diff --git a/src/driver/framebuffer_ng.cpp b/src/driver/framebuffer_ng.cpp
index 6d0c980f6..46eb05e38 100644
--- a/src/driver/framebuffer_ng.cpp
+++ b/src/driver/framebuffer_ng.cpp
@@ -308,6 +308,17 @@ unsigned int CFrameBuffer::getScreenHeight(bool real)
 		return g_settings.screen_EndY - g_settings.screen_StartY;
 }
 
+unsigned int CFrameBuffer::getScreenWidthRel()
+{
+	// always reduce a possible detailline
+	return (g_settings.screen_EndX - g_settings.screen_StartX - 2*ConnectLineBox_Width) * (g_settings.big_windows ? 100 : NON_BIG_WINDOWS) / 100;
+}
+
+unsigned int CFrameBuffer::getScreenHeightRel()
+{
+	return (g_settings.screen_EndY - g_settings.screen_StartY) * (g_settings.big_windows ? 100 : NON_BIG_WINDOWS) / 100;
+}
+
 unsigned int CFrameBuffer::getScreenX()
 {
 	return g_settings.screen_StartX;
diff --git a/src/driver/framebuffer_ng.h b/src/driver/framebuffer_ng.h
index 03f04831d..e27df034d 100644
--- a/src/driver/framebuffer_ng.h
+++ b/src/driver/framebuffer_ng.h
@@ -54,6 +54,9 @@ typedef struct fb_var_screeninfo t_fb_var_screeninfo;
 #define FADE_STEP 5
 #define FADE_RESET 0xFFFF
 
+#define NON_BIG_WINDOWS		85 // %
+#define ConnectLineBox_Width	16 // px
+
 #if HAVE_GENERIC_HARDWARE
 #define USE_OPENGL 1
 #endif
@@ -178,6 +181,8 @@ class CFrameBuffer
 		unsigned int getStride() const;             // size of a single line in the framebuffer (in bytes)
 		unsigned int getScreenWidth(bool real = false);
 		unsigned int getScreenHeight(bool real = false); 
+		unsigned int getScreenWidthRel();
+		unsigned int getScreenHeightRel();
 		unsigned int getScreenX();
 		unsigned int getScreenY();