add bitmap drawing

low_level_render.h

@@ -60,6 +60,9 @@ public:
     void draw_filled_polygon(const std::vector<std::pair<int, int>>& points, bool on);
     void draw_arc(int center_x, int center_y, int radius, int start_angle, int end_angle, bool on);
     
+    // Bitmap drawing
+    void draw_bitmap(const unsigned char* bitmap, int x, int y, int width, int height, bool invert = false);
+    
     // Clipping functions
     void set_clip_rect(int x, int y, int width, int height);
     void reset_clip_rect();