From e23c3a69d91a5c6f15a74b9dfb60f144c14024fc Mon Sep 17 00:00:00 2001
From: David Edmundson <kde@davidedmundson.co.uk>
Date: Fri, 20 May 2022 10:35:51 +0300
Subject: [PATCH] [Effects/blend] Let fullscreen effects take priority

The Blendchanges effect works by showing a snapshot of the current
screen for a few ms. Any other active full screen effect will look
broken, so it should take priority.

This is pre-empting an issue with a new Plasma feature that syncs
colours to wallpapers. Once we animate activity switches / have per
desktop wallpapers it'll glitch out.
---
 src/effects/blendchanges/blendchanges.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/effects/blendchanges/blendchanges.cpp b/src/effects/blendchanges/blendchanges.cpp
index 1d45aaeabd..c52bfdf281 100644
--- a/src/effects/blendchanges/blendchanges.cpp
+++ b/src/effects/blendchanges/blendchanges.cpp
@@ -41,6 +41,10 @@ void KWin::BlendChanges::start(int delay)
     if (!supported() || m_state != Off) {
         return;
     }
+    if (effects->hasActiveFullScreenEffect()) {
+        return;
+    }
+
     const EffectWindowList allWindows = effects->stackingOrder();
     for (auto window : allWindows) {
         redirect(window);