Power-Programmierung/CD2.mdf/c/library/dos/database/app_d_l/pulldown.c

C/C++ Source or Header | 1991-09-15 | 4.3 KB | 217 lines

/*
 *
 * Class Implementation for Pulldown menu system
 *
 * (C) 1990 Vision Software
 *
 * $Id: pulldown.c 1.2001 91/04/25 15:07:58 pcalvin release $
 *
 * Comments:
 *
 * This class provides the traditional view of Pulldown menus.  Implementation
 * is simplified because POPUP provides most of the lower level routines
 *
 * Bugs:
 *
 *    None documented
 *
 */
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <ctype.h>

#include <stdhdr.h>
#include <adl.h>
#include <menu.h>

#include "lowlevel.h"

/*
 * Pulldown system is based upon the popup menu.
 */
PULLDOWN::PULLDOWN(ROW row,CBAR cbarTotal,PBAR pbarMenu) : POPUP(szNil)
    {
    Assert(pbarMenu != pbarNil);

    rowDisplay = row;
    cbarMax = cbarTotal;
    pbar = pbarMenu;
    pcolTabs = 0;
    szHotKeys = 0;
    }

/*
 * Show the menu bar..
 */
VOID PULLDOWN::ShowBar(VOID)
    {
    CURSOR crs(fFalse);
    CHAR cch;
    COL col;
    CBAR cbar;

    if (pcolTabs != 0)
        delete pcolTabs;

    pcolTabs = new COL[cbarMax];
    if (szHotKeys != 0)
        delete szHotKeys;

    szHotKeys = new char[cbarMax+1];

    ClearRow(rowDisplay,1,colGlobalWindowRight,coRed,coCyan);

    col = 3;
    for (cbar=0;cbar<cbarMax;cbar++)
        {
        pcolTabs[cbar] = col;
        szHotKeys[cbar] = toupper(pbar[cbar].sz[pbar[cbar].cchHotKey]);
        HotString(rowDisplay,col,pbar[cbar].cchHotKey,pbar[cbar].sz,coRed,coCyan);
        col += strlen(pbar[cbar].sz) + 2;
        }

    szHotKeys[cbarMax] = '\0';
    }

/*
 * Answers with an ASCII code for the character that was entered
 * Answers cdNil if that character is used..
 */
CD PULLDOWN::CdGet(VOID)
    {
    BOOL fContinue,fSelected;
    CD cd;
    SZ sz;
    ROW rowOriginal,crow;
    COL colOriginal,colLeft,colRight;
    PENT pentBase;
    CENT cent;
    CBAR cbar;

    Assert(pcolTabs != 0);
    Assert(szHotKeys != szNil);

    /*
     * Make POPUP::Help point to this level
     */
    help.Replace("Press the Alt-Key combination for the desired menu");

    /*
     * Normalized input..
     */
    cd = CdInput();

    if (cd < 0xff)
        return (cd);
    else
        cd = CdFromAltCd(cd);

    if (cd == cdNil || (!(sz = strchr(szHotKeys,cd))))
        return (cd);
    else
        cbar = sz - szHotKeys;

    fSelected = fFalse;
    while (!fSelected)
        {
        fLeftExit = (cbar > 0) ? fTrue : fFalse;
        fRightExit = (cbar + 1 < cbarMax) ? fTrue :fFalse;

        colLeft = pcolTabs[cbar];
        HotString(rowDisplay,colLeft,pbar[cbar].cchHotKey,pbar[cbar].sz,coBlack,coGreen);
        cent = CentGet(rowDisplay,colLeft,pbar[cbar].cent,pbar[cbar].pent);
        HotString(rowDisplay,colLeft,pbar[cbar].cchHotKey,pbar[cbar].sz,coRed,coCyan);
        /*
         * If centains some legal value, exit, otherwise, find
         * out which key exited.
         */
        if (cent == centError)
            {
            switch (CdExitKey())
                {
            case cdEscape:
                return (cdNil);
            case cdCursorLeft:
                cbar -= 1;
                break;
            case cdCursorRight:
                cbar += 1;
                break;
                }
            }
        else
            {
            fSelected = fTrue;
            }
        }

    return (cdNil);
    }


/*
 * This family of methods answers CENT nil if the key should escape
 * the popup, Otherwise it returns the new CD value
 */
BOOL PULLDOWN::FHandleCd(CENT &rcent,CD cd,PENT pent,WINDOW &rwnd)
    {
    BOOL fContinue = fTrue;

    switch (cd)
        {
    case cdCursorRight:
        if (fRightExit)
            {
            fContinue = fFalse;
            rcent = centError;
            }
        break;
    case cdCursorLeft:
        if (fLeftExit)
            {
            fContinue = fFalse;
            rcent = centError;
            }
        break;
    default:
        fContinue = POPUP::FHandleCd(rcent,cd,pent,rwnd);
        break;
        }

    return (fContinue);
    }

/*
 *    Translates the input character from Alt-Alpha, into
 *    uppercase alpha.
 *    Character translation table is derived from Layout
 *    of MS-DOS keyboard.  This is obviously not-portable,
 *    similar hacking will be required for UN*X etc.
 */
CD PULLDOWN::CdFromAltCd(CD cd)
    {
    STATIC CONST CD rgcdAltTranslate[] =
        {
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
        'Q','W','E','R','T','Y','U','I','O','P',0,0,0,0,
         'A','S','D','F','G','H','J','K','L',0,0,0,0,0,
          'Z','X','C','V','B','N','M',0
        };

    STATIC CONST CD cdKeyMax = sizeof(rgcdAltTranslate) / sizeof(rgcdAltTranslate[0]);
    /*
     *    If character was Alt-Combination, translate back, otherwise
     *    it is now Nil
     */
    cd >>= 8;

    if (cd < cdKeyMax)
        cd = rgcdAltTranslate[cd];
    else
        cd = cdNil;

    return (cd);
    }