wasm: fix touch -> mouse event synth on Safari

Mobile Safari generates touch pointer events with negative
pointer id's, which causes processTochEvent() to skip
the event instead of synthesizing a mouse event.

Ensure that the id's are always positive by taking the
absolute value of the event.

Change-Id: I1514329dc76ecc4b9103f7deca9642aaf304df8b
Reviewed-by: Piotr Wierciński <[email protected]>
Reviewed-by: Lorn Potter <[email protected]>
(cherry picked from commit 7a31911b795a3d07c6cba3af8436c3a38673689e)
Reviewed-by: Qt Cherry-pick Bot <[email protected]>

1 files changed, 4 insertions, 1 deletions

diff --git a/src/plugins/platforms/wasm/qwasmwindowclientarea.cpp b/src/plugins/platforms/wasm/qwasmwindowclientarea.cpp
index e3b681adb5e..83b7dbd5304 100644
--- a/src/plugins/platforms/wasm/qwasmwindowclientarea.cpp
+++ b/src/plugins/platforms/wasm/qwasmwindowclientarea.cpp
@@ -105,7 +105,10 @@ bool ClientArea::deliverEvent(const PointerEvent &event)
                               .insert(event.pointerId, QWindowSystemInterface::TouchPoint())
                               .value();
 
-        touchPoint->id = event.pointerId;
+        // Assign touch point id. TouchPoint::id is int, but QGuiApplicationPrivate::processTouchEvent()
+        // will not synthesize mouse events for touch points with negative id; use the absolute value for
+        // the touch point id.
+        touchPoint->id = qAbs(event.pointerId);
 
         touchPoint->state = QEventPoint::State::Pressed;
     }