Save less state in minimap_view

The widget needs to compute horizontal and vertical scaling factors to
map between the displayed minimap (in pixel units) and the computed one
(essentially in tile units). It was computing them on resize events and
storing them, which was causing issues when switching maps. Compute them
when they are needed instead, it's just two float divisions.

Also remove a bunch of unused variables from the class and don't try to
move() it when shown (it's in a layout).

Closes #1657.

client/minimap.cpp

@@ -32,26 +32,10 @@ const auto always_visible_margin = 15;
 /**
    Constructor for minimap
  */
-minimap_view::minimap_view(QWidget *parent) : fcwidget()
+minimap_view::minimap_view(QWidget *parent) : fcwidget(parent)
 {
-  setParent(parent);
   setAttribute(Qt::WA_OpaquePaintEvent, true);
-  w_ratio = 0.0;
-  h_ratio = 0.0;
-  // Dark magic: This call is required for the widget to work.
-  resize(0, 0);
-  background = QBrush(QColor(0, 0, 0));
   setCursor(Qt::CrossCursor);
-  pix = new QPixmap;
-}
-
-/**
-   Minimap_view destructor
- */
-minimap_view::~minimap_view()
-{
-  delete pix;
-  pix = nullptr;
 }
 
 /**
@@ -74,20 +58,6 @@ void minimap_view::update_menu()
   ::king()->menu_bar->minimap_status->setChecked(false);
 }
 
-/**
-   Minimap is being moved, position is being remembered
- */
-void minimap_view::moveEvent(QMoveEvent *event) { position = event->pos(); }
-
-/**
-   Minimap is just unhidden, old position is restored
- */
-void minimap_view::showEvent(QShowEvent *event)
-{
-  move(position);
-  event->setAccepted(true);
-}
-
 namespace {
 
 void overview_pos_nowrap(const struct tileset *t, int *ovr_x, int *ovr_y,
@@ -134,6 +104,10 @@ void minimap_view::draw_viewport(QPainter *painter)
 
   painter->setPen(QColor(Qt::white));
 
+  auto w_ratio = static_cast<double>(width()) / gui_options->overview.width;
+  auto h_ratio =
+      static_cast<double>(height()) / gui_options->overview.height;
+
   QVector<QLineF> lines;
   for (int i = 0; i < 4; i++) {
     lines.append(QLineF(x[i] * w_ratio, y[i] * h_ratio,
@@ -239,8 +213,6 @@ void minimap_view::resizeEvent(QResizeEvent *event)
 
   if (C_S_RUNNING <= client_state() && size.width() > 0
       && size.height() > 0) {
-    w_ratio = static_cast<float>(width()) / gui_options->overview.width;
-    h_ratio = static_cast<float>(height()) / gui_options->overview.height;
     king()->qt_settings.minimap_width =
         static_cast<float>(size.width()) / mapview.width;
     king()->qt_settings.minimap_height =
@@ -258,11 +230,12 @@ void minimap_view::resizeEvent(QResizeEvent *event)
 void minimap_view::mousePressEvent(QMouseEvent *event)
 {
   if (event->button() == Qt::RightButton) {
-    cursor = event->pos();
     auto fx = event->pos().x();
     auto fy = event->pos().y();
-    fx = qRound(fx / w_ratio);
-    fy = qRound(fy / h_ratio);
+    fx = qRound(fx * gui_options->overview.width
+                / static_cast<double>(width()));
+    fy = qRound(fy * gui_options->overview.height
+                / static_cast<double>(height()));
     fx = qMax(fx, 1);
     fy = qMax(fy, 1);
     fx = qMin(fx, gui_options->overview.width - 1);

client/minimap.h

@@ -38,7 +38,7 @@ class minimap_view : public fcwidget {
 
 public:
   minimap_view(QWidget *parent);
-  ~minimap_view() override;
+
   void paint(QPainter *painter, QPaintEvent *event);
   void update_menu() override;
   void update_image();
@@ -51,14 +51,7 @@ class minimap_view : public fcwidget {
   void paintEvent(QPaintEvent *event) override;
   void resizeEvent(QResizeEvent *event) override;
   void mousePressEvent(QMouseEvent *event) override;
-  void moveEvent(QMoveEvent *event) override;
-  void showEvent(QShowEvent *event) override;
 
 private:
   void draw_viewport(QPainter *painter);
-  float w_ratio, h_ratio;
-  QBrush background;
-  QPixmap *pix;
-  QPoint cursor;
-  QPoint position;
 };