git.iko.soy/unity8
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unity8/plugins/Dash/verticaljournal.cpp
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1/*
2 * Copyright (C) 2013, 2016 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 <math.h>
32#include <private/qquickitem_p.h>
34VerticalJournal::VerticalJournal()
35 : m_columnWidth(0)
39qreal VerticalJournal::columnWidth() const
41 return m_columnWidth;
44void VerticalJournal::setColumnWidth(qreal columnWidth)
46 if (columnWidth != m_columnWidth) {
47 m_columnWidth = columnWidth;
48 Q_EMIT columnWidthChanged();
50 if (isComponentComplete()) {
51 Q_FOREACH(const auto &column, m_columnVisibleItems) {
52 Q_FOREACH(const ViewItem item, column) {
53 item.m_item->setWidth(columnWidth);
54 }
55 }
56 relayout();
57 }
58 }
61void VerticalJournal::findBottomModelIndexToAdd(int *modelIndex, qreal *yPos)
63 *modelIndex = 0;
64 *yPos = std::numeric_limits<qreal>::max();
66 Q_FOREACH(const auto &column, m_columnVisibleItems) {
67 if (!column.isEmpty()) {
68 const ViewItem &item = column.last();
69 *yPos = qMin(*yPos, item.y() + item.height() + rowSpacing());
70 *modelIndex = qMax(*modelIndex, item.m_modelIndex + 1);
71 } else {
72 *yPos = 0;
73 }
74 }
77void VerticalJournal::findTopModelIndexToAdd(int *modelIndex, qreal *yPos)
79 *modelIndex = 0;
80 *yPos = std::numeric_limits<qreal>::lowest();
81 int columnToAddTo = -1;
83 // Find the topmost free column
84 for (int i = 0; i < m_columnVisibleItems.count(); ++i) {
85 const auto &column = m_columnVisibleItems[i];
86 if (!column.isEmpty()) {
87 const ViewItem &item = column.first();
88 const auto itemTopPos = item.y() - rowSpacing();
89 if (itemTopPos > *yPos) {
90 *yPos = itemTopPos;
91 *modelIndex = item.m_modelIndex - 1;
92 columnToAddTo = i;
93 }
94 }
95 }
97 if (*modelIndex > 0) {
98 Q_ASSERT(m_indexColumnMap.contains(*modelIndex));
99 while (*modelIndex > 0 && m_indexColumnMap[*modelIndex] != columnToAddTo) {
100 // We found out that we have to add to columnToAddTo
101 // and thought that we had to add *modelIndex, but history tells
102 // it is not correct, so find up from *modelIndex until we found the index
103 // that has to end up in columnToAddTo
104 *modelIndex = *modelIndex - 1;
105 Q_ASSERT(m_indexColumnMap.contains(*modelIndex));
106 }
107 }
110bool VerticalJournal::removeNonVisibleItems(qreal bufferFromY, qreal bufferToY)
112 bool changed = false;
114 for (int i = 0; i < m_columnVisibleItems.count(); ++i) {
115 QList<ViewItem> &column = m_columnVisibleItems[i];
116 while (!column.isEmpty() && column.first().y() + column.first().height() < bufferFromY) {
117 releaseItem(column.takeFirst().m_item);
118 changed = true;
119 }
121 while (!column.isEmpty() && column.last().y() > bufferToY) {
122 releaseItem(column.takeLast().m_item);
123 changed = true;
124 }
125 }
127 return changed;
130void VerticalJournal::addItemToView(int modelIndex, QQuickItem *item)
132 if (item->width() != m_columnWidth) {
133 qWarning() << "Item" << modelIndex << "width is not the one that the columnWidth mandates, resetting it";
134 item->setWidth(m_columnWidth);
135 }
137 // Check if we add it to the bottom of existing column items
138 const QList<ViewItem> &firstColumn = m_columnVisibleItems[0];
139 qreal columnToAddY = !firstColumn.isEmpty() ? firstColumn.last().y() + firstColumn.last().height() : -rowSpacing();
140 int columnToAddTo = 0;
141 for (int i = 1; i < m_columnVisibleItems.count(); ++i) {
142 const QList<ViewItem> &column = m_columnVisibleItems[i];
143 const qreal iY = !column.isEmpty() ? column.last().y() + column.last().height() : -rowSpacing();
144 if (iY < columnToAddY) {
145 columnToAddTo = i;
146 columnToAddY = iY;
147 }
148 }
150 const QList<ViewItem> &columnToAdd = m_columnVisibleItems[columnToAddTo];
151 if (columnToAdd.isEmpty() || columnToAdd.last().m_modelIndex < modelIndex) {
152 item->setX(columnToAddTo * (m_columnWidth + columnSpacing()));
153 item->setY(columnToAddY + rowSpacing());
155 m_columnVisibleItems[columnToAddTo] << ViewItem(item, modelIndex);
156 m_indexColumnMap[modelIndex] = columnToAddTo;
157 } else {
158 Q_ASSERT(m_indexColumnMap.contains(modelIndex));
159 columnToAddTo = m_indexColumnMap[modelIndex];
160 columnToAddY = m_columnVisibleItems[columnToAddTo].first().y();
162 item->setX(columnToAddTo * (m_columnWidth + columnSpacing()));
163 item->setY(columnToAddY - rowSpacing() - item->height());
165 m_columnVisibleItems[columnToAddTo].prepend(ViewItem(item, modelIndex));
166 }
169void VerticalJournal::cleanupExistingItems()
171 // Cleanup the existing items
172 for (int i = 0; i < m_columnVisibleItems.count(); ++i) {
173 QList<ViewItem> &column = m_columnVisibleItems[i];
174 Q_FOREACH(const ViewItem item, column)
175 releaseItem(item.m_item);
176 column.clear();
177 }
178 m_indexColumnMap.clear();
179 setImplicitHeightDirty();
182void VerticalJournal::calculateImplicitHeight()
184 int lastModelIndex = -1;
185 qreal bottomMostY = 0;
186 Q_FOREACH(const auto &column, m_columnVisibleItems) {
187 if (!column.isEmpty()) {
188 const ViewItem &item = column.last();
189 lastModelIndex = qMax(lastModelIndex, item.m_modelIndex);
190 bottomMostY = qMax(bottomMostY, item.y() + item.height());
191 }
192 }
193 if (lastModelIndex >= 0) {
194 const double averageHeight = bottomMostY / (lastModelIndex + 1);
195 setImplicitHeight(bottomMostY + averageHeight * (model()->rowCount() - lastModelIndex - 1));
196 } else {
197 setImplicitHeight(0);
198 }
201void VerticalJournal::doRelayout()
203 QList<ViewItem> allItems;
204 Q_FOREACH(const auto &column, m_columnVisibleItems)
205 allItems << column;
207 qSort(allItems);
209 const int nColumns = qMax(1., floor((double)(width() + columnSpacing()) / (m_columnWidth + columnSpacing())));
210 m_columnVisibleItems.resize(nColumns);
211 m_indexColumnMap.clear();
212 for (int i = 0; i < nColumns; ++i)
213 m_columnVisibleItems[i].clear();
215 // If the first of allItems doesn't contain index 0 we need to drop them
216 // all since we can't consistently relayout without the first item being there
218 if (!allItems.isEmpty()) {
219 if (allItems.first().m_modelIndex == 0) {
220 Q_FOREACH(const ViewItem item, allItems)
221 addItemToView(item.m_modelIndex, item.m_item);
222 } else {
223 Q_FOREACH(const ViewItem item, allItems)
224 releaseItem(item.m_item);
225 }
226 }
229void VerticalJournal::updateItemCulling(qreal visibleFromY, qreal visibleToY)
231 Q_FOREACH(const auto &column, m_columnVisibleItems) {
232 Q_FOREACH(const ViewItem item, column) {
233 const bool cull = item.y() + item.height() <= visibleFromY || item.y() >= visibleToY;
234 QQuickItemPrivate::get(item.m_item)->setCulled(cull);
235 }
236 }
239void VerticalJournal::processModelRemoves(const QVector<QQmlChangeSet::Change> &removes)
241 Q_FOREACH(const QQmlChangeSet::Change remove, removes) {
242 for (int i = remove.count - 1; i >= 0; --i) {
243 const int indexToRemove = remove.index + i;
244 // Since we only support removing from the end, indexToRemove
245 // must refer to the last item of one of the columns or
246 // be bigger than them (because it's not in the viewport and
247 // thus we have not created a delegate for it)
248 bool found = false;
249 int lastCreatedIndex = INT_MIN;
250 for (int i = 0; !found && i < m_columnVisibleItems.count(); ++i) {
251 QList<ViewItem> &column = m_columnVisibleItems[i];
252 if (!column.isEmpty()) {
253 const int lastColumnIndex = column.last().m_modelIndex;
254 if (lastColumnIndex == indexToRemove) {
255 releaseItem(column.takeLast().m_item);
256 found = true;
257 }
258 lastCreatedIndex = qMax(lastCreatedIndex, lastColumnIndex);
259 }
260 }
261 if (!found) {
262 if (indexToRemove < lastCreatedIndex) {
263 qDebug() << "VerticalJournal only supports removal from the end of the model, resetting instead";
264 cleanupExistingItems();
265 break;
266 } else {
267 setImplicitHeightDirty();
268 }
269 }
270 }
271 }
274void VerticalJournal::itemGeometryChanged(QQuickItem * /*item*/, const QRectF &newGeometry, const QRectF &oldGeometry)
276 const qreal heightDiff = newGeometry.height() - oldGeometry.height();
277 if (heightDiff != 0) {
278 relayout();
279 }