Half way there with the help screen

gateway.c

@@ -33,6 +33,7 @@
 #include "server.h"
 #include "gateway.h"
 #include "config.h"
+#include "gui.h"
 
 #define VERSION	"V1.8.6"
 bool run = TRUE;
@@ -161,6 +162,9 @@ struct TBandwidth
 };
 
 int LEDCounts[2];
+
+int help_win_displayed = 0;
+
 pthread_mutex_t var = PTHREAD_MUTEX_INITIALIZER;
 
 #pragma pack(1)
@@ -367,7 +371,10 @@ void ChannelPrintf(int Channel, int row, int column, const char *format, ... )
 
     mvwaddstr( Config.LoRaDevices[Channel].Window, row, column, Buffer );
 
-    wrefresh( Config.LoRaDevices[Channel].Window );
+    if (! help_win_displayed)
+    {
+        wrefresh( Config.LoRaDevices[Channel].Window );
+    }
 
     pthread_mutex_unlock( &var );   // unlock once you are done
 
@@ -1773,6 +1780,10 @@ ProcessKeyPress( int ch )
         case 'c':
             ReTune( Channel, -0.001 );
             break;
+        case 'h':
+            help_win_displayed = 1;
+            gui_show_help();
+            break;
         default:
             //LogMessage("KeyPress %d\n", ch);
             return;

gui.c

@@ -0,0 +1,81 @@
+#include "gui.h"
+
+extern int help_win_displayed;
+
+WINDOW *create_help_win(int height, int width, int starty, int startx);
+void destroy_help_win(WINDOW *local_win);
+
+WINDOW *create_help_win(int height, int width, int starty, int startx)
+{   WINDOW *local_win;
+
+    local_win = newwin(height, width, starty, startx);
+    box(local_win, 0 , 0);      /* 0, 0 gives default characters 
+                     * for the vertical and horizontal
+                     * lines            */
+    wbkgd( local_win, COLOR_PAIR( 2 ) );
+    wrefresh(local_win);        /* Show that box        */
+
+    return local_win;
+}
+
+void destroy_help_win(WINDOW *local_win)
+{   
+    /* box(local_win, ' ', ' '); : This won't produce the desired
+     * result of erasing the window. It will leave it's four corners 
+     * and so an ugly remnant of window. 
+     */
+    wborder(local_win, ' ', ' ', ' ',' ',' ',' ',' ',' ');
+    /* The parameters taken are 
+     * 1. win: the window on which to operate
+     * 2. ls: character to be used for the left side of the window 
+     * 3. rs: character to be used for the right side of the window 
+     * 4. ts: character to be used for the top side of the window 
+     * 5. bs: character to be used for the bottom side of the window 
+     * 6. tl: character to be used for the top left corner of the window 
+     * 7. tr: character to be used for the top right corner of the window 
+     * 8. bl: character to be used for the bottom left corner of the window 
+     * 9. br: character to be used for the bottom right corner of the window
+     */
+    wrefresh(local_win);
+    delwin(local_win);
+}
+
+void gui_show_help ()
+{
+
+    WINDOW *help_win;
+
+    int startx, starty, width, height;
+    int ch;
+
+    height = 14;
+    width = 76;
+    starty = 1;  /* Calculating for a center placement */
+    startx = 2;    /* of the window        */
+    help_win = create_help_win(height, width, starty, startx);
+
+    while((ch = getch()) != 'c')
+    {   
+        switch(ch)
+        {   case KEY_LEFT:
+                destroy_help_win(help_win);
+                help_win = create_help_win(height, width, starty,--startx);
+                break;
+            case KEY_RIGHT:
+                destroy_help_win(help_win);
+                help_win = create_help_win(height, width, starty,++startx);
+                break;
+            case KEY_UP:
+                destroy_help_win(help_win);
+                help_win = create_help_win(height, width, --starty,startx);
+                break;
+            case KEY_DOWN:
+                destroy_help_win(help_win);
+                help_win = create_help_win(height, width, ++starty,startx);
+                break;  
+        }
+    }
+
+    help_win_displayed = 0;
+
+}

gui.h

@@ -0,0 +1,8 @@
+#ifndef _GUI_H
+#define _GUI_H
+
+#include <ncurses.h>
+
+void gui_show_help ();
+
+#endif