From 92eb2f691bb773744a8e427bd13ea32ba39d5078 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Wed, 14 Feb 2024 10:01:30 +0100
Subject: [PATCH] QGuiApplication: copy a Prealloc value instead of hard-coding
 16

The EventPointMap QPointingDevicePrivate::activePoints is actually a
QVarLengthFlatMap<., ., 20>, not 16, so copy the value instead of just
hard-coding something.

Amends 296ede3aab2c0cc1acd28a2adb3017ac74d7ed6b.

Change-Id: Ic8e83f4095f57be74f7708d5cec6a19971772b76
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
---
 src/gui/kernel/qguiapplication.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index 60b6c58b455..094da531ee2 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -2934,7 +2934,8 @@ void QGuiApplicationPrivate::processTouchEvent(QWindowSystemInterfacePrivate::To
         // Send the TouchCancel to all windows with active touches and clean up.
         QTouchEvent touchEvent(QEvent::TouchCancel, device, e->modifiers);
         touchEvent.setTimestamp(e->timestamp);
-        QMinimalVarLengthFlatSet<QWindow *, 16> windowsNeedingCancel;
+        constexpr qsizetype Prealloc = decltype(devPriv->activePoints)::mapped_container_type::PreallocatedSize;
+        QMinimalVarLengthFlatSet<QWindow *, Prealloc> windowsNeedingCancel;
 
         for (auto &epd : devPriv->activePoints.values()) {
             if (QWindow *w = QMutableEventPoint::window(epd.eventPoint))