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::removeItem(const LayoutItemRef& item)
61 while( LayoutItemRef child = itemAt(i) )
64 return (void)takeAt(i);
70 //----------------------------------------------------------------------------
71 void Layout::ItemData::reset()
84 //----------------------------------------------------------------------------
85 void Layout::safeAdd(int& a, int b)
87 if( SGLimits<int>::max() - b < a )
88 a = SGLimits<int>::max();
93 //----------------------------------------------------------------------------
94 void Layout::distribute(std::vector<ItemData>& items, const ItemData& space)
96 const int num_children = static_cast<int>(items.size());
97 _num_not_done = num_children;
101 "Layout::distribute(" << num_children << " items)" );
103 if( space.size < space.min_size )
106 SG_LOG( SG_GUI, SG_WARN, "Layout: not enough size (not implemented)");
108 else if( space.size < space.max_size )
113 bool less_then_hint = space.size < space.size_hint;
115 // Give min_size/size_hint to all items
116 _space_left = space.size
117 - (less_then_hint ? space.min_size : space.size_hint);
118 for(int i = 0; i < num_children; ++i)
120 ItemData& d = items[i];
121 d.size = less_then_hint ? d.min_size : d.size_hint;
122 d.padding = d.padding_orig;
123 d.done = d.size >= (less_then_hint ? d.size_hint : d.max_size);
133 _sum_stretch += d.stretch;
134 _space_stretch += d.size;
138 // Distribute remaining space to increase the size of each item up to its
139 // size_hint/max_size
140 while( _space_left > 0 )
142 if( _num_not_done <= 0 )
144 SG_LOG(SG_GUI, SG_WARN, "space left, but no more items?");
148 int space_per_element = std::max(1, _space_left / _num_not_done);
150 SG_LOG(SG_GUI, SG_DEBUG, "space/element=" << space_per_element);
152 for(int i = 0; i < num_children; ++i)
154 ItemData& d = items[i];
159 i << ") left=" << _space_left
160 << ", not_done=" << _num_not_done
161 << ", sum=" << _sum_stretch
162 << ", stretch=" << _space_stretch
163 << ", stretch/unit=" << _space_stretch / std::max(1, _sum_stretch)
169 if( _sum_stretch > 0 && d.stretch <= 0 )
174 int max_size = less_then_hint ? d.size_hint : d.max_size;
176 if( _sum_stretch > 0 )
178 target_size = (d.stretch * (_space_left + _space_stretch))
181 // Item would be smaller than minimum size or larger than maximum
182 // size, so just keep bounded size and ignore stretch factor
183 if( target_size <= d.size || target_size >= max_size )
186 _sum_stretch -= d.stretch;
187 _space_stretch -= d.size;
189 if( target_size >= max_size )
190 target_size = max_size;
192 target_size = d.size;
195 _space_stretch += target_size - d.size;
199 // Give space evenly to all remaining elements in this round
200 target_size = d.size + std::min(_space_left, space_per_element);
202 if( target_size >= max_size )
205 target_size = max_size;
209 int old_size = d.size;
210 d.size = target_size;
211 _space_left -= d.size - old_size;
218 if( _sum_stretch <= 0 && d.stretch > 0 )
219 // Distribute remaining space evenly to all non-stretchable items
228 _space_left = space.size - space.max_size;
229 for(int i = 0; i < num_children; ++i)
231 ItemData& d = items[i];
234 // Add superfluous space as padding
235 d.padding = d.padding_orig + _space_left
236 // Padding after last child...
237 / (_num_not_done + 1);
239 _space_left -= d.padding - d.padding_orig;
244 SG_LOG(SG_GUI, SG_DEBUG, "distribute:");
245 for(int i = 0; i < num_children; ++i)
247 ItemData const& d = items[i];
250 i << ") pad=" << d.padding
251 << ", size = " << d.size );
255 } // namespace canvas
256 } // namespace simgear