Add a tileset debugger skeleton class

See #632.

client/gui-qt/CMakeLists.txt

@@ -49,6 +49,7 @@ add_library(
   spaceshipdlg.cpp
   sprite.cpp
   themes.cpp
+  tileset_debugger.cpp
   tradecalculation.cpp
   tooltips.cpp
   unitreport.cpp

client/gui-qt/tileset_debugger.cpp

@@ -0,0 +1,86 @@
+/**************************************************************************
+ Copyright (c) 2021 Freeciv21 contributors. This file is
+ part of Freeciv21. Freeciv21 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 3 of the
+ License,  or (at your option) any later version. You should have received
+ a copy of the GNU General Public License along with Freeciv21. If not,
+ see https://www.gnu.org/licenses/.
+**************************************************************************/
+
+#include "tileset_debugger.h"
+
+// common
+#include "map.h"
+#include "tile.h"
+
+// utility
+#include "fcintl.h"
+
+#include <QLabel>
+#include <QToolBar>
+#include <QVBoxLayout>
+
+namespace freeciv {
+
+/**
+ * \class tileset_debugger
+ * \brief A dialog to perform debugging of the tileset.
+ */
+
+/**
+ * Constructor.
+ */
+tileset_debugger::tileset_debugger(QWidget *parent) : QDialog(parent)
+{
+  auto layout = new QVBoxLayout;
+  setLayout(layout);
+
+  auto toolbar = new QToolBar;
+  toolbar->setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
+  layout->addWidget(toolbar);
+
+  m_pick_action =
+      toolbar->addAction(QIcon::fromTheme("pointer"), _("Pick tile"));
+  m_pick_action->setToolTip(_("Pick a tile to inspect on the map"));
+  m_pick_action->setCheckable(true);
+  connect(m_pick_action, &QAction::toggled, this,
+          &tileset_debugger::pick_tile);
+
+  m_label = new QLabel;
+  layout->addWidget(m_label, 100, Qt::AlignCenter);
+
+  set_tile(nullptr);
+}
+
+/**
+ * Destructor.
+ */
+tileset_debugger::~tileset_debugger() {}
+
+/**
+ * Sets the tile being debugged.
+ */
+void tileset_debugger::set_tile(const ::tile *t)
+{
+  m_tile = t;
+
+  // Update the GUI
+  if (!t) {
+    m_label->setText(_("No tile selected"));
+    return;
+  }
+
+  m_label->setText(QStringLiteral("%1 %2").arg(
+      index_to_map_pos_x(tile_index(t)), index_to_map_pos_y(tile_index(t))));
+}
+
+/**
+ * Enters or exits tile picking mode.
+ */
+void tileset_debugger::pick_tile(bool active)
+{
+  emit tile_picking_requested(active);
+}
+
+} // namespace freeciv

client/gui-qt/tileset_debugger.h

@@ -0,0 +1,43 @@
+/**************************************************************************
+ Copyright (c) 2021 Freeciv21 contributors. This file is
+ part of Freeciv21. Freeciv21 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 3 of the
+ License,  or (at your option) any later version. You should have received
+ a copy of the GNU General Public License along with Freeciv21. If not,
+ see https://www.gnu.org/licenses/.
+**************************************************************************/
+#pragma once
+
+#include <QDialog>
+
+class QAction;
+class QLabel;
+
+struct tile;
+
+namespace freeciv {
+
+class tileset_debugger : public QDialog {
+  Q_OBJECT
+
+public:
+  explicit tileset_debugger(QWidget *parent = nullptr);
+  virtual ~tileset_debugger();
+
+  const ::tile *tile() const { return m_tile; }
+  void set_tile(const ::tile *t);
+
+signals:
+  void tile_picking_requested(bool active);
+
+private slots:
+  void pick_tile(bool active);
+
+private:
+  const ::tile *m_tile;
+  QLabel *m_label;
+  QAction *m_pick_action;
+};
+
+} // namespace freeciv