libvips/libvips/colour/colour.c

783 lines
20 KiB
C

/* base class for all colour operations
*/
/*
Copyright (C) 1991-2005 The National Gallery
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU 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 General Public License for more details.
You should have received a copy of the GNU 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 DEBUG
*/
#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>
#include <vips/internal.h>
#include "pcolour.h"
/**
* SECTION: colour
* @short_description: colour operators
* @stability: Stable
* @see_also: <link linkend="libvips-arithmetic">arithmetic</link>
* @include: vips/vips.h
*
* These operators let you transform coordinates and images between colour
* spaces, calculate colour differences, and move
* to and from device spaces.
*
* Radiance images have four 8-bits bands and store 8 bits of R, G and B and
* another 8 bits of exponent, common to all channels. They are widely used in
* the HDR imaging community.
*
*
* The colour functions can be divided into three main groups. First,
* functions to transform images between the different colour spaces supported
* by VIPS: <emphasis>RGB</emphasis>, <emphasis>sRGB</emphasis>,
* <emphasis>XYZ</emphasis>, <emphasis>Yxy</emphasis>,
* <emphasis>Lab</emphasis>, <emphasis>LabQ</emphasis>,
* <emphasis>LabS</emphasis>, <emphasis>LCh</emphasis> and
* <emphasis>CMC</emphasis>). Use vips_colourspace() to move an image to a
* target colourspace using the best sequence of colour transform operations.
* Secondly, there are a set of operations for
* calculating colour difference metrics. Finally, VIPS wraps LittleCMS and
* uses it to provide a set of operations for reading and writing images with
* ICC profiles.
*
* This figure shows how the VIPS colour spaces interconvert:
*
* <inlinegraphic fileref="interconvert.png" format="PNG" />
*
* The colour spaces supported by VIPS are:
*
* <itemizedlist>
* <listitem>
* <para>
* <emphasis><code>LabQ</code></emphasis>
*
* This is the principal VIPS colorimetric storage format.
* LabQ images have four 8-bit bands and store 10 bits of L and 11 bits
* of a and b.
*
* You cannot perform calculations on <code>LabQ</code> images (they are
* tagged with %VIPS_CODING_LABQ), though a few operations such as
* vips_extract_area() will work directly with them.
* </para>
* </listitem>
* <listitem>
* <para>
* <emphasis><code>LabS</code></emphasis>
*
* This format represents coordinates in CIELAB space as a
* three-band #VIPS_FORMAT_SHORT image, scaled to fit the full range of
* bits. It is the best format for computation, being relatively
* compact, quick, and accurate. Colour values expressed in this way
* are hard to visualise.
* </para>
* </listitem>
* <listitem>
* <para>
* <emphasis><code>Lab</code></emphasis>
*
* Lab colourspace represents CIELAB colour values with a three-band
* #VIPS_FORMAT_FLOAT image. This is the simplest format for general
* work: adding the constant 50 to the L channel, for example, has the
* expected result.
*
* VIPS uses D65 LAB, but you can use other colour temperatures with a
* little effort, see vips_XYZ2Lab().
* </para>
* </listitem>
* <listitem>
* <para>
* <emphasis><code>XYZ</code></emphasis>
*
* CIE XYZ colour space represented as a three-band #VIPS_FORMAT_FLOAT
* image.
* </para>
* </listitem>
* <listitem>
* <para>
* <emphasis><code>Yxy</code></emphasis>
*
* CIE Yxy colour space represented as a three-band #VIPS_FORMAT_FLOAT
* image.
* </para>
* </listitem>
* <listitem>
* <para>
* <emphasis><code>RGB</code> / <code>sRGB</code></emphasis>
*
* VIPS converts XYZ to and from sRGB using the usual formula:
*
* http://en.wikipedia.org/wiki/SRGB
*
* You can also use vips_icc_transform() and friends to go to and from
* device space with a generic profile.
* </para>
* </listitem>
* <listitem>
* <para>
* <emphasis><code>LCh</code></emphasis>
*
* Like <code>Lab</code>, but rectangular <code>ab</code> coordinates
* are replaced with
* polar <code>Ch</code> (Chroma and hue) coordinates.
* Hue angles are expressed in degrees.
* </para>
* </listitem>
* <listitem>
* <para>
* <emphasis><code>CMC</code></emphasis>
*
* A colour space based on the CMC(1:1) colour difference measurement.
* This is a highly uniform colour space, much better than CIELAB for
* expressing small differences.
*
* The CMC colourspace is described in "Uniform Colour Space Based on the
* CMC(l:c) Colour-difference Formula", M R Luo and B Rigg, Journal of the
* Society of Dyers and Colourists, vol 102, 1986. Distances in this
* colourspace approximate, within 10% or so, differences in the CMC(l:c)
* colour difference formula.
*
* You can calculate metrics like CMC(2:1) by scaling the spaces before
* finding differences.
* </para>
* </listitem>
* </itemizedlist>
*/
/* Areas under curves for Dxx. 2 degree observer.
*/
/**
* VIPS_D93_X0:
*
* Areas under curves for D93, 2 degree observer.
*/
/**
* VIPS_D75_X0:
*
* Areas under curves for D75, 2 degree observer.
*/
/**
* VIPS_D65_X0:
*
* Areas under curves for D65, 2 degree observer.
*/
/**
* VIPS_D55_X0:
*
* Areas under curves for D55, 2 degree observer.
*/
/**
* VIPS_D50_X0:
*
* Areas under curves for D50, 2 degree observer.
*/
/**
* VIPS_A_X0:
*
* Areas under curves for illuminant A (2856K), 2 degree observer.
*/
/**
* VIPS_B_X0:
*
* Areas under curves for illuminant B (4874K), 2 degree observer.
*/
/**
* VIPS_C_X0:
*
* Areas under curves for illuminant C (6774K), 2 degree observer.
*/
/**
* VIPS_E_X0:
*
* Areas under curves for equal energy illuminant E.
*/
/**
* VIPS_D3250_X0:
*
* Areas under curves for black body at 3250K, 2 degree observer.
*/
G_DEFINE_ABSTRACT_TYPE( VipsColour, vips_colour, VIPS_TYPE_OPERATION );
/* Maximum number of input images -- why not?
*/
#define MAX_INPUT_IMAGES (64)
static int
vips_colour_gen( VipsRegion *or,
void *seq, void *a, void *b, gboolean *stop )
{
VipsRegion **ir = (VipsRegion **) seq;
VipsColour *colour = VIPS_COLOUR( b );
VipsColourClass *class = VIPS_COLOUR_GET_CLASS( colour );
VipsRect *r = &or->valid;
int i, y;
VipsPel *p[MAX_INPUT_IMAGES], *q;
for( i = 0; ir[i]; i++ )
if( vips_region_prepare( ir[i], r ) )
return( -1 );
VIPS_GATE_START( "vips_colour_gen: work" );
for( y = 0; y < r->height; y++ ) {
for( i = 0; ir[i]; i++ )
p[i] = VIPS_REGION_ADDR( ir[i], r->left, r->top + y );
p[i] = NULL;
q = VIPS_REGION_ADDR( or, r->left, r->top + y );
class->process_line( colour, q, p, r->width );
}
VIPS_GATE_STOP( "vips_colour_gen: work" );
return( 0 );
}
static int
vips_colour_attach_profile( VipsImage *im, const char *filename )
{
char *data;
size_t data_length;
if( !(data = vips__file_read_name( filename, VIPS_ICC_DIR,
&data_length )) )
return( -1 );
vips_image_set_blob( im, VIPS_META_ICC_NAME,
(VipsCallbackFn) g_free, data, data_length );
return( 0 );
}
static int
vips_colour_build( VipsObject *object )
{
VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
VipsColour *colour = VIPS_COLOUR( object );
VipsImage **in;
VipsImage **extra_bands;
VipsImage *out;
int i;
#ifdef DEBUG
printf( "vips_colour_build: " );
vips_object_print_name( object );
printf( "\n" );
#endif /*DEBUG*/
if( VIPS_OBJECT_CLASS( vips_colour_parent_class )->
build( object ) )
return( -1 );
if( colour->n > MAX_INPUT_IMAGES ) {
vips_error( class->nickname,
"%s", _( "too many input images" ) );
return( -1 );
}
for( i = 0; i < colour->n; i++ )
if( vips_image_pio_input( colour->in[i] ) )
return( -1 );
/* colour->in[] must be NULL-terminated, we can use it as an arg to
* vips_start_many().
*/
g_assert( !colour->in[colour->n] );
in = colour->in;
extra_bands = (VipsImage **)
vips_object_local_array( object, colour->n );
/* If there are more than @input_bands bands, we detach and reattach
* after processing.
*/
if( colour->input_bands > 0 ) {
VipsImage **new_in = (VipsImage **)
vips_object_local_array( object, colour->n );
for( i = 0; i < colour->n; i++ ) {
if( vips_check_bands_atleast( class->nickname,
in[i], colour->input_bands ) )
return( -1 );
if( vips_extract_band( in[i], &new_in[i], 0,
"n", colour->input_bands,
NULL ) )
return( -1 );
if( in[i]->Bands > colour->input_bands )
if( vips_extract_band( in[i], &extra_bands[i],
colour->input_bands,
"n", in[i]->Bands -
colour->input_bands,
NULL ) )
return( -1 );
}
in = new_in;
}
out = vips_image_new();
if( vips_image_pipeline_array( out,
VIPS_DEMAND_STYLE_THINSTRIP, in ) ) {
g_object_unref( out );
return( -1 );
}
out->Coding = colour->coding;
out->Type = colour->interpretation;
out->BandFmt = colour->format;
out->Bands = colour->bands;
if( colour->profile_filename )
if( vips_colour_attach_profile( out,
colour->profile_filename ) ) {
g_object_unref( out );
return( -1 );
}
if( vips_image_generate( out,
vips_start_many, vips_colour_gen, vips_stop_many,
in, colour ) ) {
g_object_unref( out );
return( -1 );
}
/* Reattach higher bands, if necessary. If we have more than one input
* image, just use the first extra bands.
*/
for( i = 0; i < colour->n; i++ )
if( extra_bands[i] ) {
VipsImage *t1, *t2;
/* We can't just reattach the extra bands: they might
* be float (for example) and we might be trying to
* make a short image. Cast extra to match the body of
* the image.
*/
if( vips_cast( extra_bands[i], &t1, out->BandFmt,
NULL ) ) {
g_object_unref( out );
return( -1 );
}
if( vips_bandjoin2( out, t1, &t2,
NULL ) ) {
g_object_unref( t1 );
g_object_unref( out );
return( -1 );
}
g_object_unref( out );
g_object_unref( t1 );
out = t2;
break;
}
g_object_set( colour, "out", out, NULL );
return( 0 );
}
static void
vips_colour_class_init( VipsColourClass *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 = "colour";
vobject_class->description = _( "colour operations" );
vobject_class->build = vips_colour_build;
operation_class->flags = VIPS_OPERATION_SEQUENTIAL_UNBUFFERED;
VIPS_ARG_IMAGE( class, "out", 100,
_( "Output" ),
_( "Output image" ),
VIPS_ARGUMENT_REQUIRED_OUTPUT,
G_STRUCT_OFFSET( VipsColour, out ) );
}
static void
vips_colour_init( VipsColour *colour )
{
colour->coding = VIPS_CODING_NONE;
colour->interpretation = VIPS_INTERPRETATION_sRGB;
colour->format = VIPS_FORMAT_UCHAR;
colour->bands = 3;
colour->input_bands = -1;
}
G_DEFINE_ABSTRACT_TYPE( VipsColourTransform, vips_colour_transform,
VIPS_TYPE_COLOUR );
static int
vips_colour_transform_build( VipsObject *object )
{
VipsColour *colour = VIPS_COLOUR( object );
VipsColourTransform *transform = VIPS_COLOUR_TRANSFORM( object );
VipsImage **t = (VipsImage **) vips_object_local_array( object, 1 );
/* We only process float.
*/
if( vips_cast_float( transform->in, &t[0], NULL ) )
return( -1 );
/* We always do 3 bands -> 3 bands.
*/
colour->input_bands = 3;
colour->n = 1;
colour->in = t;
if( VIPS_OBJECT_CLASS( vips_colour_transform_parent_class )->
build( object ) )
return( -1 );
return( 0 );
}
static void
vips_colour_transform_class_init( VipsColourTransformClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
vobject_class->nickname = "space";
vobject_class->description = _( "colour space transformations" );
vobject_class->build = vips_colour_transform_build;
VIPS_ARG_IMAGE( class, "in", 1,
_( "Input" ),
_( "Input image" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsColourTransform, in ) );
}
static void
vips_colour_transform_init( VipsColourTransform *space )
{
VipsColour *colour = (VipsColour *) space;
/* What we write. interpretation should be overwritten in subclass
* builds.
*/
colour->coding = VIPS_CODING_NONE;
colour->interpretation = VIPS_INTERPRETATION_LAB;
colour->format = VIPS_FORMAT_FLOAT;
colour->bands = 3;
}
G_DEFINE_ABSTRACT_TYPE( VipsColourCode, vips_colour_code, VIPS_TYPE_COLOUR );
static int
vips_colour_code_build( VipsObject *object )
{
VipsColour *colour = VIPS_COLOUR( object );
VipsColourCode *code = VIPS_COLOUR_CODE( object );
VipsColourCodeClass *class = VIPS_COLOUR_CODE_GET_CLASS( object );
VipsImage **t = (VipsImage **) vips_object_local_array( object, 6 );
VipsImage *in;
in = code->in;
/* If this is a LABQ and the coder wants uncoded, unpack.
*/
if( in &&
in->Coding == VIPS_CODING_LABQ &&
code->input_coding == VIPS_CODING_NONE ) {
if( vips_LabQ2Lab( in, &t[0], NULL ) )
return( -1 );
in = t[0];
}
if( in &&
vips_check_coding( VIPS_OBJECT_CLASS( class )->nickname,
in, code->input_coding ) )
return( -1 );
if( in &&
code->input_coding == VIPS_CODING_NONE &&
code->input_format != VIPS_FORMAT_NOTSET ) {
if( vips_cast( in, &t[3], code->input_format, NULL ) )
return( -1 );
in = t[3];
}
if( in &&
code->input_coding == VIPS_CODING_NONE &&
code->input_interpretation != VIPS_INTERPRETATION_ERROR ) {
if( vips_colourspace( in, &t[4],
code->input_interpretation, NULL ) )
return( -1 );
in = t[4];
}
colour->n = 1;
colour->in = VIPS_ARRAY( object, 2, VipsImage * );
colour->in[0] = in;
colour->in[1] = NULL;
if( VIPS_OBJECT_CLASS( vips_colour_code_parent_class )->
build( object ) )
return( -1 );
return( 0 );
}
static void
vips_colour_code_class_init( VipsColourCodeClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
vobject_class->nickname = "code";
vobject_class->description = _( "change colour coding" );
vobject_class->build = vips_colour_code_build;
VIPS_ARG_IMAGE( class, "in", 1,
_( "Input" ),
_( "Input image" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsColourCode, in ) );
}
static void
vips_colour_code_init( VipsColourCode *code )
{
code->input_interpretation = VIPS_INTERPRETATION_ERROR;
}
G_DEFINE_ABSTRACT_TYPE( VipsColourDifference, vips_colour_difference,
VIPS_TYPE_COLOUR );
static int
vips_colour_difference_build( VipsObject *object )
{
VipsColour *colour = VIPS_COLOUR( object );
VipsColourDifference *difference = VIPS_COLOUR_DIFFERENCE( object );
VipsImage **t;
VipsImage *left;
VipsImage *right;
t = (VipsImage **) vips_object_local_array( object, 12 );
left = difference->left;
right = difference->right;
if( left ) {
if( vips_image_decode( left, &t[0] ) )
return( -1 );
left = t[0];
}
if( right ) {
if( vips_image_decode( right, &t[1] ) )
return( -1 );
right = t[1];
}
/* Detach and reattach any extra bands.
*/
colour->input_bands = 3;
if( vips_colourspace( left, &t[6], difference->interpretation, NULL ) )
return( -1 );
left = t[6];
if( vips_colourspace( right, &t[7], difference->interpretation, NULL ) )
return( -1 );
right = t[7];
/* We only process float.
*/
if( vips_cast_float( left, &t[8], NULL ) )
return( -1 );
left = t[8];
if( vips_cast_float( right, &t[9], NULL ) )
return( -1 );
right = t[9];
if( vips__sizealike( left, right, &t[10], &t[11] ) )
return( -1 );
left = t[10];
right = t[11];
colour->n = 2;
colour->in = VIPS_ARRAY( object, 3, VipsImage * );
colour->in[0] = left;
colour->in[1] = right;
colour->in[2] = NULL;
if( VIPS_OBJECT_CLASS( vips_colour_difference_parent_class )->
build( object ) )
return( -1 );
return( 0 );
}
static void
vips_colour_difference_class_init( VipsColourDifferenceClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
vobject_class->nickname = "difference";
vobject_class->description = _( "calculate colour difference" );
vobject_class->build = vips_colour_difference_build;
VIPS_ARG_IMAGE( class, "left", 1,
_( "Left" ),
_( "Left-hand input image" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsColourDifference, left ) );
VIPS_ARG_IMAGE( class, "right", 2,
_( "Right" ),
_( "Right-hand input image" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsColourDifference, right ) );
}
static void
vips_colour_difference_init( VipsColourDifference *difference )
{
VipsColour *colour = VIPS_COLOUR( difference );
colour->coding = VIPS_CODING_NONE;
colour->interpretation = VIPS_INTERPRETATION_B_W;
colour->format = VIPS_FORMAT_FLOAT;
colour->bands = 1;
}
/* Called from iofuncs to init all operations in this dir. Use a plugin system
* instead?
*/
void
vips_colour_operation_init( void )
{
extern GType vips_colourspace_get_type( void );
extern GType vips_Lab2XYZ_get_type( void );
extern GType vips_XYZ2Lab_get_type( void );
extern GType vips_Lab2LCh_get_type( void );
extern GType vips_LCh2Lab_get_type( void );
extern GType vips_LCh2CMC_get_type( void );
extern GType vips_CMC2LCh_get_type( void );
extern GType vips_Yxy2XYZ_get_type( void );
extern GType vips_XYZ2Yxy_get_type( void );
extern GType vips_LabQ2Lab_get_type( void );
extern GType vips_Lab2LabQ_get_type( void );
extern GType vips_LabQ2LabS_get_type( void );
extern GType vips_LabS2LabQ_get_type( void );
extern GType vips_LabS2Lab_get_type( void );
extern GType vips_Lab2LabS_get_type( void );
extern GType vips_rad2float_get_type( void );
extern GType vips_float2rad_get_type( void );
extern GType vips_LabQ2sRGB_get_type( void );
extern GType vips_XYZ2sRGB_get_type( void );
extern GType vips_sRGB2scRGB_get_type( void );
extern GType vips_scRGB2XYZ_get_type( void );
extern GType vips_XYZ2scRGB_get_type( void );
extern GType vips_scRGB2sRGB_get_type( void );
#if defined(HAVE_LCMS) || defined(HAVE_LCMS2)
extern GType vips_icc_import_get_type( void );
extern GType vips_icc_export_get_type( void );
extern GType vips_icc_transform_get_type( void );
#endif
extern GType vips_dE76_get_type( void );
extern GType vips_dE00_get_type( void );
extern GType vips_dECMC_get_type( void );
vips_colourspace_get_type();
vips_Lab2XYZ_get_type();
vips_XYZ2Lab_get_type();
vips_Lab2LCh_get_type();
vips_LCh2Lab_get_type();
vips_LCh2CMC_get_type();
vips_CMC2LCh_get_type();
vips_XYZ2Yxy_get_type();
vips_Yxy2XYZ_get_type();
vips_LabQ2Lab_get_type();
vips_Lab2LabQ_get_type();
vips_LabQ2LabS_get_type();
vips_LabS2LabQ_get_type();
vips_LabS2Lab_get_type();
vips_Lab2LabS_get_type();
vips_rad2float_get_type();
vips_float2rad_get_type();
vips_LabQ2sRGB_get_type();
vips_sRGB2scRGB_get_type();
vips_scRGB2XYZ_get_type();
vips_XYZ2scRGB_get_type();
vips_scRGB2sRGB_get_type();
#if defined(HAVE_LCMS) || defined(HAVE_LCMS2)
vips_icc_import_get_type();
vips_icc_export_get_type();
vips_icc_transform_get_type();
#endif
vips_dE76_get_type();
vips_dE00_get_type();
vips_dECMC_get_type();
}