1 // Basic class for canvas layouts
3 // Copyright (C) 2014 Thomas Geymayer <tomgey@gmail.com>
5 // This library is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU Library General Public
7 // License as published by the Free Software Foundation; either
8 // version 2 of the License, or (at your option) any later version.
10 // This library is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 // Library General Public License for more details.
15 // You should have received a copy of the GNU Library General Public
16 // License along with this library; if not, write to the Free Software
17 // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
20 #include <simgear/debug/logstream.hxx>
27 //----------------------------------------------------------------------------
30 if( !(_flags & (LAYOUT_DIRTY | SIZE_INFO_DIRTY)) )
35 _flags &= ~LAYOUT_DIRTY;
38 //----------------------------------------------------------------------------
39 void Layout::invalidate()
41 LayoutItem::invalidate();
42 _flags |= LAYOUT_DIRTY;
45 //----------------------------------------------------------------------------
46 void Layout::setGeometry(const SGRecti& geom)
48 if( geom == _geometry )
52 _flags |= LAYOUT_DIRTY;
57 //----------------------------------------------------------------------------
58 void Layout::ItemData::reset()
71 //----------------------------------------------------------------------------
72 void Layout::safeAdd(int& a, int b)
74 if( SGLimits<int>::max() - b < a )
75 a = SGLimits<int>::max();
80 //----------------------------------------------------------------------------
81 void Layout::distribute(std::vector<ItemData>& items, const ItemData& space)
83 const int num_children = static_cast<int>(items.size());
84 _num_not_done = num_children;
88 "Layout::distribute(" << num_children << " items)" );
90 if( space.size < space.min_size )
93 SG_LOG( SG_GUI, SG_WARN, "Layout: not enough size (not implemented)");
95 else if( space.size < space.max_size )
100 bool less_then_hint = space.size < space.size_hint;
102 // Give min_size/size_hint to all items
103 _space_left = space.size
104 - (less_then_hint ? space.min_size : space.size_hint);
105 for(int i = 0; i < num_children; ++i)
107 ItemData& d = items[i];
108 d.size = less_then_hint ? d.min_size : d.size_hint;
109 d.padding = d.padding_orig;
110 d.done = d.size >= (less_then_hint ? d.size_hint : d.max_size);
120 _sum_stretch += d.stretch;
121 _space_stretch += d.size;
125 // Distribute remaining space to increase the size of each item up to its
126 // size_hint/max_size
127 while( _space_left > 0 )
129 if( _num_not_done <= 0 )
131 SG_LOG(SG_GUI, SG_WARN, "space left, but no more items?");
135 int space_per_element = std::max(1, _space_left / _num_not_done);
137 SG_LOG(SG_GUI, SG_DEBUG, "space/element=" << space_per_element);
139 for(int i = 0; i < num_children; ++i)
141 ItemData& d = items[i];
146 i << ") left=" << _space_left
147 << ", not_done=" << _num_not_done
148 << ", sum=" << _sum_stretch
149 << ", stretch=" << _space_stretch
150 << ", stretch/unit=" << _space_stretch / std::max(1, _sum_stretch)
156 if( _sum_stretch > 0 && d.stretch <= 0 )
161 int max_size = less_then_hint ? d.size_hint : d.max_size;
163 if( _sum_stretch > 0 )
165 target_size = (d.stretch * (_space_left + _space_stretch))
168 // Item would be smaller than minimum size or larger than maximum
169 // size, so just keep bounded size and ignore stretch factor
170 if( target_size <= d.size || target_size >= max_size )
173 _sum_stretch -= d.stretch;
174 _space_stretch -= d.size;
176 if( target_size >= max_size )
177 target_size = max_size;
179 target_size = d.size;
182 _space_stretch += target_size - d.size;
186 // Give space evenly to all remaining elements in this round
187 target_size = d.size + std::min(_space_left, space_per_element);
189 if( target_size >= max_size )
192 target_size = max_size;
196 int old_size = d.size;
197 d.size = target_size;
198 _space_left -= d.size - old_size;
205 if( _sum_stretch <= 0 && d.stretch > 0 )
206 // Distribute remaining space evenly to all non-stretchable items
215 _space_left = space.size - space.max_size;
216 for(int i = 0; i < num_children; ++i)
218 ItemData& d = items[i];
221 // Add superfluous space as padding
222 d.padding = d.padding_orig + _space_left
223 // Padding after last child...
224 / (_num_not_done + 1);
226 _space_left -= d.padding - d.padding_orig;
231 SG_LOG(SG_GUI, SG_DEBUG, "distribute:");
232 for(int i = 0; i < num_children; ++i)
234 ItemData const& d = items[i];
237 i << ") pad=" << d.padding
238 << ", size = " << d.size );
242 } // namespace canvas
243 } // namespace simgear