GDK W32: custom (non-WM) drag-move and drag-resize code

Normally works only on CSD windows, non-CSD windows continue
to use WM modal loop for drag-resizing and drag-moving. However,
if it is activated on non-CSD windows, it does work.

Has the advantage of being completely immune to AeroSnap.
AeroSnap only worked partially on CSD windows, with the only part
that worked being "don't let users drag window titlebar outside of
the desktop". Now AeroSnap doesn't work on windows moved by
this code at all, which is good, since they currently don't work
well with it due to the way shadows are drawn.

It's possible to also re-implement AeroSnap (or something similar),
but that is a story for another commit.

This code was originally intended to fix the problem of window
size and window contents desynchronization, but failed to achieve
that result in the end. Nevertheless, it serves as a foundation for
other changes to the way window resizing works.

https://bugzilla.gnome.org/show_bug.cgi?id=761629

1 files changed, 134 insertions, 89 deletions

diff --git a/gdk/win32/gdkevents-win32.c b/gdk/win32/gdkevents-win32.c
index b6a0b61e58..da21e9f403 100644
--- a/gdk/win32/gdkevents-win32.c
+++ b/gdk/win32/gdkevents-win32.c
@@ -1408,8 +1408,14 @@ doesnt_want_char (gint mask,
   return !(mask & (GDK_KEY_PRESS_MASK | GDK_KEY_RELEASE_MASK));
 }
 
-void
-_gdk_win32_emit_configure_event (GdkWindow *window)
+/* Acquires actual client area size of the underlying native window.
+ * Rectangle is in GDK screen coordinates (_gdk_offset_* is added).
+ * Returns FALSE if configure events should be inhibited,
+ * TRUE otherwise.
+ */
+gboolean
+_gdk_win32_get_window_rect (GdkWindow *window,
+                            RECT      *rect)
 {
   GdkWindowImplWin32 *window_impl;
   RECT client_rect;
@@ -1417,8 +1423,6 @@ _gdk_win32_emit_configure_event (GdkWindow *window)
   HWND hwnd;
 
   window_impl = GDK_WINDOW_IMPL_WIN32 (window->impl);
-  if (window_impl->inhibit_configure)
-    return;
 
   hwnd = GDK_WINDOW_HWND (window);
 
@@ -1434,11 +1438,23 @@ _gdk_win32_emit_configure_event (GdkWindow *window)
       point.y += _gdk_offset_y;
     }
 
-  window->width = client_rect.right - client_rect.left;
-  window->height = client_rect.bottom - client_rect.top;
+  rect->left = point.x;
+  rect->top = point.y;
+  rect->right = point.x + client_rect.right - client_rect.left;
+  rect->bottom = point.y + client_rect.bottom - client_rect.top;
+
+  return !window_impl->inhibit_configure;
+}
+
+void
+_gdk_win32_do_emit_configure_event (GdkWindow *window,
+                                    RECT       rect)
+{
+  window->width = rect.right - rect.left;
+  window->height = rect.bottom - rect.top;
 
-  window->x = point.x;
-  window->y = point.y;
+  window->x = rect.left;
+  window->y = rect.top;
 
   _gdk_window_update_size (window);
 
@@ -1448,16 +1464,27 @@ _gdk_win32_emit_configure_event (GdkWindow *window)
 
       event->configure.window = window;
 
-      event->configure.width = client_rect.right - client_rect.left;
-      event->configure.height = client_rect.bottom - client_rect.top;
+      event->configure.width = rect.right - rect.left;
+      event->configure.height = rect.bottom - rect.top;
 
-      event->configure.x = point.x;
-      event->configure.y = point.y;
+      event->configure.x = rect.left;
+      event->configure.y = rect.top;
 
       _gdk_win32_append_event (event);
     }
 }
 
+void
+_gdk_win32_emit_configure_event (GdkWindow *window)
+{
+  RECT rect;
+
+  if (!_gdk_win32_get_window_rect (window, &rect))
+    return;
+
+  _gdk_win32_do_emit_configure_event (window, rect);
+}
+
 cairo_region_t *
 _gdk_win32_hrgn_to_region (HRGN hrgn)
 {
@@ -1874,6 +1901,76 @@ ensure_stacking_on_activate_app (MSG       *msg,
     }
 }
 
+gboolean
+_gdk_win32_window_fill_min_max_info (GdkWindow  *window,
+                                     MINMAXINFO *mmi)
+{
+  GdkWindowImplWin32 *impl;
+  RECT rect;
+
+  if (GDK_WINDOW_DESTROYED (window))
+    return FALSE;
+
+  impl = GDK_WINDOW_IMPL_WIN32 (window->impl);
+
+  if (impl->hint_flags & GDK_HINT_MIN_SIZE)
+    {
+      rect.left = rect.top = 0;
+      rect.right = impl->hints.min_width;
+      rect.bottom = impl->hints.min_height;
+
+      _gdk_win32_adjust_client_rect (window, &rect);
+
+      mmi->ptMinTrackSize.x = rect.right - rect.left;
+      mmi->ptMinTrackSize.y = rect.bottom - rect.top;
+    }
+
+  if (impl->hint_flags & GDK_HINT_MAX_SIZE)
+    {
+      int maxw, maxh;
+
+      rect.left = rect.top = 0;
+      rect.right = impl->hints.max_width;
+      rect.bottom = impl->hints.max_height;
+
+      _gdk_win32_adjust_client_rect (window, &rect);
+
+      /* at least on win9x we have the 16 bit trouble */
+      maxw = rect.right - rect.left;
+      maxh = rect.bottom - rect.top;
+      mmi->ptMaxTrackSize.x = maxw > 0 && maxw < G_MAXSHORT ? maxw : G_MAXSHORT;
+      mmi->ptMaxTrackSize.y = maxh > 0 && maxh < G_MAXSHORT ? maxh : G_MAXSHORT;
+    }
+  else
+    {
+      HMONITOR nearest_monitor;
+      MONITORINFO nearest_info;
+
+      nearest_monitor = MonitorFromWindow (GDK_WINDOW_HWND (window), MONITOR_DEFAULTTONEAREST);
+      nearest_info.cbSize = sizeof (nearest_info);
+
+      if (GetMonitorInfoA (nearest_monitor, &nearest_info))
+        {
+          /* MSDN says that we must specify maximized window
+           * size as if it was located on the primary monitor.
+           * However, we still need to account for a taskbar
+           * that might or might not be on the nearest monitor where
+           * window will actually end up.
+           * "0" here is the top-left corner of the primary monitor.
+           */
+          mmi->ptMaxPosition.x = 0 + (nearest_info.rcWork.left - nearest_info.rcMonitor.left);
+          mmi->ptMaxPosition.y = 0 + (nearest_info.rcWork.top - nearest_info.rcMonitor.top);
+          mmi->ptMaxSize.x = nearest_info.rcWork.right - nearest_info.rcWork.left;
+          mmi->ptMaxSize.y = nearest_info.rcWork.bottom - nearest_info.rcWork.top;
+        }
+
+      mmi->ptMaxTrackSize.x = GetSystemMetrics (SM_CXMAXTRACK);
+      mmi->ptMaxTrackSize.y = GetSystemMetrics (SM_CYMAXTRACK);
+    }
+
+  return TRUE;
+}
+
 #define GDK_ANY_BUTTON_MASK (GDK_BUTTON1_MASK | \
 			     GDK_BUTTON2_MASK | \
 			     GDK_BUTTON3_MASK | \
@@ -1887,7 +1984,6 @@ gdk_event_translate (MSG  *msg,
   RECT rect, *drag, orig_drag;
   POINT point;
   MINMAXINFO *mmi;
-  LONG style;
   HWND hwnd;
   GdkCursor *cursor;
   BYTE key_state[256];
@@ -2469,7 +2565,13 @@ gdk_event_translate (MSG  *msg,
       current_root_x = msg->pt.x + _gdk_offset_x;
       current_root_y = msg->pt.y + _gdk_offset_y;
 
-      if (!_gdk_input_ignore_core)
+      impl = GDK_WINDOW_IMPL_WIN32 (window->impl);
+
+      if (impl->drag_move_resize_context.op != GDK_WIN32_DRAGOP_NONE)
+        {
+          gdk_win32_window_do_move_resize_drag (window, current_root_x, current_root_y);
+        }
+      else if (!_gdk_input_ignore_core)
 	{
 	  event = gdk_event_new (GDK_MOTION_NOTIFY);
 	  event->motion.window = window;
@@ -2775,6 +2877,11 @@ gdk_event_translate (MSG  *msg,
 	  _modal_move_resize_window = NULL;
 	  _gdk_win32_end_modal_call ();
 	}
+
+      impl = GDK_WINDOW_IMPL_WIN32 (window->impl);
+
+      if (impl->drag_move_resize_context.op != GDK_WIN32_DRAGOP_NONE)
+        gdk_win32_window_end_move_resize_drag (window);
       break;
 
     case WM_WINDOWPOSCHANGING:
@@ -3130,11 +3237,8 @@ gdk_event_translate (MSG  *msg,
       break;
 
     case WM_GETMINMAXINFO:
-      if (GDK_WINDOW_DESTROYED (window))
-	break;
-
-      impl = GDK_WINDOW_IMPL_WIN32 (window->impl);
       mmi = (MINMAXINFO*) msg->lParam;
+
       GDK_NOTE (EVENTS, g_print (" (mintrack:%ldx%ld maxtrack:%ldx%ld "
 				 "maxpos:%+ld%+ld maxsize:%ldx%ld)",
 				 mmi->ptMinTrackSize.x, mmi->ptMinTrackSize.y,
@@ -3142,79 +3246,20 @@ gdk_event_translate (MSG  *msg,
 				 mmi->ptMaxPosition.x, mmi->ptMaxPosition.y,
 				 mmi->ptMaxSize.x, mmi->ptMaxSize.y));
 
-      style = GetWindowLong (GDK_WINDOW_HWND (window), GWL_STYLE);
-
-      if (impl->hint_flags & GDK_HINT_MIN_SIZE)
-	{
-	  rect.left = rect.top = 0;
-	  rect.right = impl->hints.min_width;
-	  rect.bottom = impl->hints.min_height;
-
-	  _gdk_win32_adjust_client_rect (window, &rect);
-
-	  mmi->ptMinTrackSize.x = rect.right - rect.left;
-	  mmi->ptMinTrackSize.y = rect.bottom - rect.top;
-	}
-
-      if (impl->hint_flags & GDK_HINT_MAX_SIZE)
-	{
-	  int maxw, maxh;
-
-	  rect.left = rect.top = 0;
-	  rect.right = impl->hints.max_width;
-	  rect.bottom = impl->hints.max_height;
-
-	  _gdk_win32_adjust_client_rect (window, &rect);
-
-	  /* at least on win9x we have the 16 bit trouble */
-	  maxw = rect.right - rect.left;
-	  maxh = rect.bottom - rect.top;
-	  mmi->ptMaxTrackSize.x = maxw > 0 && maxw < G_MAXSHORT ? maxw : G_MAXSHORT;
-	  mmi->ptMaxTrackSize.y = maxh > 0 && maxh < G_MAXSHORT ? maxh : G_MAXSHORT;
-	}
-      /* Assume that these styles are incompatible with CSD,
-       * so there's no reason for us to override the defaults.
-       */
-      else if ((style & (WS_BORDER | WS_THICKFRAME)) == 0)
-	{
-	  HMONITOR nearest_monitor;
-	  MONITORINFO nearest_info;
-
-	  nearest_monitor = MonitorFromWindow (GDK_WINDOW_HWND (window), MONITOR_DEFAULTTONEAREST);
-	  nearest_info.cbSize = sizeof (nearest_info);
-
-	  if (GetMonitorInfoA (nearest_monitor, &nearest_info))
-	    {
-	      /* MSDN says that we must specify maximized window
-	       * size as if it was located on the primary monitor.
-	       * However, we still need to account for a taskbar
-	       * that might or might not be on the nearest monitor where
-	       * window will actually end up.
-               * "0" here is the top-left corner of the primary monitor.
-	       */
-	      mmi->ptMaxPosition.x = 0 + (nearest_info.rcWork.left - nearest_info.rcMonitor.left);
-	      mmi->ptMaxPosition.y = 0 + (nearest_info.rcWork.top - nearest_info.rcMonitor.top);
-	      mmi->ptMaxSize.x = nearest_info.rcWork.right - nearest_info.rcWork.left;
-	      mmi->ptMaxSize.y = nearest_info.rcWork.bottom - nearest_info.rcWork.top;
-	    }
-
-	  mmi->ptMaxTrackSize.x = GetSystemMetrics (SM_CXMAXTRACK);
-	  mmi->ptMaxTrackSize.y = GetSystemMetrics (SM_CYMAXTRACK);
-	}
+      if (_gdk_win32_window_fill_min_max_info (window, mmi))
+        {
+          /* Don't call DefWindowProcW() */
+          GDK_NOTE (EVENTS,
+                    g_print (" (handled, mintrack:%ldx%ld maxtrack:%ldx%ld "
+                             "maxpos:%+ld%+ld maxsize:%ldx%ld)",
+                             mmi->ptMinTrackSize.x, mmi->ptMinTrackSize.y,
+                             mmi->ptMaxTrackSize.x, mmi->ptMaxTrackSize.y,
+                             mmi->ptMaxPosition.x, mmi->ptMaxPosition.y,
+                             mmi->ptMaxSize.x, mmi->ptMaxSize.y));
 
-      if (impl->hint_flags & (GDK_HINT_MIN_SIZE | GDK_HINT_MAX_SIZE))
-	{
-	  /* Don't call DefWindowProcW() */
-	  GDK_NOTE (EVENTS, g_print (" (handled, mintrack:%ldx%ld maxtrack:%ldx%ld "
-				     "maxpos:%+ld%+ld maxsize:%ldx%ld)",
-				     mmi->ptMinTrackSize.x, mmi->ptMinTrackSize.y,
-				     mmi->ptMaxTrackSize.x, mmi->ptMaxTrackSize.y,
-				     mmi->ptMaxPosition.x, mmi->ptMaxPosition.y,
-				     mmi->ptMaxSize.x, mmi->ptMaxSize.y));
-	  return_val = TRUE;
-	}
+          return_val = TRUE;
+        }
 
-      return_val = TRUE;
       break;
 
     case WM_CLOSE: