Introducing icon theme support

Added some static functions to QIcon to support desktop
themes based on the freedesktop spec. It is not intended to
replace KIcon and the intention is to use it when available to
share icon cache between applications.

Applications currently using icon themes are Assistant, Designer
and the textedit demo.

Reviewed-by: ogoffart

1 files changed, 599 insertions, 0 deletions

diff --git a/src/gui/image/qiconloader.cpp b/src/gui/image/qiconloader.cpp
new file mode 100644
index 0000000000..6bf8d3b353
--- /dev/null
+++ b/src/gui/image/qiconloader.cpp
@@ -0,0 +1,599 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at http://www.qtsoftware.com/contact.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <private/qiconloader_p.h>
+
+#include <private/qapplication_p.h>
+#include <private/qicon_p.h>
+#include <private/qkde_p.h>
+
+#include <QtGui/QIconEnginePlugin>
+#include <QtGui/QPixmapCache>
+#include <QtGui/QIconEngine>
+#include <QtGui/QStyleOption>
+#include <QtCore/QList>
+#include <QtCore/QHash>
+#include <QtCore/QDir>
+#include <QtCore/QSettings>
+
+#ifdef Q_WS_MAC
+#include <private/qt_cocoa_helpers_mac_p.h>
+#endif
+
+#ifdef Q_WS_X11
+#include <private/qt_x11_p.h>
+#include <private/gtksymbols_p.h>
+#endif
+
+QT_BEGIN_NAMESPACE
+
+Q_GLOBAL_STATIC(QIconLoader, iconLoaderInstance)
+
+static QString systemThemeName()
+{
+    QString result;
+#ifdef Q_WS_X11
+    if (X11->desktopEnvironment == DE_GNOME) {
+        result = QGtk::getGConfString(QLatin1String("/desktop/gnome/interface/icon_theme"),
+                                      QLatin1String("gnome"));
+    } else if (X11->desktopEnvironment == DE_KDE) {
+        QString kdeDefault = X11->desktopVersion >= 4 ?
+                             QString::fromLatin1("oxygen") :
+                             QString::fromLatin1("crystalsvg");
+
+        QSettings settings(QKde::kdeHome() +
+                           QLatin1String("/share/config/kdeglobals"),
+                           QSettings::IniFormat);
+
+        settings.beginGroup(QLatin1String("Icons"));
+
+        result = settings.value(QLatin1String("Theme"), kdeDefault).toString();
+    }
+#endif
+    return result;
+}
+
+static QString fallbackTheme()
+{
+    QString defaultTheme = systemThemeName();
+    if (defaultTheme.isEmpty())
+        defaultTheme = QLatin1String("hicolor");
+    return defaultTheme;
+}
+
+QIconLoader::QIconLoader() :
+        m_themeKey(1), m_supportsSvg(false)
+{
+    m_systemTheme = systemThemeName();
+
+    QFactoryLoader iconFactoryLoader(QIconEngineFactoryInterfaceV2_iid,
+                                     QLatin1String("/iconengines"),
+                                     Qt::CaseInsensitive);
+    if (iconFactoryLoader.keys().contains(QLatin1String("svg")))
+        m_supportsSvg = true;
+}
+
+QIconLoader *QIconLoader::instance()
+{
+   return iconLoaderInstance();
+}
+
+// Queries the system theme and invalidates existing
+// icons if the theme has changed.
+void QIconLoader::updateSystemTheme()
+{
+    // Only change if this is not explicitly set by the user
+    if (m_userTheme.isEmpty()) {
+        QString theme = systemThemeName();
+        if (theme != m_systemTheme) {
+            m_systemTheme = theme;
+            invalidateKey();
+        }
+    }
+}
+
+void QIconLoader::setThemeName(const QString &themeName)
+{
+    m_userTheme = themeName;
+    invalidateKey();
+}
+
+void QIconLoader::setThemeSearchPath(const QStringList &searchPaths)
+{
+    m_iconDirs = searchPaths;
+    themeList.clear();
+    invalidateKey();
+}
+
+QStringList QIconLoader::themeSearchPaths() const
+{
+    if (m_iconDirs.isEmpty()) {
+
+#if defined(Q_WS_X11)
+
+        QString xdgDirString = QFile::decodeName(getenv("XDG_DATA_DIRS"));
+        if (xdgDirString.isEmpty())
+            xdgDirString = QLatin1String("/usr/local/share/:/usr/share/");
+
+        QStringList xdgDirs = xdgDirString.split(QLatin1Char(':'));
+
+        for (int i = 0 ; i < xdgDirs.size() ; ++i) {
+            QDir dir(xdgDirs[i]);
+            if (dir.exists())
+                m_iconDirs.append(dir.path() +
+                                  QLatin1String("/icons"));
+        }
+
+        if (X11->desktopEnvironment == DE_KDE) {
+
+            m_iconDirs << QLatin1Char(':') +
+                    QKde::kdeHome() +
+                    QLatin1String("/share/icons");
+            QStringList kdeDirs =
+                    QFile::decodeName(getenv("KDEDIRS")).split(QLatin1Char(':'));
+
+            for (int i = 0 ; i< kdeDirs.count() ; ++i) {
+                QDir dir(QLatin1Char(':') + kdeDirs.at(i) +
+                         QLatin1String("/share/icons"));
+                if (dir.exists())
+                    m_iconDirs.append(dir.path());
+            }
+        }
+
+        // Add home directory first in search path
+        QDir homeDir(QDir::homePath() + QLatin1String("/.icons"));
+        if (homeDir.exists())
+            m_iconDirs.prepend(homeDir.path());
+
+#elif defined(Q_WS_WIN)
+        m_iconDirs.append(qApp->applicationDirPath() +
+                          QLatin1String("/icons"));
+#elif defined(Q_WS_MAC)
+        m_iconDirs.append(qApp->applicationDirPath() +
+                          QLatin1String("/../Resources/icons"));
+#endif
+    }
+    return m_iconDirs;
+}
+
+QIconTheme::QIconTheme(const QString &themeName)
+        : m_valid(false)
+{
+    QFile themeIndex;
+
+    QList <QIconDirInfo> keyList;
+    QStringList iconDirs = QIcon::themeSearchPaths();
+    for ( int i = 0 ; i < iconDirs.size() ; ++i) {
+        QDir iconDir(iconDirs[i]);
+        QString themeDir = iconDir.path() + QLatin1Char('/') + themeName;
+        themeIndex.setFileName(themeDir + QLatin1String("/index.theme"));
+        if (themeIndex.exists()) {
+            m_contentDir = themeDir;
+            m_valid = true;
+            break;
+        }
+    }
+
+    if (themeIndex.exists()) {
+        const QSettings indexReader(themeIndex.fileName(), QSettings::IniFormat);
+        QStringListIterator keyIterator(indexReader.allKeys());
+        while (keyIterator.hasNext()) {
+
+            const QString key = keyIterator.next();
+            if (key.endsWith(QLatin1String("/Size"))) {
+                // Note the QSettings ini-format does not accept
+                // slashes in key names, hence we have to cheat
+                if (int size = indexReader.value(key).toInt()) {
+                    QString directoryKey = key.left(key.size() - 5);
+                    QIconDirInfo dirInfo(directoryKey);
+                    dirInfo.size = size;
+                    QString type = indexReader.value(directoryKey +
+                                                     QLatin1String("/Type")
+                                                     ).toString();
+
+                    if (type == QLatin1String("Fixed"))
+                        dirInfo.type = QIconDirInfo::Fixed;
+                    else if (type == QLatin1String("Scalable"))
+                        dirInfo.type = QIconDirInfo::Scalable;
+                    else
+                        dirInfo.type = QIconDirInfo::Threshold;
+
+                    dirInfo.threshold = indexReader.value(directoryKey +
+                                                        QLatin1String("/Threshold"),
+                                                        2).toInt();
+
+                    dirInfo.minSize = indexReader.value(directoryKey +
+                                                         QLatin1String("/MinSize"),
+                                                         size).toInt();
+
+                    dirInfo.maxSize = indexReader.value(directoryKey +
+                                                        QLatin1String("/MaxSize"),
+                                                        size).toInt();
+                    m_keyList.append(dirInfo);
+                }
+            }
+        }
+
+        // Parent themes provide fallbacks for missing icons
+        m_parents = indexReader.value(
+                QLatin1String("Icon Theme/Inherits")).toStringList();
+
+        // Ensure a default platform fallback for all themes
+        if (m_parents.isEmpty())
+            m_parents.append(fallbackTheme());
+
+        // Ensure that all themes fall back to hicolor
+        if (!m_parents.isEmpty())
+            m_parents.append(QLatin1String("hicolor"));
+    }
+}
+
+QThemeIconEntries QIconLoader::findIconHelper(const QString &themeName,
+                                 const QString &iconName,
+                                 QStringList &visited) const
+{
+    QThemeIconEntries entries;
+    Q_ASSERT(!themeName.isEmpty());
+
+    QPixmap pixmap;
+
+    // Used to protect against potential recursions
+    visited << themeName;
+
+    QIconTheme theme = themeList.value(themeName);
+    if (!theme.isValid()) {
+        theme = QIconTheme(themeName);
+        if (!theme.isValid())
+            theme = fallbackTheme();
+
+        themeList.insert(themeName, theme);
+    }
+
+    QString contentDir = theme.contentDir() + QLatin1Char('/');
+    QList<QIconDirInfo> subDirs = theme.keyList();
+
+    const QString svgext(QLatin1String(".svg"));
+    const QString pngext(QLatin1String(".png"));
+
+    // Add all relevant files
+    for (int i = 0; i < subDirs.size() ; ++i) {
+        const QIconDirInfo &dirInfo = subDirs.at(i);
+        QString subdir = dirInfo.path;
+        QDir currentDir(contentDir + subdir);
+
+        if (dirInfo.type == QIconDirInfo::Scalable && m_supportsSvg &&
+            currentDir.exists(iconName + svgext)) {
+            ScalableEntry *iconEntry = new ScalableEntry;
+            iconEntry->dir = dirInfo;
+            iconEntry->filename = currentDir.filePath(iconName + svgext);
+            entries.append(iconEntry);
+
+        } else if (currentDir.exists(iconName + pngext)) {
+            PixmapEntry *iconEntry = new PixmapEntry;
+            iconEntry->dir = dirInfo;
+            iconEntry->filename = currentDir.filePath(iconName + pngext);
+            // Notice we ensure that pixmap entries allways come before
+            // scalable to preserve search order afterwards
+            entries.prepend(iconEntry);
+        }
+    }
+
+    if (entries.isEmpty()) {
+        const QStringList parents = theme.parents();
+        // Search recursively through inherited themes
+        for (int i = 0 ; i < parents.size() ; ++i) {
+
+            const QString parentTheme = parents.at(i).trimmed();
+
+            if (!visited.contains(parentTheme)) // guard against recursion
+                entries = findIconHelper(parentTheme, iconName, visited);
+
+            if (!entries.isEmpty()) // success
+                break;
+        }
+    }
+    return entries;
+}
+
+QThemeIconEntries QIconLoader::loadIcon(const QString &name) const
+{
+    if (!themeName().isEmpty()) {
+        QStringList visited;
+        return findIconHelper(themeName(), name, visited);
+    }
+
+    return QThemeIconEntries();
+}
+
+
+// -------- Icon Loader Engine -------- //
+
+
+QIconLoaderEngine::QIconLoaderEngine(const QString& iconName)
+        : m_iconName(iconName), m_key(0)
+{
+}
+
+QIconLoaderEngine::~QIconLoaderEngine()
+{
+    while (!m_entries.isEmpty())
+        delete m_entries.takeLast();
+    Q_ASSERT(m_entries.size() == 0);
+}
+
+QIconLoaderEngine::QIconLoaderEngine(const QIconLoaderEngine &other)
+        : QIconEngineV2(other),
+        m_iconName(other.m_iconName),
+        m_key(0)
+{
+}
+
+QIconEngineV2 *QIconLoaderEngine::clone() const
+{
+    return new QIconLoaderEngine(*this);
+}
+
+bool QIconLoaderEngine::read(QDataStream &in) {
+    in >> m_iconName;
+    return true;
+}
+
+bool QIconLoaderEngine::write(QDataStream &out) const
+{
+    out << m_iconName;
+    return true;
+}
+
+bool QIconLoaderEngine::hasIcon() const
+{
+    return !(m_entries.isEmpty());
+}
+
+// Lazily load the icon
+void QIconLoaderEngine::ensureLoaded()
+{
+    if (!(iconLoaderInstance()->themeKey() == m_key)) {
+
+        while (!m_entries.isEmpty())
+            delete m_entries.takeLast();
+
+        Q_ASSERT(m_entries.size() == 0);
+        m_entries = iconLoaderInstance()->loadIcon(m_iconName);
+        m_key = iconLoaderInstance()->themeKey();
+    }
+}
+
+void QIconLoaderEngine::paint(QPainter *painter, const QRect &rect,
+                             QIcon::Mode mode, QIcon::State state)
+{
+    QSize pixmapSize = rect.size();
+#if defined(Q_WS_MAC)
+    pixmapSize *= qt_mac_get_scalefactor();
+#endif
+    painter->drawPixmap(rect, pixmap(pixmapSize, mode, state));
+}
+
+/*
+ * This algorithm is defined by the freedesktop spec:
+ * http://standards.freedesktop.org/icon-theme-spec/icon-theme-spec-latest.html
+ */
+static bool directoryMatchesSize(const QIconDirInfo &dir, int iconsize)
+{
+    if (dir.type == QIconDirInfo::Fixed) {
+        return dir.size == iconsize;
+
+    } else if (dir.type == QIconDirInfo::Scalable) {
+        return dir.size <= dir.maxSize &&
+                iconsize >= dir.minSize;
+
+    } else if (dir.type == QIconDirInfo::Threshold) {
+        return iconsize >= dir.size - dir.threshold &&
+                iconsize <= dir.size + dir.threshold;
+    }
+
+    Q_ASSERT(1); // Not a valid value
+    return false;
+}
+
+/*
+ * This algorithm is defined by the freedesktop spec:
+ * http://standards.freedesktop.org/icon-theme-spec/icon-theme-spec-latest.html
+ */
+static int directorySizeDistance(const QIconDirInfo &dir, int iconsize)
+{
+    if (dir.type == QIconDirInfo::Fixed) {
+        return qAbs(dir.size - iconsize);
+
+    } else if (dir.type == QIconDirInfo::Scalable) {
+        if (iconsize < dir.minSize)
+            return dir.minSize - iconsize;
+        else if (iconsize > dir.maxSize)
+            return iconsize - dir.maxSize;
+        else
+            return 0;
+
+    } else if (dir.type == QIconDirInfo::Threshold) {
+        if (iconsize < dir.size - dir.threshold)
+            return dir.minSize - iconsize;
+        else if (iconsize > dir.size + dir.threshold)
+            return iconsize - dir.maxSize;
+        else return 0;
+    }
+
+    Q_ASSERT(1); // Not a valid value
+    return INT_MAX;
+}
+
+QIconLoaderEngineEntry *QIconLoaderEngine::entryForSize(const QSize &size)
+{
+    int iconsize = qMin(size.width(), size.height());
+
+    // Note that m_entries are sorted so that png-files
+    // come first
+
+    // Search for exact matches first
+    for (int i = 0; i < m_entries.count(); ++i) {
+        QIconLoaderEngineEntry *entry = m_entries.at(i);
+        if (directoryMatchesSize(entry->dir, iconsize)) {
+            return entry;
+        }
+    }
+
+    // Find the minimum distance icon
+    int minimalSize = INT_MAX;
+    QIconLoaderEngineEntry *closestMatch = 0;
+    for (int i = 0; i < m_entries.count(); ++i) {
+        QIconLoaderEngineEntry *entry = m_entries.at(i);
+        int distance = directorySizeDistance(entry->dir, iconsize);
+        if (distance < minimalSize) {
+            minimalSize  = distance;
+            closestMatch = entry;
+        }
+    }
+    return closestMatch;
+}
+
+/*
+ * Returns the actual icon size. For scalable svg's this is equivalent
+ * to the requested size. Otherwise the closest match is returned.
+ *
+ * todo: the spec is a bit fuzzy in this area, but we should probably
+ * allow scaling down pixmap icons as well.
+ *
+ */
+QSize QIconLoaderEngine::actualSize(const QSize &size, QIcon::Mode mode,
+                                   QIcon::State state)
+{
+    ensureLoaded();
+
+    QIconLoaderEngineEntry *entry = entryForSize(size);
+    if (entry) {
+        const QIconDirInfo &dir = entry->dir;
+        if (dir.type == QIconDirInfo::Scalable)
+            return size;
+        else
+            return QSize(dir.size, dir.size);
+    }
+    return QIconEngineV2::actualSize(size, mode, state);
+}
+
+QPixmap PixmapEntry::pixmap(const QSize &size, QIcon::Mode mode, QIcon::State state)
+{
+    Q_UNUSED(state);
+
+    // Ensure that basePixmap is lazily initialized before generating the
+    // key, otherwise the cache key is not unique
+    if (basePixmap.isNull())
+        basePixmap.load(filename);
+
+    int actualSize = qMin(size.width(), size.height());
+    QString key = QLatin1String("$qt_theme_")
+                  + QString::number(basePixmap.cacheKey(), 16)
+                  + QLatin1Char('_')
+                  + QString::number(mode)
+                  + QLatin1Char('_')
+                  + QString::number(qApp->palette().cacheKey(), 16)
+                  + QLatin1Char('_')
+                  + QString::number(actualSize);
+
+    QPixmap cachedPixmap;
+    if (QPixmapCache::find(key, &cachedPixmap)) {
+        return cachedPixmap;
+    } else {
+        QStyleOption opt(0);
+        opt.palette = qApp->palette();
+        cachedPixmap = qApp->style()->generatedIconPixmap(mode, basePixmap, &opt);
+        QPixmapCache::insert(key, cachedPixmap);
+    }
+    return cachedPixmap;
+}
+
+QPixmap ScalableEntry::pixmap(const QSize &size, QIcon::Mode mode, QIcon::State state)
+{
+    if (svgIcon.isNull())
+        svgIcon = QIcon(filename);
+
+    // Simply reuse svg icon engine
+    return svgIcon.pixmap(size, mode, state);
+}
+
+QPixmap QIconLoaderEngine::pixmap(const QSize &size, QIcon::Mode mode,
+                                 QIcon::State state)
+{
+    ensureLoaded();
+
+    QIconLoaderEngineEntry *entry = entryForSize(size);
+    if (entry)
+        return entry->pixmap(size, mode, state);
+
+    return QPixmap();
+}
+
+QString QIconLoaderEngine::key() const
+{
+    return QLatin1String("QIconLoaderEngine");
+}
+
+void QIconLoaderEngine::virtual_hook(int id, void *data)
+{
+    ensureLoaded();
+
+    switch (id) {
+    case QIconEngineV2::AvailableSizesHook:
+        {
+            QIconEngineV2::AvailableSizesArgument &arg
+                    = *reinterpret_cast<QIconEngineV2::AvailableSizesArgument*>(data);
+            const QList<QIconDirInfo> directoryKey = iconLoaderInstance()->theme().keyList();
+            arg.sizes.clear();
+
+            // Gets all sizes from the DirectoryInfo entries
+            for (int i = 0 ; i < m_entries.size() ; ++i) {
+                int size = m_entries.at(i)->dir.size;
+                arg.sizes.append(QSize(size, size));
+            }
+        }
+        break;
+    default:
+        QIconEngineV2::virtual_hook(id, data);
+    }
+}
+
+QT_END_NAMESPACE