diff --git a/src/libretro/StellaLIBRETRO.hxx b/src/libretro/StellaLIBRETRO.hxx
index 135a5413b..f54eac326 100644
--- a/src/libretro/StellaLIBRETRO.hxx
+++ b/src/libretro/StellaLIBRETRO.hxx
@@ -60,7 +60,7 @@ class StellaLIBRETRO
 
     void*  getROM() const { return rom_image.get(); }
     uInt32 getROMSize() const { return rom_size; }
-    constexpr uInt32 getROMMax() const { return Cartridge::maxSize(); }
+    constexpr uInt32 getROMMax() const { return uInt32(Cartridge::maxSize()); }
 
     uInt8* getRAM() { return system_ram; }
     constexpr uInt32 getRAMSize() const { return 128; }
@@ -100,6 +100,10 @@ class StellaLIBRETRO
       return myOSystem->console().tia().height() * getVideoZoom();
     }
 
+    const Common::Rect& getImageRect() const {
+      return myOSystem->frameBuffer().imageRect();
+    }
+
     float  getAudioRate() const {
       return getConsoleNTSC() ? (262 * 76 * 60) / 38.0 : (312 * 76 * 50) / 38.0;
     }
diff --git a/src/libretro/libretro.cxx b/src/libretro/libretro.cxx
index e9fe39de5..d18d3b400 100644
--- a/src/libretro/libretro.cxx
+++ b/src/libretro/libretro.cxx
@@ -129,11 +129,18 @@ static void update_input()
       break;
 
     case Controller::Type::Lightgun:
-      EVENT(Event::MouseAxisXValue, input_state_cb(pad, RETRO_DEVICE_LIGHTGUN, 0, RETRO_DEVICE_ID_LIGHTGUN_SCREEN_X));
-      EVENT(Event::MouseAxisYValue, input_state_cb(pad, RETRO_DEVICE_LIGHTGUN, 0, RETRO_DEVICE_ID_LIGHTGUN_SCREEN_Y));
+    {
+      // scale from -0x8000..0x7fff to image rect
+      const Common::Rect& rect =  stella.getImageRect();
+      const Int32 x = (input_state_cb(pad, RETRO_DEVICE_LIGHTGUN, 0, RETRO_DEVICE_ID_LIGHTGUN_SCREEN_X) + 0x8000) * rect.w() / 0xffff;
+      const Int32 y = (input_state_cb(pad, RETRO_DEVICE_LIGHTGUN, 0, RETRO_DEVICE_ID_LIGHTGUN_SCREEN_Y) + 0x8000) * rect.h() / 0xffff;
+
+      EVENT(Event::MouseAxisXValue, x);
+      EVENT(Event::MouseAxisYValue, y);
       EVENT(Event::MouseButtonLeftValue, input_state_cb(pad, RETRO_DEVICE_LIGHTGUN, 0, RETRO_DEVICE_ID_LIGHTGUN_TRIGGER));
       EVENT(Event::MouseButtonRightValue, input_state_cb(pad, RETRO_DEVICE_LIGHTGUN, 0, RETRO_DEVICE_ID_LIGHTGUN_TRIGGER));
       break;
+    }
 
     default:
       break;