From 55d219429a5430eac7d568ee826339800b483dbb Mon Sep 17 00:00:00 2001
From: David Edmundson <kde@davidedmundson.co.uk>
Date: Fri, 29 Sep 2017 13:30:42 +0100
Subject: [PATCH] Don't reload background contrast effect on screen resize

Summary:
Similar to the Blur patch. Arguably rven less reason as this doesn't
have a texture the size of the workspace.

We don't need to delete and recreate the entire effect every time the
screen changes; This deletes the wayland global which causes quite a bit
of extra work for the clients.

Test Plan:
Changed resolution under X, and scale under wayland
Panel looked the same and nothing exploded

Reviewers: #plasma, graesslin

Reviewed By: #plasma, graesslin

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

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D7937
---
 effects/backgroundcontrast/contrast.cpp | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/effects/backgroundcontrast/contrast.cpp b/effects/backgroundcontrast/contrast.cpp
index a56b5f759c..3ef1cf1e0d 100644
--- a/effects/backgroundcontrast/contrast.cpp
+++ b/effects/backgroundcontrast/contrast.cpp
@@ -67,8 +67,9 @@ ContrastEffect::ContrastEffect()
     );
 
     // Fetch the contrast regions for all windows
-    foreach (EffectWindow *window, effects->stackingOrder())
+    for (EffectWindow *window: effects->stackingOrder()) {
         updateContrastRegion(window);
+    }
 }
 
 ContrastEffect::~ContrastEffect()
@@ -78,7 +79,14 @@ ContrastEffect::~ContrastEffect()
 
 void ContrastEffect::slotScreenGeometryChanged()
 {
-    effects->reloadEffect(this);
+    effects->makeOpenGLContextCurrent();
+    if (!supported()) {
+        effects->reloadEffect(this);
+        return;
+    }
+    for (EffectWindow *window: effects->stackingOrder()) {
+        updateContrastRegion(window);
+    }
 }
 
 void ContrastEffect::reconfigure(ReconfigureFlags flags)