diff --git a/05_sdl_alapok/renderer.cpp b/05_sdl_alapok/renderer.cpp
index 898425f..6ffb8b9 100644
--- a/05_sdl_alapok/renderer.cpp
+++ b/05_sdl_alapok/renderer.cpp
@@ -11,7 +11,7 @@ void Renderer::set_draw_color(const Uint8 r, const Uint8 g, const Uint8 b, const
 }
 
 void Renderer::set_draw_color(const Color &color) {
-    SDL_SetRenderDrawColor(_renderer, color.r, color.g, color.b, color.a);
+	SDL_SetRenderDrawColor(_renderer, color.r, color.g, color.b, color.a);
 }
 
 void Renderer::clear() {
@@ -19,16 +19,51 @@ void Renderer::clear() {
 }
 
 void Renderer::draw_rect(const SDL_Rect &rect) {
-    SDL_RenderFillRect(_renderer, &rect);
+	SDL_RenderFillRect(_renderer, &rect);
 }
 void Renderer::draw_rect(const Rect2 &rect) {
-    SDL_Rect r;
+	SDL_Rect r;
 	r.x = rect.x;
 	r.y = rect.y;
 	r.w = rect.w;
 	r.h = rect.h;
 
-    SDL_RenderFillRect(_renderer, &r);
+	SDL_RenderFillRect(_renderer, &r);
+}
+
+int Renderer::get_dpi() const {
+	float ddpi;
+	float hdpi;
+	float vdpi;
+
+	if (SDL_GetDisplayDPI(_window_display_index, &ddpi, &hdpi, &vdpi)) {
+		return ddpi;
+	}
+
+	//fallback
+	return 1;
+}
+
+int Renderer::get_size_w() const {
+    int w;
+    int h;
+
+    SDL_GetWindowSize(_window, &w, &h);
+
+    return w;
+}
+
+int Renderer::get_size_h() const {
+    int w;
+    int h;
+
+    SDL_GetWindowSize(_window, &w, &h);
+
+    return h;
+}
+
+void Renderer::get_size(int *w, int *h) const {
+    SDL_GetWindowSize(_window, w, h);
 }
 
 void Renderer::initialize() {
@@ -38,22 +73,24 @@ void Renderer::initialize() {
 		return;
 	}
 
-	if (SDL_CreateWindowAndRenderer(640, 480, _window_flags, &_window, &_renderer) != 0) {
+	if (SDL_CreateWindowAndRenderer(_initial_window_width, _initial_window_height, _window_flags, &_window, &_renderer) != 0) {
 		printf("SDL_CreateWindowAndRenderer() hiba!\n");
 
 		return;
 	}
+
+	_window_display_index = SDL_GetWindowDisplayIndex(_window);
 }
 
 void Renderer::destroy() {
-    if (_window)
-	    SDL_DestroyWindow(_window);
+	if (_window)
+		SDL_DestroyWindow(_window);
 
-    if (_renderer)
-	    SDL_DestroyRenderer(_renderer);
+	if (_renderer)
+		SDL_DestroyRenderer(_renderer);
 
-    _window = nullptr;
-    _renderer = nullptr;
+	_window = nullptr;
+	_renderer = nullptr;
 }
 
 Renderer::Renderer() {
@@ -61,6 +98,9 @@ Renderer::Renderer() {
 		printf("Renderer::Renderer(): _singleton is not null!\n");
 	}
 
+	_initial_window_width = 640;
+	_initial_window_height = 480;
+
 	_singleton = this;
 
 	_flags = SDL_INIT_VIDEO | SDL_INIT_TIMER;
@@ -69,11 +109,14 @@ Renderer::Renderer() {
 	initialize();
 }
 
-Renderer::Renderer(unsigned int flags, unsigned int window_flags) {
+Renderer::Renderer(unsigned int flags, unsigned int window_flags, int initial_window_width, int initial_window_height) {
 	if (_singleton) {
 		printf("Renderer::Renderer(flags): _singleton is not null!\n");
 	}
 
+	_initial_window_width = initial_window_width;
+	_initial_window_height = initial_window_height;
+
 	_singleton = this;
 
 	_flags = flags;
diff --git a/05_sdl_alapok/renderer.h b/05_sdl_alapok/renderer.h
index dd81cd9..8c2dc99 100644
--- a/05_sdl_alapok/renderer.h
+++ b/05_sdl_alapok/renderer.h
@@ -16,22 +16,32 @@ public:
     void draw_rect(const SDL_Rect &rect);
     void draw_rect(const Rect2 &rect);
 
+    int get_dpi() const;
+    int get_size_w() const;
+    int get_size_h() const;
+    void get_size(int *w, int *h) const;
+
 	void initialize();
 	void destroy();
 
 	Renderer();
-	Renderer(unsigned int flags, unsigned int window_flags);
+	Renderer(unsigned int flags, unsigned int window_flags, int window_width = 640, int window_height = 480);
 	virtual ~Renderer();
 
 	static Renderer *get_singleton();
 
 private:
+    int _initial_window_width;
+    int _initial_window_height;
+
 	unsigned int _flags;
 	unsigned int _window_flags;
 
 	SDL_Window *_window;
 	SDL_Renderer *_renderer;
 
+    int _window_display_index;
+
 	static Renderer *_singleton;
 };