src/kitemviews/private/kitemlistsizehintresolver.cpp

   1 /*
   2  * SPDX-FileCopyrightText: 2011 Peter Penz <peter.penz19@gmail.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-or-later
   5  */
   6
   7 #include "kitemlistsizehintresolver.h"
   8 #include "kitemviews/kitemlistview.h"
   9
  10 KItemListSizeHintResolver::KItemListSizeHintResolver(const KItemListView *itemListView)
  11     : m_itemListView(itemListView)
  12     , m_logicalHeightHintCache()
  13     , m_logicalWidthHint(0.0)
  14     , m_minHeightHint(0.0)
  15     , m_needsResolving(false)
  16 {
  17 }
  18
  19 KItemListSizeHintResolver::~KItemListSizeHintResolver()
  20 {
  21 }
  22
  23 QSizeF KItemListSizeHintResolver::minSizeHint()
  24 {
  25     updateCache();
  26     return QSizeF(m_logicalWidthHint, m_minHeightHint);
  27 }
  28
  29 QSizeF KItemListSizeHintResolver::sizeHint(int index)
  30 {
  31     updateCache();
  32     return QSizeF(m_logicalWidthHint, m_logicalHeightHintCache.at(index).first);
  33 }
  34
  35 bool KItemListSizeHintResolver::isElided(int index)
  36 {
  37     return m_logicalHeightHintCache.at(index).second;
  38 }
  39
  40 void KItemListSizeHintResolver::itemsInserted(const KItemRangeList &itemRanges)
  41 {
  42     int insertedCount = 0;
  43     for (const KItemRange &range : itemRanges) {
  44         insertedCount += range.count;
  45     }
  46
  47     const int currentCount = m_logicalHeightHintCache.count();
  48     m_logicalHeightHintCache.reserve(currentCount + insertedCount);
  49
  50     // We build the new list from the end to the beginning to mimize the
  51     // number of moves.
  52     m_logicalHeightHintCache.insert(m_logicalHeightHintCache.end(), insertedCount, std::make_pair(0.0, false));
  53
  54     int sourceIndex = currentCount - 1;
  55     int targetIndex = m_logicalHeightHintCache.count() - 1;
  56     int itemsToInsertBeforeCurrentRange = insertedCount;
  57
  58     for (int rangeIndex = itemRanges.count() - 1; rangeIndex >= 0; --rangeIndex) {
  59         const KItemRange &range = itemRanges.at(rangeIndex);
  60         itemsToInsertBeforeCurrentRange -= range.count;
  61
  62         // First: move all existing items that must be put behind 'range'.
  63         while (targetIndex >= itemsToInsertBeforeCurrentRange + range.index + range.count) {
  64             m_logicalHeightHintCache[targetIndex] = m_logicalHeightHintCache[sourceIndex];
  65             --sourceIndex;
  66             --targetIndex;
  67         }
  68
  69         // Then: insert QSizeF() for the items which are inserted into 'range'.
  70         while (targetIndex >= itemsToInsertBeforeCurrentRange + range.index) {
  71             m_logicalHeightHintCache[targetIndex] = std::make_pair(0.0, false);
  72             --targetIndex;
  73         }
  74     }
  75
  76     m_needsResolving = true;
  77
  78     Q_ASSERT(m_logicalHeightHintCache.count() == m_itemListView->model()->count());
  79 }
  80
  81 void KItemListSizeHintResolver::itemsRemoved(const KItemRangeList &itemRanges)
  82 {
  83     const QVector<std::pair<qreal, bool>>::iterator begin = m_logicalHeightHintCache.begin();
  84     const QVector<std::pair<qreal, bool>>::iterator end = m_logicalHeightHintCache.end();
  85
  86     KItemRangeList::const_iterator rangeIt = itemRanges.constBegin();
  87     const KItemRangeList::const_iterator rangeEnd = itemRanges.constEnd();
  88
  89     QVector<std::pair<qreal, bool>>::iterator destIt = begin + rangeIt->index;
  90     QVector<std::pair<qreal, bool>>::iterator srcIt = destIt + rangeIt->count;
  91
  92     ++rangeIt;
  93
  94     while (srcIt != end) {
  95         *destIt = *srcIt;
  96         ++destIt;
  97         ++srcIt;
  98
  99         if (rangeIt != rangeEnd && srcIt == begin + rangeIt->index) {
 100             // Skip the items in the next removed range.
 101             srcIt += rangeIt->count;
 102             ++rangeIt;
 103         }
 104     }
 105
 106     m_logicalHeightHintCache.erase(destIt, end);
 107
 108     // Note that the cache size might temporarily not match the model size if
 109     // this function is called from KItemListView::setModel() to empty the cache.
 110     if (!m_logicalHeightHintCache.isEmpty() && m_itemListView->model()) {
 111         Q_ASSERT(m_logicalHeightHintCache.count() == m_itemListView->model()->count());
 112     }
 113 }
 114
 115 void KItemListSizeHintResolver::itemsMoved(const KItemRange &range, const QList<int> &movedToIndexes)
 116 {
 117     QVector<std::pair<qreal, bool>> newLogicalHeightHintCache(m_logicalHeightHintCache);
 118
 119     const int movedRangeEnd = range.index + range.count;
 120     for (int i = range.index; i < movedRangeEnd; ++i) {
 121         const int newIndex = movedToIndexes.at(i - range.index);
 122         newLogicalHeightHintCache[newIndex] = m_logicalHeightHintCache.at(i);
 123     }
 124
 125     m_logicalHeightHintCache = newLogicalHeightHintCache;
 126 }
 127
 128 void KItemListSizeHintResolver::itemsChanged(int index, int count, const QSet<QByteArray> &roles)
 129 {
 130     Q_UNUSED(roles)
 131     while (count) {
 132         m_logicalHeightHintCache[index] = std::make_pair(0.0, false);
 133         ++index;
 134         --count;
 135     }
 136
 137     m_needsResolving = true;
 138 }
 139
 140 void KItemListSizeHintResolver::clearCache()
 141 {
 142     m_logicalHeightHintCache.fill(std::make_pair(0.0, false));
 143     m_needsResolving = true;
 144 }
 145
 146 void KItemListSizeHintResolver::updateCache()
 147 {
 148     if (m_needsResolving) {
 149         m_itemListView->calculateItemSizeHints(m_logicalHeightHintCache, m_logicalWidthHint);
 150         m_needsResolving = false;
 151     }
 152 }