Added GroupLayer and GroupLayerItem

A GroupLayer is a new kind of layer that can contain other layers. It is
meant for organizing layers in folders in case you are working with maps
that have a large amount of layers.

The visibility, opacity and later also locked status of the group layer
will affect all child layers. Also the Layers view will allow collapsing
group layers.

This change is only the start. The addition of group layers is expected
to affect a large amount of code.

src/libtiled/grouplayer.cpp

@@ -0,0 +1,130 @@
+/*
+ * grouplayer.cpp
+ * Copyright 2017, Thorbjørn Lindeijer <bjorn@lindeijer.nl>
+ *
+ * This file is part of Tiled.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "grouplayer.h"
+
+#include "map.h"
+
+namespace Tiled {
+
+GroupLayer::GroupLayer(const QString &name, int x, int y):
+    Layer(GroupLayerType, name, x, y)
+{
+}
+
+GroupLayer::~GroupLayer()
+{
+    qDeleteAll(mLayers);
+}
+
+void GroupLayer::addLayer(Layer *layer)
+{
+    adoptLayer(layer);
+    mLayers.append(layer);
+}
+
+void GroupLayer::insertLayer(int index, Layer *layer)
+{
+    adoptLayer(layer);
+    mLayers.insert(index, layer);
+}
+
+void GroupLayer::adoptLayer(Layer *layer)
+{
+    layer->setMap(map());
+
+    if (map())
+        if (ObjectGroup *group = layer->asObjectGroup())
+            map()->initializeObjectIds(*group);
+}
+
+Layer *GroupLayer::takeLayerAt(int index)
+{
+    Layer *layer = mLayers.takeAt(index);
+    layer->setMap(nullptr);
+    return layer;
+}
+
+void GroupLayer::setMap(Map *map)
+{
+    // todo: What about initializing object IDs?
+    Layer::setMap(map);
+    for (Layer *layer : mLayers)
+        layer->setMap(map);
+}
+
+bool GroupLayer::isEmpty() const
+{
+    return mLayers.isEmpty();
+}
+
+QSet<SharedTileset> GroupLayer::usedTilesets() const
+{
+    QSet<SharedTileset> tilesets;
+
+    for (const Layer *layer : mLayers)
+        tilesets |= layer->usedTilesets();
+
+    return tilesets;
+}
+
+bool GroupLayer::referencesTileset(const Tileset *tileset) const
+{
+    for (const Layer *layer : mLayers)
+        if (layer->referencesTileset(tileset))
+            return true;
+
+    return false;
+}
+
+void GroupLayer::replaceReferencesToTileset(Tileset *oldTileset, Tileset *newTileset)
+{
+    const auto &children = mLayers;
+    for (Layer *layer : children)
+        layer->replaceReferencesToTileset(oldTileset, newTileset);
+}
+
+bool GroupLayer::canMergeWith(Layer *) const
+{
+    // Merging group layers would be possible, but duplicating all child layers
+    // is not the right approach.
+    // todo: implement special case of reparenting child layers
+    return false;
+}
+
+Layer *GroupLayer::mergedWith(Layer *) const
+{
+    return nullptr;
+}
+
+Layer *GroupLayer::clone() const
+{
+    return initializeClone(new GroupLayer(mName, mX, mY));
+}
+
+GroupLayer *GroupLayer::initializeClone(GroupLayer *clone) const
+{
+    Layer::initializeClone(clone);
+    for (const Layer *layer : mLayers)
+        clone->addLayer(layer->clone());
+    return clone;
+}
+
+} // namespace Tiled

src/libtiled/grouplayer.h

@@ -0,0 +1,81 @@
+/*
+ * grouplayer.h
+ * Copyright 2017, Thorbjørn Lindeijer <bjorn@lindeijer.nl>
+ *
+ * This file is part of Tiled.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GROUPLAYER_H
+#define GROUPLAYER_H
+
+#include "layer.h"
+
+#include <QList>
+
+namespace Tiled {
+
+class TILEDSHARED_EXPORT GroupLayer : public Layer
+{
+public:
+    GroupLayer(const QString &name, int x, int y);
+    ~GroupLayer();
+
+    int layerCount() const;
+    Layer *layerAt(int index) const;
+    const QList<Layer*> &layers() const { return mLayers; }
+
+    void addLayer(Layer *layer);
+    void insertLayer(int index, Layer *layer);
+    Layer *takeLayerAt(int index);
+
+    void setMap(Map *map) override;
+    bool isEmpty() const override;
+    QSet<SharedTileset> usedTilesets() const override;
+    bool referencesTileset(const Tileset *tileset) const override;
+    void replaceReferencesToTileset(Tileset *oldTileset, Tileset *newTileset) override;
+    bool canMergeWith(Layer *other) const override;
+    Layer *mergedWith(Layer *other) const override;
+    Layer *clone() const override;
+
+    // Enable easy iteration over children with range-based for
+    QList<Layer*>::iterator begin() { return mLayers.begin(); }
+    QList<Layer*>::iterator end() { return mLayers.end(); }
+    QList<Layer*>::const_iterator begin() const { return mLayers.begin(); }
+    QList<Layer*>::const_iterator end() const { return mLayers.end(); }
+
+protected:
+    GroupLayer *initializeClone(GroupLayer *clone) const;
+
+private:
+    void adoptLayer(Layer *layer);
+
+    QList<Layer*> mLayers;
+};
+
+
+inline int GroupLayer::layerCount() const
+{
+    return mLayers.size();
+}
+
+inline Layer *GroupLayer::layerAt(int index) const
+{
+    return mLayers.at(index);
+}
+
+} // namespace Tiled
+
+#endif // GROUPLAYER_H

src/libtiled/layer.h

@@ -55,7 +55,8 @@ class TILEDSHARED_EXPORT Layer : public Object
     enum TypeFlag {
         TileLayerType   = 0x01,
         ObjectGroupType = 0x02,
-        ImageLayerType  = 0x04
+        ImageLayerType  = 0x04,
+        GroupLayerType  = 0x08
     };
 
     enum { AnyLayerType = 0xFF };
@@ -109,7 +110,7 @@ class TILEDSHARED_EXPORT Layer : public Object
      * Sets the map this layer is part of. Should only be called from the
      * Map class.
      */
-    void setMap(Map *map) { mMap = map; }
+    virtual void setMap(Map *map) { mMap = map; }
 
     /**
      * Returns the x position of this layer (in tiles).

src/libtiled/libtiled.pro

@@ -30,6 +30,7 @@ contains(QT_CONFIG, reduce_exports): CONFIG += hide_symbols
 SOURCES += compression.cpp \
     filesystemwatcher.cpp \
     gidmapper.cpp \
+    grouplayer.cpp \
     hexagonalrenderer.cpp \
     imagelayer.cpp \
     imagereference.cpp \
@@ -58,6 +59,7 @@ SOURCES += compression.cpp \
 HEADERS += compression.h \
     filesystemwatcher.h \
     gidmapper.h \
+    grouplayer.h \
     hexagonalrenderer.h \
     imagelayer.h \
     imagereference.h \

src/libtiled/libtiled.qbs

@@ -40,6 +40,8 @@ DynamicLibrary {
         "filesystemwatcher.h",
         "gidmapper.cpp",
         "gidmapper.h",
+        "grouplayer.cpp",
+        "grouplayer.h",
         "hexagonalrenderer.cpp",
         "hexagonalrenderer.h",
         "imagelayer.cpp",

src/libtiled/map.cpp

@@ -220,12 +220,8 @@ void Map::adoptLayer(Layer *layer)
 {
     layer->setMap(this);
 
-    if (ObjectGroup *group = layer->asObjectGroup()) {
-        for (MapObject *o : group->objects()) {
-            if (o->id() == 0)
-                o->setId(takeNextObjectId());
-        }
-    }
+    if (ObjectGroup *group = layer->asObjectGroup())
+        initializeObjectIds(*group);
 }
 
 Layer *Map::takeLayerAt(int index)
@@ -298,6 +294,14 @@ bool Map::isTilesetUsed(const Tileset *tileset) const
     return false;
 }
 
+void Map::initializeObjectIds(ObjectGroup &objectGroup)
+{
+    for (MapObject *o : objectGroup) {
+        if (o->id() == 0)
+            o->setId(takeNextObjectId());
+    }
+}
+
 
 QString Tiled::staggerAxisToString(Map::StaggerAxis staggerAxis)
 {

src/libtiled/map.h

@@ -237,6 +237,9 @@ class TILEDSHARED_EXPORT Map : public Object
     int imageLayerCount() const
     { return layerCount(Layer::ImageLayerType); }
 
+    int groupLayerCount() const
+    { return layerCount(Layer::GroupLayerType); }
+
     /**
      * Returns the layer at the specified index.
      */
@@ -364,6 +367,7 @@ class TILEDSHARED_EXPORT Map : public Object
     void setNextObjectId(int nextId);
     int nextObjectId() const;
     int takeNextObjectId();
+    void initializeObjectIds(ObjectGroup &objectGroup);
 
 private:
     void adoptLayer(Layer *layer);

src/libtiled/maptovariantconverter.cpp

@@ -21,6 +21,7 @@
 
 #include "maptovariantconverter.h"
 
+#include "grouplayer.h"
 #include "imagelayer.h"
 #include "map.h"
 #include "mapobject.h"
@@ -95,6 +96,8 @@ QVariant MapToVariantConverter::toVariant(const Map *map, const QDir &mapDir)
         case Layer::ImageLayerType:
             layerVariants << toVariant(static_cast<const ImageLayer*>(layer));
             break;
+        case Layer::GroupLayerType:
+            layerVariants << toVariant(static_cast<const GroupLayer*>(layer));
         }
     }
     mapVariant[QLatin1String("layers")] = layerVariants;
@@ -395,6 +398,17 @@ QVariant MapToVariantConverter::toVariant(const ImageLayer *imageLayer) const
     return imageLayerVariant;
 }
 
+QVariant MapToVariantConverter::toVariant(const GroupLayer *groupLayer) const
+{
+    QVariantMap groupLayerVariant;
+
+    addLayerAttributes(groupLayerVariant, groupLayer);
+
+    // todo
+
+    return groupLayerVariant;
+}
+
 void MapToVariantConverter::addLayerAttributes(QVariantMap &layerVariant,
                                                const Layer *layer) const
 {

src/libtiled/maptovariantconverter.h

@@ -29,6 +29,8 @@
 
 namespace Tiled {
 
+class GroupLayer;
+
 /**
  * Converts Map instances to QVariant. Meant to be used together with
  * JsonWriter.
@@ -58,6 +60,7 @@ class TILEDSHARED_EXPORT MapToVariantConverter
                        Map::LayerDataFormat format) const;
     QVariant toVariant(const ObjectGroup *objectGroup) const;
     QVariant toVariant(const ImageLayer *imageLayer) const;
+    QVariant toVariant(const GroupLayer *groupLayer) const;
 
     void addLayerAttributes(QVariantMap &layerVariant,
                             const Layer *layer) const;

src/plugins/gmx/gmxplugin.cpp

@@ -298,6 +298,14 @@ bool GmxPlugin::write(const Map *map, const QString &fileName)
             }
             break;
         }
+
+        case Layer::ImageLayerType:
+            // todo: maybe export as backgrounds?
+            break;
+
+        case Layer::GroupLayerType:
+            // todo: recursively export group layers
+            break;
         }
 
         currentLayer--;