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_itemRects()
  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_itemRects.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_itemRects[index];
 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_itemRects[index];
 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_itemRects[index].y();
 275         const int maxIndex = m_itemRects.count() - 1;
 276         while (index <= maxIndex) {
 277             QRectF bounds = m_itemRects[index];
 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::maximumVisibleItems() const
 295 {
 296     const_cast<KItemListViewLayouter*>(this)->doLayout();
 297
 298     const int height = static_cast<int>(m_size.height());
 299     const int rowHeight = static_cast<int>(m_itemSize.height());
 300     int rows = height / rowHeight;
 301     if (height % rowHeight != 0) {
 302         ++rows;
 303     }
 304
 305     return rows * m_columnCount;
 306 }
 307
 308 bool KItemListViewLayouter::isFirstGroupItem(int itemIndex) const
 309 {
 310     const_cast<KItemListViewLayouter*>(this)->doLayout();
 311     return m_groupItemIndexes.contains(itemIndex);
 312 }
 313
 314 void KItemListViewLayouter::markAsDirty()
 315 {
 316     m_dirty = true;
 317 }
 318
 319 void KItemListViewLayouter::doLayout()
 320 {
 321     if (m_dirty) {
 322 #ifdef KITEMLISTVIEWLAYOUTER_DEBUG
 323         QElapsedTimer timer;
 324         timer.start();
 325 #endif
 326         m_visibleIndexesDirty = true;
 327
 328         QSizeF itemSize = m_itemSize;
 329         QSizeF itemMargin = m_itemMargin;
 330         QSizeF size = m_size;
 331
 332         const bool grouped = createGroupHeaders();
 333
 334         const bool horizontalScrolling = (m_scrollOrientation == Qt::Horizontal);
 335         if (horizontalScrolling) {
 336             // Flip everything so that the layout logically can work like having
 337             // a vertical scrolling
 338             itemSize.setWidth(m_itemSize.height());
 339             itemSize.setHeight(m_itemSize.width());
 340             itemMargin.setWidth(m_itemMargin.height());
 341             itemMargin.setHeight(m_itemMargin.width());
 342             size.setWidth(m_size.height());
 343             size.setHeight(m_size.width());
 344
 345             if (grouped) {
 346                 // In the horizontal scrolling case all groups are aligned
 347                 // at the top, which decreases the available height. For the
 348                 // flipped data this means that the width must be decreased.
 349                 size.rwidth() -= m_groupHeaderHeight;
 350             }
 351         }
 352
 353         m_columnWidth = itemSize.width() + itemMargin.width();
 354         const qreal widthForColumns = size.width() - itemMargin.width();
 355         m_columnCount = qMax(1, int(widthForColumns / m_columnWidth));
 356         m_xPosInc = itemMargin.width();
 357
 358         const int itemCount = m_model->count();
 359         if (itemCount > m_columnCount && m_columnWidth >= 32) {
 360             // Apply the unused width equally to each column
 361             const qreal unusedWidth = widthForColumns - m_columnCount * m_columnWidth;
 362             if (unusedWidth > 0) {
 363                 const qreal columnInc = unusedWidth / (m_columnCount + 1);
 364                 m_columnWidth += columnInc;
 365                 m_xPosInc += columnInc;
 366             }
 367         }
 368
 369         int rowCount = itemCount / m_columnCount;
 370         if (itemCount % m_columnCount != 0) {
 371             ++rowCount;
 372         }
 373
 374         m_itemRects.reserve(itemCount);
 375
 376         qreal y = m_headerHeight + itemMargin.height();
 377         int rowIndex = 0;
 378
 379         int index = 0;
 380         while (index < itemCount) {
 381             qreal x = m_xPosInc;
 382             qreal maxItemHeight = itemSize.height();
 383
 384             if (grouped) {
 385                 if (horizontalScrolling) {
 386                     // All group headers will always be aligned on the top and not
 387                     // flipped like the other properties
 388                     x += m_groupHeaderHeight;
 389                 }
 390
 391                 if (m_groupItemIndexes.contains(index)) {
 392                     // The item is the first item of a group.
 393                     // Increase the y-position to provide space
 394                     // for the group header.
 395                     if (index > 0) {
 396                         // Only add a margin if there has been added another
 397                         // group already before
 398                         y += m_groupHeaderMargin;
 399                     } else if (!horizontalScrolling) {
 400                         // The first group header should be aligned on top
 401                         y -= itemMargin.height();
 402                     }
 403
 404                     if (!horizontalScrolling) {
 405                         y += m_groupHeaderHeight;
 406                     }
 407                 }
 408             }
 409
 410             int column = 0;
 411             while (index < itemCount && column < m_columnCount) {
 412                 qreal requiredItemHeight = itemSize.height();
 413                 if (m_sizeHintResolver) {
 414                     const QSizeF sizeHint = m_sizeHintResolver->sizeHint(index);
 415                     const qreal sizeHintHeight = horizontalScrolling ? sizeHint.width() : sizeHint.height();
 416                     if (sizeHintHeight > requiredItemHeight) {
 417                         requiredItemHeight = sizeHintHeight;
 418                     }
 419                 }
 420
 421                 const QRectF bounds(x, y, itemSize.width(), requiredItemHeight);
 422                 if (index < m_itemRects.count()) {
 423                     m_itemRects[index] = bounds;
 424                 } else {
 425                     m_itemRects.append(bounds);
 426                 }
 427
 428                 if (grouped && horizontalScrolling) {
 429                     // When grouping is enabled in the horizontal mode, the header alignment
 430                     // looks like this:
 431                     //   Header-1 Header-2 Header-3
 432                     //   Item 1   Item 4   Item 7
 433                     //   Item 2   Item 5   Item 8
 434                     //   Item 3   Item 6   Item 9
 435                     // In this case 'requiredItemHeight' represents the column-width. We don't
 436                     // check the content of the header in the layouter to determine the required
 437                     // width, hence assure that at least a minimal width of 15 characters is given
 438                     // (in average a character requires the halve width of the font height).
 439                     //
 440                     // TODO: Let the group headers provide a minimum width and respect this width here
 441                     const qreal headerWidth = minimumGroupHeaderWidth();
 442                     if (requiredItemHeight < headerWidth) {
 443                         requiredItemHeight = headerWidth;
 444                     }
 445                 }
 446
 447                 maxItemHeight = qMax(maxItemHeight, requiredItemHeight);
 448                 x += m_columnWidth;
 449                 ++index;
 450                 ++column;
 451
 452                 if (grouped && m_groupItemIndexes.contains(index)) {
 453                     // The item represents the first index of a group
 454                     // and must aligned in the first column
 455                     break;
 456                 }
 457             }
 458
 459             y += maxItemHeight + itemMargin.height();
 460             ++rowIndex;
 461         }
 462         if (m_itemRects.count() > itemCount) {
 463             m_itemRects.erase(m_itemRects.begin() + itemCount,
 464                               m_itemRects.end());
 465         }
 466
 467         if (itemCount > 0) {
 468             // Calculate the maximum y-range of the last row for m_maximumScrollOffset
 469             m_maximumScrollOffset = m_itemRects.last().bottom();
 470             const qreal rowY = m_itemRects.last().y();
 471
 472             int index = m_itemRects.count() - 2;
 473             while (index >= 0 && m_itemRects.at(index).bottom() >= rowY) {
 474                 m_maximumScrollOffset = qMax(m_maximumScrollOffset, m_itemRects.at(index).bottom());
 475                 --index;
 476             }
 477
 478             m_maximumScrollOffset += itemMargin.height();
 479
 480             m_maximumItemOffset = m_columnCount * m_columnWidth;
 481         } else {
 482             m_maximumScrollOffset = 0;
 483             m_maximumItemOffset = 0;
 484         }
 485
 486 #ifdef KITEMLISTVIEWLAYOUTER_DEBUG
 487         kDebug() << "[TIME] doLayout() for " << m_model->count() << "items:" << timer.elapsed();
 488 #endif
 489         m_dirty = false;
 490     }
 491
 492     updateVisibleIndexes();
 493 }
 494
 495 void KItemListViewLayouter::updateVisibleIndexes()
 496 {
 497     if (!m_visibleIndexesDirty) {
 498         return;
 499     }
 500
 501     Q_ASSERT(!m_dirty);
 502
 503     if (m_model->count() <= 0) {
 504         m_firstVisibleIndex = -1;
 505         m_lastVisibleIndex = -1;
 506         m_visibleIndexesDirty = false;
 507         return;
 508     }
 509
 510     const int maxIndex = m_model->count() - 1;
 511
 512     // Calculate the first visible index that is fully visible
 513     int min = 0;
 514     int max = maxIndex;
 515     int mid = 0;
 516     do {
 517         mid = (min + max) / 2;
 518         if (m_itemRects[mid].top() < m_scrollOffset) {
 519             min = mid + 1;
 520         } else {
 521             max = mid - 1;
 522         }
 523     } while (min <= max);
 524
 525     if (mid > 0) {
 526         // Include the row before the first fully visible index, as it might
 527         // be partly visible
 528         if (m_itemRects[mid].top() >= m_scrollOffset) {
 529             --mid;
 530             Q_ASSERT(m_itemRects[mid].top() < m_scrollOffset);
 531         }
 532
 533         const qreal rowTop = m_itemRects[mid].top();
 534         while (mid > 0 && m_itemRects[mid - 1].top() == rowTop) {
 535             --mid;
 536         }
 537     }
 538     m_firstVisibleIndex = mid;
 539
 540     // Calculate the last visible index that is (at least partly) visible
 541     const int visibleHeight = (m_scrollOrientation == Qt::Horizontal) ? m_size.width() : m_size.height();
 542     qreal bottom = m_scrollOffset + visibleHeight;
 543     if (m_model->groupedSorting()) {
 544         bottom += m_groupHeaderHeight;
 545     }
 546
 547     min = m_firstVisibleIndex;
 548     max = maxIndex;
 549     do {
 550         mid = (min + max) / 2;
 551         if (m_itemRects[mid].y() <= bottom) {
 552             min = mid + 1;
 553         } else {
 554             max = mid - 1;
 555         }
 556     } while (min <= max);
 557
 558     while (mid > 0 && m_itemRects[mid].y() > bottom) {
 559         --mid;
 560     }
 561     m_lastVisibleIndex = mid;
 562
 563     m_visibleIndexesDirty = false;
 564 }
 565
 566 bool KItemListViewLayouter::createGroupHeaders()
 567 {
 568     if (!m_model->groupedSorting()) {
 569         return false;
 570     }
 571
 572     m_groupItemIndexes.clear();
 573
 574     const QList<QPair<int, QVariant> > groups = m_model->groups();
 575     if (groups.isEmpty()) {
 576         return false;
 577     }
 578
 579     for (int i = 0; i < groups.count(); ++i) {
 580         const int firstItemIndex = groups.at(i).first;
 581         m_groupItemIndexes.insert(firstItemIndex);
 582     }
 583
 584     return true;
 585 }
 586
 587 qreal KItemListViewLayouter::minimumGroupHeaderWidth() const
 588 {
 589     return 100;
 590 }
 591
 592 #include "kitemlistviewlayouter_p.moc"