wayland: Wire in subpixel information

kwaylandserver has all the code to send subpixel information but kwin
doesn't really use it.

src/abstract_wayland_output.cpp

@@ -132,6 +132,16 @@ void AbstractWaylandOutput::setScale(qreal scale)
     }
 }
 
+AbstractWaylandOutput::SubPixel AbstractWaylandOutput::subPixel() const
+{
+    return m_subPixel;
+}
+
+void AbstractWaylandOutput::setSubPixelInternal(SubPixel subPixel)
+{
+    m_subPixel = subPixel;
+}
+
 void AbstractWaylandOutput::applyChanges(const KWaylandServer::OutputChangeSet *changeSet)
 {
     qCDebug(KWIN_CORE) << "Apply changes to the Wayland output.";

src/abstract_wayland_output.h

@@ -68,6 +68,15 @@ public:
     };
     Q_DECLARE_FLAGS(Capabilities, Capability)
 
+    enum class SubPixel {
+        Unknown,
+        None,
+        Horizontal_RGB,
+        Horizontal_BGR,
+        Vertical_RGB,
+        Vertical_BGR,
+    };
+
     explicit AbstractWaylandOutput(QObject *parent = nullptr);
 
     QString name() const override;
@@ -111,6 +120,7 @@ public:
     bool isEnabled() const override;
     void setEnabled(bool enable) override;
 
+    SubPixel subPixel() const;
     QString description() const;
     Capabilities capabilities() const;
     QByteArray edid() const;
@@ -167,6 +177,7 @@ protected:
     void setTransformInternal(Transform transform);
     void setDpmsModeInternal(DpmsMode dpmsMode);
     void setCapabilityInternal(Capability capability, bool on = true);
+    void setSubPixelInternal(SubPixel subPixel);
 
     QSize orientateSize(const QSize &size) const;
 
@@ -186,6 +197,7 @@ private:
     QByteArray m_edid;
     QVector<Mode> m_modes;
     DpmsMode m_dpmsMode = DpmsMode::On;
+    SubPixel m_subPixel = SubPixel::Unknown;
     int m_refreshRate = -1;
     int m_recorders = 0;
     bool m_isEnabled = true;

src/plugins/platforms/drm/drm_output.cpp

@@ -185,6 +185,24 @@ quint64 refreshRateForMode(_drmModeModeInfo *m)
 }
 }
 
+static AbstractWaylandOutput::SubPixel drmSubPixelToKWinSubPixel(drmModeSubPixel subpixel)
+{
+    switch (subpixel) {
+    case DRM_MODE_SUBPIXEL_UNKNOWN:
+        return AbstractWaylandOutput::SubPixel::Unknown;
+    case DRM_MODE_SUBPIXEL_NONE:
+        return AbstractWaylandOutput::SubPixel::None;
+    case DRM_MODE_SUBPIXEL_HORIZONTAL_RGB:
+        return AbstractWaylandOutput::SubPixel::Horizontal_RGB;
+    case DRM_MODE_SUBPIXEL_HORIZONTAL_BGR:
+        return AbstractWaylandOutput::SubPixel::Horizontal_BGR;
+    case DRM_MODE_SUBPIXEL_VERTICAL_RGB:
+        return AbstractWaylandOutput::SubPixel::Vertical_RGB;
+    case DRM_MODE_SUBPIXEL_VERTICAL_BGR:
+        return AbstractWaylandOutput::SubPixel::Vertical_BGR;
+    }
+}
+
 bool DrmOutput::init(drmModeConnector *connector)
 {
     initUuid();
@@ -192,6 +210,7 @@ bool DrmOutput::init(drmModeConnector *connector)
         return false;
     }
 
+    setSubPixelInternal(drmSubPixelToKWinSubPixel(connector->subpixel));
     setInternal(m_conn->isInternal());
     setCapabilityInternal(DrmOutput::Capability::Dpms);
     initOutputDevice(connector);

src/waylandoutput.cpp

@@ -36,6 +36,26 @@ static KWaylandServer::OutputInterface::Transform kwinTransformToOutputTransform
     }
 }
 
+static KWaylandServer::OutputInterface::SubPixel kwinSubPixelToOutputSubPixel(AbstractWaylandOutput::SubPixel subPixel)
+{
+    switch (subPixel) {
+    case AbstractWaylandOutput::SubPixel::Unknown:
+        return KWaylandServer::OutputInterface::SubPixel::Unknown;
+    case AbstractWaylandOutput::SubPixel::None:
+        return KWaylandServer::OutputInterface::SubPixel::None;
+    case AbstractWaylandOutput::SubPixel::Horizontal_RGB:
+        return KWaylandServer::OutputInterface::SubPixel::HorizontalRGB;
+    case AbstractWaylandOutput::SubPixel::Horizontal_BGR:
+        return KWaylandServer::OutputInterface::SubPixel::HorizontalBGR;
+    case AbstractWaylandOutput::SubPixel::Vertical_RGB:
+        return KWaylandServer::OutputInterface::SubPixel::VerticalRGB;
+    case AbstractWaylandOutput::SubPixel::Vertical_BGR:
+        return KWaylandServer::OutputInterface::SubPixel::VerticalBGR;
+    default:
+        Q_UNREACHABLE();
+    }
+}
+
 static KWaylandServer::OutputInterface::DpmsMode kwinDpmsModeToOutputDpmsMode(AbstractWaylandOutput::DpmsMode dpmsMode)
 {
     switch (dpmsMode) {
@@ -85,6 +105,7 @@ WaylandOutput::WaylandOutput(AbstractWaylandOutput *output, QObject *parent)
     m_waylandOutput->setGlobalPosition(geometry.topLeft());
     m_waylandOutput->setScale(std::ceil(output->scale()));
     m_waylandOutput->setMode(output->modeSize(), output->refreshRate());
+    m_waylandOutput->setSubPixel(kwinSubPixelToOutputSubPixel(output->subPixel()));
 
     m_xdgOutputV1->setName(output->name());
     m_xdgOutputV1->setDescription(output->description());

src/waylandoutputdevice.cpp

@@ -15,6 +15,11 @@ static KWaylandServer::OutputDeviceInterface::Transform kwinTransformToOutputDev
     return static_cast<KWaylandServer::OutputDeviceInterface::Transform>(transform);
 }
 
+static KWaylandServer::OutputDeviceInterface::SubPixel kwinSubPixelToOutputDeviceSubPixel(AbstractWaylandOutput::SubPixel subPixel)
+{
+    return static_cast<KWaylandServer::OutputDeviceInterface::SubPixel>(subPixel);
+}
+
 WaylandOutputDevice::WaylandOutputDevice(AbstractWaylandOutput *output, QObject *parent)
     : QObject(parent)
     , m_platformOutput(output)
@@ -30,6 +35,7 @@ WaylandOutputDevice::WaylandOutputDevice(AbstractWaylandOutput *output, QObject
     m_outputDevice->setTransform(kwinTransformToOutputDeviceTransform(output->transform()));
     m_outputDevice->setEisaId(output->eisaId());
     m_outputDevice->setSerialNumber(output->serialNumber());
+    m_outputDevice->setSubPixel(kwinSubPixelToOutputDeviceSubPixel(output->subPixel()));
 
     const auto modes = output->modes();
     for (const AbstractWaylandOutput::Mode &mode : modes) {