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     pos.ry() -= m_groupHeaderHeight;
 261
 262     QSizeF size;
 263     if (m_scrollOrientation == Qt::Vertical) {
 264         pos.rx() = 0;
 265         size = QSizeF(m_size.width(), m_groupHeaderHeight);
 266     } else {
 267         size = QSizeF(minimumGroupHeaderWidth(), m_groupHeaderHeight);
 268     }
 269     return QRectF(pos, size);
 270 }
 271
 272 int KItemListViewLayouter::maximumVisibleItems() const
 273 {
 274     const_cast<KItemListViewLayouter*>(this)->doLayout();
 275
 276     const int height = static_cast<int>(m_size.height());
 277     const int rowHeight = static_cast<int>(m_itemSize.height());
 278     int rows = height / rowHeight;
 279     if (height % rowHeight != 0) {
 280         ++rows;
 281     }
 282
 283     return rows * m_columnCount;
 284 }
 285
 286 bool KItemListViewLayouter::isFirstGroupItem(int itemIndex) const
 287 {
 288     const_cast<KItemListViewLayouter*>(this)->doLayout();
 289     return m_groupItemIndexes.contains(itemIndex);
 290 }
 291
 292 void KItemListViewLayouter::markAsDirty()
 293 {
 294     m_dirty = true;
 295 }
 296
 297 void KItemListViewLayouter::doLayout()
 298 {
 299     if (m_dirty) {
 300 #ifdef KITEMLISTVIEWLAYOUTER_DEBUG
 301         QElapsedTimer timer;
 302         timer.start();
 303 #endif
 304         m_visibleIndexesDirty = true;
 305
 306         QSizeF itemSize = m_itemSize;
 307         QSizeF itemMargin = m_itemMargin;
 308         QSizeF size = m_size;
 309
 310         const bool grouped = createGroupHeaders();
 311
 312         const bool horizontalScrolling = (m_scrollOrientation == Qt::Horizontal);
 313         if (horizontalScrolling) {
 314             // Flip everything so that the layout logically can work like having
 315             // a vertical scrolling
 316             itemSize.setWidth(m_itemSize.height());
 317             itemSize.setHeight(m_itemSize.width());
 318             itemMargin.setWidth(m_itemMargin.height());
 319             itemMargin.setHeight(m_itemMargin.width());
 320             size.setWidth(m_size.height());
 321             size.setHeight(m_size.width());
 322
 323             if (grouped) {
 324                 // In the horizontal scrolling case all groups are aligned
 325                 // at the top, which decreases the available height. For the
 326                 // flipped data this means that the width must be decreased.
 327                 size.rwidth() -= m_groupHeaderMargin + m_groupHeaderHeight;
 328             }
 329         }
 330
 331         m_columnWidth = itemSize.width() + itemMargin.width();
 332         const qreal widthForColumns = size.width() - itemMargin.width();
 333         m_columnCount = qMax(1, int(widthForColumns / m_columnWidth));
 334         m_xPosInc = itemMargin.width();
 335
 336         const int itemCount = m_model->count();
 337         if (itemCount > m_columnCount && m_columnWidth >= 32) {
 338             // Apply the unused width equally to each column
 339             const qreal unusedWidth = widthForColumns - m_columnCount * m_columnWidth;
 340             if (unusedWidth > 0) {
 341                 const qreal columnInc = unusedWidth / (m_columnCount + 1);
 342                 m_columnWidth += columnInc;
 343                 m_xPosInc += columnInc;
 344             }
 345         }
 346
 347         int rowCount = itemCount / m_columnCount;
 348         if (itemCount % m_columnCount != 0) {
 349             ++rowCount;
 350         }
 351
 352         m_itemRects.reserve(itemCount);
 353
 354         qreal y = m_headerHeight + itemMargin.height();
 355         int rowIndex = 0;
 356
 357         int index = 0;
 358         while (index < itemCount) {
 359             qreal x = m_xPosInc;
 360             qreal maxItemHeight = itemSize.height();
 361
 362             if (grouped) {
 363                 if (horizontalScrolling) {
 364                     // All group headers will always be aligned on the top and not
 365                     // flipped like the other properties
 366                     x +=  m_groupHeaderMargin + m_groupHeaderHeight;
 367                 }
 368
 369                 if (m_groupItemIndexes.contains(index) && !horizontalScrolling) {
 370                     // The item is the first item of a group.
 371                     // Increase the y-position to provide space
 372                     // for the group header.
 373                     if (index == 0) {
 374                         // The first group header should be aligned on top
 375                         y -= itemMargin.height();
 376                     } else {
 377                         // Only add a margin if there has been added another
 378                         // group already before
 379                         y += m_groupHeaderMargin;
 380                     }
 381                     y += m_groupHeaderHeight;
 382                 }
 383             }
 384
 385             int column = 0;
 386             while (index < itemCount && column < m_columnCount) {
 387                 qreal requiredItemHeight = itemSize.height();
 388                 if (m_sizeHintResolver) {
 389                     const QSizeF sizeHint = m_sizeHintResolver->sizeHint(index);
 390                     const qreal sizeHintHeight = horizontalScrolling ? sizeHint.width() : sizeHint.height();
 391                     if (sizeHintHeight > requiredItemHeight) {
 392                         requiredItemHeight = sizeHintHeight;
 393                     }
 394                 }
 395
 396                 const QRectF bounds(x, y, itemSize.width(), requiredItemHeight);
 397                 if (index < m_itemRects.count()) {
 398                     m_itemRects[index] = bounds;
 399                 } else {
 400                     m_itemRects.append(bounds);
 401                 }
 402
 403                 if (grouped && horizontalScrolling) {
 404                     // When grouping is enabled in the horizontal mode, the header alignment
 405                     // looks like this:
 406                     //   Header-1 Header-2 Header-3
 407                     //   Item 1   Item 4   Item 7
 408                     //   Item 2   Item 5   Item 8
 409                     //   Item 3   Item 6   Item 9
 410                     // In this case 'requiredItemHeight' represents the column-width. We don't
 411                     // check the content of the header in the layouter to determine the required
 412                     // width, hence assure that at least a minimal width of 15 characters is given
 413                     // (in average a character requires the halve width of the font height).
 414                     //
 415                     // TODO: Let the group headers provide a minimum width and respect this width here
 416                     const qreal headerWidth = minimumGroupHeaderWidth();
 417                     if (requiredItemHeight < headerWidth) {
 418                         requiredItemHeight = headerWidth;
 419                     }
 420                 }
 421
 422                 maxItemHeight = qMax(maxItemHeight, requiredItemHeight);
 423                 x += m_columnWidth;
 424                 ++index;
 425                 ++column;
 426
 427                 if (grouped && m_groupItemIndexes.contains(index)) {
 428                     // The item represents the first index of a group
 429                     // and must aligned in the first column
 430                     break;
 431                 }
 432             }
 433
 434             y += maxItemHeight + itemMargin.height();
 435             ++rowIndex;
 436         }
 437         if (m_itemRects.count() > itemCount) {
 438             m_itemRects.erase(m_itemRects.begin() + itemCount,
 439                               m_itemRects.end());
 440         }
 441
 442         if (itemCount > 0) {
 443             // Calculate the maximum y-range of the last row for m_maximumScrollOffset
 444             m_maximumScrollOffset = m_itemRects.last().bottom();
 445             const qreal rowY = m_itemRects.last().y();
 446
 447             int index = m_itemRects.count() - 2;
 448             while (index >= 0 && m_itemRects.at(index).bottom() >= rowY) {
 449                 m_maximumScrollOffset = qMax(m_maximumScrollOffset, m_itemRects.at(index).bottom());
 450                 --index;
 451             }
 452
 453             m_maximumScrollOffset += itemMargin.height();
 454
 455             m_maximumItemOffset = m_columnCount * m_columnWidth;
 456         } else {
 457             m_maximumScrollOffset = 0;
 458             m_maximumItemOffset = 0;
 459         }
 460
 461 #ifdef KITEMLISTVIEWLAYOUTER_DEBUG
 462         kDebug() << "[TIME] doLayout() for " << m_model->count() << "items:" << timer.elapsed();
 463 #endif
 464         m_dirty = false;
 465     }
 466
 467     updateVisibleIndexes();
 468 }
 469
 470 void KItemListViewLayouter::updateVisibleIndexes()
 471 {
 472     if (!m_visibleIndexesDirty) {
 473         return;
 474     }
 475
 476     Q_ASSERT(!m_dirty);
 477
 478     if (m_model->count() <= 0) {
 479         m_firstVisibleIndex = -1;
 480         m_lastVisibleIndex = -1;
 481         m_visibleIndexesDirty = false;
 482         return;
 483     }
 484
 485     const int maxIndex = m_model->count() - 1;
 486
 487     // Calculate the first visible index that is fully visible
 488     int min = 0;
 489     int max = maxIndex;
 490     int mid = 0;
 491     do {
 492         mid = (min + max) / 2;
 493         if (m_itemRects[mid].top() < m_scrollOffset) {
 494             min = mid + 1;
 495         } else {
 496             max = mid - 1;
 497         }
 498     } while (min <= max);
 499
 500     if (mid > 0) {
 501         // Include the row before the first fully visible index, as it might
 502         // be partly visible
 503         if (m_itemRects[mid].top() >= m_scrollOffset) {
 504             --mid;
 505             Q_ASSERT(m_itemRects[mid].top() < m_scrollOffset);
 506         }
 507
 508         const qreal rowTop = m_itemRects[mid].top();
 509         while (mid > 0 && m_itemRects[mid - 1].top() == rowTop) {
 510             --mid;
 511         }
 512     }
 513     m_firstVisibleIndex = mid;
 514
 515     // Calculate the last visible index that is (at least partly) visible
 516     const int visibleHeight = (m_scrollOrientation == Qt::Horizontal) ? m_size.width() : m_size.height();
 517     qreal bottom = m_scrollOffset + visibleHeight;
 518     if (m_model->groupedSorting()) {
 519         bottom += m_groupHeaderHeight;
 520     }
 521
 522     min = m_firstVisibleIndex;
 523     max = maxIndex;
 524     do {
 525         mid = (min + max) / 2;
 526         if (m_itemRects[mid].y() <= bottom) {
 527             min = mid + 1;
 528         } else {
 529             max = mid - 1;
 530         }
 531     } while (min <= max);
 532
 533     while (mid > 0 && m_itemRects[mid].y() > bottom) {
 534         --mid;
 535     }
 536     m_lastVisibleIndex = mid;
 537
 538     m_visibleIndexesDirty = false;
 539 }
 540
 541 bool KItemListViewLayouter::createGroupHeaders()
 542 {
 543     if (!m_model->groupedSorting()) {
 544         return false;
 545     }
 546
 547     m_groupItemIndexes.clear();
 548
 549     const QList<QPair<int, QVariant> > groups = m_model->groups();
 550     if (groups.isEmpty()) {
 551         return false;
 552     }
 553
 554     for (int i = 0; i < groups.count(); ++i) {
 555         const int firstItemIndex = groups.at(i).first;
 556         m_groupItemIndexes.insert(firstItemIndex);
 557     }
 558
 559     return true;
 560 }
 561
 562 qreal KItemListViewLayouter::minimumGroupHeaderWidth() const
 563 {
 564     return m_groupHeaderHeight * 15 / 2;
 565 }
 566
 567 #include "kitemlistviewlayouter_p.moc"