From 95c983e6d858afb3ba69b30aaf36db0d32600475 Mon Sep 17 00:00:00 2001
From: David Edmundson <kde@davidedmundson.co.uk>
Date: Thu, 24 Aug 2017 17:57:38 +0100
Subject: [PATCH] Handle buffer scales changing dynamically

Summary:
Currently when a client changes it's buffer size the result is corrupt
until we move the window.

When a client buffer scale changes we need to redraw the whole window,
and most importantly flush the cached window quads, which reference the
scale.

This is not handled by the doSetGeometry() from the size changing as the
normalised size of the client remains the same so it no-ops.

Test Plan:
Opened gtk3-demo and changed screen scale. It's now perfect.
Patch for Qt to work correctly incoming.

Reviewers: #plasma, graesslin

Reviewed By: #plasma, graesslin

Subscribers: graesslin, plasma-devel, kwin, #kwin

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D7486
---
 scene.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/scene.cpp b/scene.cpp
index 79147a53cd..a51bbe9be2 100644
--- a/scene.cpp
+++ b/scene.cpp
@@ -399,6 +399,10 @@ void Scene::windowAdded(Toplevel *c)
     m_windows[ c ] = w;
     connect(c, SIGNAL(geometryShapeChanged(KWin::Toplevel*,QRect)), SLOT(windowGeometryShapeChanged(KWin::Toplevel*)));
     connect(c, SIGNAL(windowClosed(KWin::Toplevel*,KWin::Deleted*)), SLOT(windowClosed(KWin::Toplevel*,KWin::Deleted*)));
+    //A change of scale won't affect the geometry in compositor co-ordinates, but will affect the window quads.
+    if (c->surface()) {
+        connect(c->surface(), &KWayland::Server::SurfaceInterface::scaleChanged, this, std::bind(&Scene::windowGeometryShapeChanged, this, c));
+    }
     c->effectWindow()->setSceneWindow(w);
     c->getShadow();
     w->updateShadow(c->shadow());