Compositor: Map touch ids to contiguous ids

The protocol doesn't require this, but some clients seem to depend on it
nevertheless.

Fixes: QTBUG-75667
Change-Id: I47491c396d3c9193c7e51e13c7ca1586246e335c
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>
(cherry picked from commit 869a38c082daf150a16b2abb230b420de3e4af31)
 

2 files changed, 20 insertions, 1 deletions

diff --git a/src/compositor/compositor_api/qwaylandtouch.cpp b/src/compositor/compositor_api/qwaylandtouch.cpp
index 3e729800..15746cb5 100644
--- a/src/compositor/compositor_api/qwaylandtouch.cpp
+++ b/src/compositor/compositor_api/qwaylandtouch.cpp
@@ -98,6 +98,20 @@ void QWaylandTouchPrivate::sendMotion(QWaylandClient *client, uint32_t time, int
                          wl_fixed_from_double(position.x()), wl_fixed_from_double(position.y()));
 }
 
+int QWaylandTouchPrivate::toSequentialWaylandId(int touchId)
+{
+    const int waylandId = ids.indexOf(touchId);
+    if (waylandId != -1)
+        return waylandId;
+    const int availableId = ids.indexOf(-1);
+    if (availableId != -1) {
+        ids[availableId] = touchId;
+        return availableId;
+    }
+    ids.append(touchId);
+    return ids.length() - 1;
+}
+
 /*!
  * \class QWaylandTouch
  * \inmodule QtWaylandCompositor
@@ -212,7 +226,10 @@ void QWaylandTouch::sendFullTouchEvent(QWaylandSurface *surface, QTouchEvent *ev
     for (int i = 0; i < pointCount; ++i) {
         const QTouchEvent::TouchPoint &tp(points.at(i));
         // Convert the local pos in the compositor window to surface-relative.
-        sendTouchPointEvent(surface, tp.id(), tp.pos(), tp.state());
+        const int id = d->toSequentialWaylandId(tp.id());
+        sendTouchPointEvent(surface, id, tp.pos(), tp.state());
+        if (tp.state() == Qt::TouchPointReleased)
+            d->ids[id] = -1;
     }
     sendFrameEvent(surface->client());
 }
diff --git a/src/compositor/compositor_api/qwaylandtouch_p.h b/src/compositor/compositor_api/qwaylandtouch_p.h
index de1b748d..0b87f847 100644
--- a/src/compositor/compositor_api/qwaylandtouch_p.h
+++ b/src/compositor/compositor_api/qwaylandtouch_p.h
@@ -80,8 +80,10 @@ public:
 
 private:
     void touch_release(Resource *resource) override;
+    int toSequentialWaylandId(int touchId);
 
     QWaylandSeat *seat = nullptr;
+    QVarLengthArray<int, 10> ids;
 };
 
 QT_END_NAMESPACE