331 lines
8.1 KiB
C++
331 lines
8.1 KiB
C++
/* various interpolation templates
|
|
*/
|
|
|
|
/*
|
|
|
|
This file is part of VIPS.
|
|
|
|
VIPS is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser 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
|
|
|
|
*/
|
|
|
|
/*
|
|
|
|
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
|
|
|
|
*/
|
|
|
|
/*
|
|
* FAST_PSEUDO_FLOOR is a floor and floorf replacement which has been
|
|
* found to be faster on several linux boxes than the library
|
|
* version. It returns the floor of its argument unless the argument
|
|
* is a negative integer, in which case it returns one less than the
|
|
* floor. For example:
|
|
*
|
|
* FAST_PSEUDO_FLOOR(0.5) = 0
|
|
*
|
|
* FAST_PSEUDO_FLOOR(0.) = 0
|
|
*
|
|
* FAST_PSEUDO_FLOOR(-.5) = -1
|
|
*
|
|
* as expected, but
|
|
*
|
|
* FAST_PSEUDO_FLOOR(-1.) = -2
|
|
*
|
|
* The locations of the discontinuities of FAST_PSEUDO_FLOOR are the
|
|
* same as floor and floorf; it is just that at negative integers the
|
|
* function is discontinuous on the right instead of the left.
|
|
*/
|
|
#define FAST_PSEUDO_FLOOR(x) ( (int)(x) - ( (x) < 0. ) )
|
|
|
|
/*
|
|
* Various casts which assume that the data is already in range. (That
|
|
* is, they are to be used with monotone samplers.)
|
|
*/
|
|
template <typename T> static T inline
|
|
to_fptypes( const double val )
|
|
{
|
|
const T newval = val;
|
|
|
|
return( newval );
|
|
}
|
|
|
|
template <typename T> static T inline
|
|
to_withsign( const double val )
|
|
{
|
|
const int sign_of_val = 2 * ( val >= 0. ) - 1;
|
|
const int rounded_abs_val = .5 + sign_of_val * val;
|
|
const T newval = sign_of_val * rounded_abs_val;
|
|
|
|
return( newval );
|
|
}
|
|
|
|
template <typename T> static T inline
|
|
to_nosign( const double val )
|
|
{
|
|
const T newval = .5 + val;
|
|
|
|
return( newval );
|
|
}
|
|
|
|
/*
|
|
* Various bilinear implementation templates. Note that no clampling
|
|
* is used: There is an assumption that the data is such that
|
|
* over/underflow is not an issue:
|
|
*/
|
|
|
|
/*
|
|
* Bilinear interpolation for float and double types. The first four
|
|
* inputs are weights, the last four are the corresponding pixel
|
|
* values:
|
|
*/
|
|
template <typename T> static T inline
|
|
bilinear_fptypes(
|
|
const double w_times_z,
|
|
const double x_times_z,
|
|
const double w_times_y,
|
|
const double x_times_y,
|
|
const double tre_thr,
|
|
const double tre_thrfou,
|
|
const double trequa_thr,
|
|
const double trequa_thrfou )
|
|
{
|
|
const T newval =
|
|
w_times_z * tre_thr +
|
|
x_times_z * tre_thrfou +
|
|
w_times_y * trequa_thr +
|
|
x_times_y * trequa_thrfou;
|
|
|
|
return( newval );
|
|
}
|
|
|
|
/*
|
|
* Bilinear interpolation for signed integer types:
|
|
*/
|
|
template <typename T> static T inline
|
|
bilinear_withsign(
|
|
const double w_times_z,
|
|
const double x_times_z,
|
|
const double w_times_y,
|
|
const double x_times_y,
|
|
const double tre_thr,
|
|
const double tre_thrfou,
|
|
const double trequa_thr,
|
|
const double trequa_thrfou )
|
|
{
|
|
const double val =
|
|
w_times_z * tre_thr +
|
|
x_times_z * tre_thrfou +
|
|
w_times_y * trequa_thr +
|
|
x_times_y * trequa_thrfou;
|
|
|
|
const int sign_of_val = 2 * ( val >= 0. ) - 1;
|
|
|
|
const int rounded_abs_val = .5 + sign_of_val * val;
|
|
|
|
const T newval = sign_of_val * rounded_abs_val;
|
|
|
|
return( newval );
|
|
}
|
|
|
|
/*
|
|
* Bilinear Interpolation for unsigned integer types:
|
|
*/
|
|
template <typename T> static T inline
|
|
bilinear_nosign(
|
|
const double w_times_z,
|
|
const double x_times_z,
|
|
const double w_times_y,
|
|
const double x_times_y,
|
|
const double tre_thr,
|
|
const double tre_thrfou,
|
|
const double trequa_thr,
|
|
const double trequa_thrfou )
|
|
{
|
|
const T newval =
|
|
w_times_z * tre_thr +
|
|
x_times_z * tre_thrfou +
|
|
w_times_y * trequa_thr +
|
|
x_times_y * trequa_thrfou +
|
|
0.5;
|
|
|
|
return( newval );
|
|
}
|
|
|
|
/*
|
|
* Bicubic (Catmull-Rom) interpolation templates:
|
|
*/
|
|
|
|
static int inline
|
|
unsigned_fixed_round( int v )
|
|
{
|
|
const int round_by = VIPS_INTERPOLATE_SCALE >> 1;
|
|
|
|
return( (v + round_by) >> VIPS_INTERPOLATE_SHIFT );
|
|
}
|
|
|
|
/* Fixed-point integer bicubic, used for 8 and 16-bit types.
|
|
*/
|
|
template <typename T> static int inline
|
|
bicubic_unsigned_int(
|
|
const T uno_one, const T uno_two, const T uno_thr, const T uno_fou,
|
|
const T dos_one, const T dos_two, const T dos_thr, const T dos_fou,
|
|
const T tre_one, const T tre_two, const T tre_thr, const T tre_fou,
|
|
const T qua_one, const T qua_two, const T qua_thr, const T qua_fou,
|
|
const int* restrict cx, const int* restrict cy )
|
|
{
|
|
const int r0 = unsigned_fixed_round(
|
|
cx[0] * uno_one +
|
|
cx[1] * uno_two +
|
|
cx[2] * uno_thr +
|
|
cx[3] * uno_fou );
|
|
|
|
const int r1 = unsigned_fixed_round(
|
|
cx[0] * dos_one +
|
|
cx[1] * dos_two +
|
|
cx[2] * dos_thr +
|
|
cx[3] * dos_fou );
|
|
|
|
const int r2 = unsigned_fixed_round(
|
|
cx[0] * tre_one +
|
|
cx[1] * tre_two +
|
|
cx[2] * tre_thr +
|
|
cx[3] * tre_fou );
|
|
|
|
const int r3 = unsigned_fixed_round(
|
|
cx[0] * qua_one +
|
|
cx[1] * qua_two +
|
|
cx[2] * qua_thr +
|
|
cx[3] * qua_fou );
|
|
|
|
return( unsigned_fixed_round(
|
|
cy[0] * r0 +
|
|
cy[1] * r1 +
|
|
cy[2] * r2 +
|
|
cy[3] * r3 ) );
|
|
}
|
|
|
|
static int inline
|
|
signed_fixed_round( int v )
|
|
{
|
|
const int sign_of_v = 2 * (v > 0) - 1;
|
|
const int round_by = sign_of_v * (VIPS_INTERPOLATE_SCALE >> 1);
|
|
|
|
return( (v + round_by) >> VIPS_INTERPOLATE_SHIFT );
|
|
}
|
|
|
|
/* Fixed-point integer bicubic, used for 8 and 16-bit types.
|
|
*/
|
|
template <typename T> static int inline
|
|
bicubic_signed_int(
|
|
const T uno_one, const T uno_two, const T uno_thr, const T uno_fou,
|
|
const T dos_one, const T dos_two, const T dos_thr, const T dos_fou,
|
|
const T tre_one, const T tre_two, const T tre_thr, const T tre_fou,
|
|
const T qua_one, const T qua_two, const T qua_thr, const T qua_fou,
|
|
const int* restrict cx, const int* restrict cy )
|
|
{
|
|
const int r0 = signed_fixed_round(
|
|
cx[0] * uno_one +
|
|
cx[1] * uno_two +
|
|
cx[2] * uno_thr +
|
|
cx[3] * uno_fou );
|
|
|
|
const int r1 = signed_fixed_round(
|
|
cx[0] * dos_one +
|
|
cx[1] * dos_two +
|
|
cx[2] * dos_thr +
|
|
cx[3] * dos_fou );
|
|
|
|
const int r2 = signed_fixed_round(
|
|
cx[0] * tre_one +
|
|
cx[1] * tre_two +
|
|
cx[2] * tre_thr +
|
|
cx[3] * tre_fou );
|
|
|
|
const int r3 = signed_fixed_round(
|
|
cx[0] * qua_one +
|
|
cx[1] * qua_two +
|
|
cx[2] * qua_thr +
|
|
cx[3] * qua_fou );
|
|
|
|
return( signed_fixed_round(
|
|
cy[0] * r0 +
|
|
cy[1] * r1 +
|
|
cy[2] * r2 +
|
|
cy[3] * r3 ) );
|
|
}
|
|
|
|
/* Floating-point bicubic, used for int/float/double types.
|
|
*/
|
|
template <typename T> static T inline
|
|
bicubic_float(
|
|
const T uno_one, const T uno_two, const T uno_thr, const T uno_fou,
|
|
const T dos_one, const T dos_two, const T dos_thr, const T dos_fou,
|
|
const T tre_one, const T tre_two, const T tre_thr, const T tre_fou,
|
|
const T qua_one, const T qua_two, const T qua_thr, const T qua_fou,
|
|
const double* restrict cx, const double* restrict cy )
|
|
{
|
|
return(
|
|
cy[0] * (cx[0] * uno_one +
|
|
cx[1] * uno_two +
|
|
cx[2] * uno_thr +
|
|
cx[3] * uno_fou)
|
|
+
|
|
cy[1] * (cx[0] * dos_one +
|
|
cx[1] * dos_two +
|
|
cx[2] * dos_thr +
|
|
cx[3] * dos_fou)
|
|
+
|
|
cy[2] * (cx[0] * tre_one +
|
|
cx[1] * tre_two +
|
|
cx[2] * tre_thr +
|
|
cx[3] * tre_fou)
|
|
+
|
|
cy[3] * (cx[0] * qua_one +
|
|
cx[1] * qua_two +
|
|
cx[2] * qua_thr +
|
|
cx[3] * qua_fou) );
|
|
}
|
|
|
|
/* Given an offset in [0,1] (we can have x == 1 when building tables),
|
|
* calculate c0, c1, c2, c3, the catmull-rom coefficients. This is called
|
|
* from the interpolator as well as from the table builder.
|
|
*/
|
|
static void inline
|
|
calculate_coefficients_catmull( const double x, double c[4] )
|
|
{
|
|
/* Nicolas believes that the following is an hitherto unknown
|
|
* hyper-efficient method of computing Catmull-Rom coefficients. It
|
|
* only uses 4* & 1+ & 5- for a total of only 10 flops to compute
|
|
* four coefficients.
|
|
*/
|
|
const double cr1 = 1. - x;
|
|
const double cr2 = -.5 * x;
|
|
const double cr3 = cr1 * cr2;
|
|
const double cone = cr1 * cr3;
|
|
const double cfou = x * cr3;
|
|
const double cr4 = cfou - cone;
|
|
const double ctwo = cr1 - cone + cr4;
|
|
const double cthr = x - cfou - cr4;
|
|
|
|
g_assert( x >= 0. && x <= 1. );
|
|
|
|
c[0] = cone;
|
|
c[3] = cfou;
|
|
c[1] = ctwo;
|
|
c[2] = cthr;
|
|
}
|