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libvips/libvips/colour/colour.c

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/* base class for all colour operations
*/
/*
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 DEBUG
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <glib/gi18n-lib.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.
*
* All operations process colour from the first few bands and pass other bands
* through unaltered. This means you can operate on images with alpha channels
* safely. If you move to or from 16-bit RGB, any alpha channels are rescaled
* for you.
*
* 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: #VIPS_INTERPRETATION_sRGB, #VIPS_INTERPRETATION_scRGB,
* #VIPS_INTERPRETATION_B_W,
* #VIPS_INTERPRETATION_XYZ, #VIPS_INTERPRETATION_YXY,
* #VIPS_INTERPRETATION_LAB,
* #VIPS_INTERPRETATION_LCH, and
* #VIPS_INTERPRETATION_CMC.
*
* There are also a set of minor colourspaces which are one of the above in a
* slightly different format:
* #VIPS_INTERPRETATION_LAB, #VIPS_INTERPRETATION_LABQ,
* #VIPS_INTERPRETATION_LABS, #VIPS_INTERPRETATION_LCH,
* #VIPS_INTERPRETATION_RGB16, and #VIPS_INTERPRETATION_GREY16.
*
* 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:
*
* <para>
* <inlinegraphic fileref="interconvert.png" format="PNG" />
* </para>
*
* The colour spaces supported by VIPS are:
*
* * #VIPS_INTERPRETATION_LAB -- CIELAB '76 colourspace with a D65 white. This
* uses three floats for each band, and bands have the obvious range.
*
* There are two
* variants, #VIPS_INTERPRETATION_LABQ and #VIPS_INTERPRETATION_LABS, which
* use ints to store values. These are less precise, but can be quicker to
* store and process.
*
* #VIPS_INTERPRETATION_LCH is the same, but with a*b* as polar coordinates.
* Hue is expressed in degrees.
*
* * #VIPS_INTERPRETATION_XYZ -- CIE XYZ. This uses three floats.
* See #VIPS_D75_X0 and friends for values for the ranges
* under various illuminants.
*
* #VIPS_INTERPRETATION_YXY is the same, but with little x and y.
*
* * #VIPS_INTERPRETATION_scRGB -- a linear colourspace with the sRGB
* primaries. This is useful if you need linear light and don't care
* much what the primaries are.
*
* Linearization is performed with the usual sRGB equations, see below.
*
* * #VIPS_INTERPRETATION_sRGB -- the standard sRGB colourspace, see:
* [wikipedia sRGB](http://en.wikipedia.org/wiki/SRGB).
*
* This uses three 8-bit values for each of RGB.
*
* #VIPS_INTERPRETATION_RGB16 is the same, but using three 16-bit values for
* RGB.
*
* #VIPS_INTERPRETATION_HSV is sRGB, but in polar coordinates.
* #VIPS_INTERPRETATION_LCH is much better, only use HSV if you have to.
*
* * #VIPS_INTERPRETATION_B_W -- a monochrome image, roughly G from sRGB.
* The grey value is
* calculated in #VIPS_INTERPRETATION_scRGB space with the usual 0.2, 0.7, 0.1
* RGB ratios.
*
* #VIPS_INTERPRETATION_GREY16 is the same, but using 16-bits.
*
* * #VIPS_INTERPRETATION_CMC -- 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.
*
*/
/* 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;
/*
printf( "vips_colour_gen: %s, "
"left = %d, top = %d, width = %d, height = %d\n",
VIPS_OBJECT_CLASS( class )->nickname,
r->left, r->top, r->width, r->height );
*/
if( vips_reorder_prepare_many( or->im, ir, 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" );
VIPS_COUNT_PIXELS( or, VIPS_OBJECT_GET_CLASS( colour )->nickname );
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( in[i]->Bands > colour->input_bands ) {
if( vips_extract_band( in[i], &new_in[i], 0,
"n", colour->input_bands,
NULL ) )
return( -1 );
}
else {
new_in[i] = in[i];
g_object_ref( new_in[i] );
}
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 &&
vips__profile_set( out, colour->profile_filename ) )
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 = _( "color operations" );
vobject_class->build = vips_colour_build;
operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
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( transform->in &&
transform->in->BandFmt != VIPS_FORMAT_FLOAT ) {
if( vips_cast_float( transform->in, &t[0], NULL ) )
return( -1 );
}
else {
t[0] = transform->in;
g_object_ref( t[0] );
}
/* 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 = _( "color 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 &&
in->BandFmt != code->input_format ) {
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 &&
in->Type != code->input_interpretation ) {
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 color 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_coding = VIPS_CODING_NONE;
code->input_interpretation = VIPS_INTERPRETATION_ERROR;
code->input_format = VIPS_FORMAT_NOTSET;
}
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( left &&
left->Type != difference->interpretation ) {
if( vips_colourspace( left, &t[6],
difference->interpretation, NULL ) )
return( -1 );
left = t[6];
}
if( right &&
right->Type != difference->interpretation ) {
if( vips_colourspace( right, &t[7],
difference->interpretation, NULL ) )
return( -1 );
right = t[7];
}
/* We only process float.
*/
if( left &&
left->BandFmt != VIPS_FORMAT_FLOAT ) {
if( vips_cast_float( left, &t[8], NULL ) )
return( -1 );
left = t[8];
}
if( right &&
right->BandFmt != VIPS_FORMAT_FLOAT ) {
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 color 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_sRGB2HSV_get_type( void );
extern GType vips_HSV2sRGB_get_type( void );
extern GType vips_scRGB2XYZ_get_type( void );
extern GType vips_scRGB2BW_get_type( void );
extern GType vips_XYZ2scRGB_get_type( void );
extern GType vips_scRGB2sRGB_get_type( void );
extern GType vips_CMYK2XYZ_get_type( void );
extern GType vips_XYZ2CMYK_get_type( void );
extern GType vips_profile_load_get_type( void );
#ifdef 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_scRGB2BW_get_type();
vips_sRGB2HSV_get_type();
vips_HSV2sRGB_get_type();
vips_XYZ2scRGB_get_type();
vips_scRGB2sRGB_get_type();
vips_CMYK2XYZ_get_type();
vips_XYZ2CMYK_get_type();
vips_profile_load_get_type();
#ifdef 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();
}
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