Use defined constants for button size in redraw request

nanovna.h

@@ -268,7 +268,7 @@ extern void tlv320aic3204_select(int channel);
  */
 
 // Offset of plot area
-#define OFFSETX 29
+#define OFFSETX 30
 #define OFFSETY 0
 
 #ifdef __SCROLL__
@@ -281,7 +281,7 @@ extern int _height;
 #define HEIGHT 230
 // WIDTH better be n*(POINTS_COUNT-1)
 #endif
-#define WIDTH  290
+#define WIDTH  (320 - 1 - OFFSETX)
 
 #define CELLWIDTH  (32)
 #define CELLHEIGHT (32)

plot.c

@@ -1741,9 +1741,9 @@ request_to_draw_cells_behind_menu(void)
 {
   // Values Hardcoded from ui.c
   if (current_menu_is_form())
-    invalidate_rect(25, 0, LCD_WIDTH-1, LCD_HEIGHT-1);
+    invalidate_rect(0, 0, LCD_WIDTH-1, LCD_HEIGHT-1);
   else
-    invalidate_rect(LCD_WIDTH-60 - 25, 0, LCD_WIDTH-1, LCD_HEIGHT-1);
+    invalidate_rect(AREA_WIDTH_NORMAL-MENU_BUTTON_WIDTH, 0, LCD_WIDTH-1, LCD_HEIGHT-1);
   redraw_request |= REDRAW_CELLS;
 }
 
@@ -1751,7 +1751,7 @@ void
 request_to_draw_cells_behind_numeric_input(void)
 {
   // Values Hardcoded from ui.c
-  invalidate_rect(0, LCD_HEIGHT-32, LCD_WIDTH-1, LCD_HEIGHT-1);
+  invalidate_rect(0, LCD_HEIGHT-NUM_INPUT_HEIGHT, LCD_WIDTH-1, LCD_HEIGHT-1);
   redraw_request |= REDRAW_CELLS;
 }