src/GUI/flowlayout.cpp

   1 #include <QtWidgets>
   2 #include "flowlayout.h"
   3
   4 struct FlowLayoutItem
   5 {
   6         FlowLayoutItem() : item(0) {}
   7         FlowLayoutItem(QLayoutItem *item, int x, int y) : item(item), pos(x, y) {}
   8
   9         QLayoutItem *item;
  10         QPoint pos;
  11 };
  12
  13 FlowLayout::FlowLayout(QWidget *parent, int margin, int hSpacing, int vSpacing)
  14     : QLayout(parent), _hSpace(hSpacing), _vSpace(vSpacing)
  15 {
  16         setContentsMargins(margin, margin, margin, margin);
  17 }
  18
  19 FlowLayout::FlowLayout(int margin, int hSpacing, int vSpacing)
  20     : _hSpace(hSpacing), _vSpace(vSpacing)
  21 {
  22         setContentsMargins(margin, margin, margin, margin);
  23 }
  24
  25 FlowLayout::~FlowLayout()
  26 {
  27         qDeleteAll(_items);
  28 }
  29
  30 void FlowLayout::addItem(QLayoutItem *item)
  31 {
  32         _items.append(item);
  33 }
  34
  35 int FlowLayout::horizontalSpacing() const
  36 {
  37         return (_hSpace >= 0)
  38           ? _hSpace
  39           : smartSpacing(QStyle::PM_LayoutHorizontalSpacing);
  40 }
  41
  42 int FlowLayout::verticalSpacing() const
  43 {
  44         return (_vSpace >= 0)
  45           ? _vSpace
  46           : smartSpacing(QStyle::PM_LayoutVerticalSpacing);
  47 }
  48
  49 int FlowLayout::count() const
  50 {
  51         return _items.size();
  52 }
  53
  54 QLayoutItem *FlowLayout::itemAt(int index) const
  55 {
  56         return _items.value(index);
  57 }
  58
  59 QLayoutItem *FlowLayout::takeAt(int index)
  60 {
  61         if (index >= 0 && index < _items.size())
  62                 return _items.takeAt(index);
  63
  64         return 0;
  65 }
  66
  67 Qt::Orientations FlowLayout::expandingDirections() const
  68 {
  69         return {};
  70 }
  71
  72 bool FlowLayout::hasHeightForWidth() const
  73 {
  74         return true;
  75 }
  76
  77 int FlowLayout::heightForWidth(int width) const
  78 {
  79         int height = doLayout(QRect(0, 0, width, 0), true);
  80         return height;
  81 }
  82
  83 void FlowLayout::setGeometry(const QRect &rect)
  84 {
  85         QLayout::setGeometry(rect);
  86         doLayout(rect, false);
  87 }
  88
  89 QSize FlowLayout::sizeHint() const
  90 {
  91         return minimumSize();
  92 }
  93
  94 QSize FlowLayout::minimumSize() const
  95 {
  96         QSize size;
  97
  98         for (int i = 0; i < _items.size(); i++)
  99                 size = size.expandedTo(_items.at(i)->minimumSize());
 100
 101         const QMargins margins = contentsMargins();
 102         size += QSize(margins.left() + margins.right(), margins.top()
 103           + margins.bottom());
 104
 105         return size;
 106 }
 107
 108 int FlowLayout::doLayout(const QRect &rect, bool testOnly) const
 109 {
 110         int left, top, right, bottom;
 111         getContentsMargins(&left, &top, &right, &bottom);
 112         QRect effectiveRect = rect.adjusted(+left, +top, -right, -bottom);
 113         int x = effectiveRect.x();
 114         int y = effectiveRect.y();
 115         int lineHeight = 0;
 116         QVector<QVector<FlowLayoutItem>> rows;
 117
 118         for (int i = 0; i < _items.size(); i++) {
 119                 QLayoutItem *item = _items.at(i);
 120                 const QWidget *wid = item->widget();
 121                 int spaceX = horizontalSpacing();
 122                 if (spaceX == -1)
 123                         spaceX = wid->style()->layoutSpacing(QSizePolicy::PushButton,
 124                           QSizePolicy::PushButton, Qt::Horizontal);
 125                 int spaceY = verticalSpacing();
 126                 if (spaceY == -1)
 127                         spaceY = wid->style()->layoutSpacing(QSizePolicy::PushButton,
 128                           QSizePolicy::PushButton, Qt::Vertical);
 129
 130                 int nextX = x + item->sizeHint().width() + spaceX;
 131                 if (nextX - spaceX > effectiveRect.right() && lineHeight > 0) {
 132                         x = effectiveRect.x();
 133                         y = y + lineHeight + spaceY;
 134                         nextX = x + item->sizeHint().width() + spaceX;
 135                         lineHeight = 0;
 136                         rows.append(QVector<FlowLayoutItem>());
 137                 }
 138
 139                 if (rows.isEmpty())
 140                         rows.append(QVector<FlowLayoutItem>());
 141                 rows.last().append(FlowLayoutItem(item, x, y));
 142
 143                 x = nextX;
 144                 lineHeight = qMax(lineHeight, item->sizeHint().height());
 145         }
 146
 147         if (!testOnly) {
 148                 for (int i = 0; i < rows.size(); i++) {
 149                         const FlowLayoutItem &li = rows.at(i).last();
 150                         int width = li.item->sizeHint().width() + li.pos.x()
 151                           - effectiveRect.x();
 152                         int offset = (effectiveRect.width() - width) / 2;
 153
 154                         int height = 0;
 155                         for (int j = 0; j < rows.at(i).size(); j++)
 156                                 height = qMax(rows.at(i).at(j).item->sizeHint().height(), height);
 157
 158                         for (int j = 0; j < rows.at(i).size(); j++) {
 159                                 QLayoutItem *item = rows.at(i).at(j).item;
 160                                 const QPoint &p = rows.at(i).at(j).pos;
 161                                 QSize sh(item->sizeHint());
 162                                 item->setGeometry(QRect(QPoint(p.x() + offset, p.y() + height
 163                                   - sh.height()), sh));
 164                         }
 165                 }
 166         }
 167
 168         return y + lineHeight - rect.y() + bottom;
 169 }
 170
 171 int FlowLayout::smartSpacing(QStyle::PixelMetric pm) const
 172 {
 173         QObject *parent = this->parent();
 174         if (!parent)
 175                 return -1;
 176         else if (parent->isWidgetType()) {
 177                 QWidget *pw = static_cast<QWidget *>(parent);
 178                 return pw->style()->pixelMetric(pm, 0, pw);
 179         } else
 180                 return static_cast<QLayout *>(parent)->spacing();
 181 }