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im_scaleps() is a class 

actually an option to vips_scale(), with a param for the exponent as
well
This commit is contained in:
John Cupitt 2013-05-30 16:55:32 +01:00
parent 4311d452f1
commit caed1199ed
8 changed files with 57 additions and 105 deletions
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3
ChangeLog
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@ -3,7 +3,8 @@
- turn off caching for im_copy()/vips_copy(), we use copy to stop sharing, and
it's cheap so caching doesn't help anyway
- auto rshift down to 8 bits on save, if necessary
- im_gaussnoise(), im_copy_file(), im_grid(), im_scale() redone as classes
- im_gaussnoise(), im_copy_file(), im_grid(), im_scale(), im_scaleps()
redone as classes
- add --angle option to dzsave
14/5/13 started 7.32.4

1
libvips/conversion/Makefile.am
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@ -30,7 +30,6 @@ libconversion_la_SOURCES = \
im_msb.c \
grid.c \
scale.c \
im_scaleps.c \
im_subsample.c \
im_system.c \
im_system_image.c \

100
libvips/conversion/im_scaleps.c
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@ -1,100 +0,0 @@
/* im_scaleps
*
* Copyright: 1990, N. Dessipris.
*
* Author: Nicos Dessipris
* Written on: 02/05/1990
* Modified on: 14/03/1991
* 15/6/93 J.Cupitt
* - externs fixed
* - includes fixed
* 13/2/95 JC
* - ANSIfied
* - cleaned up
* 11/7/02 JC
* - rewritten ... got rid of the stuff for handling -ves, never used
* (and was broken anyway)
* 1/2/10
* - gtkdoc
*/
/*
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
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <vips/vips.h>
/**
* im_scaleps:
* @in: input image
* @out: output image
*
* Scale a power spectrum. Transform with log10(1.0 + pow(x, 0.25)) + .5,
* then scale so max == 255.
*
* See also: im_scale().
*
* Returns: 0 on success, -1 on error
*/
int
im_scaleps( IMAGE *in, IMAGE *out )
{
IMAGE *t[4];
double mx;
double scale;
if( im_open_local_array( out, t, 4, "im_scaleps-1", "p" ) ||
im_max( in, &mx ) )
return( -1 );
if( mx <= 0.0 )
/* Range of zero: just return black.
*/
return( im_black( out, in->Xsize, in->Ysize, in->Bands ) );
scale = 255.0 / log10( 1.0 + pow( mx, .25 ) );
/* Transform!
*/
if( im_powtra( in, t[0], 0.25 ) ||
im_lintra( 1.0, t[0], 1.0, t[1] ) ||
im_log10tra( t[1], t[2] ) ||
im_lintra( scale, t[2], 0.0, t[3] ) ||
im_clip2fmt( t[3], out, IM_BANDFMT_UCHAR ) )
return( -1 );
return( 0 );
}

38
libvips/conversion/scale.c
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@ -17,6 +17,7 @@
* - gtkdoc
* 30/5/13
* - redo as a class
* - add log scale and exponent as an option
*/
/*
@ -63,6 +64,9 @@ typedef struct _VipsScale {
VipsImage *in;
gboolean log;
double exp;
} VipsScale;
typedef VipsConversionClass VipsScaleClass;
@ -98,6 +102,17 @@ vips_scale_build( VipsObject *object )
vips_image_write( t[1], conversion->out ) )
return( -1 );
}
else if( scale->log ) {
double f = 255.0 / log10( 1.0 + pow( mx, scale->exp ) );
if( vips_pow_const1( scale->in, &t[2], scale->exp, NULL ) ||
vips_linear1( t[2], &t[3], 1.0, 1.0, NULL ) ||
vips_log10( t[3], &t[4], NULL ) ||
vips_linear1( t[4], &t[5], f, 0.0, NULL ) ||
vips_cast( t[5], &t[6], VIPS_FORMAT_UCHAR, NULL ) ||
vips_image_write( t[6], conversion->out ) )
return( -1 );
}
else {
double f = 255.0 / (mx - mn);
double a = -(mn * f);
@ -130,11 +145,26 @@ vips_scale_class_init( VipsScaleClass *class )
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsScale, in ) );
VIPS_ARG_BOOL( class, "log", 3,
_( "Log" ),
_( "Log scale" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsScale, log ),
FALSE );
VIPS_ARG_DOUBLE( class, "exp", 3,
_( "Exponent" ),
_( "Exponent for log scale" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsScale, exp ),
0.00001, 10000, 0.25 );
}
static void
vips_scale_init( VipsScale *scale )
{
scale->exp = 0.25;
}
/**
@ -143,10 +173,18 @@ vips_scale_init( VipsScale *scale )
* @out: output image
* @...: %NULL-terminated list of optional named arguments
*
* Optional arguments:
*
* @log: log scale pixels
* @exp: exponent for log scale
*
* Search the image for the maximum and minimum value, then return the image
* as unsigned 8-bit, scaled so that the maximum value is 255 and the
* minimum is zero.
*
* If @log is set, transform with log10(1.0 + pow(x, @exp)) + .5,
* then scale so max == 255. By default, @exp is 0.25.
*
* See also: vips_cast().
*
* Returns: 0 on success, -1 on error

16
libvips/deprecated/vips7compat.c
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@ -1527,6 +1527,22 @@ im_scale( VipsImage *in, VipsImage *out )
return( 0 );
}
int
im_scaleps( VipsImage *in, VipsImage *out )
{
VipsImage *t;
if( vips_scale( in, &t, "log", TRUE, NULL ) )
return( -1 );
if( vips_image_write( t, out ) ) {
g_object_unref( t );
return( -1 );
}
g_object_unref( t );
return( 0 );
}
static int
vips__math( VipsImage *in, VipsImage *out, VipsOperationMath math )
{

2
libvips/include/vips/conversion.h
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@ -258,8 +258,6 @@ int vips_flatten( VipsImage *in, VipsImage **out, ... )
int im_msb( VipsImage *in, VipsImage *out );
int im_msb_band( VipsImage *in, VipsImage *out, int band );
int im_scaleps( VipsImage *in, VipsImage *out );
int im_falsecolour( VipsImage *in, VipsImage *out );
int im_text( VipsImage *out, const char *text, const char *font,

1
libvips/include/vips/vips7compat.h
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@ -712,6 +712,7 @@ int im_black( VipsImage *out, int x, int y, int bands );
int im_gaussnoise( VipsImage *out, int x, int y, double mean, double sigma );
int im_grid( VipsImage *in, VipsImage *out, int tile_height, int across, int down );
int im_scale( VipsImage *in, VipsImage *out );
int im_scaleps( VipsImage *in, VipsImage *out );
int im_c2amph( VipsImage *in, VipsImage *out );
int im_c2rect( VipsImage *in, VipsImage *out );

1
po/POTFILES.in
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@ -75,7 +75,6 @@ libvips/conversion/replicate.c
libvips/conversion/join.c
libvips/conversion/im_text.c
libvips/conversion/conver_dispatch.c
libvips/conversion/im_scaleps.c
libvips/conversion/im_wrap.c
libvips/conversion/insert.c
libvips/conversion/tilecache.c