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wmaker/m4/wm_libmath.m4
Christophe CURIS b64d9e6be0 wrlib: changed Gamma Correction calculation to use single-precision float
The original code was using double precision floating point to perform the
color corrections for the creation of the standard colormap. This precision
is not necessary because color coding is 16 bits anyway, and on some
architecture the double precision comes with a cost.

Signed-off-by: Christophe CURIS <christophe.curis@free.fr>
2015-05-24 23:25:57 +01:00

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# wm_libmath.m4 - Macros to check proper libMath usage for WINGs
#
# Copyright (c) 2013 Christophe Curis
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
# WM_CHECK_LIBM
# -------------
#
# Checks the needed library link flags needed to have math lib
# Sets variable LIBM with the appropriates flags
AC_DEFUN_ONCE([WM_CHECK_LIBM],
[AC_CHECK_HEADER([math.h], [],
[AC_MSG_ERROR([header for math library not found])])
AC_CHECK_FUNC(atan,
[LIBM=],
[AC_CHECK_LIB(m, [atan],
[LIBM=-lm],
[AC_MSG_WARN(Could not find Math library, you may experience problems)
LIBM=] )] ) dnl
AC_CACHE_CHECK([if M_PI is defined in math.h], [wm_cv_libm_pi],
[wm_cv_libm_pi="no"
wm_save_CFLAGS="$CFLAGS"
for wm_arg in dnl
"% yes" dnl natively available (Unix98 compliant?)
"-D_XOPEN_SOURCE=500" ; dnl Explicit request
do
AS_IF([wm_fn_lib_try_compile "math.h" "double val;" "val = M_PI" dnl
"`echo "$wm_arg" | sed -e 's, *%.*$,,' `"],
[wm_cv_libm_pi="`echo "$wm_arg" | sed -e 's,^.*% *,,' `" ; break])
done
CFLAGS="$wm_save_CFLAGS"])
AS_IF([test "x$wm_cv_libm_pi" = "xno"],
[AC_DEFINE([WM_PI], [(3.14159265358979323846)],
[Defines how to access the value of Pi])],
[AC_DEFINE([WM_PI], [(M_PI)],
[Defines how to access the value of Pi])
AS_IF([test "x$wm_cv_libm_pi" != "xyes"],
[CFLAGS="$CFLAGS $wm_cv_libm_pi"]) ])
AC_CACHE_CHECK([if sinf+cosf are defined in math.h], [wm_cv_libm_sinf],
[wm_cv_libm_sinf="no"
wm_save_CFLAGS="$CFLAGS"
wm_save_LIBS="$LIBS"
LIBS="$LIBS $LIBM"
for wm_arg in dnl
"% yes" dnl natively available (C99 compliant)
"-D_XOPEN_SOURCE=600" ; dnl Explicit request
do
CFLAGS="$wm_save_CFLAGS `echo "$wm_arg" | sed -e 's, *%.*$,,' `"
AC_LINK_IFELSE([AC_LANG_PROGRAM([dnl
@%:@include <math.h>
], [dnl
float a, b;
a = WM_PI;
b = sqrtf(a);
a = atan2f(a, b);
b = cosf(a);
a = sinf(b);
a = powf(a, b);
return (int)a;])],
[wm_cv_libm_sinf="`echo "$wm_arg" | sed -e 's,^.*% *,,' `" ; break])
done
LIBS="$wm_save_LIBS"
CFLAGS="$wm_save_CFLAGS"])
AS_IF([test "x$wm_cv_libm_sinf" != "xno"],
[AC_DEFINE([HAVE_FLOAT_MATHFUNC], [1],
[Defined if the 'float'-typed math function are available (sinf, cosf)])
AS_IF([test "x$wm_cv_libm_sinf" != "xyes"],
[CFLAGS="$CFLAGS $wm_cd_libm_sinf"]) ])
AC_SUBST(LIBM) dnl
])