MENU.C

#include <stdio.h>
#include <conio.h>
#include <mem.h>
#include <dos.h>

#include "main.h"

item_t	*current;
menu_t	*currentmenu;
int		curitem;				// current item #
char		inv_attrib;			// inversion attribute
char		buffer[160];		// save the entire screen line!
short		menukey;				// globally set after GetMenuInput()

//
// Make a sound!
//
void Sound(int freq, int dly)
{
	sound(freq);
	delay(dly);
	nosound();
}

//
//	Draw a dot if "value" is > 0 at item->x - 3
//
void SetMark(item_t *item,int value)
{
	char	far *screen;

	screen = MK_FP(0xb800,item->y*160 + (item->x-3)*2);
	*screen = ' ';
	if (value)
		*screen = 7;
}

//
// Invert the menu item
//
void Invert(item_t *item)
{
	char	far *screen;
	int	i;

	movedata(0xb800,item->y*160,FP_SEG(&buffer),FP_OFF(&buffer),160);
	screen = MK_FP(0xb800,item->y*160 + item->x*2);

	for (i = 0; i < item->w; i++)
	{
		*(screen+1) = inv_attrib;
		screen += 2;
	}
}

//
//	Restore the screen line (uninvert)
//
void UnInvert(item_t *item)
{
	movedata(FP_SEG(&buffer),FP_OFF(&buffer),0xb800,item->y*160,160);
}

//
//	Set "current" to first menu item
//
void SetupMenu(menu_t *menu)
{
	currentmenu = menu;
	current = menu->items;
	current += menu->startitem;
	curitem = menu->startitem;

	inv_attrib = menu->invert;
	Invert(current);
}

//
//	Get menu input for current menu
// Exit:	-1 = ESC was pressed, xx = item id
//
int	GetMenuInput(void)
{
	char	c;
	while(1)
	{
		c = getch();
//		gotoxy(1,2);
//		printf("char:%x  ",c);
		switch(c)
		{
			case 0x48:		// UP
				if (!curitem)
					break;
				UnInvert(current);
				if (current->up)
				{
					curitem = current->up;
					current = currentmenu->items + curitem;
				}
				else
				{
					curitem--;
					current--;
				}
				Invert(current);
				Sound(50,10);
				break;

			case 0x50:		// DOWN
				if (curitem == currentmenu->maxitems - 1)
					break;
				UnInvert(current);
				if (current->down)
				{
					curitem = current->down;
					current = currentmenu->items + curitem;
				}
				else
				{
					curitem++;
					current++;
				}
				Invert(current);
				Sound(50,10);
				break;

			case 0x4b:		// LEFT
				if (current->left != -1)
				{
					UnInvert(current);
					curitem = current->left;
					current = currentmenu->items+curitem;
					Invert(current);
					Sound(50,10);
				}
				break;

			case 0x4d:		// RIGHT
				if (current->right != -1)
				{
					UnInvert(current);
					curitem = current->right;
					current = currentmenu->items+curitem;
					Invert(current);
					Sound(50,10);
				}
				break;

			case 0x44:		// F10
			case 0x3b:		// F1
			case 0x3c:		// F2
				UnInvert(current);
				menukey = c;
				currentmenu->startitem = curitem;
				Sound(50,10);
				return current->id;

			case 0x0d:		// ENTER
				UnInvert(current);
				menukey = c;
				currentmenu->startitem = curitem;
				Sound(2000,10);
				return current->id;

			case 0x1b:		// ESC
				UnInvert(current);
				menukey = c;
				Sound(3000,10);
				return -1;
		}
	}
}