Custom output chunk size can now be specified in the map properties

src/libtiled/map.cpp

@@ -59,6 +59,7 @@ Map::Map(Orientation orientation,
     mHexSideLength(0),
     mStaggerAxis(StaggerY),
     mStaggerIndex(StaggerOdd),
+    mChunkSize(CHUNK_SIZE, CHUNK_SIZE),
     mDrawMarginsDirty(true),
     mLayerDataFormat(Base64Zlib),
     mNextLayerId(1),
@@ -337,6 +338,7 @@ Map *Map::clone() const
     o->mStaggerAxis = mStaggerAxis;
     o->mStaggerIndex = mStaggerIndex;
     o->mBackgroundColor = mBackgroundColor;
+    o->mChunkSize = mChunkSize;
     o->mDrawMargins = mDrawMargins;
     o->mDrawMarginsDirty = mDrawMarginsDirty;
     for (const Layer *layer : mLayers) {

src/libtiled/map.h

@@ -415,6 +415,16 @@ class TILEDSHARED_EXPORT Map : public Object
      */
     void setBackgroundColor(QColor color) { mBackgroundColor = color; }
 
+    /**
+     * Returns the chunk size used when saving tile layers of this map.
+     */
+    QSize chunkSize() const { return mChunkSize; }
+
+    /**
+     * Sets the chunk size used when saving tile layers of this map.
+     */
+    void setChunkSize(QSize size) { mChunkSize = size; }
+
     /**
      * Returns whether the given \a tileset is used by any tile layer of this
      * map.
@@ -470,6 +480,7 @@ class TILEDSHARED_EXPORT Map : public Object
     StaggerAxis mStaggerAxis;
     StaggerIndex mStaggerIndex;
     QColor mBackgroundColor;
+    QSize mChunkSize;
     mutable QMargins mDrawMargins;
     mutable bool mDrawMarginsDirty;
     QList<Layer*> mLayers;

src/libtiled/mapreader.cpp

@@ -791,6 +791,14 @@ void MapReaderPrivate::readTileLayerData(TileLayer &tileLayer)
 
     mMap->setLayerDataFormat(layerDataFormat);
 
+    int chunkWidth = atts.value(QLatin1String("outputchunkwidth")).toInt();
+    int chunkHeight = atts.value(QLatin1String("outputchunkheight")).toInt();
+
+    chunkWidth = chunkWidth == 0 ? CHUNK_SIZE : qMax(CHUNK_SIZE_MIN, chunkWidth);
+    chunkHeight = chunkHeight == 0 ? CHUNK_SIZE : qMax(CHUNK_SIZE_MIN, chunkHeight);
+
+    mMap->setChunkSize(QSize(chunkWidth, chunkHeight));
+
     readTileLayerRect(tileLayer,
                       layerDataFormat,
                       encoding,

src/libtiled/maptovariantconverter.cpp

@@ -91,7 +91,8 @@ QVariant MapToVariantConverter::toVariant(const Map &map, const QDir &mapDir)
     mapVariant[QLatin1String("tilesets")] = tilesetVariants;
 
     mapVariant[QLatin1String("layers")] = toVariant(map.layers(),
-                                                    map.layerDataFormat());
+                                                    map.layerDataFormat(),
+                                                    map.chunkSize());
 
     return mapVariant;
 }
@@ -385,14 +386,15 @@ QVariant MapToVariantConverter::toVariant(const WangColor &wangColor) const
 }
 
 QVariant MapToVariantConverter::toVariant(const QList<Layer *> &layers,
-                                          Map::LayerDataFormat format) const
+                                          Map::LayerDataFormat format,
+                                          QSize chunkSize) const
 {
     QVariantList layerVariants;
 
     for (const Layer *layer : layers) {
         switch (layer->layerType()) {
         case Layer::TileLayerType:
-            layerVariants << toVariant(*static_cast<const TileLayer*>(layer), format);
+            layerVariants << toVariant(*static_cast<const TileLayer*>(layer), format, chunkSize);
             break;
         case Layer::ObjectGroupType:
             layerVariants << toVariant(*static_cast<const ObjectGroup*>(layer));
@@ -401,15 +403,16 @@ QVariant MapToVariantConverter::toVariant(const QList<Layer *> &layers,
             layerVariants << toVariant(*static_cast<const ImageLayer*>(layer));
             break;
         case Layer::GroupLayerType:
-            layerVariants << toVariant(*static_cast<const GroupLayer*>(layer), format);
+            layerVariants << toVariant(*static_cast<const GroupLayer*>(layer), format, chunkSize);
         }
     }
 
     return layerVariants;
 }
 
 QVariant MapToVariantConverter::toVariant(const TileLayer &tileLayer,
-                                          Map::LayerDataFormat format) const
+                                          Map::LayerDataFormat format,
+                                          QSize chunkSize) const
 {
     QVariantMap tileLayerVariant;
     tileLayerVariant[QLatin1String("type")] = QLatin1String("tilelayer");
@@ -446,9 +449,14 @@ QVariant MapToVariantConverter::toVariant(const TileLayer &tileLayer,
     }
 
     if (tileLayer.map()->infinite()) {
+        if (chunkSize.width() != CHUNK_SIZE || chunkSize.height() != CHUNK_SIZE) {
+            tileLayerVariant[QLatin1String("outputchunkwidth")] = chunkSize.width();
+            tileLayerVariant[QLatin1String("outputchunkheight")] = chunkSize.height();
+        }
+
         QVariantList chunkVariants;
 
-        const auto chunks = tileLayer.sortedChunksToWrite();
+        const auto chunks = tileLayer.sortedChunksToWrite(chunkSize);
         for (const QRect &rect : chunks) {
             QVariantMap chunkVariant;
 
@@ -649,15 +657,17 @@ QVariant MapToVariantConverter::toVariant(const ImageLayer &imageLayer) const
 }
 
 QVariant MapToVariantConverter::toVariant(const GroupLayer &groupLayer,
-                                          Map::LayerDataFormat format) const
+                                          Map::LayerDataFormat format,
+                                          QSize chunkSize) const
 {
     QVariantMap groupLayerVariant;
     groupLayerVariant[QLatin1String("type")] = QLatin1String("group");
 
     addLayerAttributes(groupLayerVariant, groupLayer);
 
     groupLayerVariant[QLatin1String("layers")] = toVariant(groupLayer.layers(),
-                                                           format);
+                                                           format,
+                                                           chunkSize);
 
     return groupLayerVariant;
 }

src/libtiled/maptovariantconverter.h

@@ -68,13 +68,13 @@ class TILEDSHARED_EXPORT MapToVariantConverter
     QVariant propertyTypesToVariant(const Properties &properties) const;
     QVariant toVariant(const WangSet &wangSet) const;
     QVariant toVariant(const WangColor &wangColor) const;
-    QVariant toVariant(const QList<Layer*> &layers, Map::LayerDataFormat format) const;
-    QVariant toVariant(const TileLayer &tileLayer, Map::LayerDataFormat format) const;
+    QVariant toVariant(const QList<Layer*> &layers, Map::LayerDataFormat format, QSize chunkSize) const;
+    QVariant toVariant(const TileLayer &tileLayer, Map::LayerDataFormat format, QSize chunkSize) const;
     QVariant toVariant(const ObjectGroup &objectGroup) const;
     QVariant toVariant(const MapObject &object) const;
     QVariant toVariant(const TextData &textData) const;
     QVariant toVariant(const ImageLayer &imageLayer) const;
-    QVariant toVariant(const GroupLayer &groupLayer, Map::LayerDataFormat format) const;
+    QVariant toVariant(const GroupLayer &groupLayer, Map::LayerDataFormat format, QSize chunkSize) const;
 
     void addTileLayerData(QVariantMap &variant,
                           const TileLayer &tileLayer,

src/libtiled/mapwriter.cpp

@@ -85,6 +85,7 @@ class MapWriterPrivate
     QString mError;
     Map::LayerDataFormat mLayerDataFormat;
     bool mDtdEnabled;
+    QSize mChunkSize;
 
 private:
     void writeMap(QXmlStreamWriter &w, const Map &map);
@@ -114,6 +115,7 @@ class MapWriterPrivate
 MapWriterPrivate::MapWriterPrivate()
     : mLayerDataFormat(Map::Base64Zlib)
     , mDtdEnabled(false)
+    , mChunkSize(CHUNK_SIZE, CHUNK_SIZE)
     , mUseAbsolutePaths(false)
 {
 }
@@ -149,6 +151,7 @@ void MapWriterPrivate::writeMap(const Map *map, QIODevice *device,
     mMapDir = QDir(path);
     mUseAbsolutePaths = path.isEmpty();
     mLayerDataFormat = map->layerDataFormat();
+    mChunkSize = map->chunkSize();
 
     AutoFormattingWriter writer(device);
     writer.writeStartDocument();
@@ -588,7 +591,12 @@ void MapWriterPrivate::writeTileLayer(QXmlStreamWriter &w,
         w.writeAttribute(QLatin1String("compression"), compression);
 
     if (tileLayer.map()->infinite()) {
-        const auto chunks = tileLayer.sortedChunksToWrite();
+        if (mChunkSize.width() != CHUNK_SIZE || mChunkSize.height() != CHUNK_SIZE) {
+            w.writeAttribute(QLatin1String("outputchunkwidth"), QString::number(mChunkSize.width()));
+            w.writeAttribute(QLatin1String("outputchunkheight"), QString::number(mChunkSize.height()));
+        }
+
+        const auto chunks = tileLayer.sortedChunksToWrite(mChunkSize);
         for (const QRect &rect : chunks) {
             w.writeStartElement(QLatin1String("chunk"));
             w.writeAttribute(QLatin1String("x"), QString::number(rect.x()));

src/libtiled/tiled.h

@@ -68,6 +68,7 @@ enum LoadingStatus {
 };
 
 const int CHUNK_SIZE = 16;
+const int CHUNK_SIZE_MIN = 4;
 const int CHUNK_MASK = CHUNK_SIZE - 1;
 
 static const char TILES_MIMETYPE[] = "application/vnd.tile.list";

src/libtiled/tilelayer.cpp

@@ -35,6 +35,8 @@
 #include <algorithm>
 #include <memory>
 
+#include <QSet>
+
 using namespace Tiled;
 
 Cell Cell::empty;
@@ -760,19 +762,72 @@ static bool compareRectPos(const QRect &a, const QRect &b)
  * This function is used to determine the chunks to write when saving a tile
  * layer.
  */
-QVector<QRect> TileLayer::sortedChunksToWrite() const
+QVector<QRect> TileLayer::sortedChunksToWrite(QSize chunkSize) const
 {
     QVector<QRect> chunksToWrite;
-    chunksToWrite.reserve(mChunks.size());
+    QSet<QPoint> existingChunks;
+
+    bool isNativeChunkSize = (chunkSize.width() == CHUNK_SIZE &&
+                              chunkSize.height() == CHUNK_SIZE);
+
+    if (isNativeChunkSize)
+        chunksToWrite.reserve(mChunks.size());
 
     QHashIterator<QPoint, Chunk> it(mChunks);
     while (it.hasNext()) {
-        it.next();
-        if (!it.value().isEmpty()) {
-            const QPoint p = it.key();
+        const Chunk &chunk = it.next().value();
+        if (chunk.isEmpty())
+            continue;
+
+        const QPoint &p = it.key();
+
+        if (isNativeChunkSize) {
+            // If the desired chunk size is equal to our native chunk size,
+            // then we just we just have to iterate our chunk list and return
+            // the bounds of each chunk.
             chunksToWrite.append(QRect(p.x() * CHUNK_SIZE,
                                        p.y() * CHUNK_SIZE,
                                        CHUNK_SIZE, CHUNK_SIZE));
+        } else {
+            // If the desired chunk size is not the native size, we have to do
+            // a bit of extra work and "rearrange" chunks as we iterate our
+            // list. We do this by iterating every cell in a chunk. If it's not
+            // empty, we check what chunk it should go into with the new chunk
+            // size. If that chunk doesn't exist yet, we create it.
+            //
+            // NOTE: Rather than checking every cell in every chunk, we could
+            // also just test which "new" chunks our "old" chunk would
+            // intersect with and return all of those, this would be faster.
+            // However, that way we could end up with completely empty chunks,
+            // so we'll take the slower route and iterate all cells instead to
+            // avoid that.
+            int oldChunkStartX = p.x() * CHUNK_SIZE;
+            int oldChunkStartY = p.y() * CHUNK_SIZE;
+
+            for (int y = 0; y < CHUNK_SIZE; ++y) {
+                for (int x = 0; x < CHUNK_SIZE; ++x) {
+                    const Cell &cell = chunk.cellAt(x, y);
+
+                    if (!cell.isEmpty()) {
+                        int tileX = oldChunkStartX + x;
+                        int tileY = oldChunkStartY + y;
+
+                        // Nasty conditionals because of potentially negative
+                        // chunk start position. Modulo with negative numbers
+                        // is weird and unintuitive in C++...
+                        int moduloX = tileX % chunkSize.width();
+                        int newChunkStartX = tileX - (moduloX < 0 ? moduloX + chunkSize.width() : moduloX);
+                        int moduloY = tileY % chunkSize.height();
+                        int newChunkStartY = tileY - (moduloY < 0 ? moduloY + chunkSize.height() : moduloY);
+                        QPoint startPoint(newChunkStartX, newChunkStartY);
+
+                        if (!existingChunks.contains(startPoint)) {
+                            existingChunks.insert(startPoint);
+                            chunksToWrite.append(QRect(newChunkStartX, newChunkStartY, chunkSize.width(), chunkSize.height()));
+                        }
+                    }
+                }
+            }
         }
     }
 

src/libtiled/tilelayer.h

@@ -520,7 +520,7 @@ class TILEDSHARED_EXPORT TileLayer : public Layer
     const_iterator begin() const { return const_iterator(mChunks.begin(), mChunks.end()); }
     const_iterator end() const { return const_iterator(mChunks.end(), mChunks.end()); }
 
-    QVector<QRect> sortedChunksToWrite() const;
+    QVector<QRect> sortedChunksToWrite(QSize chunkSize) const;
 
 protected:
     TileLayer *initializeClone(TileLayer *clone) const;

src/libtiled/varianttomapconverter.cpp

@@ -541,6 +541,14 @@ std::unique_ptr<TileLayer> VariantToMapConverter::toTileLayer(const QVariantMap
     }
     mMap->setLayerDataFormat(layerDataFormat);
 
+    int chunkWidth = variantMap[QLatin1String("outputchunkwidth")].toInt();
+    int chunkHeight = variantMap[QLatin1String("outputchunkheight")].toInt();
+
+    chunkWidth = chunkWidth == 0 ? CHUNK_SIZE : qMax(CHUNK_SIZE_MIN, chunkWidth);
+    chunkHeight = chunkHeight == 0 ? CHUNK_SIZE : qMax(CHUNK_SIZE_MIN, chunkHeight);
+
+    mMap->setChunkSize(QSize(chunkWidth, chunkHeight));
+
     if (dataVariant.isValid() && !dataVariant.isNull()) {
         if (!readTileLayerData(*tileLayer, dataVariant, layerDataFormat,
                                QRect(startX, startY, tileLayer->width(), tileLayer->height()))) {