440 lines
9.8 KiB
C
440 lines
9.8 KiB
C
/* flatten the alpha out of an image, replacing it with a constant background
|
|
*
|
|
* Author: John Cupitt
|
|
* Written on: 18/6/12
|
|
*/
|
|
|
|
/*
|
|
|
|
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
|
|
|
|
*/
|
|
|
|
/*
|
|
#define VIPS_DEBUG
|
|
*/
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
#include <config.h>
|
|
#endif /*HAVE_CONFIG_H*/
|
|
#include <vips/intl.h>
|
|
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <stdlib.h>
|
|
#include <math.h>
|
|
|
|
#include <vips/vips.h>
|
|
#include <vips/internal.h>
|
|
#include <vips/debug.h>
|
|
|
|
#include "pconversion.h"
|
|
|
|
typedef struct _VipsFlatten {
|
|
VipsConversion parent_instance;
|
|
|
|
VipsImage *in;
|
|
|
|
/* Background colour.
|
|
*/
|
|
VipsArea *background;
|
|
|
|
/* The [double] converted to the input image format.
|
|
*/
|
|
VipsPel *ink;
|
|
|
|
} VipsFlatten;
|
|
|
|
typedef VipsConversionClass VipsFlattenClass;
|
|
|
|
G_DEFINE_TYPE( VipsFlatten, vips_flatten, VIPS_TYPE_CONVERSION );
|
|
|
|
/* Shift A down N places, rounding to nearest.
|
|
*
|
|
* This calculates A / B, rounding the result to nearest, ie.
|
|
*
|
|
* (a + (b / 2)) / b
|
|
*
|
|
* We mustn't overflow during the add, so we actually do:
|
|
*
|
|
* ((a / 2) + (b / 4)) / (b / 2)
|
|
*
|
|
* slightly less accurate, but safe from overflow.
|
|
*/
|
|
#define SHIFT_ROUND( A, N ) \
|
|
((((A) >> 1) + (1 << ((N) - 2)) - 1) >> ((N) - 1))
|
|
|
|
/* Flatten with shift + round, black background.
|
|
*/
|
|
#define VIPS_FLATTEN_INT_BLACK( TYPE, N ) { \
|
|
TYPE *p = (TYPE *) in; \
|
|
TYPE *q = (TYPE *) out; \
|
|
\
|
|
for( x = 0; x < width; x++ ) { \
|
|
TYPE alpha = p[bands - 1]; \
|
|
int b; \
|
|
\
|
|
for( b = 0; b < bands - 1; b++ ) \
|
|
q[b] = SHIFT_ROUND( p[b] * alpha, N ); \
|
|
\
|
|
p += bands; \
|
|
q += bands - 1; \
|
|
} \
|
|
}
|
|
|
|
/* Flatten with shift + round, any background.
|
|
*/
|
|
#define VIPS_FLATTEN_INT( TYPE, N ) { \
|
|
TYPE *p = (TYPE *) in; \
|
|
TYPE *q = (TYPE *) out; \
|
|
\
|
|
for( x = 0; x < width; x++ ) { \
|
|
TYPE alpha = p[bands - 1]; \
|
|
TYPE nalpha = ((1 << (N)) - 1) - alpha; \
|
|
TYPE *bg = (TYPE *) flatten->ink; \
|
|
int b; \
|
|
\
|
|
for( b = 0; b < bands - 1; b++ ) \
|
|
q[b] = SHIFT_ROUND( p[b] * alpha, (N) ) + \
|
|
SHIFT_ROUND( bg[b] * nalpha, (N) ); \
|
|
\
|
|
p += bands; \
|
|
q += bands - 1; \
|
|
} \
|
|
}
|
|
|
|
/* Flatten via float division, black background.
|
|
*/
|
|
#define VIPS_FLATTEN_FLOAT_BLACK( TYPE, SCALE ) { \
|
|
TYPE *p = (TYPE *) in; \
|
|
TYPE *q = (TYPE *) out; \
|
|
\
|
|
for( x = 0; x < width; x++ ) { \
|
|
TYPE alpha = p[bands - 1]; \
|
|
int b; \
|
|
\
|
|
for( b = 0; b < bands - 1; b++ ) \
|
|
q[b] = ((double) p[b] * alpha) / (SCALE); \
|
|
\
|
|
p += bands; \
|
|
q += bands - 1; \
|
|
} \
|
|
}
|
|
|
|
/* Flatten via float division, any background.
|
|
*/
|
|
#define VIPS_FLATTEN_FLOAT( TYPE, SCALE ) { \
|
|
TYPE *p = (TYPE *) in; \
|
|
TYPE *q = (TYPE *) out; \
|
|
\
|
|
for( x = 0; x < width; x++ ) { \
|
|
TYPE alpha = p[bands - 1]; \
|
|
TYPE nalpha = (SCALE) - alpha; \
|
|
TYPE *bg = (TYPE *) flatten->ink; \
|
|
int b; \
|
|
\
|
|
for( b = 0; b < bands - 1; b++ ) \
|
|
q[b] = ((double) p[b] * alpha) / (SCALE) + \
|
|
((double) bg[b] * nalpha) / (SCALE); \
|
|
\
|
|
p += bands; \
|
|
q += bands - 1; \
|
|
} \
|
|
}
|
|
|
|
static int
|
|
vips_flatten_black_gen( VipsRegion *or, void *vseq, void *a, void *b,
|
|
gboolean *stop )
|
|
{
|
|
VipsRegion *ir = (VipsRegion *) vseq;
|
|
VipsFlatten *flatten = (VipsFlatten *) b;
|
|
VipsRect *r = &or->valid;
|
|
int width = r->width;
|
|
int bands = ir->im->Bands;
|
|
|
|
int x, y;
|
|
|
|
if( vips_region_prepare( ir, r ) )
|
|
return( -1 );
|
|
|
|
for( y = 0; y < r->height; y++ ) {
|
|
VipsPel *in = VIPS_REGION_ADDR( ir, r->left, r->top + y );
|
|
VipsPel *out = VIPS_REGION_ADDR( or, r->left, r->top + y );
|
|
|
|
switch( flatten->in->BandFmt ) {
|
|
case VIPS_FORMAT_UCHAR:
|
|
VIPS_FLATTEN_INT_BLACK( unsigned char, 8 );
|
|
break;
|
|
|
|
case VIPS_FORMAT_CHAR:
|
|
/* Alpha is 0 - 127? No idea, really.
|
|
*/
|
|
VIPS_FLATTEN_INT_BLACK( signed char, 7 );
|
|
break;
|
|
|
|
case VIPS_FORMAT_USHORT:
|
|
VIPS_FLATTEN_INT_BLACK( unsigned short, 16 );
|
|
break;
|
|
|
|
case VIPS_FORMAT_SHORT:
|
|
VIPS_FLATTEN_INT_BLACK( signed short, 15 );
|
|
break;
|
|
|
|
case VIPS_FORMAT_UINT:
|
|
VIPS_FLATTEN_FLOAT_BLACK( unsigned int, UINT_MAX );
|
|
break;
|
|
|
|
case VIPS_FORMAT_INT:
|
|
VIPS_FLATTEN_FLOAT_BLACK( signed int, INT_MAX );
|
|
break;
|
|
|
|
case VIPS_FORMAT_FLOAT:
|
|
VIPS_FLATTEN_FLOAT_BLACK( float, 1.0 );
|
|
break;
|
|
|
|
case VIPS_FORMAT_DOUBLE:
|
|
VIPS_FLATTEN_FLOAT_BLACK( double, 1.0 );
|
|
break;
|
|
|
|
case VIPS_FORMAT_COMPLEX:
|
|
case VIPS_FORMAT_DPCOMPLEX:
|
|
default:
|
|
g_assert( 0 );
|
|
}
|
|
}
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
/* Any background.
|
|
*/
|
|
static int
|
|
vips_flatten_gen( VipsRegion *or, void *vseq, void *a, void *b,
|
|
gboolean *stop )
|
|
{
|
|
VipsRegion *ir = (VipsRegion *) vseq;
|
|
VipsFlatten *flatten = (VipsFlatten *) b;
|
|
VipsRect *r = &or->valid;
|
|
int width = r->width;
|
|
int bands = ir->im->Bands;
|
|
|
|
int x, y;
|
|
|
|
if( vips_region_prepare( ir, r ) )
|
|
return( -1 );
|
|
|
|
for( y = 0; y < r->height; y++ ) {
|
|
VipsPel *in = VIPS_REGION_ADDR( ir, r->left, r->top + y );
|
|
VipsPel *out = VIPS_REGION_ADDR( or, r->left, r->top + y );
|
|
|
|
switch( flatten->in->BandFmt ) {
|
|
case VIPS_FORMAT_UCHAR:
|
|
VIPS_FLATTEN_INT( unsigned char, 8 );
|
|
break;
|
|
|
|
case VIPS_FORMAT_CHAR:
|
|
/* Alpha is 0 - 127? No idea, really.
|
|
*/
|
|
VIPS_FLATTEN_INT( signed char, 7 );
|
|
break;
|
|
|
|
case VIPS_FORMAT_USHORT:
|
|
VIPS_FLATTEN_INT( unsigned short, 16 );
|
|
break;
|
|
|
|
case VIPS_FORMAT_SHORT:
|
|
VIPS_FLATTEN_INT( signed short, 15 );
|
|
break;
|
|
|
|
case VIPS_FORMAT_UINT:
|
|
VIPS_FLATTEN_FLOAT( unsigned int, UINT_MAX );
|
|
break;
|
|
|
|
case VIPS_FORMAT_INT:
|
|
VIPS_FLATTEN_FLOAT( signed int, INT_MAX );
|
|
break;
|
|
|
|
case VIPS_FORMAT_FLOAT:
|
|
VIPS_FLATTEN_FLOAT( float, 1.0 );
|
|
break;
|
|
|
|
case VIPS_FORMAT_DOUBLE:
|
|
VIPS_FLATTEN_FLOAT( double, 1.0 );
|
|
break;
|
|
|
|
case VIPS_FORMAT_COMPLEX:
|
|
case VIPS_FORMAT_DPCOMPLEX:
|
|
default:
|
|
g_assert( 0 );
|
|
}
|
|
}
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
|
|
static int
|
|
vips_flatten_build( VipsObject *object )
|
|
{
|
|
VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
|
|
VipsConversion *conversion = VIPS_CONVERSION( object );
|
|
VipsFlatten *flatten = (VipsFlatten *) object;
|
|
VipsImage **t = (VipsImage **) vips_object_local_array( object, 1 );
|
|
|
|
VipsImage *in;
|
|
int i;
|
|
gboolean black;
|
|
|
|
if( VIPS_OBJECT_CLASS( vips_flatten_parent_class )->build( object ) )
|
|
return( -1 );
|
|
|
|
in = flatten->in;
|
|
|
|
if( vips_image_decode( in, &t[0] ) )
|
|
return( -1 );
|
|
in = t[0];
|
|
|
|
/* Trivial case: fall back to copy().
|
|
*/
|
|
if( flatten->in->Bands == 1 )
|
|
return( vips_image_write( in, conversion->out ) );
|
|
|
|
if( vips_check_noncomplex( class->nickname, in ) )
|
|
return( -1 );
|
|
|
|
if( vips_image_pipelinev( conversion->out,
|
|
VIPS_DEMAND_STYLE_THINSTRIP, in, NULL ) )
|
|
return( -1 );
|
|
|
|
conversion->out->Bands -= 1;
|
|
|
|
/* Is the background black? We have a special path for this.
|
|
*/
|
|
black = TRUE;
|
|
for( i = 0; i < flatten->background->n; i++ )
|
|
if( ((double *) flatten->background->data)[i] != 0.0 ) {
|
|
black = FALSE;
|
|
break;
|
|
}
|
|
|
|
if( black ) {
|
|
if( vips_image_generate( conversion->out,
|
|
vips_start_one, vips_flatten_black_gen, vips_stop_one,
|
|
in, flatten ) )
|
|
return( -1 );
|
|
}
|
|
else {
|
|
/* Convert the background to the image's format.
|
|
*/
|
|
if( !(flatten->ink = vips__vector_to_ink(
|
|
class->nickname, conversion->out,
|
|
flatten->background->data, flatten->background->n )) )
|
|
return( -1 );
|
|
|
|
if( vips_image_generate( conversion->out,
|
|
vips_start_one, vips_flatten_gen, vips_stop_one,
|
|
in, flatten ) )
|
|
return( -1 );
|
|
}
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
static void
|
|
vips_flatten_class_init( VipsFlattenClass *class )
|
|
{
|
|
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
|
|
VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
|
|
VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
|
|
|
|
VIPS_DEBUG_MSG( "vips_flatten_class_init\n" );
|
|
|
|
gobject_class->set_property = vips_object_set_property;
|
|
gobject_class->get_property = vips_object_get_property;
|
|
|
|
vobject_class->nickname = "flatten";
|
|
vobject_class->description = _( "flatten alpha out of an image" );
|
|
vobject_class->build = vips_flatten_build;
|
|
|
|
operation_class->flags = VIPS_OPERATION_SEQUENTIAL_UNBUFFERED;
|
|
|
|
VIPS_ARG_IMAGE( class, "in", 1,
|
|
_( "Input" ),
|
|
_( "Input image" ),
|
|
VIPS_ARGUMENT_REQUIRED_INPUT,
|
|
G_STRUCT_OFFSET( VipsFlatten, in ) );
|
|
|
|
VIPS_ARG_BOXED( class, "background", 2,
|
|
_( "Background" ),
|
|
_( "Background value" ),
|
|
VIPS_ARGUMENT_OPTIONAL_INPUT,
|
|
G_STRUCT_OFFSET( VipsFlatten, background ),
|
|
VIPS_TYPE_ARRAY_DOUBLE );
|
|
}
|
|
|
|
static void
|
|
vips_flatten_init( VipsFlatten *flatten )
|
|
{
|
|
flatten->background =
|
|
vips_area_new_array( G_TYPE_DOUBLE, sizeof( double ), 1 );
|
|
((double *) (flatten->background->data))[0] = 0.0;
|
|
}
|
|
|
|
/**
|
|
* vips_flatten:
|
|
* @in: input image
|
|
* @out: output image
|
|
* @...: %NULL-terminated list of optional named arguments
|
|
*
|
|
* Optional arguments:
|
|
*
|
|
* @background: colour for new pixels
|
|
*
|
|
* Take the last band of @in as an alpha and use it to blend the
|
|
* remaining channels with @background.
|
|
*
|
|
* The alpha channel is 0 - 255 for
|
|
* integer images and 0 - 1 for float images, where 255 means 100% image and 0
|
|
* means 100% background. Non-complex images only.
|
|
* @background defaults to zero (black).
|
|
*
|
|
* Useful for flattening PNG images to RGB.
|
|
*
|
|
* See also: pngload().
|
|
*
|
|
* Returns: 0 on success, -1 on error
|
|
*/
|
|
int
|
|
vips_flatten( VipsImage *in, VipsImage **out, ... )
|
|
{
|
|
va_list ap;
|
|
int result;
|
|
|
|
va_start( ap, out );
|
|
result = vips_call_split( "flatten", ap, in, out );
|
|
va_end( ap );
|
|
|
|
return( result );
|
|
}
|