fixed stretching in MapDisplay

.idea/vcs.xml

@@ -1,5 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="CommitMessageInspectionProfile">
+    <profile version="1.0">
+      <inspection_tool class="SubjectLimit" enabled="true" level="WARNING" enabled_by_default="true">
+        <option name="RIGHT_MARGIN" value="50" />
+      </inspection_tool>
+    </profile>
+  </component>
   <component name="VcsDirectoryMappings">
     <mapping directory="$PROJECT_DIR$" vcs="Git" />
   </component>

map_display.py

@@ -26,14 +26,26 @@ class MapDisplay(Display):
         self.max_lon: float = max_lon
         self.min_lat: float = min_lat
         self.max_lat: float = max_lat
+        self._precomputeDisplayValues()
         self.cities: list[tuple[Vec2, str, str]] = cities
 
-    def real_to_screen(self, lon: float, lat: float) -> tuple[float, float]:
-        x = (lon - self.min_lon) / (self.max_lon - self.min_lon)
-        y = (lat - self.min_lat) / (self.max_lat - self.min_lat)
+    def _precomputeDisplayValues(self) -> None:
+        width, height = self.surf.get_size()
+        self._lon_span = self.max_lon - self.min_lon
+        self._lat_span = self.max_lat - self.min_lat
+        r1 = width / self._lon_span
+        r2 = height / self._lat_span
 
-        w, h = self.surf.get_size()
-        return x * w, h - y * h
+        self._r = min(r1, r2)
+
+        self._ox = (width - self._lon_span * self._r) / 2
+        self._oy = (height - self._lat_span * self._r) / 2
+
+    def real_to_screen(self, lon: float, lat: float) -> tuple[float, float]:
+        x = (lon - self.min_lon) * self._r + self._ox
+        y = (lat - self.min_lat) * self._r + self._oy
+
+        return x, self.surf.get_height() - y
 
     def draw_path(self, path: Path) -> None:
         self.draw_colored_path(path, None)