Add scaling factor option

src/options.cpp

@@ -1594,6 +1594,12 @@ void options_manager::add_options_graphics()
         { "linear", translate_marker( "Linear filtering" ) }
     },
     "none", COPT_CURSES_HIDE );
+
+    add( "SCALING_FACTOR", "graphics", translate_marker( "Scaling factor" ),
+         translate_marker( "Factor by which to scale the display" ),
+         1.0, 20.0, 1.0, 1.0, COPT_CURSES_HIDE
+       );
+
 }
 
 void options_manager::add_options_debug()

src/sdltiles.cpp

@@ -198,6 +198,7 @@ int fontheight;         //the height of the font, background is always this size
 static int TERMINAL_WIDTH;
 static int TERMINAL_HEIGHT;
 bool fullscreen;
+float scaling_factor;
 
 static SDL_Joystick *joystick; // Only one joystick for now.
 
@@ -338,6 +339,8 @@ void WinCreate()
         SDL_SetHint( SDL_HINT_RENDER_SCALE_QUALITY, get_option<std::string>( "SCALING_MODE" ).c_str() );
     }
 
+    scaling_factor = get_option<float>( "SCALING_FACTOR" );
+
 #ifndef __ANDROID__
     if (get_option<std::string>( "FULLSCREEN" ) == "fullscreen") {
         window_flags |= SDL_WINDOW_FULLSCREEN;
@@ -754,6 +757,7 @@ void refresh_display()
     // Select default target (the window), copy rendered buffer
     // there, present it, select the buffer as target again.
     SetRenderTarget( renderer, NULL );
+    SDL_RenderSetLogicalSize( renderer.get(), TERMINAL_WIDTH * fontwidth / scaling_factor, TERMINAL_HEIGHT * fontheight / scaling_factor );
 #ifdef __ANDROID__
     SDL_Rect dstrect = get_android_render_rect( TERMINAL_WIDTH * fontwidth, TERMINAL_HEIGHT * fontheight );
     SetRenderDrawColor( renderer, 0, 0, 0, 255 );