Fix: Inconsistent layer number if we change from background layer to …

…layer

This patch fixes #4084.

Currently if we set layer to background and then back to layer, last
used name isn't preserved. This patch makes layer save last used layer name before
it gets converted to background so it won't get lost.

src/app/cmd/configure_background.cpp

@@ -25,8 +25,13 @@ ConfigureBackground::ConfigureBackground(Layer* layer)
  LayerFlags newFlags = LayerFlags(int(layer->flags())
  | int(LayerFlags::BackgroundLayerFlags));
 
+ // save previous layer name so it will be the same
+ // if user changes layer from background to layer once again
+ layer->setLayerPrevName(layer->name());
+
  add(new cmd::SetLayerFlags(layer, newFlags));
- add(new cmd::SetLayerName(layer, "Background"));
+ add(new cmd::SetLayerName(layer, layer->prevBgName().empty() ?
+ "Background" : layer->prevBgName()));
 
  if (layer->isImage() &&
  static_cast<LayerImage*>(layer)->opacity() < 255) {

src/app/cmd/layer_from_background.cpp

@@ -9,7 +9,6 @@
 #endif
 
 #include "app/cmd/layer_from_background.h"
-
 #include "app/cmd/set_layer_flags.h"
 #include "app/cmd/set_layer_name.h"
 #include "doc/layer.h"
@@ -32,8 +31,12 @@ LayerFromBackground::LayerFromBackground(Layer* layer)
  LayerFlags newFlags = LayerFlags(int(layer->flags())
  & ~int(LayerFlags::BackgroundLayerFlags));
 
+ layer->setBgPrevName(layer->name());
+
  add(new cmd::SetLayerFlags(layer, newFlags));
- add(new cmd::SetLayerName(layer, "Layer 0"));
+
+ // set previous set layer name before layer got changed to background
+ add(new cmd::SetLayerName(layer, layer->prevName()));
 }
 
 } // namespace cmd

src/doc/layer.h

@@ -59,6 +59,10 @@ namespace doc {
 
  const std::string& name() const { return m_name; }
  void setName(const std::string& name) { m_name = name; }
+ void setLayerPrevName(const std::string& name) { m_prev_name = name; }
+ void setBgPrevName(const std::string& name) { m_prev_bg_name = name; }
+ const std::string& prevName() const { return m_prev_name; }
+ const std::string& prevBgName() const { return m_prev_bg_name; }
 
  Sprite* sprite() const { return m_sprite; }
  LayerGroup* parent() const { return m_parent; }
@@ -129,8 +133,10 @@ namespace doc {
 
  private:
  std::string m_name; // layer name
+ std::string m_prev_name; // previous layer name (before conversion to bg)
+ std::string m_prev_bg_name; // previous background layer name (before conversion to layer)
  Sprite* m_sprite; // owner of the layer
- LayerGroup* m_parent; // parent layer
+ LayerGroup* m_parent;  // parent layer
  LayerFlags m_flags; // stack order cannot be changed
 
  // Disable assigment