From b0897a9aa5919178044123c22dad7e1daa10f07c Mon Sep 17 00:00:00 2001
From: Kai Uwe Broulik <kde@privat.broulik.de>
Date: Tue, 8 Aug 2023 20:02:06 +0200
Subject: [PATCH] wayland: Don't send preferred scale and transform if not
 determined yet

Rather not send anything than a potentially wrong default scale value
of 1.0 or transform of Normal.
---
 src/wayland/fractionalscale_v1_interface.cpp | 4 +++-
 src/wayland/surface_interface.cpp            | 8 ++++++--
 src/wayland/surface_interface_p.h            | 6 ++++--
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/wayland/fractionalscale_v1_interface.cpp b/src/wayland/fractionalscale_v1_interface.cpp
index fa29e3d7cd..45da57b9d9 100644
--- a/src/wayland/fractionalscale_v1_interface.cpp
+++ b/src/wayland/fractionalscale_v1_interface.cpp
@@ -49,7 +49,9 @@ FractionalScaleV1Interface::FractionalScaleV1Interface(SurfaceInterface *surface
 {
     SurfaceInterfacePrivate *surfacePrivate = SurfaceInterfacePrivate::get(surface);
     surfacePrivate->fractionalScaleExtension = this;
-    setPreferredScale(surfacePrivate->preferredBufferScale);
+    if (surfacePrivate->preferredBufferScale.has_value()) {
+        setPreferredScale(surfacePrivate->preferredBufferScale.value());
+    }
 }
 
 FractionalScaleV1Interface::~FractionalScaleV1Interface()
diff --git a/src/wayland/surface_interface.cpp b/src/wayland/surface_interface.cpp
index 144ad6bde2..262f9493df 100644
--- a/src/wayland/surface_interface.cpp
+++ b/src/wayland/surface_interface.cpp
@@ -69,8 +69,12 @@ void SurfaceInterfacePrivate::addChild(SubSurfaceInterface *child)
     cached.above.append(child);
     current.above.append(child);
     child->surface()->setOutputs(outputs);
-    child->surface()->setPreferredBufferScale(preferredBufferScale);
-    child->surface()->setPreferredBufferTransform(preferredBufferTransform);
+    if (preferredBufferScale.has_value()) {
+        child->surface()->setPreferredBufferScale(preferredBufferScale.value());
+    }
+    if (preferredBufferTransform.has_value()) {
+        child->surface()->setPreferredBufferTransform(preferredBufferTransform.value());
+    }
 
     Q_EMIT q->childSubSurfaceAdded(child);
     Q_EMIT q->childSubSurfacesChanged();
diff --git a/src/wayland/surface_interface_p.h b/src/wayland/surface_interface_p.h
index 799a9dae81..d01f7121e2 100644
--- a/src/wayland/surface_interface_p.h
+++ b/src/wayland/surface_interface_p.h
@@ -14,6 +14,8 @@
 #include <QVector>
 // Wayland
 #include "qwayland-server-wayland.h"
+// C++
+#include <optional>
 
 namespace KWaylandServer
 {
@@ -135,8 +137,8 @@ public:
     qreal pendingScaleOverride = 1.;
 
     QVector<OutputInterface *> outputs;
-    qreal preferredBufferScale = 1.0;
-    KWin::OutputTransform preferredBufferTransform = KWin::OutputTransform::Normal;
+    std::optional<qreal> preferredBufferScale;
+    std::optional<KWin::OutputTransform> preferredBufferTransform;
 
     LockedPointerV1Interface *lockedPointer = nullptr;
     ConfinedPointerV1Interface *confinedPointer = nullptr;