From 67b2746ecdfd4c343db9d3fca088ae86d80a57f0 Mon Sep 17 00:00:00 2001
From: Vlad Zagorodniy <vladzzag@gmail.com>
Date: Fri, 3 May 2019 16:36:18 +0300
Subject: [PATCH] Compute correct boundaries in checkWorkspacePosition

Summary:
When a client sets a strut, checkWorkspacePosition will be called to
bump clients that touch corresponding screen edge.

In order to do that, checkWorkspacePosition needs to calculate client
boundaries before and after the restricted move area was changed. As it
turns out, if the client reserves space "between" screens, calculated
boundaries can be incorrect, which may lead to some funky results, e.g.
shrunken clients.

For example, let's say that there is a dual-monitor setup. If a client
reserves some amount of space at the right border of the left screen,
then clients on the right monitor will have rightMax which is equal to
the x coordinate of screenArea.

To fix that, this change ensures that only restricted areas belonging
to the same screen as the client are taken into account when computing
the boundaries.

BUG: 404837
BUG: 406573

Reviewers: #kwin, davidedmundson

Reviewed By: #kwin, davidedmundson

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D20987
---
 geometry.cpp | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/geometry.cpp b/geometry.cpp
index 0a8613187f..e971f9488f 100644
--- a/geometry.cpp
+++ b/geometry.cpp
@@ -1141,14 +1141,9 @@ void AbstractClient::checkWorkspacePosition(QRect oldGeometry, int oldDesktop, Q
     // Old and new maximums have different starting values so windows on the screen
     // edge will move when a new strut is placed on the edge.
     QRect oldScreenArea;
-    QRect oldGeomTall;
-    QRect oldGeomWide;
-    const auto displaySize = screens()->displaySize();
     if( workspace()->inUpdateClientArea()) {
         // we need to find the screen area as it was before the change
         oldScreenArea = QRect( 0, 0, workspace()->oldDisplayWidth(), workspace()->oldDisplayHeight());
-        oldGeomTall = QRect(oldGeometry.x(), 0, oldGeometry.width(), workspace()->oldDisplayHeight());   // Full screen height
-        oldGeomWide = QRect(0, oldGeometry.y(), workspace()->oldDisplayWidth(), oldGeometry.height());   // Full screen width
         int distance = INT_MAX;
         foreach(const QRect &r, workspace()->previousScreenSizes()) {
             int d = r.contains( oldGeometry.center()) ? 0 : ( r.center() - oldGeometry.center()).manhattanLength();
@@ -1159,9 +1154,9 @@ void AbstractClient::checkWorkspacePosition(QRect oldGeometry, int oldDesktop, Q
         }
     } else {
         oldScreenArea = workspace()->clientArea(ScreenArea, oldGeometry.center(), oldDesktop);
-        oldGeomTall = QRect(oldGeometry.x(), 0, oldGeometry.width(), displaySize.height());   // Full screen height
-        oldGeomWide = QRect(0, oldGeometry.y(), displaySize.width(), oldGeometry.height());   // Full screen width
     }
+    const QRect oldGeomTall = QRect(oldGeometry.x(), oldScreenArea.y(), oldGeometry.width(), oldScreenArea.height());   // Full screen height
+    const QRect oldGeomWide = QRect(oldScreenArea.x(), oldGeometry.y(), oldScreenArea.width(), oldGeometry.height());   // Full screen width
     int oldTopMax = oldScreenArea.y();
     int oldRightMax = oldScreenArea.x() + oldScreenArea.width();
     int oldBottomMax = oldScreenArea.y() + oldScreenArea.height();
@@ -1173,8 +1168,8 @@ void AbstractClient::checkWorkspacePosition(QRect oldGeometry, int oldDesktop, Q
     int leftMax = screenArea.x();
     QRect newGeom = geometryRestore(); // geometry();
     QRect newClientGeom = newGeom.adjusted(border[Left], border[Top], -border[Right], -border[Bottom]);
-    const QRect newGeomTall = QRect(newGeom.x(), 0, newGeom.width(), displaySize.height());   // Full screen height
-    const QRect newGeomWide = QRect(0, newGeom.y(), displaySize.width(), newGeom.height());   // Full screen width
+    const QRect newGeomTall = QRect(newGeom.x(), screenArea.y(), newGeom.width(), screenArea.height());   // Full screen height
+    const QRect newGeomWide = QRect(screenArea.x(), newGeom.y(), screenArea.width(), newGeom.height());   // Full screen width
     // Get the max strut point for each side where the window is (E.g. Highest point for
     // the bottom struts bounded by the window's left and right sides).