--- hatari/src/includes/screen.h	2019/04/01 07:13:38	1.1.1.11
+++ hatari/src/includes/screen.h	2019/04/01 07:14:44	1.1.1.12
@@ -27,11 +27,11 @@
 #define SCREENBYTES_MONOLINE 80         /* Byte per line in ST-high resolution */
 
 /* Overscan values */
-#define OVERSCAN_TOP        29
-#define OVERSCAN_BOTTOM     47
+#define OVERSCAN_TOP         29
+#define MAX_OVERSCAN_BOTTOM  47 	/* number of bottom lines to display on screen */
 
 /* Number of visible screen lines including top/bottom borders */
-#define NUM_VISIBLE_LINES  (OVERSCAN_TOP+200+OVERSCAN_BOTTOM)
+#define NUM_VISIBLE_LINES  (OVERSCAN_TOP+200+MAX_OVERSCAN_BOTTOM)
 
 
 /* Frame buffer, used to store details in screen conversion */
@@ -42,7 +42,7 @@ typedef struct
   Uint8 *pSTScreen;             /* Copy of screen built up during frame (copy each line on HBL to simulate monitor raster) */
   Uint8 *pSTScreenCopy;         /* Previous frames copy of above  */
   int OverscanModeCopy;         /* Previous screen overscan mode */
-  BOOL bFullUpdate;             /* Set TRUE to cause full update on next draw */
+  bool bFullUpdate;             /* Set TRUE to cause full update on next draw */
 } FRAMEBUFFER;
 
 /* Number of frame buffers (1 or 2) - should be 2 for supporting screen flipping */
@@ -99,8 +99,8 @@ enum
 };
 
 
-extern BOOL bGrabMouse;
-extern BOOL bInFullScreen;
+extern bool bGrabMouse;
+extern bool bInFullScreen;
 extern int nScreenZoomX, nScreenZoomY;
 extern int nBorderPixelsLeft, nBorderPixelsRight;
 extern int STScreenStartHorizLine;
@@ -118,6 +118,6 @@ extern void Screen_SetFullUpdate(void);
 extern void Screen_EnterFullScreen(void);
 extern void Screen_ReturnFromFullScreen(void);
 extern void Screen_ModeChanged(void);
-extern void Screen_Draw(void);
+extern bool Screen_Draw(void);
 
 #endif  /* ifndef HATARI_SCREEN_H */