[gtk+] added NSEventTypeMagnify and NSEventTypeRotate for ZOOM and ROTATE gestures

[Matthias Clasen <matthiasc src gnome org>]

commit 887905288763da0378162dc1e67560320dd7709d
Author: Friedrich Beckmann <friedrich beckmann gmx de>
Date:   Thu Jan 7 15:51:31 2016 +0100

    added NSEventTypeMagnify and NSEventTypeRotate for ZOOM and ROTATE gestures
    
    MacOS provides the NSEventTypeMagnify which is very similar to the
    Gtk ZOOM gesture and NSEventTypeRotate which is very similar to the
    Gtk Rotate gesture. Those two event sequences are translated to a
    sequence of GDK_TOUCHPAD_PINCH events. This sequence is then detected
    in the upper gtk layers as Gtk Zoom/Rotate Gestures.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=760276

 gdk/quartz/gdkevents-quartz.c |  124 ++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 123 insertions(+), 1 deletions(-)
---
diff --git a/gdk/quartz/gdkevents-quartz.c b/gdk/quartz/gdkevents-quartz.c
index 7bde85c..c8f1c19 100644
--- a/gdk/quartz/gdkevents-quartz.c
+++ b/gdk/quartz/gdkevents-quartz.c
@@ -353,6 +353,9 @@ get_event_mask_from_ns_event (NSEvent *nsevent)
 
        return mask;
       }
+    case NSEventTypeMagnify:
+    case NSEventTypeRotate:
+      return GDK_TOUCHPAD_GESTURE_MASK;
     case NSKeyDown:
     case NSKeyUp:
     case NSFlagsChanged:
@@ -829,6 +832,8 @@ find_window_for_ns_event (NSEvent *nsevent,
     case NSLeftMouseDragged:
     case NSRightMouseDragged:
     case NSOtherMouseDragged:
+    case NSEventTypeMagnify:
+    case NSEventTypeRotate:
       return find_toplevel_for_mouse_event (nsevent, x, y);
       
     case NSMouseEntered:
@@ -888,6 +893,114 @@ fill_crossing_event (GdkWindow       *toplevel,
   /* FIXME: Focus and button state? */
 }
 
+/* fill_pinch_event handles the conversion from the two OSX gesture events
+   NSEventTypeMagnfiy and NSEventTypeRotate to the GDK_TOUCHPAD_PINCH event.
+   The normal behavior of the OSX events is that they produce as sequence of
+     1 x NSEventPhaseBegan,
+     n x NSEventPhaseChanged,
+     1 x NSEventPhaseEnded
+   This can happen for both the Magnify and the Rotate events independently.
+   As both events are summarized in one GDK_TOUCHPAD_PINCH event sequence, a
+   little state machine handles the case of two NSEventPhaseBegan events in
+   a sequence, e.g. Magnify(Began), Magnify(Changed)..., Rotate(Began)...
+   such that PINCH(STARTED), PINCH(UPDATE).... will not show a second
+   PINCH(STARTED) event.
+*/
+#ifdef AVAILABLE_MAC_OS_X_VERSION_10_7_AND_LATER
+static void
+fill_pinch_event (GdkWindow *window,
+                  GdkEvent  *event,
+                  NSEvent   *nsevent,
+                  gint       x,
+                  gint       y,
+                  gint       x_root,
+                  gint       y_root)
+{
+  static double last_scale = 1.0;
+  static enum {
+    FP_STATE_IDLE,
+    FP_STATE_UPDATE
+  } last_state = FP_STATE_IDLE;
+
+  event->any.type = GDK_TOUCHPAD_PINCH;
+  event->touchpad_pinch.window = window;
+  event->touchpad_pinch.time = get_time_from_ns_event (nsevent);
+  event->touchpad_pinch.x = x;
+  event->touchpad_pinch.y = y;
+  event->touchpad_pinch.x_root = x_root;
+  event->touchpad_pinch.y_root = y_root;
+  event->touchpad_pinch.state = get_keyboard_modifiers_from_ns_event (nsevent);
+  event->touchpad_pinch.n_fingers = 2;
+  event->touchpad_pinch.dx = 0.0;
+  event->touchpad_pinch.dy = 0.0;
+  gdk_event_set_device (event, _gdk_display->core_pointer);
+
+  switch ([nsevent phase])
+    {
+    case NSEventPhaseBegan:
+      switch (last_state)
+        {
+        case FP_STATE_IDLE:
+          event->touchpad_pinch.phase = GDK_TOUCHPAD_GESTURE_PHASE_BEGIN;
+          last_state = FP_STATE_UPDATE;
+          last_scale = 1.0;
+          break;
+        case FP_STATE_UPDATE:
+          /* We have already received a PhaseBegan event but no PhaseEnded
+             event. This can happen, e.g. Magnify(Began), Magnify(Change)...
+             Rotate(Began), Rotate (Change),...., Magnify(End) Rotate(End)
+          */
+          event->touchpad_pinch.phase = GDK_TOUCHPAD_GESTURE_PHASE_UPDATE;
+          break;
+        }
+      break;
+    case NSEventPhaseChanged:
+      event->touchpad_pinch.phase = GDK_TOUCHPAD_GESTURE_PHASE_UPDATE;
+      break;
+    case NSEventPhaseEnded:
+      event->touchpad_pinch.phase = GDK_TOUCHPAD_GESTURE_PHASE_END;
+      switch (last_state)
+        {
+        case FP_STATE_IDLE:
+          /* We are idle but have received a second PhaseEnded event.
+             This can happen because we have Magnify and Rotate OSX
+             event sequences. We just send a second end GDK_PHASE_END.
+          */
+          break;
+        case FP_STATE_UPDATE:
+          last_state = FP_STATE_IDLE;
+          break;
+        }
+      break;
+    case NSEventPhaseCancelled:
+      event->touchpad_pinch.phase = GDK_TOUCHPAD_GESTURE_PHASE_CANCEL;
+      last_state = FP_STATE_IDLE;
+      break;
+    case NSEventPhaseMayBegin:
+    case NSEventPhaseStationary:
+      event->touchpad_pinch.phase = GDK_TOUCHPAD_GESTURE_PHASE_CANCEL;
+      break;
+    default:
+      g_assert_not_reached ();
+      break;
+    }
+
+  switch ([nsevent type])
+    {
+    case NSEventTypeMagnify:
+      last_scale *= [nsevent magnification] + 1.0;
+      event->touchpad_pinch.angle_delta = 0.0;
+      break;
+    case NSEventTypeRotate:
+      event->touchpad_pinch.angle_delta = - [nsevent rotation] * G_PI / 180.0;
+      break;
+    default:
+      g_assert_not_reached ();
+    }
+  event->touchpad_pinch.scale = last_scale;
+}
+#endif /* OSX Version >= 10.7 */
+
 static void
 fill_button_event (GdkWindow *window,
                    GdkEvent  *event,
@@ -1531,7 +1644,16 @@ gdk_event_translate (GdkEvent *event,
           }
       }
       break;
-
+#ifdef AVAILABLE_MAC_OS_X_VERSION_10_7_AND_LATER
+    case NSEventTypeMagnify:
+    case NSEventTypeRotate:
+      /* Event handling requires [NSEvent phase] which was introduced in 10.7 */
+      if (gdk_quartz_osx_version () >= GDK_OSX_LION)
+        fill_pinch_event (window, event, nsevent, x, y, x_root, y_root);
+      else
+        return_val = FALSE;
+      break;
+#endif
     case NSMouseExited:
       if (WINDOW_IS_TOPLEVEL (window))
           [[NSCursor arrowCursor] set];