flowlayout.cpp

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#include <QWidget>
 
#include "flowlayout.h"
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);
}
 
FlowLayout::~FlowLayout()
{
    QLayoutItem* item;
    while ((item = takeAt(0)))
        delete item;
}
 
void FlowLayout::addItem(QLayoutItem* item)
{
    itemList.append(item);
}
 
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);
}
 
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 nullptr;
}
 
Qt::Orientations FlowLayout::expandingDirections() const
{
    return {};
}
 
bool FlowLayout::hasHeightForWidth() const
{
    return true;
}
 
int FlowLayout::heightForWidth(int width) const
{
    int height = doLayout(QRect(0, 0, width, 0), true);
    return height;
}
 
void FlowLayout::setGeometry(const QRect& rect)
{
    QLayout::setGeometry(rect);
    doLayout(rect, false);
}
 
QSize FlowLayout::sizeHint() const
{
    return minimumSize();
}
 
QSize FlowLayout::minimumSize() const
{
    QSize size;
    foreach (QLayoutItem* item, itemList)
        size = size.expandedTo(item->minimumSize());
 
    size += QSize(2 * margin(), 2 * margin());
    return size;
}
 
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;
 
    QLayoutItem* item;
    foreach (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);
 
        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;
}
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, nullptr, pw);
    } else {
        return static_cast<QLayout*>(parent)->spacing();
    }
}