setwind.c

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C语言 代码 · 共 90 行

/****************************************************************************
*
*                            Open Watcom Project
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*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
*  ========================================================================
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*    This file contains Original Code and/or Modifications of Original
*    Code as defined in and that are subject to the Sybase Open Watcom
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* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
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****************************************************************************/


#include <gdefn.h>


short _WCI86FAR _CGRAPH _setwindow( short invert, double left, double top,
/*==========================*/ double right, double bottom )

/* This function maps the current viewport to the window given by
   the corners ( left, top ) and ( right, bottom ). If the "invert" flag
   is set, the limits "top" and "bottom" are inverted.  */

{
    float               l, r;
    float               t, b;
    float               tmp;

    if( !_GraphMode() ) {
        return( 0 );
    }
    l = left;       // convert to float's
    r = right;
    t = top;
    b = bottom;
    if( l == r || t == b ) {
        _ErrorStatus = _GRINVALIDPARAMETER;
        return( 0 );
    }
    if( t < b ) {        // ensure bottom < top
        tmp = t;
        t = b;
        b = tmp;
    }
    _Window.xleft = l;
    _Window.xright = r;
    _Window.invert = invert;
    if( invert ) {
        _Window.ytop = t;
        _Window.ybottom = b;
    } else {
        _Window.ytop = b;
        _Window.ybottom = t;
    }
    _resetscalefactor();
    _moveto_w( l, _Window.ybottom );
    return( 1 );
}

Entry( _SETWINDOW, _setwindow ) // alternate entry-point


short _WCI86FAR _CGRAPH _setwindow_87( short invert, double left, double top,
/*===========================================*/ double right, double bottom )

{
    return( _setwindow( invert, left, top, right, bottom ) );
}

Entry( _SETWINDOW_87, _setwindow_87 ) // alternate entry-point