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_itemMargin(),
  37     m_headerHeight(0),
  38     m_model(0),
  39     m_sizeHintResolver(0),
  40     m_scrollOffset(0),
  41     m_maximumScrollOffset(0),
  42     m_itemOffset(0),
  43     m_maximumItemOffset(0),
  44     m_firstVisibleIndex(-1),
  45     m_lastVisibleIndex(-1),
  46     m_columnWidth(0),
  47     m_xPosInc(0),
  48     m_columnCount(0),
  49     m_groupItemIndexes(),
  50     m_groupHeaderHeight(0),
  51     m_groupHeaderMargin(0),
  52     m_itemInfos()
  53 {
  54 }
  55
  56 KItemListViewLayouter::~KItemListViewLayouter()
  57 {
  58 }
  59
  60 void KItemListViewLayouter::setScrollOrientation(Qt::Orientation orientation)
  61 {
  62     if (m_scrollOrientation != orientation) {
  63         m_scrollOrientation = orientation;
  64         m_dirty = true;
  65     }
  66 }
  67
  68 Qt::Orientation KItemListViewLayouter::scrollOrientation() const
  69 {
  70     return m_scrollOrientation;
  71 }
  72
  73 void KItemListViewLayouter::setSize(const QSizeF& size)
  74 {
  75     if (m_size != size) {
  76         m_size = size;
  77         m_dirty = true;
  78     }
  79 }
  80
  81 QSizeF KItemListViewLayouter::size() const
  82 {
  83     return m_size;
  84 }
  85
  86 void KItemListViewLayouter::setItemSize(const QSizeF& size)
  87 {
  88     if (m_itemSize != size) {
  89         m_itemSize = size;
  90         m_dirty = true;
  91     }
  92 }
  93
  94 QSizeF KItemListViewLayouter::itemSize() const
  95 {
  96     return m_itemSize;
  97 }
  98
  99 void KItemListViewLayouter::setItemMargin(const QSizeF& margin)
 100 {
 101     if (m_itemMargin != margin) {
 102         m_itemMargin = margin;
 103         m_dirty = true;
 104     }
 105 }
 106
 107 QSizeF KItemListViewLayouter::itemMargin() const
 108 {
 109     return m_itemMargin;
 110 }
 111
 112 void KItemListViewLayouter::setHeaderHeight(qreal height)
 113 {
 114     if (m_headerHeight != height) {
 115         m_headerHeight = height;
 116         m_dirty = true;
 117     }
 118 }
 119
 120 qreal KItemListViewLayouter::headerHeight() const
 121 {
 122     return m_headerHeight;
 123 }
 124
 125 void KItemListViewLayouter::setGroupHeaderHeight(qreal height)
 126 {
 127     if (m_groupHeaderHeight != height) {
 128         m_groupHeaderHeight = height;
 129         m_dirty = true;
 130     }
 131 }
 132
 133 qreal KItemListViewLayouter::groupHeaderHeight() const
 134 {
 135     return m_groupHeaderHeight;
 136 }
 137
 138 void KItemListViewLayouter::setGroupHeaderMargin(qreal margin)
 139 {
 140     if (m_groupHeaderMargin != margin) {
 141         m_groupHeaderMargin = margin;
 142         m_dirty = true;
 143     }
 144 }
 145
 146 qreal KItemListViewLayouter::groupHeaderMargin() const
 147 {
 148     return m_groupHeaderMargin;
 149 }
 150
 151 void KItemListViewLayouter::setScrollOffset(qreal offset)
 152 {
 153     if (m_scrollOffset != offset) {
 154         m_scrollOffset = offset;
 155         m_visibleIndexesDirty = true;
 156     }
 157 }
 158
 159 qreal KItemListViewLayouter::scrollOffset() const
 160 {
 161     return m_scrollOffset;
 162 }
 163
 164 qreal KItemListViewLayouter::maximumScrollOffset() const
 165 {
 166     const_cast<KItemListViewLayouter*>(this)->doLayout();
 167     return m_maximumScrollOffset;
 168 }
 169
 170 void KItemListViewLayouter::setItemOffset(qreal offset)
 171 {
 172     if (m_itemOffset != offset) {
 173         m_itemOffset = offset;
 174         m_visibleIndexesDirty = true;
 175     }
 176 }
 177
 178 qreal KItemListViewLayouter::itemOffset() const
 179 {
 180     return m_itemOffset;
 181 }
 182
 183 qreal KItemListViewLayouter::maximumItemOffset() const
 184 {
 185     const_cast<KItemListViewLayouter*>(this)->doLayout();
 186     return m_maximumItemOffset;
 187 }
 188
 189 void KItemListViewLayouter::setModel(const KItemModelBase* model)
 190 {
 191     if (m_model != model) {
 192         m_model = model;
 193         m_dirty = true;
 194     }
 195 }
 196
 197 const KItemModelBase* KItemListViewLayouter::model() const
 198 {
 199     return m_model;
 200 }
 201
 202 void KItemListViewLayouter::setSizeHintResolver(const KItemListSizeHintResolver* sizeHintResolver)
 203 {
 204     if (m_sizeHintResolver != sizeHintResolver) {
 205         m_sizeHintResolver = sizeHintResolver;
 206         m_dirty = true;
 207     }
 208 }
 209
 210 const KItemListSizeHintResolver* KItemListViewLayouter::sizeHintResolver() const
 211 {
 212     return m_sizeHintResolver;
 213 }
 214
 215 int KItemListViewLayouter::firstVisibleIndex() const
 216 {
 217     const_cast<KItemListViewLayouter*>(this)->doLayout();
 218     return m_firstVisibleIndex;
 219 }
 220
 221 int KItemListViewLayouter::lastVisibleIndex() const
 222 {
 223     const_cast<KItemListViewLayouter*>(this)->doLayout();
 224     return m_lastVisibleIndex;
 225 }
 226
 227 QRectF KItemListViewLayouter::itemRect(int index) const
 228 {
 229     const_cast<KItemListViewLayouter*>(this)->doLayout();
 230     if (index < 0 || index >= m_itemInfos.count()) {
 231         return QRectF();
 232     }
 233
 234     if (m_scrollOrientation == Qt::Horizontal) {
 235         // Rotate the logical direction which is always vertical by 90°
 236         // to get the physical horizontal direction
 237         const QRectF& b = m_itemInfos[index].rect;
 238         QRectF bounds(b.y(), b.x(), b.height(), b.width());
 239         QPointF pos = bounds.topLeft();
 240         pos.rx() -= m_scrollOffset;
 241         bounds.moveTo(pos);
 242         return bounds;
 243     }
 244
 245     QRectF bounds = m_itemInfos[index].rect;
 246     bounds.moveTo(bounds.topLeft() - QPointF(m_itemOffset, m_scrollOffset));
 247     return bounds;
 248 }
 249
 250 QRectF KItemListViewLayouter::groupHeaderRect(int index) const
 251 {
 252     const_cast<KItemListViewLayouter*>(this)->doLayout();
 253
 254     const QRectF firstItemRect = itemRect(index);
 255     QPointF pos = firstItemRect.topLeft();
 256     if (pos.isNull()) {
 257         return QRectF();
 258     }
 259
 260     QSizeF size;
 261     if (m_scrollOrientation == Qt::Vertical) {
 262         pos.rx() = 0;
 263         pos.ry() -= m_groupHeaderHeight;
 264         size = QSizeF(m_size.width(), m_groupHeaderHeight);
 265     } else {
 266         pos.rx() -= m_itemMargin.width();
 267         pos.ry() = 0;
 268
 269         // Determine the maximum width used in the
 270         // current column. As the scroll-direction is
 271         // Qt::Horizontal and m_itemRects is accessed directly,
 272         // the logical height represents the visual width.
 273         qreal width = minimumGroupHeaderWidth();
 274         const qreal y = m_itemInfos[index].rect.y();
 275         const int maxIndex = m_itemInfos.count() - 1;
 276         while (index <= maxIndex) {
 277             QRectF bounds = m_itemInfos[index].rect;
 278             if (bounds.y() != y) {
 279                 break;
 280             }
 281
 282             if (bounds.height() > width) {
 283                 width = bounds.height();
 284             }
 285
 286             ++index;
 287         }
 288
 289         size = QSizeF(width, m_size.height());
 290     }
 291     return QRectF(pos, size);
 292 }
 293
 294 int KItemListViewLayouter::itemColumn(int index) const
 295 {
 296     const_cast<KItemListViewLayouter*>(this)->doLayout();
 297     if (index < 0 || index >= m_itemInfos.count()) {
 298         return -1;
 299     }
 300
 301     return (m_scrollOrientation == Qt::Vertical)
 302             ? m_itemInfos[index].column
 303             : m_itemInfos[index].row;
 304 }
 305
 306 int KItemListViewLayouter::itemRow(int index) const
 307 {
 308     const_cast<KItemListViewLayouter*>(this)->doLayout();
 309     if (index < 0 || index >= m_itemInfos.count()) {
 310         return -1;
 311     }
 312
 313     return (m_scrollOrientation == Qt::Vertical)
 314             ? m_itemInfos[index].row
 315             : m_itemInfos[index].column;
 316 }
 317
 318 int KItemListViewLayouter::maximumVisibleItems() const
 319 {
 320     const_cast<KItemListViewLayouter*>(this)->doLayout();
 321
 322     const int height = static_cast<int>(m_size.height());
 323     const int rowHeight = static_cast<int>(m_itemSize.height());
 324     int rows = height / rowHeight;
 325     if (height % rowHeight != 0) {
 326         ++rows;
 327     }
 328
 329     return rows * m_columnCount;
 330 }
 331
 332 bool KItemListViewLayouter::isFirstGroupItem(int itemIndex) const
 333 {
 334     const_cast<KItemListViewLayouter*>(this)->doLayout();
 335     return m_groupItemIndexes.contains(itemIndex);
 336 }
 337
 338 void KItemListViewLayouter::markAsDirty()
 339 {
 340     m_dirty = true;
 341 }
 342
 343 void KItemListViewLayouter::doLayout()
 344 {
 345     if (m_dirty) {
 346 #ifdef KITEMLISTVIEWLAYOUTER_DEBUG
 347         QElapsedTimer timer;
 348         timer.start();
 349 #endif
 350         m_visibleIndexesDirty = true;
 351
 352         QSizeF itemSize = m_itemSize;
 353         QSizeF itemMargin = m_itemMargin;
 354         QSizeF size = m_size;
 355
 356         const bool grouped = createGroupHeaders();
 357
 358         const bool horizontalScrolling = (m_scrollOrientation == Qt::Horizontal);
 359         if (horizontalScrolling) {
 360             // Flip everything so that the layout logically can work like having
 361             // a vertical scrolling
 362             itemSize.setWidth(m_itemSize.height());
 363             itemSize.setHeight(m_itemSize.width());
 364             itemMargin.setWidth(m_itemMargin.height());
 365             itemMargin.setHeight(m_itemMargin.width());
 366             size.setWidth(m_size.height());
 367             size.setHeight(m_size.width());
 368
 369             if (grouped) {
 370                 // In the horizontal scrolling case all groups are aligned
 371                 // at the top, which decreases the available height. For the
 372                 // flipped data this means that the width must be decreased.
 373                 size.rwidth() -= m_groupHeaderHeight;
 374             }
 375         }
 376
 377         m_columnWidth = itemSize.width() + itemMargin.width();
 378         const qreal widthForColumns = size.width() - itemMargin.width();
 379         m_columnCount = qMax(1, int(widthForColumns / m_columnWidth));
 380         m_xPosInc = itemMargin.width();
 381
 382         const int itemCount = m_model->count();
 383         if (itemCount > m_columnCount && m_columnWidth >= 32) {
 384             // Apply the unused width equally to each column
 385             const qreal unusedWidth = widthForColumns - m_columnCount * m_columnWidth;
 386             if (unusedWidth > 0) {
 387                 const qreal columnInc = unusedWidth / (m_columnCount + 1);
 388                 m_columnWidth += columnInc;
 389                 m_xPosInc += columnInc;
 390             }
 391         }
 392
 393         int rowCount = itemCount / m_columnCount;
 394         if (itemCount % m_columnCount != 0) {
 395             ++rowCount;
 396         }
 397
 398         m_itemInfos.reserve(itemCount);
 399
 400         qreal y = m_headerHeight + itemMargin.height();
 401         int row = 0;
 402
 403         int index = 0;
 404         while (index < itemCount) {
 405             qreal x = m_xPosInc;
 406             qreal maxItemHeight = itemSize.height();
 407
 408             if (grouped) {
 409                 if (horizontalScrolling) {
 410                     // All group headers will always be aligned on the top and not
 411                     // flipped like the other properties
 412                     x += m_groupHeaderHeight;
 413                 }
 414
 415                 if (m_groupItemIndexes.contains(index)) {
 416                     // The item is the first item of a group.
 417                     // Increase the y-position to provide space
 418                     // for the group header.
 419                     if (index > 0) {
 420                         // Only add a margin if there has been added another
 421                         // group already before
 422                         y += m_groupHeaderMargin;
 423                     } else if (!horizontalScrolling) {
 424                         // The first group header should be aligned on top
 425                         y -= itemMargin.height();
 426                     }
 427
 428                     if (!horizontalScrolling) {
 429                         y += m_groupHeaderHeight;
 430                     }
 431                 }
 432             }
 433
 434             int column = 0;
 435             while (index < itemCount && column < m_columnCount) {
 436                 qreal requiredItemHeight = itemSize.height();
 437                 if (m_sizeHintResolver) {
 438                     const QSizeF sizeHint = m_sizeHintResolver->sizeHint(index);
 439                     const qreal sizeHintHeight = horizontalScrolling ? sizeHint.width() : sizeHint.height();
 440                     if (sizeHintHeight > requiredItemHeight) {
 441                         requiredItemHeight = sizeHintHeight;
 442                     }
 443                 }
 444
 445                 const QRectF bounds(x, y, itemSize.width(), requiredItemHeight);
 446                 if (index < m_itemInfos.count()) {
 447                     m_itemInfos[index].rect = bounds;
 448                     m_itemInfos[index].column = column;
 449                     m_itemInfos[index].row = row;
 450                 } else {
 451                     ItemInfo itemInfo;
 452                     itemInfo.rect = bounds;
 453                     itemInfo.column = column;
 454                     itemInfo.row = row;
 455                     m_itemInfos.append(itemInfo);
 456                 }
 457
 458                 if (grouped && horizontalScrolling) {
 459                     // When grouping is enabled in the horizontal mode, the header alignment
 460                     // looks like this:
 461                     //   Header-1 Header-2 Header-3
 462                     //   Item 1   Item 4   Item 7
 463                     //   Item 2   Item 5   Item 8
 464                     //   Item 3   Item 6   Item 9
 465                     // In this case 'requiredItemHeight' represents the column-width. We don't
 466                     // check the content of the header in the layouter to determine the required
 467                     // width, hence assure that at least a minimal width of 15 characters is given
 468                     // (in average a character requires the halve width of the font height).
 469                     //
 470                     // TODO: Let the group headers provide a minimum width and respect this width here
 471                     const qreal headerWidth = minimumGroupHeaderWidth();
 472                     if (requiredItemHeight < headerWidth) {
 473                         requiredItemHeight = headerWidth;
 474                     }
 475                 }
 476
 477                 maxItemHeight = qMax(maxItemHeight, requiredItemHeight);
 478                 x += m_columnWidth;
 479                 ++index;
 480                 ++column;
 481
 482                 if (grouped && m_groupItemIndexes.contains(index)) {
 483                     // The item represents the first index of a group
 484                     // and must aligned in the first column
 485                     break;
 486                 }
 487             }
 488
 489             y += maxItemHeight + itemMargin.height();
 490             ++row;
 491         }
 492         if (m_itemInfos.count() > itemCount) {
 493             m_itemInfos.erase(m_itemInfos.begin() + itemCount,
 494                               m_itemInfos.end());
 495         }
 496
 497         if (itemCount > 0) {
 498             // Calculate the maximum y-range of the last row for m_maximumScrollOffset
 499             m_maximumScrollOffset = m_itemInfos.last().rect.bottom();
 500             const qreal rowY = m_itemInfos.last().rect.y();
 501
 502             int index = m_itemInfos.count() - 2;
 503             while (index >= 0 && m_itemInfos[index].rect.bottom() >= rowY) {
 504                 m_maximumScrollOffset = qMax(m_maximumScrollOffset, m_itemInfos[index].rect.bottom());
 505                 --index;
 506             }
 507
 508             m_maximumScrollOffset += itemMargin.height();
 509
 510             m_maximumItemOffset = m_columnCount * m_columnWidth;
 511         } else {
 512             m_maximumScrollOffset = 0;
 513             m_maximumItemOffset = 0;
 514         }
 515
 516 #ifdef KITEMLISTVIEWLAYOUTER_DEBUG
 517         kDebug() << "[TIME] doLayout() for " << m_model->count() << "items:" << timer.elapsed();
 518 #endif
 519         m_dirty = false;
 520     }
 521
 522     updateVisibleIndexes();
 523 }
 524
 525 void KItemListViewLayouter::updateVisibleIndexes()
 526 {
 527     if (!m_visibleIndexesDirty) {
 528         return;
 529     }
 530
 531     Q_ASSERT(!m_dirty);
 532
 533     if (m_model->count() <= 0) {
 534         m_firstVisibleIndex = -1;
 535         m_lastVisibleIndex = -1;
 536         m_visibleIndexesDirty = false;
 537         return;
 538     }
 539
 540     const int maxIndex = m_model->count() - 1;
 541
 542     // Calculate the first visible index that is fully visible
 543     int min = 0;
 544     int max = maxIndex;
 545     int mid = 0;
 546     do {
 547         mid = (min + max) / 2;
 548         if (m_itemInfos[mid].rect.top() < m_scrollOffset) {
 549             min = mid + 1;
 550         } else {
 551             max = mid - 1;
 552         }
 553     } while (min <= max);
 554
 555     if (mid > 0) {
 556         // Include the row before the first fully visible index, as it might
 557         // be partly visible
 558         if (m_itemInfos[mid].rect.top() >= m_scrollOffset) {
 559             --mid;
 560             Q_ASSERT(m_itemInfos[mid].rect.top() < m_scrollOffset);
 561         }
 562
 563         const qreal rowTop = m_itemInfos[mid].rect.top();
 564         while (mid > 0 && m_itemInfos[mid - 1].rect.top() == rowTop) {
 565             --mid;
 566         }
 567     }
 568     m_firstVisibleIndex = mid;
 569
 570     // Calculate the last visible index that is (at least partly) visible
 571     const int visibleHeight = (m_scrollOrientation == Qt::Horizontal) ? m_size.width() : m_size.height();
 572     qreal bottom = m_scrollOffset + visibleHeight;
 573     if (m_model->groupedSorting()) {
 574         bottom += m_groupHeaderHeight;
 575     }
 576
 577     min = m_firstVisibleIndex;
 578     max = maxIndex;
 579     do {
 580         mid = (min + max) / 2;
 581         if (m_itemInfos[mid].rect.y() <= bottom) {
 582             min = mid + 1;
 583         } else {
 584             max = mid - 1;
 585         }
 586     } while (min <= max);
 587
 588     while (mid > 0 && m_itemInfos[mid].rect.y() > bottom) {
 589         --mid;
 590     }
 591     m_lastVisibleIndex = mid;
 592
 593     m_visibleIndexesDirty = false;
 594 }
 595
 596 bool KItemListViewLayouter::createGroupHeaders()
 597 {
 598     if (!m_model->groupedSorting()) {
 599         return false;
 600     }
 601
 602     m_groupItemIndexes.clear();
 603
 604     const QList<QPair<int, QVariant> > groups = m_model->groups();
 605     if (groups.isEmpty()) {
 606         return false;
 607     }
 608
 609     for (int i = 0; i < groups.count(); ++i) {
 610         const int firstItemIndex = groups.at(i).first;
 611         m_groupItemIndexes.insert(firstItemIndex);
 612     }
 613
 614     return true;
 615 }
 616
 617 qreal KItemListViewLayouter::minimumGroupHeaderWidth() const
 618 {
 619     return 100;
 620 }
 621
 622 #include "kitemlistviewlayouter_p.moc"