src/kitemviews/kitemlistviewlayouter.cpp

   1 /***************************************************************************
   2  *   Copyright (C) 2011 by Peter Penz <peter.penz19@gmail.com>             *
   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; either version 2 of the License, or     *
   7  *   (at your option) any later version.                                   *
   8  *                                                                         *
   9  *   This program is distributed in the hope that it will be useful,       *
  10  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  11  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  12  *   GNU General Public License for more details.                          *
  13  *                                                                         *
  14  *   You should have received a copy of the GNU General Public License     *
  15  *   along with this program; if not, write to the                         *
  16  *   Free Software Foundation, Inc.,                                       *
  17  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  18  ***************************************************************************/
  19
  20 #include "kitemlistviewlayouter_p.h"
  21
  22 #include "kitemmodelbase.h"
  23 #include "kitemlistsizehintresolver_p.h"
  24
  25 #include <KDebug>
  26
  27 #define KITEMLISTVIEWLAYOUTER_DEBUG
  28
  29 namespace {
  30     // TODO
  31     const int HeaderHeight = 50;
  32 };
  33
  34 KItemListViewLayouter::KItemListViewLayouter(QObject* parent) :
  35     QObject(parent),
  36     m_dirty(true),
  37     m_visibleIndexesDirty(true),
  38     m_grouped(false),
  39     m_scrollOrientation(Qt::Vertical),
  40     m_size(),
  41     m_itemSize(128, 128),
  42     m_headerHeight(0),
  43     m_model(0),
  44     m_sizeHintResolver(0),
  45     m_scrollOffset(0),
  46     m_maximumScrollOffset(0),
  47     m_itemOffset(0),
  48     m_maximumItemOffset(0),
  49     m_firstVisibleIndex(-1),
  50     m_lastVisibleIndex(-1),
  51     m_firstVisibleGroupIndex(-1),
  52     m_columnWidth(0),
  53     m_xPosInc(0),
  54     m_columnCount(0),
  55     m_groups(),
  56     m_groupIndexes(),
  57     m_itemBoundingRects()
  58 {
  59 }
  60
  61 KItemListViewLayouter::~KItemListViewLayouter()
  62 {
  63 }
  64
  65 void KItemListViewLayouter::setScrollOrientation(Qt::Orientation orientation)
  66 {
  67     if (m_scrollOrientation != orientation) {
  68         m_scrollOrientation = orientation;
  69         m_dirty = true;
  70     }
  71 }
  72
  73 Qt::Orientation KItemListViewLayouter::scrollOrientation() const
  74 {
  75     return m_scrollOrientation;
  76 }
  77
  78 void KItemListViewLayouter::setSize(const QSizeF& size)
  79 {
  80     if (m_size != size) {
  81         m_size = size;
  82         m_dirty = true;
  83     }
  84 }
  85
  86 QSizeF KItemListViewLayouter::size() const
  87 {
  88     return m_size;
  89 }
  90
  91 void KItemListViewLayouter::setItemSize(const QSizeF& size)
  92 {
  93     if (m_itemSize != size) {
  94         m_itemSize = size;
  95         m_dirty = true;
  96     }
  97 }
  98
  99 QSizeF KItemListViewLayouter::itemSize() const
 100 {
 101     return m_itemSize;
 102 }
 103
 104 void KItemListViewLayouter::setHeaderHeight(qreal height)
 105 {
 106     if (m_headerHeight != height) {
 107         m_headerHeight = height;
 108         m_dirty = true;
 109     }
 110 }
 111
 112 qreal KItemListViewLayouter::headerHeight() const
 113 {
 114     return m_headerHeight;
 115 }
 116
 117 void KItemListViewLayouter::setScrollOffset(qreal offset)
 118 {
 119     if (m_scrollOffset != offset) {
 120         m_scrollOffset = offset;
 121         m_visibleIndexesDirty = true;
 122     }
 123 }
 124
 125 qreal KItemListViewLayouter::scrollOffset() const
 126 {
 127     return m_scrollOffset;
 128 }
 129
 130 qreal KItemListViewLayouter::maximumScrollOffset() const
 131 {
 132     const_cast<KItemListViewLayouter*>(this)->doLayout();
 133     return m_maximumScrollOffset;
 134 }
 135
 136 void KItemListViewLayouter::setItemOffset(qreal offset)
 137 {
 138     if (m_itemOffset != offset) {
 139         m_itemOffset = offset;
 140         m_visibleIndexesDirty = true;
 141     }
 142 }
 143
 144 qreal KItemListViewLayouter::itemOffset() const
 145 {
 146     return m_itemOffset;
 147 }
 148
 149 qreal KItemListViewLayouter::maximumItemOffset() const
 150 {
 151     const_cast<KItemListViewLayouter*>(this)->doLayout();
 152     return m_maximumItemOffset;
 153 }
 154
 155 void KItemListViewLayouter::setModel(const KItemModelBase* model)
 156 {
 157     if (m_model != model) {
 158         m_model = model;
 159         m_dirty = true;
 160     }
 161 }
 162
 163 const KItemModelBase* KItemListViewLayouter::model() const
 164 {
 165     return m_model;
 166 }
 167
 168 void KItemListViewLayouter::setSizeHintResolver(const KItemListSizeHintResolver* sizeHintResolver)
 169 {
 170     if (m_sizeHintResolver != sizeHintResolver) {
 171         m_sizeHintResolver = sizeHintResolver;
 172         m_dirty = true;
 173     }
 174 }
 175
 176 const KItemListSizeHintResolver* KItemListViewLayouter::sizeHintResolver() const
 177 {
 178     return m_sizeHintResolver;
 179 }
 180
 181 int KItemListViewLayouter::firstVisibleIndex() const
 182 {
 183     const_cast<KItemListViewLayouter*>(this)->doLayout();
 184     return m_firstVisibleIndex;
 185 }
 186
 187 int KItemListViewLayouter::lastVisibleIndex() const
 188 {
 189     const_cast<KItemListViewLayouter*>(this)->doLayout();
 190     return m_lastVisibleIndex;
 191 }
 192
 193 QRectF KItemListViewLayouter::itemBoundingRect(int index) const
 194 {
 195     const_cast<KItemListViewLayouter*>(this)->doLayout();
 196     if (index < 0 || index >= m_itemBoundingRects.count()) {
 197         return QRectF();
 198     }
 199
 200     if (m_scrollOrientation == Qt::Horizontal) {
 201         // Rotate the logical direction which is always vertical by 90°
 202         // to get the physical horizontal direction
 203         const QRectF& b = m_itemBoundingRects[index];
 204         QRectF bounds(b.y(), b.x(), b.height(), b.width());
 205         QPointF pos = bounds.topLeft();
 206         pos.rx() -= m_scrollOffset;
 207         bounds.moveTo(pos);
 208         return bounds;
 209     }
 210
 211     QRectF bounds = m_itemBoundingRects[index];
 212     bounds.moveTo(bounds.topLeft() - QPointF(m_itemOffset, m_scrollOffset));
 213     return bounds;
 214 }
 215
 216 int KItemListViewLayouter::maximumVisibleItems() const
 217 {
 218     const_cast<KItemListViewLayouter*>(this)->doLayout();
 219
 220     const int height = static_cast<int>(m_size.height());
 221     const int rowHeight = static_cast<int>(m_itemSize.height());
 222     int rows = height / rowHeight;
 223     if (height % rowHeight != 0) {
 224         ++rows;
 225     }
 226
 227     return rows * m_columnCount;
 228 }
 229
 230 int KItemListViewLayouter::itemsPerOffset() const
 231 {
 232     return m_columnCount;
 233 }
 234
 235 bool KItemListViewLayouter::isFirstGroupItem(int itemIndex) const
 236 {
 237     return m_groupIndexes.contains(itemIndex);
 238 }
 239
 240 void KItemListViewLayouter::markAsDirty()
 241 {
 242     m_dirty = true;
 243 }
 244
 245 void KItemListViewLayouter::doLayout()
 246 {
 247     if (m_dirty) {
 248 #ifdef KITEMLISTVIEWLAYOUTER_DEBUG
 249         QElapsedTimer timer;
 250         timer.start();
 251 #endif
 252         m_visibleIndexesDirty = true;
 253
 254         QSizeF itemSize = m_itemSize;
 255         QSizeF size = m_size;
 256
 257         const bool horizontalScrolling = (m_scrollOrientation == Qt::Horizontal);
 258         if (horizontalScrolling) {
 259             itemSize.setWidth(m_itemSize.height());
 260             itemSize.setHeight(m_itemSize.width());
 261             size.setWidth(m_size.height());
 262             size.setHeight(m_size.width());
 263         }
 264
 265         m_columnWidth = itemSize.width();
 266         m_columnCount = qMax(1, int(size.width() / m_columnWidth));
 267         m_xPosInc = 0;
 268
 269         const int itemCount = m_model->count();
 270         if (itemCount > m_columnCount) {
 271             // Apply the unused width equally to each column
 272             const qreal unusedWidth = size.width() - m_columnCount * m_columnWidth;
 273             if (unusedWidth > 0) {
 274                 const qreal columnInc = unusedWidth / (m_columnCount + 1);
 275                 m_columnWidth += columnInc;
 276                 m_xPosInc += columnInc;
 277             }
 278         }
 279
 280         int rowCount = itemCount / m_columnCount;
 281         if (itemCount % m_columnCount != 0) {
 282             ++rowCount;
 283         }
 284
 285         m_itemBoundingRects.reserve(itemCount);
 286
 287         qreal y = m_headerHeight;
 288         int rowIndex = 0;
 289
 290         int index = 0;
 291         while (index < itemCount) {
 292             qreal x = m_xPosInc;
 293             qreal maxItemHeight = itemSize.height();
 294
 295             int column = 0;
 296             while (index < itemCount && column < m_columnCount) {
 297                 qreal requiredItemHeight = itemSize.height();
 298                 if (m_sizeHintResolver) {
 299                     const QSizeF sizeHint = m_sizeHintResolver->sizeHint(index);
 300                     const qreal sizeHintHeight = horizontalScrolling ? sizeHint.width() : sizeHint.height();
 301                     if (sizeHintHeight > requiredItemHeight) {
 302                         requiredItemHeight = sizeHintHeight;
 303                     }
 304                 }
 305
 306                 const QRectF bounds(x, y, itemSize.width(), requiredItemHeight);
 307                 if (index < m_itemBoundingRects.count()) {
 308                     m_itemBoundingRects[index] = bounds;
 309                 } else {
 310                     m_itemBoundingRects.append(bounds);
 311                 }
 312
 313                 maxItemHeight = qMax(maxItemHeight, requiredItemHeight);
 314                 x += m_columnWidth;
 315                 ++index;
 316                 ++column;
 317             }
 318
 319             y += maxItemHeight;
 320             ++rowIndex;
 321         }
 322         if (m_itemBoundingRects.count() > itemCount) {
 323             m_itemBoundingRects.erase(m_itemBoundingRects.begin() + itemCount,
 324                                       m_itemBoundingRects.end());
 325         }
 326
 327         if (itemCount > 0) {
 328             m_maximumScrollOffset = m_itemBoundingRects.last().bottom();
 329             m_maximumItemOffset = m_columnCount * m_columnWidth;
 330         } else {
 331             m_maximumScrollOffset = 0;
 332             m_maximumItemOffset = 0;
 333         }
 334
 335         m_grouped = m_model->groupedSorting();
 336         if (m_grouped) {
 337             createGroupHeaders();
 338
 339             const int lastGroupItemCount = m_model->count() - m_groups.last().firstItemIndex;
 340             m_maximumScrollOffset = m_groups.last().y + (lastGroupItemCount / m_columnCount) * itemSize.height();
 341             if (lastGroupItemCount % m_columnCount != 0) {
 342                 m_maximumScrollOffset += itemSize.height();
 343             }
 344         }
 345
 346 #ifdef KITEMLISTVIEWLAYOUTER_DEBUG
 347         kDebug() << "[TIME] doLayout() for " << m_model->count() << "items:" << timer.elapsed();
 348 #endif
 349         m_dirty = false;
 350     }
 351
 352     if (m_grouped) {
 353         updateGroupedVisibleIndexes();
 354     } else {
 355         updateVisibleIndexes();
 356     }
 357 }
 358
 359 void KItemListViewLayouter::updateVisibleIndexes()
 360 {
 361     if (!m_visibleIndexesDirty) {
 362         return;
 363     }
 364
 365     Q_ASSERT(!m_grouped);
 366     Q_ASSERT(!m_dirty);
 367
 368     if (m_model->count() <= 0) {
 369         m_firstVisibleIndex = -1;
 370         m_lastVisibleIndex = -1;
 371         m_visibleIndexesDirty = false;
 372         return;
 373     }
 374
 375     const bool horizontalScrolling = (m_scrollOrientation == Qt::Horizontal);
 376     const int minimumHeight =  horizontalScrolling ? m_itemSize.width()
 377                                                    : m_itemSize.height();
 378
 379     // Calculate the first visible index:
 380     // 1. Guess the index by using the minimum row height
 381     const int maxIndex = m_model->count() - 1;
 382     m_firstVisibleIndex = int(m_scrollOffset / minimumHeight) * m_columnCount;
 383
 384     // 2. Decrease the index by checking the real row heights
 385     int prevRowIndex = m_firstVisibleIndex - m_columnCount;
 386     while (prevRowIndex > maxIndex) {
 387         prevRowIndex -= m_columnCount;
 388     }
 389
 390     const qreal top = m_scrollOffset + m_headerHeight;
 391     while (prevRowIndex >= 0 && m_itemBoundingRects[prevRowIndex].bottom() >= top) {
 392         m_firstVisibleIndex = prevRowIndex;
 393         prevRowIndex -= m_columnCount;
 394     }
 395     m_firstVisibleIndex = qBound(0, m_firstVisibleIndex, maxIndex);
 396
 397     // Calculate the last visible index
 398     const int visibleHeight = horizontalScrolling ? m_size.width() : m_size.height();
 399     const qreal bottom = m_scrollOffset + visibleHeight;
 400     m_lastVisibleIndex = m_firstVisibleIndex; // first visible row, first column
 401     int nextRowIndex = m_lastVisibleIndex + m_columnCount;
 402     while (nextRowIndex <= maxIndex && m_itemBoundingRects[nextRowIndex].y() <= bottom) {
 403         m_lastVisibleIndex = nextRowIndex;
 404         nextRowIndex += m_columnCount;
 405     }
 406     m_lastVisibleIndex += m_columnCount - 1; // move it to the last column
 407     m_lastVisibleIndex = qBound(0, m_lastVisibleIndex, maxIndex);
 408
 409     m_visibleIndexesDirty = false;
 410 }
 411
 412 void KItemListViewLayouter::updateGroupedVisibleIndexes()
 413 {
 414     if (!m_visibleIndexesDirty) {
 415         return;
 416     }
 417
 418     Q_ASSERT(m_grouped);
 419     Q_ASSERT(!m_dirty);
 420
 421     if (m_model->count() <= 0) {
 422         m_firstVisibleIndex = -1;
 423         m_lastVisibleIndex = -1;
 424         m_visibleIndexesDirty = false;
 425         return;
 426     }
 427
 428     // Find the first visible group
 429     const int lastGroupIndex = m_groups.count() - 1;
 430     int groupIndex = lastGroupIndex;
 431     for (int i = 1; i < m_groups.count(); ++i) {
 432         if (m_groups[i].y >= m_scrollOffset) {
 433             groupIndex = i - 1;
 434             break;
 435         }
 436     }
 437
 438     // Calculate the first visible index
 439     qreal groupY = m_groups[groupIndex].y;
 440     m_firstVisibleIndex = m_groups[groupIndex].firstItemIndex;
 441     const int invisibleRowCount = int(m_scrollOffset - groupY) / int(m_itemSize.height());
 442     m_firstVisibleIndex += invisibleRowCount * m_columnCount;
 443     if (groupIndex + 1 <= lastGroupIndex) {
 444         // Check whether the calculated first visible index remains inside the current
 445         // group. If this is not the case let the first element of the next group be the first
 446         // visible index.
 447         const int nextGroupIndex = m_groups[groupIndex + 1].firstItemIndex;
 448         if (m_firstVisibleIndex > nextGroupIndex) {
 449             m_firstVisibleIndex = nextGroupIndex;
 450         }
 451     }
 452
 453     m_firstVisibleGroupIndex = groupIndex;
 454
 455     const int maxIndex = m_model->count() - 1;
 456     m_firstVisibleIndex = qBound(0, m_firstVisibleIndex, maxIndex);
 457
 458     // Calculate the last visible index: Find group where the last visible item is shown.
 459     const qreal visibleBottom = m_scrollOffset + m_size.height(); // TODO: respect Qt::Horizontal alignment
 460     while ((groupIndex < lastGroupIndex) && (m_groups[groupIndex + 1].y < visibleBottom)) {
 461         ++groupIndex;
 462     }
 463
 464     groupY = m_groups[groupIndex].y;
 465     m_lastVisibleIndex = m_groups[groupIndex].firstItemIndex;
 466     const int availableHeight = static_cast<int>(visibleBottom - groupY);
 467     int visibleRowCount = availableHeight / int(m_itemSize.height());
 468     if (availableHeight % int(m_itemSize.height()) != 0) {
 469         ++visibleRowCount;
 470     }
 471     m_lastVisibleIndex += visibleRowCount * m_columnCount - 1;
 472
 473     if (groupIndex + 1 <= lastGroupIndex) {
 474         // Check whether the calculate last visible index remains inside the current group.
 475         // If this is not the case let the last element of this group be the last visible index.
 476         const int nextGroupIndex = m_groups[groupIndex + 1].firstItemIndex;
 477         if (m_lastVisibleIndex >= nextGroupIndex) {
 478             m_lastVisibleIndex = nextGroupIndex - 1;
 479         }
 480     }
 481     m_lastVisibleIndex = qBound(0, m_lastVisibleIndex, maxIndex);
 482
 483     m_visibleIndexesDirty = false;
 484 }
 485
 486 void KItemListViewLayouter::createGroupHeaders()
 487 {
 488     m_groups.clear();
 489     m_groupIndexes.clear();
 490
 491     const QList<QPair<int, QVariant> > groups = m_model->groups();
 492
 493     qreal y = 0;
 494     for (int i = 0; i < groups.count(); ++i) {
 495         const int firstItemIndex = groups.at(i).first;
 496         if (i > 0) {
 497             const int previousGroupItemCount = firstItemIndex - m_groups.last().firstItemIndex;
 498             int previousGroupRowCount = previousGroupItemCount / m_columnCount;
 499             if (previousGroupItemCount % m_columnCount != 0) {
 500                 ++previousGroupRowCount;
 501             }
 502             const qreal previousGroupHeight = previousGroupRowCount * m_itemSize.height();
 503             y += previousGroupHeight;
 504         }
 505         y += HeaderHeight;
 506
 507         ItemGroup itemGroup;
 508         itemGroup.firstItemIndex = firstItemIndex;
 509         itemGroup.y = y;
 510
 511         m_groups.append(itemGroup);
 512         m_groupIndexes.insert(firstItemIndex);
 513     }
 514 }
 515
 516 #include "kitemlistviewlayouter_p.moc"