WindowServer: More natural mouse menu navigation

Libraries/LibDraw/Triangle.h

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2020, Shannon Booth <[email protected]>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <LibDraw/Point.h>
+
+class Triangle {
+public:
+ Triangle(Point a, Point b, Point c)
+ : m_a(a)
+ , m_b(b)
+ , m_c(c)
+ {
+ m_det = (m_b.x() - m_a.x()) * (m_c.y() - m_a.y()) - (m_b.y() - m_a.y()) * (m_c.x() - m_a.x());
+ }
+
+ Point a() const { return m_a; }
+ Point b() const { return m_b; }
+ Point c() const { return m_c; }
+
+ bool contains(Point p) const
+ {
+ int x = p.x();
+ int y = p.y();
+
+ int ax = m_a.x();
+ int bx = m_b.x();
+ int cx = m_c.x();
+
+ int ay = m_a.y();
+ int by = m_b.y();
+ int cy = m_c.y();
+
+ if (m_det * ((bx - ax) * (y - ay) - (by - ay) * (x - ax)) <= 0)
+ return false;
+ if (m_det * ((cx - bx) * (y - by) - (cy - by) * (x - bx)) <= 0)
+ return false;
+ if (m_det * ((ax - cx) * (y - cy) - (ay - cy) * (x - cx)) <= 0)
+ return false;
+ return true;
+ }
+
+ String to_string() const { return String::format("(%s,%s,%s)", m_a.to_string().characters(), m_b.to_string().characters(), m_c.to_string().characters()); }
+
+private:
+ int m_det;
+ Point m_a;
+ Point m_b;
+ Point m_c;
+};
+
+inline const LogStream& operator<<(const LogStream& stream, const Triangle& value)
+{
+ return stream << value.to_string();
+}

Servers/WindowServer/WSMenu.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2018-2020, Andreas Kling <[email protected]>
+ * Copyright (c) 2020, Shannon Booth <[email protected]>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -37,6 +38,7 @@
 #include <LibDraw/GraphicsBitmap.h>
 #include <LibDraw/Painter.h>
 #include <LibDraw/StylePainter.h>
+#include <LibDraw/Triangle.h>
 #include <WindowServer/WSClientConnection.h>
 #include <WindowServer/WindowClientEndpoint.h>
 
@@ -279,7 +281,23 @@ void WSMenu::event(CEvent& event)
 {
  if (event.type() == WSEvent::MouseMove) {
  ASSERT(menu_window());
- int index = item_index_at(static_cast<const WSMouseEvent&>(event).position());
+ auto mouse_event = static_cast<const WSMouseEvent&>(event);
+
+ if (hovered_item() && hovered_item()->is_submenu()) {
+
+ auto item = *hovered_item();
+ auto submenu_top_left = item.rect().location() + Point { item.rect().width(), 0 };
+ auto submenu_bottom_left = submenu_top_left + Point { 0, item.submenu()->height() };
+
+ auto safe_hover_triangle = Triangle { m_last_position_in_hover, submenu_top_left, submenu_bottom_left };
+ m_last_position_in_hover = mouse_event.position();
+
+ // Don't update the hovered item if mouse is moving towards a submenu
+ if (safe_hover_triangle.contains(mouse_event.position()))
+ return;
+ }
+
+ int index = item_index_at(mouse_event.position());
  if (m_hovered_item_index == index)
  return;
  m_hovered_item_index = index;

Servers/WindowServer/WSMenu.h

@@ -133,7 +133,7 @@ class WSMenu final : public CObject {
 
  WeakPtr<WSWindow> m_window_menu_of;
  bool m_is_window_menu_open = { false };
-
+ Point m_last_position_in_hover;
  int m_theme_index_at_last_paint { -1 };
  int m_hovered_item_index { -1 };
  bool m_in_submenu { false };