juce/source/src/gui/components/keyboard/juce_KeyboardFocusTraverser.cpp

   1 /*
   2   ==============================================================================
   3
   4    This file is part of the JUCE library - "Jules' Utility Class Extensions"
   5    Copyright 2004-11 by Raw Material Software Ltd.
   6
   7   ------------------------------------------------------------------------------
   8
   9    JUCE can be redistributed and/or modified under the terms of the GNU General
  10    Public License (Version 2), as published by the Free Software Foundation.
  11    A copy of the license is included in the JUCE distribution, or can be found
  12    online at www.gnu.org/licenses.
  13
  14    JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
  15    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  16    A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
  17
  18   ------------------------------------------------------------------------------
  19
  20    To release a closed-source product which uses JUCE, commercial licenses are
  21    available: visit www.rawmaterialsoftware.com/juce for more information.
  22
  23   ==============================================================================
  24 */
  25
  26 #include "../../../core/juce_StandardHeader.h"
  27
  28 BEGIN_JUCE_NAMESPACE
  29
  30 #include "juce_KeyboardFocusTraverser.h"
  31 #include "../juce_Component.h"
  32
  33
  34 //==============================================================================
  35 KeyboardFocusTraverser::KeyboardFocusTraverser()
  36 {
  37 }
  38
  39 KeyboardFocusTraverser::~KeyboardFocusTraverser()
  40 {
  41 }
  42
  43 //==============================================================================
  44 namespace KeyboardFocusHelpers
  45 {
  46     // This will sort a set of components, so that they are ordered in terms of
  47     // left-to-right and then top-to-bottom.
  48     class ScreenPositionComparator
  49     {
  50     public:
  51         ScreenPositionComparator() {}
  52
  53         static int compareElements (const Component* const first, const Component* const second)
  54         {
  55             int explicitOrder1 = first->getExplicitFocusOrder();
  56             if (explicitOrder1 <= 0)
  57                 explicitOrder1 = std::numeric_limits<int>::max() / 2;
  58
  59             int explicitOrder2 = second->getExplicitFocusOrder();
  60             if (explicitOrder2 <= 0)
  61                 explicitOrder2 = std::numeric_limits<int>::max() / 2;
  62
  63             if (explicitOrder1 != explicitOrder2)
  64                 return explicitOrder1 - explicitOrder2;
  65
  66             const int diff = first->getY() - second->getY();
  67
  68             return (diff == 0) ? first->getX() - second->getX()
  69                                : diff;
  70         }
  71     };
  72
  73     static void findAllFocusableComponents (Component* const parent, Array <Component*>& comps)
  74     {
  75         if (parent->getNumChildComponents() > 0)
  76         {
  77             Array <Component*> localComps;
  78             ScreenPositionComparator comparator;
  79
  80             int i;
  81             for (i = parent->getNumChildComponents(); --i >= 0;)
  82             {
  83                 Component* const c = parent->getChildComponent (i);
  84
  85                 if (c->isVisible() && c->isEnabled())
  86                     localComps.addSorted (comparator, c);
  87             }
  88
  89             for (i = 0; i < localComps.size(); ++i)
  90             {
  91                 Component* const c = localComps.getUnchecked (i);
  92
  93                 if (c->getWantsKeyboardFocus())
  94                     comps.add (c);
  95
  96                 if (! c->isFocusContainer())
  97                     findAllFocusableComponents (c, comps);
  98             }
  99         }
 100     }
 101 }
 102
 103 namespace KeyboardFocusHelpers
 104 {
 105     Component* getIncrementedComponent (Component* const current, const int delta)
 106     {
 107         Component* focusContainer = current->getParentComponent();
 108
 109         if (focusContainer != nullptr)
 110         {
 111             while (focusContainer->getParentComponent() != nullptr && ! focusContainer->isFocusContainer())
 112                 focusContainer = focusContainer->getParentComponent();
 113
 114             if (focusContainer != nullptr)
 115             {
 116                 Array <Component*> comps;
 117                 KeyboardFocusHelpers::findAllFocusableComponents (focusContainer, comps);
 118
 119                 if (comps.size() > 0)
 120                 {
 121                     const int index = comps.indexOf (current);
 122                     return comps [(index + comps.size() + delta) % comps.size()];
 123                 }
 124             }
 125         }
 126
 127         return nullptr;
 128     }
 129 }
 130
 131 Component* KeyboardFocusTraverser::getNextComponent (Component* current)
 132 {
 133     return KeyboardFocusHelpers::getIncrementedComponent (current, 1);
 134 }
 135
 136 Component* KeyboardFocusTraverser::getPreviousComponent (Component* current)
 137 {
 138     return KeyboardFocusHelpers::getIncrementedComponent (current, -1);
 139 }
 140
 141 Component* KeyboardFocusTraverser::getDefaultComponent (Component* parentComponent)
 142 {
 143     Array <Component*> comps;
 144
 145     if (parentComponent != nullptr)
 146         KeyboardFocusHelpers::findAllFocusableComponents (parentComponent, comps);
 147
 148     return comps.getFirst();
 149 }
 150
 151
 152 END_JUCE_NAMESPACE