderX, 1, rightBorderX, 1);
 123
 124     painter->drawPixmap(1, 1, *m_leftBorderCache);
 125     painter->drawPixmap(rightBorderX, 1, *m_rightBorderCache);
 126 }
 127
 128 void KItemListGroupHeader::roleChanged(const QByteArray& current, const QByteArray& previous)
 129 {
 130     Q_UNUSED(current);
 131     Q_UNUSED(previous);
 132 }
 133
 134 void KItemListGroupHeader::dataChanged(const QVariant& current, const QVariant& previous)
 135 {
 136     Q_UNUSED(current);
 137     Q_UNUSED(previous);
 138 }
 139
 140 void KItemListGroupHeader::styleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous)
 141 {
 142     Q_UNUSED(current);
 143     Q_UNUSED(previous);
 144 }
 145
 146 void KItemListGroupHeader::scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous)
 147 {
 148     Q_UNUSED(current);
 149     Q_UNUSED(previous);
 150 }
 151
 152 void KItemListGroupHeader::resizeEvent(QGraphicsSceneResizeEvent* event)
 153 {
 154     QGraphicsWidget::resizeEvent(event);
 155     if (event->oldSize().height() != event->newSize().height()) {
 156         m_dirtyCache = true;
 157     }
 158 }
 159
 160 void KItemListGroupHeader::updateCache()
 161 {
 162     Q_ASSERT(m_dirtyCache);
 163
 164     delete m_leftBorderCache;
 165     delete m_rightBorderCache;
 166
 167     const int length = qMax(int(size().height() - 1), 1);
 168     m_leftBorderCache = new QPixmap(length, length);
 169     m_leftBorderCache->fill(Qt::transparent);
 170
 171     m_rightBorderCache = new QPixmap(length, length);
 172     m_rightBorderCache->fill(Qt::transparent);
 173
 174     // Calculate the outline color. No alphablending is used for
 175     // performance reasons.
 176     const QColor c1 = m_styleOption.palette.text().color();
 177     const QColor c2 = m_styleOption.palette.background().color();
 178     const int p1 = 35;
 179     const int p2 = 100 - p1;
 180     m_outlineColor = QColor((c1.red()   * p1 + c2.red()   * p2) / 100,
 181                             (c1.green() * p1 + c2.green() * p2) / 100,
 182                             (c1.blue()  * p1 + c2.blue()  * p2) / 100);
 183
 184     // The drawing code is based on the code of DolphinCategoryDrawer from Dolphin 1.7
 185     // Copyright (C) 2007 Rafael Fernández López <ereslibre@kde.org>
 186     {
 187         // Cache the left border as pixmap
 188         QPainter painter(m_leftBorderCache);
 189         painter.setPen(m_outlineColor);
 190
 191         // 1. Draw top horizontal line
 192         painter.drawLine(3, 0, length, 0);
 193
 194         // 2. Draw vertical line with gradient
 195         const QPoint start(0, 3);
 196         QLinearGradient gradient(start, QPoint(0, length));
 197         gradient.setColorAt(0, m_outlineColor);
 198         gradient.setColorAt(1, Qt::transparent);
 199         painter.fillRect(QRect(start, QSize(1, length - start.y())), gradient);
 200
 201         // 3. Draw arc
 202         painter.setRenderHint(QPainter::Antialiasing);
 203         QRectF arc(QPointF(0, 0), QSizeF(4, 4));
 204         arc.translate(0.5, 0.5);
 205         painter.drawArc(arc, 1440, 1440);
 206     }
 207
 208     {
 209         // Cache the right border as pixmap
 210         QPainter painter(m_rightBorderCache);
 211         painter.setPen(m_outlineColor);
 212
 213         const int right = length - 1;
 214         if (m_scrollOrientation == Qt::Vertical) {
 215             // 1. Draw top horizontal line
 216             painter.drawLine(0, 0, length - 3, 0);
 217
 218             // 2. Draw vertical line with gradient
 219             const QPoint start(right, 3);
 220             QLinearGradient gradient(start, QPoint(right, length));
 221             gradient.setColorAt(0, m_outlineColor);
 222             gradient.setColorAt(1, Qt::transparent);
 223             painter.fillRect(QRect(start, QSize(1, length - start.y())), gradient);
 224
 225             // 3. Draw arc
 226             painter.setRenderHint(QPainter::Antialiasing);
 227             QRectF arc(QPointF(length - 5, 0), QSizeF(4, 4));
 228             arc.translate(0.5, 0.5);
 229             painter.drawArc(arc, 0, 1440);
 230         } else {
 231             // Draw a horizontal gradiented line
 232             QLinearGradient gradient(QPoint(0, 0), QPoint(length, 0));
 233             gradient.setColorAt(0, m_outlineColor);
 234             gradient.setColorAt(1, Qt::transparent);
 235             painter.fillRect(QRect(QPoint(0, 0), QSize(length, 1)), gradient);
 236         }
 237     }
 238
 239     m_dirtyCache = false;
 240 }
 241
 242 #include "kitemlistgroupheader.moc"