Image duplication for screen resize (#401)

## Link to GitHub Issue, if one exists
#399 

## Description of change
Add image duplication option to screen resize, allowing overflow images
to wrap around the other side.

## Testing
Tested with DDR, IIDX (windowed and full screen TDJ), SDVX (orientation
swap)

src/spice2x/cfg/screen_resize.cpp

@@ -87,6 +87,10 @@ namespace cfg {
             load_float_value(doc, root + prefix + "scale_x", scene.scale_x);
             load_float_value(doc, root + prefix + "scale_y", scene.scale_y);
             load_bool_value(doc, root + prefix + "keep_aspect_ratio", scene.keep_aspect_ratio);
+
+            int duplicate = 0;
+            load_int_value(doc, root + prefix + "duplicate", duplicate);
+            scene.duplicate = static_cast<cfg::ScreenDuplicateMode>(duplicate);
         }
 
         // windowed settings are always under game settings
@@ -201,6 +205,7 @@ namespace cfg {
             rapidjson::Pointer(root + prefix + "scale_x").Set(doc, scene.scale_x);
             rapidjson::Pointer(root + prefix + "scale_y").Set(doc, scene.scale_y);
             rapidjson::Pointer(root + prefix + "keep_aspect_ratio").Set(doc, scene.keep_aspect_ratio);
+            rapidjson::Pointer(root + prefix + "duplicate").Set(doc, scene.duplicate);
         }
 
         // windowed mode settings

src/spice2x/cfg/screen_resize.h

@@ -14,12 +14,19 @@ namespace cfg {
         ResizableFrame = 2
     };
 
+    enum ScreenDuplicateMode {
+        None = 0,
+        CopyLeft = 1,
+        CopyRight = 2,
+    };
+
     struct fullscreen_setting {
         int offset_x = 0;
         int offset_y = 0;
         float scale_x = 1.0;
         float scale_y = 1.0;
         bool keep_aspect_ratio = true;
+        ScreenDuplicateMode duplicate = ScreenDuplicateMode::None;
     };
 
     extern std::optional<std::string> SCREEN_RESIZE_CFG_PATH_OVERRIDE;