1 files changed, 27 insertions, 13 deletions

diff --git a/src/plugins/platforms/xcb/qxcbscreen.cpp b/src/plugins/platforms/xcb/qxcbscreen.cpp
index e637ed827c..9edba7257e 100644
--- a/src/plugins/platforms/xcb/qxcbscreen.cpp
+++ b/src/plugins/platforms/xcb/qxcbscreen.cpp
@@ -114,17 +114,13 @@ QXcbVirtualDesktop::QXcbVirtualDesktop(QXcbConnection *connection, xcb_screen_t
     }
 
     auto dpiChangedCallback = [](QXcbVirtualDesktop *desktop, const QByteArray &, const QVariant &property, void *) {
-        bool ok;
-        int dpiTimes1k = property.toInt(&ok);
-        if (!ok)
+        if (!desktop->setDpiFromXSettings(property))
             return;
-        int dpi = dpiTimes1k / 1024;
-        if (desktop->m_forcedDpi == dpi)
-            return;
-        desktop->m_forcedDpi = dpi;
+        const auto dpi = desktop->forcedDpi();
         for (QXcbScreen *screen : desktop->connection()->screens())
             QWindowSystemInterface::handleScreenLogicalDotsPerInchChange(screen->QPlatformScreen::screen(), dpi, dpi);
     };
+    setDpiFromXSettings(xSettings()->setting("Xft/DPI"));
     xSettings()->registerCallbackForProperty("Xft/DPI", dpiChangedCallback, nullptr);
 }
 
@@ -275,7 +271,7 @@ void QXcbVirtualDesktop::handleScreenChange(xcb_randr_screen_change_notify_event
     _NET_WORKAREA means with multiple attached monitors. This gets worse when monitors have
     different dimensions and/or screens are not virtually aligned. In Qt we want the available
     geometry per monitor (QScreen), not desktop (represented by _NET_WORKAREA). WM specification
-    does not have an atom for this. Thus, QScreen is limted by the lack of support from the
+    does not have an atom for this. Thus, QScreen is limited by the lack of support from the
     underlying system.
 
     One option could be that Qt does WM's job of calculating this by subtracting geometries of
@@ -301,7 +297,7 @@ QRect QXcbVirtualDesktop::getWorkArea() const
         uint32_t *geom = (uint32_t*)xcb_get_property_value(workArea.get());
         r = QRect(geom[0], geom[1], geom[2], geom[3]);
     } else {
-        r = QRect(QPoint(), size());
+        r.setWidth(-1);
     }
     return r;
 }
@@ -316,6 +312,11 @@ void QXcbVirtualDesktop::updateWorkArea()
     }
 }
 
+QRect QXcbVirtualDesktop::availableGeometry(const QRect &screenGeometry) const
+{
+    return m_workArea.width() >= 0 ? screenGeometry & m_workArea : screenGeometry;
+}
+
 static inline QSizeF sizeInMillimeters(const QSize &size, const QDpi &dpi)
 {
     return QSizeF(Q_MM_PER_INCH * size.width() / dpi.first,
@@ -420,6 +421,19 @@ void QXcbVirtualDesktop::readXResources()
     }
 }
 
+bool QXcbVirtualDesktop::setDpiFromXSettings(const QVariant &property)
+{
+    bool ok;
+    int dpiTimes1k = property.toInt(&ok);
+    if (!ok)
+        return false;
+    int dpi = dpiTimes1k / 1024;
+    if (m_forcedDpi == dpi)
+        return false;
+    m_forcedDpi = dpi;
+    return true;
+}
+
 QSurfaceFormat QXcbVirtualDesktop::surfaceFormatFor(const QSurfaceFormat &format) const
 {
     const xcb_visualid_t xcb_visualid = connection()->hasDefaultVisualId() ? connection()->defaultVisualId()
@@ -533,7 +547,7 @@ QXcbScreen::QXcbScreen(QXcbConnection *connection, QXcbVirtualDesktop *virtualDe
     } else if (xineramaScreenInfo) {
         m_geometry = QRect(xineramaScreenInfo->x_org, xineramaScreenInfo->y_org,
                            xineramaScreenInfo->width, xineramaScreenInfo->height);
-        m_availableGeometry = m_geometry & m_virtualDesktop->workArea();
+        m_availableGeometry = m_virtualDesktop->availableGeometry(m_geometry);
         m_sizeMillimeters = sizeInMillimeters(m_geometry.size(), m_virtualDesktop->dpi());
         if (xineramaScreenIdx > -1)
             m_outputName += QLatin1Char('-') + QString::number(xineramaScreenIdx);
@@ -543,7 +557,7 @@ QXcbScreen::QXcbScreen(QXcbConnection *connection, QXcbVirtualDesktop *virtualDe
         m_geometry = QRect(QPoint(), virtualDesktop->size());
 
     if (m_availableGeometry.isEmpty())
-        m_availableGeometry = m_geometry & m_virtualDesktop->workArea();
+        m_availableGeometry = m_virtualDesktop->availableGeometry(m_geometry);
 
     if (m_sizeMillimeters.isEmpty())
         m_sizeMillimeters = virtualDesktop->physicalSize();
@@ -789,7 +803,7 @@ void QXcbScreen::updateGeometry(const QRect &geometry, uint8_t rotation)
         m_sizeMillimeters = sizeInMillimeters(geometry.size(), m_virtualDesktop->dpi());
 
     m_geometry = geometry;
-    m_availableGeometry = geometry & m_virtualDesktop->workArea();
+    m_availableGeometry = m_virtualDesktop->availableGeometry(m_geometry);
     QWindowSystemInterface::handleScreenGeometryChange(QPlatformScreen::screen(), m_geometry, m_availableGeometry);
     if (m_orientation != oldOrientation)
         QWindowSystemInterface::handleScreenOrientationChange(QPlatformScreen::screen(), m_orientation);
@@ -797,7 +811,7 @@ void QXcbScreen::updateGeometry(const QRect &geometry, uint8_t rotation)
 
 void QXcbScreen::updateAvailableGeometry()
 {
-    QRect availableGeometry = m_geometry & m_virtualDesktop->workArea();
+    QRect availableGeometry = m_virtualDesktop->availableGeometry(m_geometry);
     if (m_availableGeometry != availableGeometry) {
         m_availableGeometry = availableGeometry;
         QWindowSystemInterface::handleScreenGeometryChange(QPlatformScreen::screen(), m_geometry, m_availableGeometry);