Fix T76699: Support macOS inbetween mouse/tablet.

Coalescing on macOS overwrites a singular unprocessed mouse event. To
receive all mouse and tablet events coalescing is disabled.

Disabling coalescing for macOS disables coalescing for trackpad
gestures. Repeat trackpad events are unnecessary and found to
negatively impact performance thus are re-coalesced in Window Manager.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D9574

1 files changed, 29 insertions, 5 deletions

diff --git a/source/blender/windowmanager/intern/wm_event_system.c b/source/blender/windowmanager/intern/wm_event_system.c
index bf970aa2034..1aaefeabd08 100644
--- a/source/blender/windowmanager/intern/wm_event_system.c
+++ b/source/blender/windowmanager/intern/wm_event_system.c
@@ -180,6 +180,14 @@ void wm_event_free(wmEvent *event)
   MEM_freeN(event);
 }
 
+static void wm_event_free_last(wmWindow *win)
+{
+  wmEvent *event = BLI_poptail(&win->queue);
+  if (event != NULL) {
+    wm_event_free(event);
+  }
+}
+
 void wm_event_free_all(wmWindow *win)
 {
   wmEvent *event;
@@ -4306,6 +4314,26 @@ static wmEvent *wm_event_add_mousemove(wmWindow *win, const wmEvent *event)
   return event_new;
 }
 
+static wmEvent *wm_event_add_trackpad(wmWindow *win, const wmEvent *event, int deltax, int deltay)
+{
+  /* Ignore in between trackpad events for performance, we only need high accuracy
+   * for painting with mouse moves, for navigation using the accumulated value is ok. */
+  wmEvent *event_last = win->queue.last;
+  if (event_last && event_last->type == event->type) {
+    deltax += event_last->x - event_last->prevx;
+    deltay += event_last->y - event_last->prevy;
+
+    wm_event_free_last(win);
+  }
+
+  /* Set prevx/prevy, the delta is computed from this in operators. */
+  wmEvent *event_new = wm_event_add(win, event);
+  event_new->prevx = event_new->x - deltax;
+  event_new->prevy = event_new->y - deltay;
+
+  return event_new;
+}
+
 /* Windows store own event queues, no bContext here. */
 /* Time is in 1000s of seconds, from Ghost. */
 void wm_event_add_ghostevent(wmWindowManager *wm, wmWindow *win, int type, void *customdata)
@@ -4393,14 +4421,10 @@ void wm_event_add_ghostevent(wmWindowManager *wm, wmWindow *win, int type, void
       event.y = evt->y = pd->y;
       event.val = KM_NOTHING;
 
-      /* Use prevx/prevy so we can calculate the delta later. */
-      event.prevx = event.x - pd->deltaX;
-      event.prevy = event.y - (-pd->deltaY);
-
       /* The direction is inverted from the device due to system preferences. */
       event.is_direction_inverted = pd->isDirectionInverted;
 
-      wm_event_add(win, &event);
+      wm_event_add_trackpad(win, &event, pd->deltaX, -pd->deltaY);
       break;
     }
     /* Mouse button. */