git.iko.soy/unity8
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unity8/plugins/Dash/verticaljournal.cpp
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1/*
2 * Copyright (C) 2013 Canonical, Ltd.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; version 3.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program. If not, see <http://www.gnu.org/licenses/>.
15 */
17/*
18 * The implementation is centered around m_columnVisibleItems
19 * that holds a vector of lists. There's a list for each of the
20 * columns the view has. In the list the items of the column are
21 * ordered as they appear topdown in the view. m_indexColumnMap is
22 * used when re-building the list up since given a position
23 * in the middle of the list and the need to create the previous does
24 * not give us enough information to know in which column we have
25 * to position the item so that when we reach the item the view is
26 * correctly layouted at 0 for all the columns
27 */
28#include "verticaljournal.h"
30#include <private/qquickitem_p.h>
32VerticalJournal::VerticalJournal()
33 : m_columnWidth(0)
37qreal VerticalJournal::columnWidth() const
39 return m_columnWidth;
42void VerticalJournal::setColumnWidth(qreal columnWidth)
44 if (columnWidth != m_columnWidth) {
45 m_columnWidth = columnWidth;
46 Q_EMIT columnWidthChanged();
48 if (isComponentComplete()) {
49 Q_FOREACH(const auto &column, m_columnVisibleItems) {
50 Q_FOREACH(const ViewItem item, column) {
51 item.m_item->setWidth(columnWidth);
52 }
53 }
54 relayout();
55 }
56 }
59void VerticalJournal::findBottomModelIndexToAdd(int *modelIndex, qreal *yPos)
61 *modelIndex = 0;
62 *yPos = std::numeric_limits<qreal>::max();
64 Q_FOREACH(const auto &column, m_columnVisibleItems) {
65 if (!column.isEmpty()) {
66 const ViewItem &item = column.last();
67 *yPos = qMin(*yPos, item.y() + item.height() + rowSpacing());
68 *modelIndex = qMax(*modelIndex, item.m_modelIndex + 1);
69 } else {
70 *yPos = 0;
71 }
72 }
75void VerticalJournal::findTopModelIndexToAdd(int *modelIndex, qreal *yPos)
77 *modelIndex = 0;
78 *yPos = std::numeric_limits<qreal>::lowest();
79 int columnToAddTo = -1;
81 // Find the topmost free column
82 for (int i = 0; i < m_columnVisibleItems.count(); ++i) {
83 const auto &column = m_columnVisibleItems[i];
84 if (!column.isEmpty()) {
85 const ViewItem &item = column.first();
86 const auto itemTopPos = item.y() - rowSpacing();
87 if (itemTopPos > *yPos) {
88 *yPos = itemTopPos;
89 *modelIndex = item.m_modelIndex - 1;
90 columnToAddTo = i;
91 }
92 }
93 }
95 if (*modelIndex > 0) {
96 Q_ASSERT(m_indexColumnMap.contains(*modelIndex));
97 while (m_indexColumnMap[*modelIndex] != columnToAddTo) {
98 // We found out that we have to add to columnToAddTo
99 // and thought that we had to add *modelIndex, but history tells
100 // it is not correct, so find up from *modelIndex until we found the index
101 // that has to end up in columnToAddTo
102 *modelIndex = *modelIndex - 1;
103 Q_ASSERT(m_indexColumnMap.contains(*modelIndex));
104 }
105 }
108bool VerticalJournal::removeNonVisibleItems(qreal bufferFromY, qreal bufferToY)
110 bool changed = false;
112 for (int i = 0; i < m_columnVisibleItems.count(); ++i) {
113 QList<ViewItem> &column = m_columnVisibleItems[i];
114 while (!column.isEmpty() && column.first().y() + column.first().height() < bufferFromY) {
115 releaseItem(column.takeFirst().m_item);
116 changed = true;
117 }
119 while (!column.isEmpty() && column.last().y() > bufferToY) {
120 releaseItem(column.takeLast().m_item);
121 changed = true;
122 }
123 }
125 return changed;
128void VerticalJournal::addItemToView(int modelIndex, QQuickItem *item)
130 if (item->width() != m_columnWidth) {
131 qWarning() << "Item" << modelIndex << "width is not the one that the columnWidth mandates, resetting it";
132 item->setWidth(m_columnWidth);
133 }
135 // Check if we add it to the bottom of existing column items
136 const QList<ViewItem> &firstColumn = m_columnVisibleItems[0];
137 qreal columnToAddY = !firstColumn.isEmpty() ? firstColumn.last().y() + firstColumn.last().height() : -rowSpacing();
138 int columnToAddTo = 0;
139 for (int i = 1; i < m_columnVisibleItems.count(); ++i) {
140 const QList<ViewItem> &column = m_columnVisibleItems[i];
141 const qreal iY = !column.isEmpty() ? column.last().y() + column.last().height() : -rowSpacing();
142 if (iY < columnToAddY) {
143 columnToAddTo = i;
144 columnToAddY = iY;
145 }
146 }
148 const QList<ViewItem> &columnToAdd = m_columnVisibleItems[columnToAddTo];
149 if (columnToAdd.isEmpty() || columnToAdd.last().m_modelIndex < modelIndex) {
150 item->setX(columnToAddTo * (m_columnWidth + columnSpacing()));
151 item->setY(columnToAddY + rowSpacing());
153 m_columnVisibleItems[columnToAddTo] << ViewItem(item, modelIndex);
154 m_indexColumnMap[modelIndex] = columnToAddTo;
155 } else {
156 Q_ASSERT(m_indexColumnMap.contains(modelIndex));
157 columnToAddTo = m_indexColumnMap[modelIndex];
158 columnToAddY = m_columnVisibleItems[columnToAddTo].first().y();
160 item->setX(columnToAddTo * (m_columnWidth + columnSpacing()));
161 item->setY(columnToAddY - rowSpacing() - item->height());
163 m_columnVisibleItems[columnToAddTo].prepend(ViewItem(item, modelIndex));
164 }
167void VerticalJournal::cleanupExistingItems()
169 // Cleanup the existing items
170 for (int i = 0; i < m_columnVisibleItems.count(); ++i) {
171 QList<ViewItem> &column = m_columnVisibleItems[i];
172 Q_FOREACH(const ViewItem item, column)
173 releaseItem(item.m_item);
174 column.clear();
175 }
176 m_indexColumnMap.clear();
177 setImplicitHeightDirty();
180void VerticalJournal::calculateImplicitHeight()
182 int lastModelIndex = -1;
183 qreal bottomMostY = 0;
184 Q_FOREACH(const auto &column, m_columnVisibleItems) {
185 if (!column.isEmpty()) {
186 const ViewItem &item = column.last();
187 lastModelIndex = qMax(lastModelIndex, item.m_modelIndex);
188 bottomMostY = qMax(bottomMostY, item.y() + item.height());
189 }
190 }
191 if (lastModelIndex >= 0) {
192 const double averageHeight = bottomMostY / (lastModelIndex + 1);
193 setImplicitHeight(bottomMostY + averageHeight * (model()->rowCount() - lastModelIndex - 1));
194 } else {
195 setImplicitHeight(0);
196 }
199void VerticalJournal::doRelayout()
201 QList<ViewItem> allItems;
202 Q_FOREACH(const auto &column, m_columnVisibleItems)
203 allItems << column;
205 qSort(allItems);
207 const int nColumns = qMax(1., floor((double)(width() + columnSpacing()) / (m_columnWidth + columnSpacing())));
208 m_columnVisibleItems.resize(nColumns);
209 m_indexColumnMap.clear();
210 for (int i = 0; i < nColumns; ++i)
211 m_columnVisibleItems[i].clear();
213 // If the first of allItems doesn't contain index 0 we need to drop them
214 // all since we can't consistently relayout without the first item being there
216 if (!allItems.isEmpty()) {
217 if (allItems.first().m_modelIndex == 0) {
218 Q_FOREACH(const ViewItem item, allItems)
219 addItemToView(item.m_modelIndex, item.m_item);
220 } else {
221 Q_FOREACH(const ViewItem item, allItems)
222 releaseItem(item.m_item);
223 }
224 }
227void VerticalJournal::updateItemCulling(qreal visibleFromY, qreal visibleToY)
229 Q_FOREACH(const auto &column, m_columnVisibleItems) {
230 Q_FOREACH(const ViewItem item, column) {
231 const bool cull = item.y() + item.height() <= visibleFromY || item.y() >= visibleToY;
232 QQuickItemPrivate::get(item.m_item)->setCulled(cull);
233 }
234 }
237void VerticalJournal::processModelRemoves(const QVector<QQmlChangeSet::Change> &removes)
239 Q_FOREACH(const QQmlChangeSet::Change remove, removes) {
240 for (int i = remove.count - 1; i >= 0; --i) {
241 const int indexToRemove = remove.index + i;
242 // Since we only support removing from the end, indexToRemove
243 // must refer to the last item of one of the columns or
244 // be bigger than them (because it's not in the viewport and
245 // thus we have not created a delegate for it)
246 bool found = false;
247 int lastCreatedIndex = INT_MIN;
248 for (int i = 0; !found && i < m_columnVisibleItems.count(); ++i) {
249 QList<ViewItem> &column = m_columnVisibleItems[i];
250 if (!column.isEmpty()) {
251 const int lastColumnIndex = column.last().m_modelIndex;
252 if (lastColumnIndex == indexToRemove) {
253 releaseItem(column.takeLast().m_item);
254 found = true;
255 }
256 lastCreatedIndex = qMax(lastCreatedIndex, lastColumnIndex);
257 }
258 }
259 if (!found) {
260 if (indexToRemove < lastCreatedIndex) {
261 qDebug() << "VerticalJournal only supports removal from the end of the model, resetting instead";
262 cleanupExistingItems();
263 break;
264 } else {
265 setImplicitHeightDirty();
266 }
267 }
268 }
269 }