src/UiUtils/IconLoader.cpp

   1 /* Copyright (C) 2006 - 2015 Jan Kundrát <jkt@kde.org>
   2
   3    This file is part of the Trojita Qt IMAP e-mail client,
   4    http://trojita.flaska.net/
   5
   6    This program is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU General Public License as
   8    published by the Free Software Foundation; either version 2 of
   9    the License or (at your option) version 3 or any later version
  10    accepted by the membership of KDE e.V. (or its successor approved
  11    by the membership of KDE e.V.), which shall act as a proxy
  12    defined in Section 14 of version 3 of the license.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "IconLoader.h"
  24 #include <QFileInfo>
  25 #include <QHash>
  26
  27 namespace UiUtils {
  28
  29 /** @short Wrapper around the QIcon::fromTheme with sane fallback
  30  *
  31  * The issue with the QIcon::fromTheme is that it does not really work on non-X11
  32  * platforms, unless you ship your own theme index and specify your theme name.
  33  * In Trojitá, we do not really want to hardcode anything, because the
  34  * preference is to use whatever is available from the current theme, but *also*
  35  * provide an icon as a fallback. And that is exactly why this function is here.
  36  *
  37  * It is implemented inline in order to prevent a dependency from the Imap lib
  38  * into the Gui lib.
  39  * */
  40 QIcon loadIcon(const QString &name)
  41 {
  42     static QHash<QString, QIcon> iconDict;
  43     QHash<QString, QIcon>::const_iterator it = iconDict.constFind(name);
  44     if (it != iconDict.constEnd())
  45         return *it;
  46
  47     auto overrideIcon = QStringLiteral(":/icons/%1/%2.svg").arg(QIcon::themeName(), name);
  48     if (QFileInfo(overrideIcon).exists()) {
  49         QIcon icon(overrideIcon);
  50         iconDict.insert(name, icon);
  51         return icon;
  52     }
  53
  54     QString iconInTheme = name;
  55     if (QIcon::themeName().toLower() == QLatin1String("breeze")) {
  56         if (name == QLatin1String("mail-flagged")) {
  57             iconInTheme = QStringLiteral("flag-yellow");
  58         } else if (name == QLatin1String("folder-bookmark")) {
  59             iconInTheme = QStringLiteral("folder-blue");
  60         } else if (name == QLatin1String("folder-open")) {
  61             iconInTheme = QStringLiteral("folder");
  62         } else if (name == QLatin1String("mail-read")) {
  63             iconInTheme = QStringLiteral("mail-mark-read");
  64         } else if (name == QLatin1String("mail-unread")) {
  65             iconInTheme = QStringLiteral("mail-mark-unread");
  66         }
  67     }
  68
  69     // A QIcon(QString) constructor creates non-null QIcons, even though the resulting icon will
  70     // not ever return a valid and usable pixmap. This means that we have to actually look at the
  71     // icon's pixmap to find out what to return.
  72     // If we do not do that, the GUI shows empty pixmaps instead of a text fallback, which is
  73     // clearly suboptimal.
  74     QIcon res = QIcon::fromTheme(iconInTheme, QIcon(QString::fromUtf8(":/icons/%1").arg(name)));
  75     if (res.pixmap(QSize(16, 16)).isNull()) {
  76         res = QIcon();
  77     }
  78     iconDict.insert(name, res);
  79     return res;
  80 }
  81
  82 }