QSystemTrayIcon uses D-Bus StatusNotifier on Linux when possible

Implementing org.kde.StatusNotifier DBus interface
http://www.freedesktop.org/wiki/Specifications/StatusNotifierItem/
as well as org.canonical.dbusmenu for the limited purpose of showing
the tray icon's context menu.  If a desktop environment (such as
KDE or Unity) has a StatusNotifierWatcher listening, then tray icon
information is sent to be displayed by the tray implementation
instead of being rendered directly in an XEmbed window.  This is
necessary because some modern tray implementations no longer provide
XEmbed "hosting".

[ChangeLog][QPA][Xcb] QSystemTrayIcon uses StatusNotifier D-Bus
protocol when the desktop environment supports it

Task-number: QTBUG-31762
Done-with: Marco Martin <mart@kde.org>
Change-Id: I3b1f744d621eefc7e9c61d1469460ebfcc77fc54
Reviewed-by: Jørgen Lind <jorgen.lind@theqtcompany.com>
Reviewed-by: Dmitry Shachnev <mitya57@gmail.com>

1 files changed, 30 insertions, 7 deletions

diff --git a/src/platformsupport/dbustray/qdbustraytypes.cpp b/src/platformsupport/dbustray/qdbustraytypes.cpp
index 0ca6669508..5100f8ee2c 100644
--- a/src/platformsupport/dbustray/qdbustraytypes.cpp
+++ b/src/platformsupport/dbustray/qdbustraytypes.cpp
@@ -32,20 +32,47 @@
 **
 ****************************************************************************/
 
+#ifndef QT_NO_SYSTEMTRAYICON
+
 #include "qdbustraytypes_p.h"
 
 #include <QDBusConnection>
+#include <QDBusMetaType>
 #include <QImage>
 #include <QIcon>
 #include <QImage>
 #include <QPixmap>
 #include <QDebug>
 #include <QtEndian>
+#include <qpa/qplatformmenu.h>
+#include "qdbusplatformmenu_p.h"
+
+QT_BEGIN_NAMESPACE
+
+static const int IconSizeLimit = 32;
+static const int IconNormalSmallSize = 22;
 
 QXdgDBusImageVector iconToQXdgDBusImageVector(const QIcon &icon)
 {
     QXdgDBusImageVector ret;
-    foreach (QSize size, icon.availableSizes()) {
+    QList<QSize> sizes = icon.availableSizes();
+
+    // Omit any size larger than 32 px, to save D-Bus bandwidth;
+    // and ensure that 22px or smaller exists, because it's a common size.
+    bool hasSmallIcon = false;
+    QList<QSize> toRemove;
+    Q_FOREACH (const QSize &size, sizes) {
+        if (size.width() <= IconNormalSmallSize)
+            hasSmallIcon = true;
+        else if (size.width() > IconSizeLimit)
+            toRemove << size;
+    }
+    Q_FOREACH (const QSize &size, toRemove)
+        sizes.removeOne(size);
+    if (!hasSmallIcon)
+        sizes.append(QSize(IconNormalSmallSize, IconNormalSmallSize));
+
+    foreach (QSize size, sizes) {
         QXdgDBusImageStruct kim;
         kim.width = size.width();
         kim.height = size.height();
@@ -155,9 +182,5 @@ const QDBusArgument &operator>>(const QDBusArgument &argument, QXdgDBusToolTipSt
     return argument;
 }
 
-void registerDBusTrayTypes()
-{
-    qDBusRegisterMetaType<QXdgDBusImageStruct>();
-    qDBusRegisterMetaType<QXdgDBusImageVector>();
-    qDBusRegisterMetaType<QXdgDBusToolTipStruct>();
-}
+QT_END_NAMESPACE
+#endif // QT_NO_SYSTEMTRAYICON