src/ui/flowlayout.cpp

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#include <QWidget>

#include "flowlayout.h"
//! [1]
FlowLayout::FlowLayout(QWidget* parent, int margin, int hSpacing, int vSpacing)
    : QLayout(parent), m_hSpace(hSpacing), m_vSpace(vSpacing) {
  setContentsMargins(margin, margin, margin, margin);
}

FlowLayout::FlowLayout(int margin, int hSpacing, int vSpacing)
    : m_hSpace(hSpacing), m_vSpace(vSpacing) {
  setContentsMargins(margin, margin, margin, margin);
}
//! [1]

//! [2]
FlowLayout::~FlowLayout() {
  QLayoutItem* item;
  while ((item = takeAt(0))) delete item;
}
//! [2]

//! [3]
void FlowLayout::addItem(QLayoutItem* item) { itemList.append(item); }
//! [3]

//! [4]
int FlowLayout::horizontalSpacing() const {
  if (m_hSpace >= 0) {
    return m_hSpace;
  } else {
    return smartSpacing(QStyle::PM_LayoutHorizontalSpacing);
  }
}

int FlowLayout::verticalSpacing() const {
  if (m_vSpace >= 0) {
    return m_vSpace;
  } else {
    return smartSpacing(QStyle::PM_LayoutVerticalSpacing);
  }
}
//! [4]

//! [5]
int FlowLayout::count() const { return itemList.size(); }

QLayoutItem* FlowLayout::itemAt(int index) const {
  return itemList.value(index);
}

QLayoutItem* FlowLayout::takeAt(int index) {
  if (index >= 0 && index < itemList.size())
    return itemList.takeAt(index);
  else
    return 0;
}
//! [5]

//! [6]
Qt::Orientations FlowLayout::expandingDirections() const { return 0; }
//! [6]

//! [7]
bool FlowLayout::hasHeightForWidth() const { return true; }

int FlowLayout::heightForWidth(int width) const {
  int height = doLayout(QRect(0, 0, width, 0), true);
  return height;
}
//! [7]

//! [8]
void FlowLayout::setGeometry(const QRect& rect) {
  QLayout::setGeometry(rect);
  doLayout(rect, false);
}

QSize FlowLayout::sizeHint() const { return minimumSize(); }

QSize FlowLayout::minimumSize() const {
  QSize size;
  for (QLayoutItem* item : itemList)
    size = size.expandedTo(item->minimumSize());

  size += QSize(2 * margin(), 2 * margin());
  return size;
}
//! [8]

//! [9]
int FlowLayout::doLayout(const QRect& rect, bool testOnly) const {
  int left, top, right, bottom;
  getContentsMargins(&left, &top, &right, &bottom);
  QRect effectiveRect = rect.adjusted(+left, +top, -right, -bottom);
  int x = effectiveRect.x();
  int y = effectiveRect.y();
  int lineHeight = 0;
  //! [9]

  //! [10]
  for (QLayoutItem* item : itemList) {
    QWidget* wid = item->widget();
    int spaceX = horizontalSpacing();
    if (spaceX == -1)
      spaceX = wid->style()->layoutSpacing(
          QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Horizontal);
    int spaceY = verticalSpacing();
    if (spaceY == -1)
      spaceY = wid->style()->layoutSpacing(
          QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Vertical);
    //! [10]
    //! [11]
    int nextX = x + item->sizeHint().width() + spaceX;
    if (nextX - spaceX > effectiveRect.right() && lineHeight > 0) {
      x = effectiveRect.x();
      y = y + lineHeight + spaceY;
      nextX = x + item->sizeHint().width() + spaceX;
      lineHeight = 0;
    }

    if (!testOnly) item->setGeometry(QRect(QPoint(x, y), item->sizeHint()));

    x = nextX;
    lineHeight = qMax(lineHeight, item->sizeHint().height());
  }
  return y + lineHeight - rect.y() + bottom;
}
//! [11]
//! [12]
int FlowLayout::smartSpacing(QStyle::PixelMetric pm) const {
  QObject* parent = this->parent();
  if (!parent) {
    return -1;
  } else if (parent->isWidgetType()) {
    QWidget* pw = static_cast<QWidget*>(parent);
    return pw->style()->pixelMetric(pm, 0, pw);
  } else {
    return static_cast<QLayout*>(parent)->spacing();
  }
}
//! [12]