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redo subsample as a class

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This commit is contained in:
John Cupitt 2013-06-01 21:31:45 +01:00
parent 0bbc1b20d6
commit 738fe3aeaf
9 changed files with 347 additions and 260 deletions
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2
ChangeLog
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@ -4,7 +4,7 @@
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(), im_scaleps(),
im_wrap(), im_rotquad(), im_zoom() redone as classes
im_wrap(), im_rotquad(), im_zoom(), im_subsample() redone as classes
- add --angle option to dzsave
14/5/13 started 7.32.4

2
libvips/conversion/Makefile.am
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@ -31,7 +31,7 @@ libconversion_la_SOURCES = \
grid.c \
scale.c \
wrap.c \
im_subsample.c \
subsample.c \
im_system.c \
im_system_image.c \
im_text.c \

2
libvips/conversion/conversion.c
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@ -130,6 +130,7 @@ vips_conversion_operation_init( void )
extern GType vips_scale_get_type( void );
extern GType vips_wrap_get_type( void );
extern GType vips_zoom_get_type( void );
extern GType vips_subsample_get_type( void );
vips_copy_get_type();
vips_tile_cache_get_type();
@ -157,6 +158,7 @@ vips_conversion_operation_init( void )
vips_scale_get_type();
vips_wrap_get_type();
vips_zoom_get_type();
vips_subsample_get_type();
}
/* The common part of most binary conversion

254
libvips/conversion/im_subsample.c
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@ -1,254 +0,0 @@
/* im_subsample
*
* 3/7/95 JC
* - adapted from im_shrink()
* 3/8/02 JC
* - fall back to im_copy() for x/y factors == 1
* 21/4/08
* - don't fall back to pixel-wise shrinks for smalltile, it kills
* performance, just bring IM_MAX_WIDTH down instead
* 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 <vips/vips.h>
/* Maximum width of input we ask for.
*/
#define IM_MAX_WIDTH (100)
/* Our main parameter struct.
*/
typedef struct {
int xshrink; /* Subsample factors */
int yshrink;
} SubsampleInfo;
/* Subsample a REGION. We fetch in IM_MAX_WIDTH pixel-wide strips, left-to-right
* across the input.
*/
static int
line_shrink_gen( REGION *or, void *seq, void *a, void *b )
{
REGION *ir = (REGION *) seq;
IMAGE *in = (IMAGE *) a;
SubsampleInfo *st = (SubsampleInfo *) b;
Rect *r = &or->valid;
int le = r->left;
int ri = IM_RECT_RIGHT( r );
int to = r->top;
int bo = IM_RECT_BOTTOM(r);
int ps = IM_IMAGE_SIZEOF_PEL( in );
int owidth = IM_MAX_WIDTH / st->xshrink;
Rect s;
int x, y;
int z, k;
/* Loop down the region.
*/
for( y = to; y < bo; y++ ) {
VipsPel *q = IM_REGION_ADDR( or, le, y );
VipsPel *p;
/* Loop across the region, in owidth sized pieces.
*/
for( x = le; x < ri; x += owidth ) {
/* How many pixels do we make this time?
*/
int ow = IM_MIN( owidth, ri - x );
/* Ask for this many from input ... can save a
* little here!
*/
int iw = ow * st->xshrink - (st->xshrink - 1);
/* Ask for input.
*/
s.left = x * st->xshrink;
s.top = y * st->yshrink;
s.width = iw;
s.height = 1;
if( im_prepare( ir, &s ) )
return( -1 );
/* Append new pels to output.
*/
p = IM_REGION_ADDR( ir, s.left, s.top );
for( z = 0; z < ow; z++ ) {
for( k = 0; k < ps; k++ )
q[k] = p[k];
q += ps;
p += ps * st->xshrink;
}
}
}
return( 0 );
}
/* Fetch one pixel at a time ... good for very large shrinks.
*/
static int
point_shrink_gen( REGION *or, void *seq, void *a, void *b )
{
REGION *ir = (REGION *) seq;
IMAGE *in = (IMAGE *) a;
SubsampleInfo *st = (SubsampleInfo *) b;
Rect *r = &or->valid;
int le = r->left;
int ri = IM_RECT_RIGHT( r );
int to = r->top;
int bo = IM_RECT_BOTTOM(r);
int ps = IM_IMAGE_SIZEOF_PEL( in );
Rect s;
int x, y;
int k;
/* Loop down the region.
*/
for( y = to; y < bo; y++ ) {
VipsPel *q = IM_REGION_ADDR( or, le, y );
VipsPel *p;
/* Loop across the region, in owidth sized pieces.
*/
for( x = le; x < ri; x++ ) {
/* Ask for input.
*/
s.left = x * st->xshrink;
s.top = y * st->yshrink;
s.width = 1;
s.height = 1;
if( im_prepare( ir, &s ) )
return( -1 );
/* Append new pels to output.
*/
p = IM_REGION_ADDR( ir, s.left, s.top );
for( k = 0; k < ps; k++ )
q[k] = p[k];
q += ps;
}
}
return( 0 );
}
/**
* im_subsample:
* @in: input image
* @out: output image
* @xshrink: horizontal shrink factor
* @yshrink: vertical shrink factor
*
* Subsample an image by an integer fraction. This is fast nearest-neighbour
* shrink.
*
* See also: im_shrink(), im_affinei(), im_zoom().
*
* Returns: 0 on success, -1 on error.
*/
int
im_subsample( IMAGE *in, IMAGE *out, int xshrink, int yshrink )
{
SubsampleInfo *st;
/* Check parameters.
*/
if( xshrink < 1 || yshrink < 1 ) {
im_error( "im_subsample",
"%s", _( "factors should both be >= 1" ) );
return( -1 );
}
if( xshrink == 1 && yshrink == 1 )
return( im_copy( in, out ) );
if( im_piocheck( in, out ) ||
im_check_coding_known( "im_subsample", in ) )
return( -1 );
/* Prepare output. Note: we round the output width down!
*/
if( im_cp_desc( out, in ) )
return( -1 );
out->Xsize = in->Xsize / xshrink;
out->Ysize = in->Ysize / yshrink;
out->Xres = in->Xres / xshrink;
out->Yres = in->Yres / yshrink;
if( out->Xsize <= 0 || out->Ysize <= 0 ) {
im_error( "im_subsample",
"%s", _( "image has shrunk to nothing" ) );
return( -1 );
}
/* Build and attach state struct.
*/
if( !(st = IM_NEW( out, SubsampleInfo )) )
return( -1 );
st->xshrink = xshrink;
st->yshrink = yshrink;
/* Set demand hints. We want THINSTRIP, as we will be demanding a
* large area of input for each output line.
*/
if( im_demand_hint( out, IM_THINSTRIP, in, NULL ) )
return( -1 );
/* Generate! If this is a very large shrink, then it's
* probably faster to do it a pixel at a time.
*/
if( xshrink > 10 ) {
if( im_generate( out,
im_start_one, point_shrink_gen, im_stop_one, in, st ) )
return( -1 );
}
else {
if( im_generate( out,
im_start_one, line_shrink_gen, im_stop_one, in, st ) )
return( -1 );
}
return( 0 );
}

322
libvips/conversion/subsample.c Normal file
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@ -0,0 +1,322 @@
/* subsample
*
* 3/7/95 JC
* - adapted from im_shrink()
* 3/8/02 JC
* - fall back to im_copy() for x/y factors == 1
* 21/4/08
* - don't fall back to pixel-wise shrinks for smalltile, it kills
* performance, just bring VIPS_MAX_WIDTH down instead
* 1/2/10
* - gtkdoc
* 1/6/13
* - redo as a class
*/
/*
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 <vips/vips.h>
#include "conversion.h"
typedef struct _VipsSubsample {
VipsConversion parent_instance;
/* The input image.
*/
VipsImage *in;
int xfac; /* Subsample factors */
int yfac;
} VipsSubsample;
typedef VipsConversionClass VipsSubsampleClass;
G_DEFINE_TYPE( VipsSubsample, vips_subsample, VIPS_TYPE_CONVERSION );
/* Maximum width of input we ask for.
*/
#define VIPS_MAX_WIDTH (100)
/* Subsample a VipsRegion. We fetch in VIPS_MAX_WIDTH pixel-wide strips,
* left-to-right across the input.
*/
static int
vips_subsample_line_gen( VipsRegion *or,
void *seq, void *a, void *b, gboolean *stop )
{
VipsRegion *ir = (VipsRegion *) seq;
VipsSubsample *subsample = (VipsSubsample *) b;
VipsImage *in = (VipsImage *) a;
VipsRect *r = &or->valid;
int le = r->left;
int ri = VIPS_RECT_RIGHT( r );
int to = r->top;
int bo = VIPS_RECT_BOTTOM( r );
int ps = VIPS_IMAGE_SIZEOF_PEL( in );
int owidth = VIPS_MAX_WIDTH / subsample->xfac;
VipsRect s;
int x, y;
int z, k;
/* Loop down the region.
*/
for( y = to; y < bo; y++ ) {
VipsPel *q = VIPS_REGION_ADDR( or, le, y );
VipsPel *p;
/* Loop across the region, in owidth sized pieces.
*/
for( x = le; x < ri; x += owidth ) {
/* How many pixels do we make this time?
*/
int ow = VIPS_MIN( owidth, ri - x );
/* Ask for this many from input ... can save a
* little here!
*/
int iw = ow * subsample->xfac - (subsample->xfac - 1);
/* Ask for input.
*/
s.left = x * subsample->xfac;
s.top = y * subsample->yfac;
s.width = iw;
s.height = 1;
if( vips_region_prepare( ir, &s ) )
return( -1 );
/* Append new pels to output.
*/
p = VIPS_REGION_ADDR( ir, s.left, s.top );
for( z = 0; z < ow; z++ ) {
for( k = 0; k < ps; k++ )
q[k] = p[k];
q += ps;
p += ps * subsample->xfac;
}
}
}
return( 0 );
}
/* Fetch one pixel at a time ... good for very large shrinks.
*/
static int
vips_subsample_point_gen( VipsRegion *or,
void *seq, void *a, void *b, gboolean *stop )
{
VipsRegion *ir = (VipsRegion *) seq;
VipsSubsample *subsample = (VipsSubsample *) b;
VipsImage *in = (VipsImage *) a;
VipsRect *r = &or->valid;
int le = r->left;
int ri = VIPS_RECT_RIGHT( r );
int to = r->top;
int bo = VIPS_RECT_BOTTOM(r);
int ps = VIPS_IMAGE_SIZEOF_PEL( in );
VipsRect s;
int x, y;
int k;
/* Loop down the region.
*/
for( y = to; y < bo; y++ ) {
VipsPel *q = VIPS_REGION_ADDR( or, le, y );
VipsPel *p;
/* Loop across the region, in owidth sized pieces.
*/
for( x = le; x < ri; x++ ) {
/* Ask for input.
*/
s.left = x * subsample->xfac;
s.top = y * subsample->yfac;
s.width = 1;
s.height = 1;
if( vips_region_prepare( ir, &s ) )
return( -1 );
/* Append new pels to output.
*/
p = VIPS_REGION_ADDR( ir, s.left, s.top );
for( k = 0; k < ps; k++ )
q[k] = p[k];
q += ps;
}
}
return( 0 );
}
static int
vips_subsample_build( VipsObject *object )
{
VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
VipsConversion *conversion = VIPS_CONVERSION( object );
VipsSubsample *subsample = (VipsSubsample *) object;
VipsGenerateFn subsample_fn;
if( VIPS_OBJECT_CLASS( vips_subsample_parent_class )->build( object ) )
return( -1 );
g_assert( subsample->xfac > 0 );
g_assert( subsample->yfac > 0 );
if( subsample->xfac == 1 &&
subsample->yfac == 1 )
return( vips_image_write( subsample->in, conversion->out ) );
if( vips_image_pio_input( subsample->in ) ||
vips_check_coding_known( class->nickname, subsample->in ) )
return( -1 );
/* Prepare output. Note: we round the output width down!
*/
if( vips_image_copy_fields( conversion->out, subsample->in ) )
return( -1 );
conversion->out->Xsize = subsample->in->Xsize / subsample->xfac;
conversion->out->Ysize = subsample->in->Ysize / subsample->yfac;
conversion->out->Xres = subsample->in->Xres / subsample->xfac;
conversion->out->Yres = subsample->in->Yres / subsample->yfac;
if( conversion->out->Xsize <= 0 ||
conversion->out->Ysize <= 0 ) {
vips_error( class->nickname,
"%s", _( "image has shrunk to nothing" ) );
return( -1 );
}
/* Set demand hints. We want THINSTRIP, as we will be demanding a
* large area of input for each output line.
*/
vips_demand_hint( conversion->out,
VIPS_DEMAND_STYLE_THINSTRIP, subsample->in, NULL );
/* Generate! If this is a very large shrink, then it's
* probably faster to do it a pixel at a time.
*/
if( subsample->xfac > 10 )
subsample_fn = vips_subsample_point_gen;
else
subsample_fn = vips_subsample_line_gen;
if( vips_image_generate( conversion->out,
vips_start_one, subsample_fn, vips_stop_one,
subsample->in, subsample ) )
return( -1 );
return( 0 );
}
/* xy range we sanity check on ... just to stop crazy numbers from divide by 0
* etc. causing g_assert() failures later.
*/
#define RANGE (100000000)
static void
vips_subsample_class_init( VipsSubsampleClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
vobject_class->nickname = "subsample";
vobject_class->description = _( "subsample an image" );
vobject_class->build = vips_subsample_build;
operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
VIPS_ARG_IMAGE( class, "input", 0,
_( "Input" ),
_( "Input image" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsSubsample, in ) );
VIPS_ARG_INT( class, "xfac", 2,
_( "Xfac" ),
_( "Horizontal subsample factor" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsSubsample, xfac ),
1, RANGE, 1 );
VIPS_ARG_INT( class, "yfac", 3,
_( "Yfac" ),
_( "Vertical subsample factor" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsSubsample, yfac ),
1, RANGE, 1 );
}
static void
vips_subsample_init( VipsSubsample *subsample )
{
}
/**
* vips_subsample:
* @in: input image
* @out: output image
* @xfac: horizontal shrink factor
* @yfac: vertical shrink factor
* @...: %NULL-terminated list of optional named arguments
*
* Subsample an image by an integer fraction. This is fast, nearest-neighbour
* shrink.
*
* See also: vips_affine(), vips_shrink(), vips_zoom().
*
* Returns: 0 on success, -1 on error.
*/
int
vips_subsample( VipsImage *in, VipsImage **out, int xfac, int yfac, ... )
{
va_list ap;
int result;
va_start( ap, yfac );
result = vips_call_split( "subsample", ap, in, out, xfac, yfac );
va_end( ap );
return( result );
}

16
libvips/deprecated/vips7compat.c
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@ -1581,6 +1581,22 @@ im_zoom( VipsImage *in, VipsImage *out, int xfac, int yfac )
return( 0 );
}
int
im_subsample( VipsImage *in, VipsImage *out, int xfac, int yfac )
{
VipsImage *t;
if( vips_subsample( in, &t, xfac, yfac, 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 )
{

4
libvips/include/vips/conversion.h
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@ -196,6 +196,8 @@ int vips_wrap( VipsImage *in, VipsImage **out, ... )
__attribute__((sentinel));
int vips_zoom( VipsImage *in, VipsImage **out, int xfac, int yfac, ... )
__attribute__((sentinel));
int vips_subsample( VipsImage *in, VipsImage **out, int xfac, int yfac, ... )
__attribute__((sentinel));
int vips_cast( VipsImage *in, VipsImage **out, VipsBandFormat format, ... )
__attribute__((sentinel));
@ -269,8 +271,6 @@ int im_text( VipsImage *out, const char *text, const char *font,
int im_insertset( VipsImage *main, VipsImage *sub, VipsImage *out, int n, int *x, int *y );
int im_subsample( VipsImage *in, VipsImage *out, int xshrink, int yshrink );
int im_system( VipsImage *im, const char *cmd, char **out );
VipsImage *im_system_image( VipsImage *im,
const char *in_format, const char *out_format, const char *cmd_format,

1
libvips/include/vips/vips7compat.h
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@ -716,6 +716,7 @@ int im_grid( VipsImage *in, VipsImage *out, int tile_height, int across, int dow
int im_scale( VipsImage *in, VipsImage *out );
int im_scaleps( VipsImage *in, VipsImage *out );
int im_zoom( VipsImage *in, VipsImage *out, int xfac, int yfac );
int im_subsample( VipsImage *in, VipsImage *out, int xshrink, int yshrink );
int im_c2amph( VipsImage *in, VipsImage *out );
int im_c2rect( VipsImage *in, VipsImage *out );

4
po/POTFILES.in
View File

@ -54,14 +54,14 @@ libvips/colour/dECMC.c
libvips/colour/scRGB2sRGB.c
libvips/conversion/flip.c
libvips/conversion/bandmean.c
libvips/conversion/im_zoom.c
libvips/conversion/zoom.c
libvips/conversion/im_system.c
libvips/conversion/gaussnoise.c
libvips/conversion/bandary.c
libvips/conversion/cast.c
libvips/conversion/conversion.c
libvips/conversion/flatten.c
libvips/conversion/im_subsample.c
libvips/conversion/subsample.c
libvips/conversion/grid.c
libvips/conversion/extract.c
libvips/conversion/bandjoin.c