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 KItemListViewLayouter::KItemListViewLayouter(QObject* parent) :
  30     QObject(parent),
  31     m_dirty(true),
  32     m_visibleIndexesDirty(true),
  33     m_scrollOrientation(Qt::Vertical),
  34     m_size(),
  35     m_itemSize(128, 128),
  36     m_headerHeight(0),
  37     m_model(0),
  38     m_sizeHintResolver(0),
  39     m_scrollOffset(0),
  40     m_maximumScrollOffset(0),
  41     m_itemOffset(0),
  42     m_maximumItemOffset(0),
  43     m_firstVisibleIndex(-1),
  44     m_lastVisibleIndex(-1),
  45     m_columnWidth(0),
  46     m_xPosInc(0),
  47     m_columnCount(0),
  48     m_groupItemIndexes(),
  49     m_groupHeaderHeight(0),
  50     m_itemRects()
  51 {
  52 }
  53
  54 KItemListViewLayouter::~KItemListViewLayouter()
  55 {
  56 }
  57
  58 void KItemListViewLayouter::setScrollOrientation(Qt::Orientation orientation)
  59 {
  60     if (m_scrollOrientation != orientation) {
  61         m_scrollOrientation = orientation;
  62         m_dirty = true;
  63     }
  64 }
  65
  66 Qt::Orientation KItemListViewLayouter::scrollOrientation() const
  67 {
  68     return m_scrollOrientation;
  69 }
  70
  71 void KItemListViewLayouter::setSize(const QSizeF& size)
  72 {
  73     if (m_size != size) {
  74         m_size = size;
  75         m_dirty = true;
  76     }
  77 }
  78
  79 QSizeF KItemListViewLayouter::size() const
  80 {
  81     return m_size;
  82 }
  83
  84 void KItemListViewLayouter::setItemSize(const QSizeF& size)
  85 {
  86     if (m_itemSize != size) {
  87         m_itemSize = size;
  88         m_dirty = true;
  89     }
  90 }
  91
  92 QSizeF KItemListViewLayouter::itemSize() const
  93 {
  94     return m_itemSize;
  95 }
  96
  97 void KItemListViewLayouter::setHeaderHeight(qreal height)
  98 {
  99     if (m_headerHeight != height) {
 100         m_headerHeight = height;
 101         m_dirty = true;
 102     }
 103 }
 104
 105 qreal KItemListViewLayouter::headerHeight() const
 106 {
 107     return m_headerHeight;
 108 }
 109
 110 void KItemListViewLayouter::setGroupHeaderHeight(qreal height)
 111 {
 112     if (m_groupHeaderHeight != height) {
 113         m_groupHeaderHeight = height;
 114         m_dirty = true;
 115     }
 116 }
 117
 118 qreal KItemListViewLayouter::groupHeaderHeight() const
 119 {
 120     return m_groupHeaderHeight;
 121 }
 122
 123 void KItemListViewLayouter::setScrollOffset(qreal offset)
 124 {
 125     if (m_scrollOffset != offset) {
 126         m_scrollOffset = offset;
 127         m_visibleIndexesDirty = true;
 128     }
 129 }
 130
 131 qreal KItemListViewLayouter::scrollOffset() const
 132 {
 133     return m_scrollOffset;
 134 }
 135
 136 qreal KItemListViewLayouter::maximumScrollOffset() const
 137 {
 138     const_cast<KItemListViewLayouter*>(this)->doLayout();
 139     return m_maximumScrollOffset;
 140 }
 141
 142 void KItemListViewLayouter::setItemOffset(qreal offset)
 143 {
 144     if (m_itemOffset != offset) {
 145         m_itemOffset = offset;
 146         m_visibleIndexesDirty = true;
 147     }
 148 }
 149
 150 qreal KItemListViewLayouter::itemOffset() const
 151 {
 152     return m_itemOffset;
 153 }
 154
 155 qreal KItemListViewLayouter::maximumItemOffset() const
 156 {
 157     const_cast<KItemListViewLayouter*>(this)->doLayout();
 158     return m_maximumItemOffset;
 159 }
 160
 161 void KItemListViewLayouter::setModel(const KItemModelBase* model)
 162 {
 163     if (m_model != model) {
 164         m_model = model;
 165         m_dirty = true;
 166     }
 167 }
 168
 169 const KItemModelBase* KItemListViewLayouter::model() const
 170 {
 171     return m_model;
 172 }
 173
 174 void KItemListViewLayouter::setSizeHintResolver(const KItemListSizeHintResolver* sizeHintResolver)
 175 {
 176     if (m_sizeHintResolver != sizeHintResolver) {
 177         m_sizeHintResolver = sizeHintResolver;
 178         m_dirty = true;
 179     }
 180 }
 181
 182 const KItemListSizeHintResolver* KItemListViewLayouter::sizeHintResolver() const
 183 {
 184     return m_sizeHintResolver;
 185 }
 186
 187 int KItemListViewLayouter::firstVisibleIndex() const
 188 {
 189     const_cast<KItemListViewLayouter*>(this)->doLayout();
 190     return m_firstVisibleIndex;
 191 }
 192
 193 int KItemListViewLayouter::lastVisibleIndex() const
 194 {
 195     const_cast<KItemListViewLayouter*>(this)->doLayout();
 196     return m_lastVisibleIndex;
 197 }
 198
 199 QRectF KItemListViewLayouter::itemRect(int index) const
 200 {
 201     const_cast<KItemListViewLayouter*>(this)->doLayout();
 202     if (index < 0 || index >= m_itemRects.count()) {
 203         return QRectF();
 204     }
 205
 206     if (m_scrollOrientation == Qt::Horizontal) {
 207         // Rotate the logical direction which is always vertical by 90°
 208         // to get the physical horizontal direction
 209         const QRectF& b = m_itemRects[index];
 210         QRectF bounds(b.y(), b.x(), b.height(), b.width());
 211         QPointF pos = bounds.topLeft();
 212         pos.rx() -= m_scrollOffset;
 213         bounds.moveTo(pos);
 214         return bounds;
 215     }
 216
 217     QRectF bounds = m_itemRects[index];
 218     bounds.moveTo(bounds.topLeft() - QPointF(m_itemOffset, m_scrollOffset));
 219     return bounds;
 220 }
 221
 222 QRectF KItemListViewLayouter::groupHeaderRect(int index) const
 223 {
 224     const_cast<KItemListViewLayouter*>(this)->doLayout();
 225
 226     const QRectF firstItemRect = itemRect(index);
 227     QPointF pos = firstItemRect.topLeft();
 228     if (pos.isNull()) {
 229         return QRectF();
 230     }
 231
 232     pos.ry() -= m_groupHeaderHeight;
 233
 234     QSizeF size;
 235     if (m_scrollOrientation == Qt::Vertical) {
 236         pos.rx() = 0;
 237         size = QSizeF(m_size.width(), m_groupHeaderHeight);
 238     } else {
 239         size = QSizeF(minimumGroupHeaderWidth(), m_groupHeaderHeight);
 240     }
 241     return QRectF(pos, size);
 242 }
 243
 244 int KItemListViewLayouter::maximumVisibleItems() const
 245 {
 246     const_cast<KItemListViewLayouter*>(this)->doLayout();
 247
 248     const int height = static_cast<int>(m_size.height());
 249     const int rowHeight = static_cast<int>(m_itemSize.height());
 250     int rows = height / rowHeight;
 251     if (height % rowHeight != 0) {
 252         ++rows;
 253     }
 254
 255     return rows * m_columnCount;
 256 }
 257
 258 bool KItemListViewLayouter::isFirstGroupItem(int itemIndex) const
 259 {
 260     const_cast<KItemListViewLayouter*>(this)->doLayout();
 261     return m_groupItemIndexes.contains(itemIndex);
 262 }
 263
 264 void KItemListViewLayouter::markAsDirty()
 265 {
 266     m_dirty = true;
 267 }
 268
 269 void KItemListViewLayouter::doLayout()
 270 {
 271     if (m_dirty) {
 272 #ifdef KITEMLISTVIEWLAYOUTER_DEBUG
 273         QElapsedTimer timer;
 274         timer.start();
 275 #endif
 276         m_visibleIndexesDirty = true;
 277
 278         QSizeF itemSize = m_itemSize;
 279         QSizeF size = m_size;
 280
 281         const bool horizontalScrolling = (m_scrollOrientation == Qt::Horizontal);
 282         if (horizontalScrolling) {
 283             itemSize.setWidth(m_itemSize.height());
 284             itemSize.setHeight(m_itemSize.width());
 285             size.setWidth(m_size.height());
 286             size.setHeight(m_size.width());
 287         }
 288
 289         m_columnWidth = itemSize.width();
 290         m_columnCount = qMax(1, int(size.width() / m_columnWidth));
 291         m_xPosInc = 0;
 292
 293         const int itemCount = m_model->count();
 294         if (itemCount > m_columnCount) {
 295             // Apply the unused width equally to each column
 296             const qreal unusedWidth = size.width() - m_columnCount * m_columnWidth;
 297             if (unusedWidth > 0) {
 298                 const qreal columnInc = unusedWidth / (m_columnCount + 1);
 299                 m_columnWidth += columnInc;
 300                 m_xPosInc += columnInc;
 301             }
 302         }
 303
 304         int rowCount = itemCount / m_columnCount;
 305         if (itemCount % m_columnCount != 0) {
 306             ++rowCount;
 307         }
 308
 309         m_itemRects.reserve(itemCount);
 310
 311         qreal y = m_headerHeight;
 312         int rowIndex = 0;
 313
 314         const bool grouped = createGroupHeaders();
 315
 316         int index = 0;
 317         while (index < itemCount) {
 318             qreal x = m_xPosInc;
 319             qreal maxItemHeight = itemSize.height();
 320
 321             if (grouped) {
 322                 if (horizontalScrolling) {
 323                     // All group headers will always be aligned on the top and not
 324                     // flipped like the other properties
 325                     x += m_groupHeaderHeight;
 326                 }
 327
 328                 if (m_groupItemIndexes.contains(index)) {
 329                     if (!horizontalScrolling) {
 330                         // The item is the first item of a group.
 331                         // Increase the y-position to provide space
 332                         // for the group header.
 333                         y += m_groupHeaderHeight;
 334                     }
 335                 }
 336             }
 337
 338             int column = 0;
 339             while (index < itemCount && column < m_columnCount) {
 340                 qreal requiredItemHeight = itemSize.height();
 341                 if (m_sizeHintResolver) {
 342                     const QSizeF sizeHint = m_sizeHintResolver->sizeHint(index);
 343                     const qreal sizeHintHeight = horizontalScrolling ? sizeHint.width() : sizeHint.height();
 344                     if (sizeHintHeight > requiredItemHeight) {
 345                         requiredItemHeight = sizeHintHeight;
 346                     }
 347                 }
 348
 349                 const QRectF bounds(x, y, itemSize.width(), requiredItemHeight);
 350                 if (index < m_itemRects.count()) {
 351                     m_itemRects[index] = bounds;
 352                 } else {
 353                     m_itemRects.append(bounds);
 354                 }
 355
 356                 if (grouped && horizontalScrolling) {
 357                     // When grouping is enabled in the horizontal mode, the header alignment
 358                     // looks like this:
 359                     //   Header-1 Header-2 Header-3
 360                     //   Item 1   Item 4   Item 7
 361                     //   Item 2   Item 5   Item 8
 362                     //   Item 3   Item 6   Item 9
 363                     // In this case 'requiredItemHeight' represents the column-width. We don't
 364                     // check the content of the header in the layouter to determine the required
 365                     // width, hence assure that at least a minimal width of 15 characters is given
 366                     // (in average a character requires the halve width of the font height).
 367                     //
 368                     // TODO: Let the group headers provide a minimum width and respect this width here
 369                     const qreal headerWidth = minimumGroupHeaderWidth();
 370                     if (requiredItemHeight < headerWidth) {
 371                         requiredItemHeight = headerWidth;
 372                     }
 373                 }
 374
 375                 maxItemHeight = qMax(maxItemHeight, requiredItemHeight);
 376                 x += m_columnWidth;
 377                 ++index;
 378                 ++column;
 379
 380                 if (grouped && m_groupItemIndexes.contains(index)) {
 381                     // The item represents the first index of a group
 382                     // and must aligned in the first column
 383                     break;
 384                 }
 385             }
 386
 387             y += maxItemHeight;
 388             ++rowIndex;
 389         }
 390         if (m_itemRects.count() > itemCount) {
 391             m_itemRects.erase(m_itemRects.begin() + itemCount,
 392                                       m_itemRects.end());
 393         }
 394
 395         if (itemCount > 0) {
 396             // Calculate the maximum y-range of the last row for m_maximumScrollOffset
 397             m_maximumScrollOffset = m_itemRects.last().bottom();
 398             const qreal rowY = m_itemRects.last().y();
 399
 400             int index = m_itemRects.count() - 2;
 401             while (index >= 0 && m_itemRects.at(index).bottom() >= rowY) {
 402                 m_maximumScrollOffset = qMax(m_maximumScrollOffset, m_itemRects.at(index).bottom());
 403                 --index;
 404             }
 405
 406             m_maximumItemOffset = m_columnCount * m_columnWidth;
 407         } else {
 408             m_maximumScrollOffset = 0;
 409             m_maximumItemOffset = 0;
 410         }
 411
 412 #ifdef KITEMLISTVIEWLAYOUTER_DEBUG
 413         kDebug() << "[TIME] doLayout() for " << m_model->count() << "items:" << timer.elapsed();
 414 #endif
 415         m_dirty = false;
 416     }
 417
 418     updateVisibleIndexes();
 419 }
 420
 421 void KItemListViewLayouter::updateVisibleIndexes()
 422 {
 423     if (!m_visibleIndexesDirty) {
 424         return;
 425     }
 426
 427     Q_ASSERT(!m_dirty);
 428
 429     if (m_model->count() <= 0) {
 430         m_firstVisibleIndex = -1;
 431         m_lastVisibleIndex = -1;
 432         m_visibleIndexesDirty = false;
 433         return;
 434     }
 435
 436     const int maxIndex = m_model->count() - 1;
 437
 438     // Calculate the first visible index that is fully visible
 439     int min = 0;
 440     int max = maxIndex;
 441     int mid = 0;
 442     do {
 443         mid = (min + max) / 2;
 444         if (m_itemRects[mid].top() < m_scrollOffset) {
 445             min = mid + 1;
 446         } else {
 447             max = mid - 1;
 448         }
 449     } while (min <= max);
 450
 451     if (mid > 0) {
 452         // Include the row before the first fully visible index, as it might
 453         // be partly visible
 454         if (m_itemRects[mid].top() >= m_scrollOffset) {
 455             --mid;
 456             Q_ASSERT(m_itemRects[mid].top() < m_scrollOffset);
 457         }
 458
 459         const qreal rowTop = m_itemRects[mid].top();
 460         while (mid > 0 && m_itemRects[mid - 1].top() == rowTop) {
 461             --mid;
 462         }
 463     }
 464     m_firstVisibleIndex = mid;
 465
 466     // Calculate the last visible index that is (at least partly) visible
 467     const int visibleHeight = (m_scrollOrientation == Qt::Horizontal) ? m_size.width() : m_size.height();
 468     qreal bottom = m_scrollOffset + visibleHeight;
 469     if (m_model->groupedSorting()) {
 470         bottom += m_groupHeaderHeight;
 471     }
 472
 473     min = m_firstVisibleIndex;
 474     max = maxIndex;
 475     do {
 476         mid = (min + max) / 2;
 477         if (m_itemRects[mid].y() <= bottom) {
 478             min = mid + 1;
 479         } else {
 480             max = mid - 1;
 481         }
 482     } while (min <= max);
 483
 484     while (mid > 0 && m_itemRects[mid].y() > bottom) {
 485         --mid;
 486     }
 487     m_lastVisibleIndex = mid;
 488
 489     m_visibleIndexesDirty = false;
 490 }
 491
 492 bool KItemListViewLayouter::createGroupHeaders()
 493 {
 494     if (!m_model->groupedSorting()) {
 495         return false;
 496     }
 497
 498     m_groupItemIndexes.clear();
 499
 500     const QList<QPair<int, QVariant> > groups = m_model->groups();
 501     if (groups.isEmpty()) {
 502         return false;
 503     }
 504
 505     for (int i = 0; i < groups.count(); ++i) {
 506         const int firstItemIndex = groups.at(i).first;
 507         m_groupItemIndexes.insert(firstItemIndex);
 508     }
 509
 510     return true;
 511 }
 512
 513 qreal KItemListViewLayouter::minimumGroupHeaderWidth() const
 514 {
 515     return m_groupHeaderHeight * 15 / 2;
 516 }
 517
 518 #include "kitemlistviewlayouter_p.moc"