src/gui/flowlayout.cpp

   1 /*
   2  * Bittorrent Client using Qt and libtorrent.
   3  * Copyright (C) 2023  Vladimir Golovnev <glassez@yandex.ru>
   4  * Copyright (C) 2016  The Qt Company Ltd.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19  *
  20  * In addition, as a special exception, the copyright holders give permission to
  21  * link this program with the OpenSSL project's "OpenSSL" library (or with
  22  * modified versions of it that use the same license as the "OpenSSL" library),
  23  * and distribute the linked executables. You must obey the GNU General Public
  24  * License in all respects for all of the code used other than "OpenSSL".  If you
  25  * modify file(s), you may extend this exception to your version of the file(s),
  26  * but you are not obligated to do so. If you do not wish to do so, delete this
  27  * exception statement from your version.
  28  */
  29
  30 #include "flowlayout.h"
  31
  32 #include <QHash>
  33 #include <QWidget>
  34
  35 #include "base/global.h"
  36
  37 FlowLayout::FlowLayout(QWidget *parent, const int margin, const int hSpacing, const int vSpacing)
  38     : QLayout(parent)
  39     , m_hSpace {hSpacing}
  40     , m_vSpace {vSpacing}
  41 {
  42     setContentsMargins(margin, margin, margin, margin);
  43 }
  44
  45 FlowLayout::FlowLayout(const int margin, const int hSpacing, const int vSpacing)
  46     : m_hSpace {hSpacing}
  47     , m_vSpace {vSpacing}
  48 {
  49     setContentsMargins(margin, margin, margin, margin);
  50 }
  51
  52 FlowLayout::~FlowLayout()
  53 {
  54     QLayoutItem *item;
  55     while ((item = takeAt(0)))
  56         delete item;
  57 }
  58
  59 void FlowLayout::addItem(QLayoutItem *item)
  60 {
  61     m_itemList.append(item);
  62 }
  63
  64 int FlowLayout::horizontalSpacing() const
  65 {
  66     if (m_hSpace >= 0)
  67         return m_hSpace;
  68
  69     return smartSpacing(QStyle::PM_LayoutHorizontalSpacing);
  70 }
  71
  72 int FlowLayout::verticalSpacing() const
  73 {
  74     if (m_vSpace >= 0)
  75         return m_vSpace;
  76
  77     return smartSpacing(QStyle::PM_LayoutVerticalSpacing);
  78 }
  79
  80 int FlowLayout::count() const
  81 {
  82     return m_itemList.size();
  83 }
  84
  85 QLayoutItem *FlowLayout::itemAt(const int index) const
  86 {
  87     return m_itemList.value(index);
  88 }
  89
  90 QLayoutItem *FlowLayout::takeAt(const int index)
  91 {
  92     if ((index >= 0) && (index < m_itemList.size()))
  93         return m_itemList.takeAt(index);
  94
  95     return nullptr;
  96 }
  97
  98 Qt::Orientations FlowLayout::expandingDirections() const
  99 {
 100     return {};
 101 }
 102
 103 bool FlowLayout::hasHeightForWidth() const
 104 {
 105     return true;
 106 }
 107
 108 int FlowLayout::heightForWidth(const int width) const
 109 {
 110     const int height = doLayout(QRect(0, 0, width, 0), true);
 111     return height;
 112 }
 113
 114 void FlowLayout::setGeometry(const QRect &rect)
 115 {
 116     QLayout::setGeometry(rect);
 117     doLayout(rect, false);
 118 }
 119
 120 QSize FlowLayout::sizeHint() const
 121 {
 122     return minimumSize();
 123 }
 124
 125 QSize FlowLayout::minimumSize() const
 126 {
 127     QSize size;
 128     for (const QLayoutItem *item : asConst(m_itemList))
 129         size = size.expandedTo(item->minimumSize());
 130
 131     const QMargins margins = contentsMargins();
 132     size += QSize(margins.left() + margins.right(), margins.top() + margins.bottom());
 133     return size;
 134 }
 135
 136 int FlowLayout::doLayout(const QRect &rect, const bool testOnly) const
 137 {
 138     int left, top, right, bottom;
 139     getContentsMargins(&left, &top, &right, &bottom);
 140
 141     const QRect effectiveRect = rect.adjusted(+left, +top, -right, -bottom);
 142     int x = effectiveRect.x();
 143     int y = effectiveRect.y();
 144     int lineHeight = 0;
 145
 146     QHash<QLayoutItem *, QPoint> lineItems;
 147     for (QLayoutItem *item : asConst(m_itemList))
 148     {
 149         const QWidget *wid = item->widget();
 150
 151         int spaceX = horizontalSpacing();
 152         if (spaceX == -1)
 153         {
 154             spaceX = wid->style()->layoutSpacing(
 155                 QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Horizontal);
 156         }
 157
 158         int spaceY = verticalSpacing();
 159         if (spaceY == -1)
 160         {
 161             spaceY = wid->style()->layoutSpacing(
 162                 QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Vertical);
 163         }
 164
 165         int nextX = x + item->sizeHint().width() + spaceX;
 166         if (((nextX - spaceX) > effectiveRect.right()) && (lineHeight > 0))
 167         {
 168             if (!testOnly)
 169             {
 170                 applyItemsGeometry(lineItems, lineHeight);
 171                 lineItems.clear();
 172             }
 173
 174             x = effectiveRect.x();
 175             y = y + lineHeight + spaceY;
 176             nextX = x + item->sizeHint().width() + spaceX;
 177             lineHeight = 0;
 178         }
 179
 180         if (!testOnly)
 181             lineItems[item] = QPoint(x, y);
 182
 183         x = nextX;
 184         lineHeight = std::max(lineHeight, item->sizeHint().height());
 185     }
 186
 187     if (!testOnly)
 188         applyItemsGeometry(lineItems, lineHeight);
 189
 190     return y + lineHeight - rect.y() + bottom;
 191 }
 192
 193 int FlowLayout::smartSpacing(const QStyle::PixelMetric pm) const
 194 {
 195     QObject *parent = this->parent();
 196     if (!parent)
 197         return -1;
 198
 199     if (parent->isWidgetType())
 200     {
 201         auto *pw = static_cast<QWidget *>(parent);
 202         return pw->style()->pixelMetric(pm, nullptr, pw);
 203     }
 204
 205     return static_cast<QLayout *>(parent)->spacing();
 206 }
 207
 208 void FlowLayout::applyItemsGeometry(const QHash<QLayoutItem *, QPoint> &items, const int lineHeight) const
 209 {
 210     for (auto it = items.cbegin(); it != items.cend(); ++it)
 211     {
 212         QLayoutItem *item = it.key();
 213         QPoint point = it.value();
 214
 215         const auto alignment = item->alignment();
 216         const int vSpace = lineHeight - item->sizeHint().height();
 217         if (alignment & Qt::AlignVCenter)
 218             point.ry() += vSpace / 2;
 219         else if (alignment & Qt::AlignBottom)
 220             point.ry() += vSpace;
 221         item->setGeometry(QRect(point, item->sizeHint()));
 222     }
 223 }