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libvips/libsrc/mosaicing/nohalo.cpp
John Cupitt 603c7f9cee better bounds check for nohalo
2009-01-28 10:01:18 +00:00

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/* nohalo interpolator
*/
/*
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
/*
* 2009 (c) Nicolas Robidoux
*
* Thanks: Geert Jordaens, John Cupitt, Minglun Gong, Øyvind Kolås and
* Sven Neumann for useful comments and code.
*
* Acknowledgement: Nicolas Robidoux's research on nohalo funded in
* part by an NSERC (National Science and Engineering Research Council
* of Canada) Discovery Grant.
*/
/* Hacked for vips by J. Cupitt, 20/1/09
*/
/*
* ================
* NOHALO RESAMPLER
* ================
*
* "Nohalo" is a family of parameterized resamplers with a mission:
* smoothly straightening oblique lines without undesirable
* side-effects.
*
* The key parameter, which may be described as a "quality" parameter,
* is an integer which specifies the number of "levels" of binary
* subdivision which are performed. level = 0 can be thought of as
* being plain vanilla bilinear resampling; level = 1 is then the
* first "non-classical" method of the familiy.
*
* Although it increases computational cost, additional levels
* increase the quality of the resampled pixel value unless the
* resampled location happens to be exactly where a subdivided grid
* point (for this level) is located, in which case further levels do
* not change the answer, and consequently do not increase its
* quality.
*
* ============================================================
* WARNING: THIS CODE ONLY IMPLEMENTS THE LOWEST QUALITY NOHALO
* ============================================================
*
* This code implement nohalo for (quality) level = 1. Nohalo for
* higher quality levels will be implemented later.
*
* Key properties:
*
* =======================
* Nohalo is interpolatory
* =======================
*
* That is, nohalo preserves point values: If asked for the value at
* the center of an input pixel, the sampler returns the corresponding
* value, unchanged. In addition, because nohalo is continuous, if
* asked for a value at a location "very close" to the center of an
* input pixel, then the sampler returns a value "very close" to
* it. (Nohalo is not smoothing like, say, B-Spline
* pseudo-interpolation.)
*
* ========================================================
* Nohalo is co-monotone (this is why it's called "nohalo")
* ========================================================
*
* What monotonicity means here is that the resampled value is in the
* range of the four closest input values. Consequently, nohalo does
* not add haloing. It also means that clamping is unnecessary
* (provided abyss values are within the range of acceptable values,
* which is always the case). (Note: plain vanilla bilinear is also
* co-monotone.)
*
* Note: If the abyss policy is an extrapolating one---for example,
* linear or bilinear extrapolation---clamping is still unnecessary
* unless one attempts to resample outside of the convex hull of the
* input pixel positions. Consequence: the "corner" image size
* convention does not require clamping when using linear
* extrapolation abyss policy when performing image resizing, but the
* "center" one does, when upscaling, at locations very close to the
* boundary. If computing values at locations outside of the convex
* hull of the pixel locations of the input image, nearest neighbour
* abyss policy is most likely better anyway, because linear
* extrapolation produces "streaks" if positions far outside the
* original image boundary are resampled.
*
* ========================
* Nohalo is a local method
* ========================
*
* The value of the reconstructed intensity surface at any point
* depends on the values of (at most) 12 nearby input values, located
* in a "cross" centered at the closest four input pixel centers. For
* computational expediency, the input values corresponding to the
* nearest 21 input pixel locations (5x5 minus the four corners)
* should be made available through a data pointer. The code then
* selects the needed ones from this enlarged stencil.
*
* ===========================================================
* When level = infinity, nohalo's intensity surface is smooth
* ===========================================================
*
* It is conjectured that the intensity surface is infinitely
* differentiable. Consequently, "Mach banding" (primarily caused by
* sharp "ridges" in the reconstructed intensity surface and
* particularly noticeable, for example, when using bilinear
* resampling) is (essentially) absent, even at high magnifications,
* WHEN THE LEVEL IS HIGH (more or less when 2^(level+1) is at least
* the largest local magnification factor, which means that the level
* 1 nohalo does not show much Mach banding up to a magnification of
* about 4).
*
* ===============================
* Nohalo is second order accurate
* ===============================
*
* (Except possibly near the boundary: it is easy to make this
* property carry over everywhere but this requires a tuned abyss
* policy or building the boundary conditions inside the sampler.)
* Nohalo is exact on linear intensity profiles, meaning that if the
* input pixel values (in the stencil) are obtained from a function of
* the form f(x,y) = a + b*x + c*y (a, b, c constants), then the
* computed pixel value is exactly the value of f(x,y) at the
* asked-for sampling location. The boundary condition which is
* emulated by VIPS throught the "extend" extension of the input
* image---this corresponds to the nearest neighbour abyss
* policy---does NOT make this resampler exact on linears at the
* boundary. It does, however, guarantee that no clamping is required
* even when resampled values are computed at positions outside of the
* extent of the input image (when extrapolation is required).
*
* ===================
* Nohalo is nonlinear
* ===================
*
* In particular, resampling a sum of images may not be the same as
* summing the resamples (this occurs even without taking into account
* over and underflow issues: images can only take values within a
* banded range, and consequently no sampler is truly linear.)
*
* ====================
* Weaknesses of nohalo
* ====================
*
* In some cases, the first level nonlinear computation is wasted:
*
* If a region is bichromatic, the nonlinear component of the level 1
* nohalo is zero in the interior of the region, and consequently
* nohalo boils down to bilinear. For such images, either stick to
* bilinear, or use a higher level (quality) setting. (There is no
* real harm in using nohalo when it boils down to bilinear if one
* does not mind wasting cycles.)
*
* Low quality levels do NOT produce a continuously differentiable
* intensity surface:
*
* With a "finite" level is used (that is, in practice), the nohalo
* intensity surface is only continuous: there are gradient
* discontinuities because the "final interpolation step" is performed
* with bilinear. (Exception: if the "corner" image size convention is
* used and the magnification factor is 2, that is, if the resampled
* points sit exactly on the binary subdivided grid, then nohalo level
* 1 gives the same result as as level=infinity, and consequently the
* intensity surface can be treated as if smooth.)
*/
/*
*/
#define DEBUG
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <stdlib.h>
#include <vips/vips.h>
#include <vips/internal.h>
#include "templates.h"
#ifndef restrict
#ifdef __restrict
#define restrict __restrict
#else
#ifdef __restrict__
#define restrict __restrict__
#else
#define restrict
#endif
#endif
#endif
/*
* 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.f) = 0
*
* FAST_PSEUDO_FLOOR(-.5) = -1
*
* as expected, but
*
* FAST_PSEUDO_FLOOR(-1.f) = -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. ) )
/*
* Alternative (if conditional move is fast and correctly identified
* by the compiler):
*
* #define FAST_PSEUDO_FLOOR(x) ( (x)>=0 ? (int)(x) : (int)(x)-1 )
*/
#define FAST_MIN(a,b) ( (a) <= (b) ? (a) : (b) )
#define VIPS_TYPE_INTERPOLATE_NOHALO \
(vips_interpolate_nohalo_get_type())
#define VIPS_INTERPOLATE_NOHALO( obj ) \
(G_TYPE_CHECK_INSTANCE_CAST( (obj), \
VIPS_TYPE_INTERPOLATE_NOHALO, VipsInterpolateNohalo ))
#define VIPS_INTERPOLATE_NOHALO_CLASS( klass ) \
(G_TYPE_CHECK_CLASS_CAST( (klass), \
VIPS_TYPE_INTERPOLATE_NOHALO, VipsInterpolateNohaloClass))
#define VIPS_IS_INTERPOLATE_NOHALO( obj ) \
(G_TYPE_CHECK_INSTANCE_TYPE( (obj), VIPS_TYPE_INTERPOLATE_NOHALO ))
#define VIPS_IS_INTERPOLATE_NOHALO_CLASS( klass ) \
(G_TYPE_CHECK_CLASS_TYPE( (klass), VIPS_TYPE_INTERPOLATE_NOHALO ))
#define VIPS_INTERPOLATE_NOHALO_GET_CLASS( obj ) \
(G_TYPE_INSTANCE_GET_CLASS( (obj), \
VIPS_TYPE_INTERPOLATE_NOHALO, VipsInterpolateNohaloClass ))
typedef struct _VipsInterpolateNohalo {
VipsInterpolate parent_object;
} VipsInterpolateNohalo;
typedef struct _VipsInterpolateNohaloClass {
VipsInterpolateClass parent_class;
} VipsInterpolateNohaloClass;
/* Calculate the four results surrounding the target point, our caller does
* bilinear interpolation of them.
*/
static void inline
nohalo_sharp_level_1(
const double dos_thr,
const double dos_fou,
const double tre_two,
const double tre_thr,
const double tre_fou,
const double tre_fiv,
const double qua_two,
const double qua_thr,
const double qua_fou,
const double qua_fiv,
const double cin_thr,
const double cin_fou,
double *r1,
double *r2,
double *r3 )
{
/* Start of copy-paste from Nicolas's source.
*/
/*
* The potentially needed input pixel values are described by the
* following stencil, where (ix,iy) are the coordinates of the
* closest input pixel center (with ties resolved arbitrarily).
*
* Spanish abbreviations are used to label positions from top to
* bottom (rows), English ones to label positions from left to right
* (columns).
*
* (ix-1,iy-2) (ix,iy-2) (ix+1,iy-2)
* = uno_two = uno_thr = uno_fou
*
* (ix-2,iy-1) (ix-1,iy-1) (ix,iy-1) (ix+1,iy-1) (ix+2,iy-1)
* = dos_one = dos_two = dos_thr = dos_fou = dos_fiv
*
* (ix-2,iy) (ix-1,iy) (ix,iy) (ix+1,iy) (ix+2,iy)
* = tre_one = tre_two = tre_thr = tre_fou = tre_fiv
*
* (ix-2,iy+1) (ix-1,iy+1) (ix,iy+1) (ix+1,iy+1) (ix+2,iy+1)
* = qua_one = qua_two = qua_thr = qua_fou = qua_fiv
*
* (ix-1,iy+2) (ix,iy+2) (ix+1,iy+2)
* = cin_two = cin_thr = cin_fou
*
* The above is the "enlarged" stencil: about half the values will
* not be used. Once symmetry has been used to assume that the
* sampling point is to the right and bottom of tre_thr---this is
* done by implicitly reflecting the data if needed---the actually
* used input values are named thus:
*
* dos_thr dos_fou
*
* tre_two tre_thr tre_fou tre_fiv
*
* qua_two qua_thr qua_fou qua_fiv
*
* cin_thr cin_fou
*
* (If, for exammple, relative_x_is_left is 1 but relative_y_is___up
* = 0, then dos_fou in this post-reflexion reduced stencil really
* corresponds to dos_two in the "enlarged" one, etc.)
*
* Given that the reflexions are performed "outside of the
* nohalo_sharp_level_1 function," the above 12 input values are the
* only ones which are read from the buffer.
*/
/*
* Computation of the nonlinear slopes: If two consecutive pixel
* value differences have the same sign, the smallest one (in
* absolute value) is taken to be the corresponding slope; if the
* two consecutive pixel value differences don't have the same sign,
* the corresponding slope is set to 0.
*/
/*
* Tre(s) horizontal differences:
*/
const double deux_tre = tre_thr - tre_two;
const double troi_tre = tre_fou - tre_thr;
const double quat_tre = tre_fiv - tre_fou;
/*
* Qua(ttro) horizontal differences:
*/
const double deux_qua = qua_thr - qua_two;
const double troi_qua = qua_fou - qua_thr;
const double quat_qua = qua_fiv - qua_fou;
/*
* Thr(ee) vertical differences:
*/
const double deux_thr = tre_thr - dos_thr;
const double troi_thr = qua_thr - tre_thr;
const double quat_thr = cin_thr - qua_thr;
/*
* Fou(r) vertical differences:
*/
const double deux_fou = tre_fou - dos_fou;
const double troi_fou = qua_fou - tre_fou;
const double quat_fou = cin_fou - qua_fou;
/*
* Tre:
*/
const double half_sign_deux_tre = deux_tre >= 0. ? .5 : -.5;
const double half_sign_troi_tre = troi_tre >= 0. ? .5 : -.5;
const double half_sign_quat_tre = quat_tre >= 0. ? .5 : -.5;
/*
* Qua:
*/
const double half_sign_deux_qua = deux_qua >= 0. ? .5 : -.5;
const double half_sign_troi_qua = troi_qua >= 0. ? .5 : -.5;
const double half_sign_quat_qua = quat_qua >= 0. ? .5 : -.5;
/*
* Thr:
*/
const double half_sign_deux_thr = deux_thr >= 0. ? .5 : -.5;
const double half_sign_troi_thr = troi_thr >= 0. ? .5 : -.5;
const double half_sign_quat_thr = quat_thr >= 0. ? .5 : -.5;
/*
* Fou:
*/
const double half_sign_deux_fou = deux_fou >= 0. ? .5 : -.5;
const double half_sign_troi_fou = troi_fou >= 0. ? .5 : -.5;
const double half_sign_quat_fou = quat_fou >= 0. ? .5 : -.5;
/*
* Useful later:
*/
const double tre_thr_plus_tre_fou = tre_thr + tre_fou;
const double tre_thr_plus_qua_thr = tre_thr + qua_thr;
const double qua_fou_minus_tre_thr = qua_fou - tre_thr;
/*
* Tre:
*/
const double half_abs_deux_tre = half_sign_deux_tre * deux_tre;
const double sign_tre_thr_horizo = half_sign_deux_tre + half_sign_troi_tre;
const double half_abs_troi_tre = half_sign_troi_tre * troi_tre;
const double sign_tre_fou_horizo = half_sign_troi_tre + half_sign_quat_tre;
const double half_abs_quat_tre = half_sign_quat_tre * quat_tre;
/*
* Thr:
*/
const double half_abs_deux_thr = half_sign_deux_thr * deux_thr;
const double sign_tre_thr_vertic = half_sign_deux_thr + half_sign_troi_thr;
const double half_abs_troi_thr = half_sign_troi_thr * troi_thr;
const double sign_qua_thr_vertic = half_sign_troi_thr + half_sign_quat_thr;
const double half_abs_quat_thr = half_sign_quat_thr * quat_thr;
/*
* Qua:
*/
const double half_abs_deux_qua = half_sign_deux_qua * deux_qua;
const double sign_qua_thr_horizo = half_sign_deux_qua + half_sign_troi_qua;
const double half_abs_troi_qua = half_sign_troi_qua * troi_qua;
const double sign_qua_fou_horizo = half_sign_troi_qua + half_sign_quat_qua;
const double half_abs_quat_qua = half_sign_quat_qua * quat_qua;
/*
* Fou:
*/
const double half_abs_deux_fou = half_sign_deux_fou * deux_fou;
const double sign_tre_fou_vertic = half_sign_deux_fou + half_sign_troi_fou;
const double half_abs_troi_fou = half_sign_troi_fou * troi_fou;
const double sign_qua_fou_vertic = half_sign_troi_fou + half_sign_quat_fou;
const double half_abs_quat_fou = half_sign_quat_fou * quat_fou;
/*
* Tre:
*/
const double half_size_tre_thr_horizo =
FAST_MIN( half_abs_deux_tre, half_abs_troi_tre );
const double half_size_tre_fou_horizo =
FAST_MIN( half_abs_quat_tre, half_abs_troi_tre );
/*
* Thr:
*/
const double half_size_tre_thr_vertic =
FAST_MIN( half_abs_deux_thr, half_abs_troi_thr );
const double half_size_qua_thr_vertic =
FAST_MIN( half_abs_quat_thr, half_abs_troi_thr );
/*
* Qua:
*/
const double half_size_qua_thr_horizo =
FAST_MIN( half_abs_deux_qua, half_abs_troi_qua );
const double half_size_qua_fou_horizo =
FAST_MIN( half_abs_quat_qua, half_abs_troi_qua );
/*
* Fou:
*/
const double half_size_tre_fou_vertic =
FAST_MIN( half_abs_deux_fou, half_abs_troi_fou );
const double half_size_qua_fou_vertic =
FAST_MIN( half_abs_quat_fou, half_abs_troi_fou );
/*
* Compute the needed "right" (at the boundary between two input
* pixel areas) double resolution pixel value:
*/
/*
* Tre:
*/
const double two_times_tre_thrfou =
tre_thr_plus_tre_fou
+
sign_tre_thr_horizo * half_size_tre_thr_horizo
-
sign_tre_fou_horizo * half_size_tre_fou_horizo;
/*
* Compute the needed "down" double resolution pixel value:
*/
/*
* Thr:
*/
const double two_times_trequa_thr =
tre_thr_plus_qua_thr
+
sign_tre_thr_vertic * half_size_tre_thr_vertic
-
sign_qua_thr_vertic * half_size_qua_thr_vertic;
/*
* Compute the "diagonal" (at the boundary between four input
* pixel areas) double resolution pixel value:
*/
const double four_times_trequa_thrfou =
qua_fou_minus_tre_thr
+
sign_qua_thr_horizo * half_size_qua_thr_horizo
-
sign_qua_fou_horizo * half_size_qua_fou_horizo
+
sign_tre_fou_vertic * half_size_tre_fou_vertic
-
sign_qua_fou_vertic * half_size_qua_fou_vertic
+
two_times_tre_thrfou
+
two_times_trequa_thr;
/* End of copy-paste from Nicolas' source.
*/
*r1 = two_times_tre_thrfou;
*r2 = two_times_trequa_thr;
*r3 = four_times_trequa_thrfou;
}
/* Call nohalo_sharp_level_1 with an interpolator as a parameter.
* It'd be nice to do this with templates somehow :-( but I can't see a
* clean way to do it.
*/
#define NOHALO_SHARP_LEVEL_1_INTER( inter ) \
template <typename T> static void inline \
nohalo_sharp_level_1_ ## inter( PEL *pout, const PEL *pin, const int bands, \
const int pskip, const int lskip, \
const double w_times_z, \
const double x_times_z_over_2, \
const double w_times_y_over_2, \
const double x_times_y_over_4 ) \
{ \
T* restrict out = (T *) pout; \
const T* restrict in = (T *) pin; \
\
const int b1 = pskip; \
const int b2 = 2 * b1; \
const int b3 = 3 * b1; \
const int b4 = 4 * b1; \
\
const int l1 = lskip; \
const int l2 = 2 * l1; \
const int l3 = 3 * l1; \
const int l4 = 4 * l1; \
\
for( int z = 0; z < bands; z++ ) { \
const T dos_thr = in[b2 + l1]; \
const T dos_fou = in[b3 + l1]; \
\
const T tre_two = in[b1 + l2]; \
const T tre_thr = in[b2 + l2]; \
const T tre_fou = in[b3 + l2]; \
const T tre_fiv = in[b4 + l2]; \
\
const T qua_two = in[b1 + l3]; \
const T qua_thr = in[b2 + l3]; \
const T qua_fou = in[b3 + l3]; \
const T qua_fiv = in[b4 + l3]; \
\
const T cin_thr = in[b2 + l4]; \
const T cin_fou = in[b3 + l4]; \
\
double two_times_tre_thrfou; \
double two_times_trequa_thr; \
double four_times_trequa_thrfou; \
\
nohalo_sharp_level_1( \
dos_thr, dos_fou, \
tre_two, tre_thr, tre_fou, tre_fiv, \
qua_two, qua_thr, qua_fou, qua_fiv, \
cin_thr, cin_fou, \
&two_times_tre_thrfou, \
&two_times_trequa_thr, \
&four_times_trequa_thrfou ); \
\
const T result = bilinear_ ## inter<T>( \
w_times_z, \
x_times_z_over_2, \
w_times_y_over_2, \
x_times_y_over_4, \
tre_thr, \
two_times_tre_thrfou, \
two_times_trequa_thr, \
four_times_trequa_thrfou ); \
\
out[z] = result; \
\
in += 1; \
} \
}
NOHALO_SHARP_LEVEL_1_INTER( float )
NOHALO_SHARP_LEVEL_1_INTER( signed )
NOHALO_SHARP_LEVEL_1_INTER( unsigned )
/* We need C linkage for this.
*/
extern "C" {
G_DEFINE_TYPE( VipsInterpolateNohalo, vips_interpolate_nohalo,
VIPS_TYPE_INTERPOLATE );
}
static void
vips_interpolate_nohalo_interpolate( VipsInterpolate *interpolate,
PEL *out, REGION *in, double absolute_x, double absolute_y )
{
/* VIPS versions of Nicolas's pixel addressing values.
*/
const int bands = in->im->Bands;
const int lskip =
IM_REGION_LSKIP( in ) / IM_IMAGE_SIZEOF_ELEMENT( in->im );
/* Copy-paste of Nicolas's pixel addressing code starts.
*/
/*
* floor's surrogate FAST_PSEUDO_FLOOR is used to make sure that the
* transition through 0 is smooth. If it is known that absolute_x
* and absolute_y will never be less than -.5, plain cast---that is,
* const int ix = absolute_x + .5---should be used instead. Any
* function which agrees with floor for non-integer values, and
* picks one of the two possibilities for integer values, can be
* used.
*/
const int ix = FAST_PSEUDO_FLOOR (absolute_x + 0.5);
const int iy = FAST_PSEUDO_FLOOR (absolute_y + 0.5);
/*
* x is the x-coordinate of the sampling point relative to the
* position of the tre_thr pixel center. Similarly for y. Range of
* values: [-.5,.5].
*/
const double relative_x = absolute_x - ix;
const double relative_y = absolute_y - iy;
/*
* Start of the computation of values needed to extract the properly
* reflected needed values:
*/
const int relative_x_is_left = ( relative_x < 0. );
const int relative_y_is___up = ( relative_y < 0. );
/*
* "DIRTY" TRICK: In order to minimize the number of computed
* "double density" pixels, we use symmetry to appropriately "flip
* the data." (An alternative approach is to "compute everything and
* select by zeroing coefficients.")
*/
/*
* The direction of movement within the (extended) possibly
* reflected stencil is then determined by the following signs:
*/
const int sign_of_relative_x = 1 - 2 * relative_x_is_left;
const int sign_of_relative_y = 1 - 2 * relative_y_is___up;
/*
* Basic shifts:
*/
const int shift_1_pixel = sign_of_relative_x * bands;
const int shift_1_row = sign_of_relative_y * lskip;
/*
* POST REFLEXION/POST RESCALING "DOUBLE DENSITY" COORDINATES:
*
* With the appropriate reflexions, we can assume that the
* coordinates are positive (that we are in the bottom right
* quadrant (in quadrant III) relative to tre_thr). It is also
* convenient to scale things by 2, so that the "double density
* pixels" are 1---instead of 1/2---apart:
*/
const double x = ( 2 * sign_of_relative_x ) * relative_x;
const double y = ( 2 * sign_of_relative_y ) * relative_y;
/*
* BILINEAR WEIGHTS:
*
* (w = 1-x and z = 1-y.)
*/
const double x_times_y = x * y;
const double w_times_y = y - x_times_y;
const double x_times_z = x - x_times_y;
const double w_times_z = 1. - x - w_times_y;
/*
* WEIGHTED BILINEAR WEIGHTS (with forthcoming coefficient
* "folded in"):
*/
const double x_times_y_over_4 = .25 * x_times_y;
const double w_times_y_over_2 = .5 * w_times_y;
const double x_times_z_over_2 = .5 * x_times_z;
/* We need to shift and reflect the start point.
*/
const int target_x = ix - 2 + relative_x_is_left * 4;
const int target_y = iy - 2 + relative_y_is___up * 4;
const PEL * restrict p =
(PEL *) IM_REGION_ADDR( in, target_x, target_y );
/* Optional bounds checking.
*/
#ifdef DEBUG
{
/* Corner of pixel we are interpolating. No round up here!
*/
const int vix = FAST_PSEUDO_FLOOR (absolute_x);
const int viy = FAST_PSEUDO_FLOOR (absolute_y);
/* Top-left corner of our window.
*/
const PEL * restrict tl =
(PEL *) IM_REGION_ADDR( in, vix - 2, viy - 2 );
/* Bottom-right corner of our window.
*/
const PEL * restrict br =
(PEL *) IM_REGION_ADDR( in, vix + 2, viy + 2 );
g_assert( p >= tl );
g_assert( p <= br );
/* Last pixel we address.
*/
const PEL * restrict last = p +
IM_IMAGE_SIZEOF_ELEMENT( in->im ) * (
4 * shift_1_pixel +
4 * shift_1_row
);
g_assert( last >= tl );
g_assert( last <= br );
}
#endif /*DEBUG*/
#define CALL( T, inter ) \
nohalo_sharp_level_1_ ## inter<T>( out, p, \
bands, shift_1_pixel, shift_1_row, \
w_times_z, \
x_times_z_over_2, \
w_times_y_over_2, \
x_times_y_over_4 );
switch( in->im->BandFmt ) {
case IM_BANDFMT_UCHAR:
CALL( unsigned char, unsigned );
break;
case IM_BANDFMT_CHAR:
CALL( signed char, signed );
break;
case IM_BANDFMT_USHORT:
CALL( unsigned short, unsigned );
break;
case IM_BANDFMT_SHORT:
CALL( signed short, signed );
break;
case IM_BANDFMT_UINT:
CALL( unsigned int, unsigned );
break;
case IM_BANDFMT_INT:
CALL( signed int, signed );
break;
case IM_BANDFMT_FLOAT:
CALL( float, float );
break;
case IM_BANDFMT_DOUBLE:
CALL( double, float );
break;
case IM_BANDFMT_COMPLEX:
nohalo_sharp_level_1_float<float>( out, p,
bands * 2, shift_1_pixel * 2, shift_1_row,
w_times_z,
x_times_z_over_2,
w_times_y_over_2,
x_times_y_over_4 );
break;
case IM_BANDFMT_DPCOMPLEX:
nohalo_sharp_level_1_float<double>( out, p,
bands * 2, shift_1_pixel * 2, shift_1_row,
w_times_z,
x_times_z_over_2,
w_times_y_over_2,
x_times_y_over_4 );
break;
default:
g_assert( 0 );
break;
}
}
static void
vips_interpolate_nohalo_class_init( VipsInterpolateNohaloClass *klass )
{
VipsObjectClass *object_class = VIPS_OBJECT_CLASS( klass );
VipsInterpolateClass *interpolate_class =
VIPS_INTERPOLATE_CLASS( klass );
object_class->nickname = "nohalo";
object_class->description = _( "Bilinear plus edge enhance" );
interpolate_class->interpolate =
vips_interpolate_nohalo_interpolate;
interpolate_class->window_size = 5;
}
static void
vips_interpolate_nohalo_init( VipsInterpolateNohalo *nohalo )
{
}
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