libvips/libvips/histograms_lut/im_histgr.c
2010-04-19 11:00:28 +00:00

380 lines
7.9 KiB
C

/* find histograms
*
* Copyright: 1990, 1991, N. Dessipris.
*
* Author: Nicos Dessipris.
* Written on: 09/07/1990
* Modified on : 11/03/1991
* 19/7/93 JC
* - test for Coding type added
* 26/10/94 JC
* - rewritten for ANSI
* - now does USHORT too
* - 5 x faster!
* 2/6/95 JC
* - rewritten for partials
* 3/3/01 JC
* - tiny speed ups
* 21/1/07
* - number bands from zero
* 24/3/10
* - gtkdoc
* - small celanups
*/
/*
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
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <vips/vips.h>
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
/* Accumulate a histogram in one of these.
*/
typedef struct {
int bands; /* Number of bands in output */
int which; /* If one band in out, which band of input */
int size; /* Length of bins */
int mx; /* Maximum value we have seen */
unsigned int **bins; /* All the bins! */
} Histogram;
/* Build a Histogram.
*/
static Histogram *
build_hist( IMAGE *out, int bands, int which, int size )
{
int i;
Histogram *hist = IM_NEW( out, Histogram );
if( !hist || !(hist->bins = IM_ARRAY( out, bands, unsigned int * )) )
return( NULL );
for( i = 0; i < bands; i++ ) {
if( !(hist->bins[i] = IM_ARRAY( out, size, unsigned int )) )
return( NULL );
memset( hist->bins[i], 0, size * sizeof( unsigned int ) );
}
hist->bands = bands;
hist->which = which;
hist->size = size;
hist->mx = 0;
return( hist );
}
/* Build a sub-hist, based on the main hist.
*/
static void *
build_subhist( IMAGE *out, void *a, void *b )
{
Histogram *mhist = (Histogram *) a;
return( (void *)
build_hist( out, mhist->bands, mhist->which, mhist->size ) );
}
/* Join a sub-hist onto the main hist.
*/
static int
merge_subhist( void *seq, void *a, void *b )
{
Histogram *shist = (Histogram *) seq;
Histogram *mhist = (Histogram *) a;
int i, j;
g_assert( shist->bands == mhist->bands && shist->size == mhist->size );
/* Add on sub-data.
*/
mhist->mx = IM_MAX( mhist->mx, shist->mx );
for( i = 0; i < mhist->bands; i++ )
for( j = 0; j < mhist->size; j++ )
mhist->bins[i][j] += shist->bins[i][j];
/* Blank out sub-hist to make sure we can't add it again.
*/
shist->mx = 0;
for( i = 0; i < shist->bands; i++ )
shist->bins[i] = NULL;
return( 0 );
}
/* Histogram of all bands of a uchar image.
*/
static int
find_uchar_hist( REGION *reg, void *seq, void *a, void *b )
{
Histogram *hist = (Histogram *) seq;
Rect *r = &reg->valid;
IMAGE *im = reg->im;
int le = r->left;
int to = r->top;
int bo = IM_RECT_BOTTOM(r);
int nb = im->Bands;
int x, y, z;
/* Accumulate!
*/
for( y = to; y < bo; y++ ) {
PEL *p = (PEL *) IM_REGION_ADDR( reg, le, y );
int i;
for( i = 0, x = 0; x < r->width; x++ )
for( z = 0; z < nb; z++, i++ )
hist->bins[z][p[i]]++;
}
/* Note the maximum.
*/
hist->mx = 255;
return( 0 );
}
/* Histogram of a selected band of a uchar image.
*/
static int
find_uchar_hist_extract( REGION *reg, void *seq, void *a, void *b )
{
Histogram *hist = (Histogram *) seq;
Rect *r = &reg->valid;
IMAGE *im = reg->im;
int le = r->left;
int to = r->top;
int bo = IM_RECT_BOTTOM(r);
unsigned int *bins = hist->bins[0];
int nb = im->Bands;
int max = r->width * nb;
int x, y;
/* Accumulate!
*/
for( y = to; y < bo; y++ ) {
PEL *p = (PEL *) IM_REGION_ADDR( reg, le, y );
for( x = hist->which; x < max; x += nb )
bins[p[x]]++;
}
/* Note the maximum.
*/
hist->mx = 255;
return( 0 );
}
/* Histogram of all bands of a ushort image.
*/
static int
find_ushort_hist( REGION *reg, void *seq, void *a, void *b )
{
Histogram *hist = (Histogram *) seq;
Rect *r = &reg->valid;
IMAGE *im = reg->im;
int le = r->left;
int to = r->top;
int bo = IM_RECT_BOTTOM(r);
int mx = hist->mx;
int nb = im->Bands;
int x, y, z;
/* Accumulate!
*/
for( y = to; y < bo; y++ ) {
unsigned short *p = (unsigned short *)
IM_REGION_ADDR( reg, le, y );
int i;
for( i = 0, x = 0; x < r->width; x++ )
for( z = 0; z < nb; z++, i++ ) {
int v = p[i];
/* Adjust maximum.
*/
if( v > mx )
mx = v;
hist->bins[z][v]++;
}
}
/* Note the maximum.
*/
hist->mx = mx;
return( 0 );
}
/* Histogram of all bands of a ushort image.
*/
static int
find_ushort_hist_extract( REGION *reg, void *seq, void *a, void *b )
{
Histogram *hist = (Histogram *) seq;
Rect *r = &reg->valid;
IMAGE *im = reg->im;
int le = r->left;
int to = r->top;
int bo = IM_RECT_BOTTOM(r);
int mx = hist->mx;
unsigned int *bins = hist->bins[0];
int nb = im->Bands;
int max = nb * r->width;
int x, y;
/* Accumulate!
*/
for( y = to; y < bo; y++ ) {
unsigned short *p = (unsigned short *)
IM_REGION_ADDR( reg, le, y ) + hist->which;
for( x = hist->which; x < max; x += nb ) {
int v = p[x];
/* Adjust maximum.
*/
if( v > mx )
mx = v;
bins[v]++;
}
}
/* Note the maximum.
*/
hist->mx = mx;
return( 0 );
}
/**
* im_histgr:
* @in: input image
* @out: output image
* @bandno: band to equalise
*
* Find the histogram of @in. Find the histogram for band @bandno (producing a
* one-band histogram), or for all bands (producing an n-band histogram) if
* @bandno is -1.
*
* @in must be u8 or u16. @out is always u32.
*
* See also: im_hist_indexed(), im_histeq().
*
* Returns: 0 on success, -1 on error
*/
int
im_histgr( IMAGE *in, IMAGE *out, int bandno )
{
int size; /* Length of hist */
int bands; /* Number of bands in output */
Histogram *mhist;
im_generate_fn scanfn;
int i, j;
unsigned int *obuffer, *q;
/* Check images. PIO from in, WIO to out.
*/
if( im_check_uncoded( "im_histgr", in ) ||
im_check_u8or16( "im_histgr", in ) ||
im_check_bandno( "im_histgr", in, bandno ) ||
im_pincheck( in ) ||
im_outcheck( out ) )
return( -1 );
/* Find the range of pixel values we must handle.
*/
size = in->BandFmt == IM_BANDFMT_UCHAR ? 256 : 65536;
/* How many output bands?
*/
if( bandno == -1 )
bands = in->Bands;
else
bands = 1;
/* Build main hist we accumulate data in.
*/
if( !(mhist = build_hist( out, bands, bandno, size )) )
return( -1 );
/* Select scan function.
*/
if( in->BandFmt == IM_BANDFMT_UCHAR && bandno == -1 )
scanfn = find_uchar_hist;
else if( in->BandFmt == IM_BANDFMT_UCHAR )
scanfn = find_uchar_hist_extract;
else if( in->BandFmt == IM_BANDFMT_USHORT && bandno == -1 )
scanfn = find_ushort_hist;
else
scanfn = find_ushort_hist_extract;
/* Accumulate data.
*/
if( vips_sink( in,
build_subhist, scanfn, merge_subhist, mhist, NULL ) )
return( -1 );
/* Make the output image.
*/
if( im_cp_desc( out, in ) )
return( -1 );
im_initdesc( out,
mhist->mx + 1, 1, bands, IM_BBITS_INT, IM_BANDFMT_UINT,
IM_CODING_NONE, IM_TYPE_HISTOGRAM, 1.0, 1.0, 0, 0 );
if( im_setupout( out ) )
return( -1 );
/* Interleave for output.
*/
if( !(obuffer = IM_ARRAY( out,
IM_IMAGE_N_ELEMENTS( out ), unsigned int )) )
return( -1 );
for( q = obuffer, j = 0; j < out->Xsize; j++ )
for( i = 0; i < out->Bands; i++ )
*q++ = mhist->bins[i][j];
/* Write interleaved buffer into hist.
*/
if( im_writeline( 0, out, (PEL *) obuffer ) )
return( -1 );
return( 0 );
}