136 lines
3.5 KiB
C
136 lines
3.5 KiB
C
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/* various interpolation templates
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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/* "fast" floor() ... on my laptop, anyway.
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*/
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#define FLOOR( V ) ((V) >= 0 ? (int)(V) : (int)((V) - 1))
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#ifndef restrict
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#ifdef __restrict
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#define restrict __restrict
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#else
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#ifdef __restrict__
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#define restrict __restrict__
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#else
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#define restrict
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#endif
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#endif
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#endif
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/* Fixed-point integer bicubic, used for 8 and 16-bit types.
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*/
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template <typename T> static int inline
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bicubic_int(
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const T uno_one, const T uno_two, const T uno_thr, const T uno_fou,
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const T dos_one, const T dos_two, const T dos_thr, const T dos_fou,
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const T tre_one, const T tre_two, const T tre_thr, const T tre_fou,
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const T qua_one, const T qua_two, const T qua_thr, const T qua_fou,
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const int *cx, const int *cy )
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{
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const int r0 =
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(cx[0] * uno_one +
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cx[1] * uno_two +
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cx[2] * uno_thr +
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cx[3] * uno_fou) >> VIPS_INTERPOLATE_SHIFT;
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const int r1 =
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(cx[0] * dos_one +
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cx[1] * dos_two +
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cx[2] * dos_thr +
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cx[3] * dos_fou) >> VIPS_INTERPOLATE_SHIFT;
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const int r2 =
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(cx[0] * tre_one +
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cx[1] * tre_two +
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cx[2] * tre_thr +
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cx[3] * tre_fou) >> VIPS_INTERPOLATE_SHIFT;
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const int r3 =
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(cx[0] * qua_one +
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cx[1] * qua_two +
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cx[2] * qua_thr +
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cx[3] * qua_fou) >> VIPS_INTERPOLATE_SHIFT;
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return( (cy[0] * r0 +
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cy[1] * r1 +
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cy[2] * r2 +
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cy[3] * r3) >> VIPS_INTERPOLATE_SHIFT );
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}
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/* Floating-point bicubic, used for int/float/double types.
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*/
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template <typename T> static T inline
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bicubic_float(
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const T uno_one, const T uno_two, const T uno_thr, const T uno_fou,
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const T dos_one, const T dos_two, const T dos_thr, const T dos_fou,
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const T tre_one, const T tre_two, const T tre_thr, const T tre_fou,
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const T qua_one, const T qua_two, const T qua_thr, const T qua_fou,
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const double *cx, const double *cy )
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{
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return(
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cy[0] * (cx[0] * uno_one +
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cx[1] * uno_two +
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cx[2] * uno_thr +
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cx[3] * uno_fou) +
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cy[1] * (cx[0] * dos_one +
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cx[1] * dos_two +
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cx[2] * dos_thr +
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cx[3] * dos_fou) +
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cy[2] * (cx[0] * tre_one +
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cx[1] * tre_two +
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cx[2] * tre_thr +
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cx[3] * tre_fou) +
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cy[3] * (cx[0] * qua_one +
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cx[1] * qua_two +
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cx[2] * qua_thr +
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cx[3] * qua_fou) );
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}
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/* Given an offset in [0,1] (we can have x == 1 when building tables),
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* calculate c0, c1, c2, c3, the catmull-rom coefficients. This is called
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* from the interpolator, as well as from the table builder.
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*/
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static void inline
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calculate_coefficients_catmull( const double x, double c[4] )
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{
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const double dx = 1.f - x;
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const double x2 = dx * x;
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const double mx2 = -.5f * x2;
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g_assert( x >= 0 && x <= 1 );
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c[0] = mx2 * dx;
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c[1] = x2 * (-1.5f * x + 1.f) + dx;
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c[2] = 1.f - (mx2 + c[1]);
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c[3] = mx2 * x;
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}
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