From 84e3ff88c3337db72de7458ff8c1500c0d3e11c3 Mon Sep 17 00:00:00 2001
From: Vlad Zahorodnii <vlad.zahorodnii@kde.org>
Date: Tue, 2 Jul 2024 12:07:25 +0300
Subject: [PATCH] Round X window gravity adjustment

Qt applications use Static window gravity by default. This means that if
a window decoration is created, the client window should remain at the same
position in the global coordinate space. To do that, X11Window needs to
move the frame geometry by (-borderLeft(), -borderTop()).

On the other hand, after making X11Window::framePosToClientPos() round
the window borders, the client window can end up being moved more than
expected when applying the gravity adjustment.

This change makes X11Window also round the gravity adjustment so the math
is consistent there and in the framePosToClientPos() function.

BUG: 489016
---
 src/x11window.cpp | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/src/x11window.cpp b/src/x11window.cpp
index 979f3a6bc9..b8f94df058 100644
--- a/src/x11window.cpp
+++ b/src/x11window.cpp
@@ -3948,48 +3948,48 @@ QPointF X11Window::gravityAdjustment(xcb_gravity_t gravity) const
     switch (gravity) {
     case XCB_GRAVITY_NORTH_WEST: // move down right
     default:
-        dx = borderLeft();
-        dy = borderTop();
+        dx = Xcb::nativeRound(borderLeft());
+        dy = Xcb::nativeRound(borderTop());
         break;
     case XCB_GRAVITY_NORTH: // move right
         dx = 0;
-        dy = borderTop();
+        dy = Xcb::nativeRound(borderTop());
         break;
     case XCB_GRAVITY_NORTH_EAST: // move down left
-        dx = -borderRight();
-        dy = borderTop();
+        dx = -Xcb::nativeRound(borderRight());
+        dy = Xcb::nativeRound(borderTop());
         break;
     case XCB_GRAVITY_WEST: // move right
         dx = borderLeft();
         dy = 0;
         break;
     case XCB_GRAVITY_CENTER:
-        dx = (borderLeft() - borderRight()) / 2;
-        dy = (borderTop() - borderBottom()) / 2;
+        dx = Xcb::fromXNative((int(Xcb::toXNative(borderLeft())) - int(Xcb::toXNative(borderRight()))) / 2);
+        dy = Xcb::fromXNative((int(Xcb::toXNative(borderTop())) - int(Xcb::toXNative(borderBottom()))) / 2);
         break;
     case XCB_GRAVITY_STATIC: // don't move
         dx = 0;
         dy = 0;
         break;
     case XCB_GRAVITY_EAST: // move left
-        dx = -borderRight();
+        dx = -Xcb::nativeRound(borderRight());
         dy = 0;
         break;
     case XCB_GRAVITY_SOUTH_WEST: // move up right
-        dx = borderLeft();
-        dy = -borderBottom();
+        dx = Xcb::nativeRound(borderLeft());
+        dy = -Xcb::nativeRound(borderBottom());
         break;
     case XCB_GRAVITY_SOUTH: // move up
         dx = 0;
-        dy = -borderBottom();
+        dy = -Xcb::nativeRound(borderBottom());
         break;
     case XCB_GRAVITY_SOUTH_EAST: // move up left
-        dx = -borderRight();
-        dy = -borderBottom();
+        dx = -Xcb::nativeRound(borderRight());
+        dy = -Xcb::nativeRound(borderBottom());
         break;
     }
 
-    return QPoint(dx, dy);
+    return QPointF(dx, dy);
 }
 
 const QPointF X11Window::calculateGravitation(bool invert) const
@@ -3997,8 +3997,8 @@ const QPointF X11Window::calculateGravitation(bool invert) const
     const QPointF adjustment = gravityAdjustment(m_geometryHints.windowGravity());
 
     // translate from client movement to frame movement
-    const qreal dx = adjustment.x() - borderLeft();
-    const qreal dy = adjustment.y() - borderTop();
+    const qreal dx = adjustment.x() - Xcb::nativeRound(borderLeft());
+    const qreal dy = adjustment.y() - Xcb::nativeRound(borderTop());
 
     if (!invert) {
         return QPointF(x() + dx, y() + dy);