src/Widget/ManagedWidget.hpp

   1 /*
   2 Copyright_License {
   3
   4   XCSoar Glide Computer - http://www.xcsoar.org/
   5   Copyright (C) 2000-2013 The XCSoar Project
   6   A detailed list of copyright holders can be found in the file "AUTHORS".
   7
   8   This program is free software; you can redistribute it and/or
   9   modify it under the terms of the GNU General Public License
  10   as published by the Free Software Foundation; either version 2
  11   of the License, or (at your option) any later version.
  12
  13   This program is distributed in the hope that it will be useful,
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16   GNU General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with this program; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21 }
  22 */
  23
  24 #ifndef XCSOAR_MANAGED_WIDGET_HPP
  25 #define XCSOAR_MANAGED_WIDGET_HPP
  26
  27 #include "Screen/Point.hpp"
  28 #include "Util/DebugFlag.hpp"
  29
  30 class ContainerWindow;
  31 class Widget;
  32
  33 /**
  34  * A wrapper for a #Widget pointer that keeps track of the Widget's
  35  * state.  It will enforce some of the #Widget API rules.  It will
  36  * take care for hiding, unpreparing and deleting the given #Widget
  37  * instance, and will not call Widget::Prepare() and Widget::Show()
  38  * twice.
  39  */
  40 class ManagedWidget {
  41   ContainerWindow &parent;
  42   PixelRect position;
  43
  44   Widget *widget;
  45
  46   bool prepared, visible;
  47
  48   DebugFlag have_position;
  49
  50 public:
  51   ManagedWidget(ContainerWindow &_parent)
  52     :parent(_parent), widget(nullptr) {}
  53
  54   ManagedWidget(ContainerWindow &_parent, Widget *_widget)
  55     :parent(_parent), widget(_widget), prepared(false) {}
  56
  57   ~ManagedWidget() {
  58     Clear();
  59   }
  60
  61   /**
  62    * Return the Widget object (in the current state), and "forget"
  63    * about it.
  64    */
  65   Widget *Steal() {
  66     Widget *result = widget;
  67     widget = nullptr;
  68     return result;
  69   }
  70
  71   bool IsDefined() const {
  72     return widget != nullptr;
  73   }
  74
  75   bool IsPrepared() const {
  76     return IsDefined() && prepared;
  77   }
  78
  79   bool IsVisible() const {
  80     return IsPrepared() && visible;
  81   }
  82
  83   /**
  84    * Ensure that the Widget is prepared.
  85    */
  86   void Prepare();
  87
  88   void Unprepare();
  89   void Clear();
  90
  91   /**
  92    * @param widget an uninitialised Widget
  93    */
  94   void Set(Widget *widget);
  95
  96   Widget *Get() {
  97     return widget;
  98   }
  99
 100   void Move(const PixelRect &position);
 101
 102   void Show();
 103   void Hide();
 104
 105   void SetVisible(bool _visible);
 106 };
 107
 108 #endif