Fixed copying and capturing stamps on staggered maps

When copying a selected area or creating a tile stamp from the
selection, the captured stamp would only have the tiles in the correct
position when the selection started at even positions.

When capturing an area at an odd position, the stagger index needs to be
adjusted. This was already done for right-click capturing in the
CaptureStampHelper, and now it also happens in
Map::normalizeTileLayerPositionsAndMapSize.

Fixes #2874

(cherry picked from commit 0f7804c)

src/libtiled/map.cpp

@@ -416,15 +416,20 @@ void Map::normalizeTileLayerPositionsAndMapSize()
     while (auto tileLayer = static_cast<TileLayer*>(it.next()))
         contentRect |= tileLayer->region().boundingRect();
 
-    if (!contentRect.isEmpty()) {
-        QPoint offset = contentRect.topLeft();
+    if (!contentRect.topLeft().isNull()) {
         it.toFront();
         while (auto tileLayer = static_cast<TileLayer*>(it.next()))
-            tileLayer->setPosition(tileLayer->position() - offset);
+            tileLayer->setPosition(tileLayer->position() - contentRect.topLeft());
 
-        setWidth(contentRect.width());
-        setHeight(contentRect.height());
+        // Adjust the stagger index when layers are moved by odd amounts
+        const int staggerOffSet = (staggerAxis() == Map::StaggerX ? contentRect.x()
+                                                                  : contentRect.y()) % 2;
+
+        setStaggerIndex(static_cast<Map::StaggerIndex>((staggerIndex() + staggerOffSet) % 2));
     }
+
+    setWidth(contentRect.width());
+    setHeight(contentRect.height());
 }
 
 /**

src/tiled/capturestamphelper.cpp

@@ -72,16 +72,12 @@ TileStamp CaptureStampHelper::endCapture(const MapDocument &mapDocument, QPoint
     }
 
     if (stamp->layerCount() > 0) {
-        auto staggerIndex = stamp->staggerIndex();
+        // Adjust the stagger index when the capture starts at an odd offset
+        const auto staggerIndex = stamp->staggerIndex();
+        const int staggerOffSet = (stamp->staggerAxis() == Map::StaggerX ? captured.x()
+                                                                         : captured.y()) % 2;
 
-        // Gets if the relative stagger should be the same as the base layer
-        int staggerIndexOffSet;
-        if (stamp->staggerAxis() == Map::StaggerX)
-            staggerIndexOffSet = captured.x() % 2;
-        else
-            staggerIndexOffSet = captured.y() % 2;
-
-        stamp->setStaggerIndex(static_cast<Map::StaggerIndex>((staggerIndex + staggerIndexOffSet) % 2));
+        stamp->setStaggerIndex(static_cast<Map::StaggerIndex>((staggerIndex + staggerOffSet) % 2));
 
         // Add tileset references to map
         stamp->addTilesets(stamp->usedTilesets());