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tetex-bin  3.0
magstep.h
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00001 /* magstep.h: declaration for magstep fixing.
00002 
00003 Copyright (C) 1994 Karl Berry.
00004 
00005 This library is free software; you can redistribute it and/or
00006 modify it under the terms of the GNU Library General Public
00007 License as published by the Free Software Foundation; either
00008 version 2 of the License, or (at your option) any later version.
00009 
00010 This library is distributed in the hope that it will be useful,
00011 but WITHOUT ANY WARRANTY; without even the implied warranty of
00012 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013 Library General Public License for more details.
00014 
00015 You should have received a copy of the GNU Library General Public
00016 License along with this library; if not, write to the Free Software
00017 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
00018 
00019 #ifndef KPATHSEA_MAGSTEP_H
00020 #define KPATHSEA_MAGSTEP_H
00021 
00022 #include <kpathsea/c-proto.h>
00023 #include <kpathsea/types.h>
00024 
00025 /* If DPI is close enough to some magstep of BDPI, return the true dpi
00026    value, and the magstep found (or zero) in M_RET (if
00027    non-null). ``Close enough'' means within one pixel.
00028    
00029    M_RET is slightly encoded: the least significant bit is on for a
00030    half-magstep, off otherwise.  Thus, a returned M_RET of 1 means
00031    \magstephalf, i.e., sqrt(1.2), i.e., 1.09544.  Put another way,
00032    return twice the number of magsteps.
00033    
00034    In practice, this matters for magstephalf.  Floating-point computation
00035    with the fixed-point DVI representation leads to 328 (for BDPI ==
00036    300); specifying `at 11pt' yields 330; the true \magstephalf is 329
00037    (that's what you get if you run Metafont with mag:=magstep(.5)).
00038    
00039    The time to call this is after you read the font spec from the DVI
00040    file, but before you look up any files -- do the usual floating-point
00041    computations, and then fix up the result.  */
00042 
00043 extern KPSEDLL unsigned kpse_magstep_fix P3H(unsigned dpi, unsigned bdpi, int *m_ret);
00044 
00045 #endif /* not KPATHSEA_MAGSTEP_H */