Aminet 7/Aminet 7 - August 1995.iso/Aminet/docs/misc/ConcNews.lha/news/amiga.programming/comp.sys.amiga.programmer_3886_000020.msg

Internet Message Format | 1994-11-27 | 4.6 KB

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Newsgroups: comp.sys.amiga.programmer
From: [e-mail] (Michael B. Smith)
Subject: Re: Using Display Database
Distribution: world
References:  <[e-mail]>
X-NewsSoftware: GRn 2.0j Jan 8, 1994
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Date: Mon, 10 Jan 94 22:14:00 EDT
Organization: Well, I haven't decided on a name yet...
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In article <[e-mail]> [e-mail] (Dimitri Favre) writes:
> I'm developping a tool and I need to allow user to use whatever screen
> it wants. I'm searching a demo code showing how to use the display database
> (I mean, the Monitors in Devs:Monitors) to implement a WorkBench like
> screen Requester (even through GadToolBox).

Here is some example code from GRn. It compiles with commercial and
registered DICE; but should be trivial to modify for SAS/C. It DOES
require asl.library v38 or higher. Regardless, you can take the
information from ModeSize() and FitWB() and come up with routines
that should work on v37 as well.
--
  //   Michael B. Smith
\X/    [e-mail]  -or-  uunet.uu.net!virginia.edu!adastra!mbs

static ULONG
ModeSize (ULONG modeID, int *x, int *y)
{
    /*
    **  ModeSize
    **
    **    Returns the size of the passed ModeID.
    **    The 'X' and 'Y' sizes are stored in the parameters.
    **
    **    On failure, returns INVALID_ID.
    **    On success, returns modeID.
    */
    struct DimensionInfo
        di;

    if (GetDisplayInfoData (NULL, (void *) &di, sizeof di, DTAG_DIMS, modeID)) {
        *x = di.TxtOScan.MaxX - di.TxtOScan.MinX + 1;
        *y = di.TxtOScan.MaxY - di.TxtOScan.MinY + 1;
        return modeID;
    }

    return INVALID_ID;
}

static ULONG
FitWB (int *x, int *y)
{
    /*
    **  FitWB:   returns the modeID which "first fits" the passed X and
    **         Y parameters, and is suitable for a Workbench screen.
    **
    **  On failure, returns INVALID_ID.
    */

    ULONG
        modeID = INVALID_ID;
    int
        X = 0,
        Y = 0;
    struct DisplayInfo
        ds;

    while ((modeID = NextDisplayInfo (modeID)) != INVALID_ID) {

        if (ModeNotAvailable (modeID))
            continue;

        if ((modeID & MONITOR_ID_MASK) == DEFAULT_MONITOR_ID)
            continue;

        if (GetDisplayInfoData (NULL, (void *) &ds, sizeof (struct DisplayInfo), DTAG_DISP, modeID))
            if (!(ds.PropertyFlags & DIPF_IS_WB))
                continue;

        if (ModeSize (modeID, &X, &Y) != INVALID_ID) {
            if (X >= *x && Y >= *y) {
                *x = X;
                *y = Y;
                return modeID;
            }
        }
    }

    return INVALID_ID;
}

#define MINIMUM_HEIGHT        200
#define MINIMUM_WIDTH        600

__geta4 __asm ULONG
ScreenModeHook (__a0 struct Hook *myhook,
        __a2 struct ScreenModeRequester *myScreenReq,
        __a1 APTR data)
{
    ULONG
        modeID = (ULONG) data;
    int
        x,
        y;

    if (ModeNotAvailable (modeID))
        return FALSE;

    if (ModeSize (modeID, &x, &y) == INVALID_ID)
        return FALSE;

    if (x < MINIMUM_WIDTH || y < MINIMUM_HEIGHT)
        return FALSE;

    return TRUE;
}

int
GetScreenMode (ULONG *modeID, int *height, int *width, int *autoscroll)
{
    int
        rslt,
        mode_width  = *width ? *width : DEFAULT_WIDTH,
        mode_height = *height ? *height : DEFAULT_HEIGHT;
    ULONG
        pref_mode = FitWB (&mode_width, &mode_height);
    struct Hook
        ScreenReqHook;
    struct ScreenModeRequester
        *screenReq;
    static const char
        routine [] = { "GRn - Select Screen Mode" };

    ScreenReqHook.h_Data = NULL;
    ScreenReqHook.h_Entry = (ULONG (*)()) ScreenModeHook;
    ScreenReqHook.h_SubEntry = NULL;

    screenReq = (struct ScreenModeRequester *) AllocAslRequestTags (ASL_ScreenModeRequest,
        /*
        ** initial conditions
        */
        ASLSM_InitialDisplayID,     pref_mode,
        ASLSM_InitialDisplayWidth,  mode_width,
        ASLSM_InitialDisplayHeight, mode_height,
        /*
        ** setup stuff
        */
        ASLSM_SleepWindow,  TRUE,
        ASLSM_TitleText,    routine,
        ASLSM_MinWidth,     MINIMUM_WIDTH,
        ASLSM_MinHeight,    MINIMUM_HEIGHT,
        ASLSM_FilterFunc,   &ScreenReqHook,
        /*
        ** what can the user specify
        */
        ASLSM_DoWidth,        TRUE,
        ASLSM_DoHeight,     TRUE,
        ASLSM_DoAutoScroll, TRUE,
        TAG_DONE);

    if (!screenReq) {
        panic ("Failed, couldn't allocate ScreenModeRequester");
    }

    if (!AslRequest (screenReq, NULL)) {
        rslt = 0;
    }
    else {
        *modeID = screenReq->sm_DisplayID;
        *height = screenReq->sm_DisplayHeight;
        *width    = screenReq->sm_DisplayWidth;
        *autoscroll = screenReq->sm_AutoScroll;
        rslt = 1;
    }

    FreeAslRequest (screenReq);

    return rslt;
}