add scRGB functions

ChangeLog

@@ -31,6 +31,7 @@
 - add binary complex operations, with cross_phase as the only one so far
 - added vips_bandbool(), with vips_bandand(), _bandor(), _bandeor() as
   convenience functions
+- added scRGB colourspace, linear light float space with sRGB primaries
 
 14/11/12 started 7.30.6
 - capture tiff warnings earlier

TODO

@@ -1,3 +1,10 @@
+- get rid of RGB, RGB16, just have sRGB and scRGB? maybe get rid of GREY16
+  too?
+
+- get rid of sRGB2XYZ? is using two ops much slower?
+
+- add colourconvert paths for scRGB
+
 - now we've removed round-to-nearest from NN, we need something extra in the
   affine transform to displace the input cods
 

libvips/colour/LabQ2sRGB.c

@@ -98,6 +98,29 @@ static VipsPel vips_red[64 * 64 * 64];
 static VipsPel vips_green[64 * 64 * 64];
 static VipsPel vips_blue[64 * 64 * 64];
 
+/* sRGB to scRGB. 
+ *
+ * @range is eg. 256 for 8-bit data.
+ */
+static int
+vips_col_sRGB2scRGB( int range, float *lut, 
+	int r, int g, int b, float *R, float *G, float *B )
+{
+	int maxval = range - 1;
+	int i;
+
+  	i = VIPS_CLIP( 0, r, maxval );
+	*R = lut[i];
+
+  	i = VIPS_CLIP( 0, g, maxval );
+	*G = lut[i];
+
+  	i = VIPS_CLIP( 0, b, maxval );
+	*B = lut[i];
+
+	return( 0 );
+}
+
 /* Create the sRGB linear and unlinear luts. @range is eg. 256 for 8-bit luts.
  */
 static void 
@@ -156,58 +179,12 @@ vips_col_make_tables_RGB_8( void )
 	}
 }
 
-/* sRGB to scRGB. 
- *
- * @range is eg. 256 for 8-bit data.
- */
-static int
-vips_col_sRGB2scRGB( int range, float *lut, 
-	int r, int g, int b, float *R, float *G, float *B )
-{
-	int maxval = range - 1;
-	int i;
-
-  	i = VIPS_CLIP( 0, r, maxval );
-	*R = lut[i];
-
-  	i = VIPS_CLIP( 0, g, maxval );
-	*G = lut[i];
-
-  	i = VIPS_CLIP( 0, b, maxval );
-	*B = lut[i];
-
-	return( 0 );
-}
-
-/* We need Y in 0 - 100. We can save three muls later if we pre-scale the
- * matrix.
- *
- * The matrix already includes the D65 channel weighting, so we just scale by
- * Y.
- */
-#define SCALE (VIPS_D65_Y0)
-
-/* scRGB to XYZ. 
- */
-static int
-vips_col_scRGB2XYZ( float R, float G, float B, float *X, float *Y, float *Z )
-{
-	*X = SCALE * 0.4124 * R + SCALE * 0.3576 * G + SCALE * 0.18056 * B;
-	*Y = SCALE * 0.2126 * R + SCALE * 0.7152 * G + SCALE * 0.07220 * B;
-	*Z = SCALE * 0.0193 * R + SCALE * 0.1192 * G + SCALE * 0.9505 * B;
-
-	return( 0 );
-}
-
 int
-vips_col_sRGB2XYZ_8( int r, int g, int b, float *X, float *Y, float *Z )
+vips_col_sRGB2scRGB_8( int r, int g, int b, float *R, float *G, float *B )
 {
-	float R, G, B;
-
 	vips_col_make_tables_RGB_8();
 
-	return( vips_col_sRGB2scRGB( 256, vips_v2Y_8, r, g, b, &R, &G, &B ) ||
+	return( vips_col_sRGB2scRGB( 256, vips_v2Y_8, r, g, b, R, G, B ) ); 
-		vips_col_scRGB2XYZ( R, G, B, X, Y, Z ) );
 }
 
 static void *
@@ -235,20 +212,33 @@ vips_col_make_tables_RGB_16( void )
 }
 
 int
-vips_col_sRGB2XYZ_16( int r, int g, int b, float *X, float *Y, float *Z )
+vips_col_sRGB2scRGB_16( int r, int g, int b, float *R, float *G, float *B )
 {
-	float R, G, B;
-
 	vips_col_make_tables_RGB_16();
 
-	return( vips_col_sRGB2scRGB( 65536, vips_v2Y_16, 
+	return( vips_col_sRGB2scRGB( 65536, vips_v2Y_16, r, g, b, R, G, B ) ); 
-			r, g, b, &R, &G, &B ) ||
+}
-		vips_col_scRGB2XYZ( R, G, B, X, Y, Z ) );
+
+/* The matrix already includes the D65 channel weighting, so we just scale by
+ * Y.
+ */
+#define SCALE (VIPS_D65_Y0)
+
+/* scRGB to XYZ. 
+ */
+int
+vips_col_scRGB2XYZ( float R, float G, float B, float *X, float *Y, float *Z )
+{
+	*X = SCALE * 0.4124 * R + SCALE * 0.3576 * G + SCALE * 0.18056 * B;
+	*Y = SCALE * 0.2126 * R + SCALE * 0.7152 * G + SCALE * 0.07220 * B;
+	*Z = SCALE * 0.0193 * R + SCALE * 0.1192 * G + SCALE * 0.9505 * B;
+
+	return( 0 );
 }
 
 /* Turn XYZ into scRGB. 
  */
-static int
+int
 vips_col_XYZ2scRGB( float X, float Y, float Z, float *R, float *G, float *B ) 
 {
 	*R =  3.2406 / SCALE * X + -1.5372 / SCALE * Y + -0.4986 / SCALE * Z;
@@ -335,31 +325,24 @@ vips_col_scRGB2sRGB( int range, int *lut,
 } 
 
 int
-vips_col_XYZ2sRGB_8( float X, float Y, float Z, 
+vips_col_scRGB2sRGB_8( float R, float G, float B, 
 	int *r, int *g, int *b, 
 	int *or )
 {
-	float R, G, B;
-
 	vips_col_make_tables_RGB_8();
 
-	return( vips_col_XYZ2scRGB( X, Y, Z, &R, &G, &B ) ||
+	return( vips_col_scRGB2sRGB( 256, vips_Y2v_8, R, G, B, r, g, b, or ) ); 
-		vips_col_scRGB2sRGB( 256, vips_Y2v_8, 
-			R, G, B, r, g, b, or ) ); 
 }
 
 int
-vips_col_XYZ2sRGB_16( float X, float Y, float Z, 
+vips_col_scRGB2sRGB_16( float R, float G, float B, 
 	int *r, int *g, int *b, 
 	int *or )
 {
-	float R, G, B;
-
 	vips_col_make_tables_RGB_16();
 
-	return( vips_col_XYZ2scRGB( X, Y, Z, &R, &G, &B ) ||
+	return( vips_col_scRGB2sRGB( 65536, vips_Y2v_16, 
-		vips_col_scRGB2sRGB( 65536, vips_Y2v_16, 
+		R, G, B, r, g, b, or ) ); 
-			R, G, B, r, g, b, or ) ); 
 }
 
 /* Build Lab->disp dither tables. 
@@ -379,11 +362,13 @@ build_tables( void *client )
                                 float A = (signed char) (a << 2);
                                 float B = (signed char) (b << 2);
                                 float X, Y, Z;
+                                float Rf, Gf, Bf;
                                 int rb, gb, bb;
                                 int oflow;
  
                                 vips_col_Lab2XYZ( L, A, B, &X, &Y, &Z );
-                                vips_col_XYZ2sRGB_8( X, Y, Z, 
+                                vips_col_XYZ2scRGB( X, Y, Z, &Rf, &Gf, &Bf );
+                                vips_col_scRGB2sRGB_8( Rf, Gf, Bf,
 					&rb, &gb, &bb, &oflow );
 
 				t = INDEX( l, a, b );

libvips/colour/Makefile.am

@@ -26,6 +26,10 @@ libcolour_la_SOURCES = \
 	LabQ2LabS.c \
 	LabQ2sRGB.c \
 	XYZ2sRGB.c \
-	sRGB2XYZ.c 
+	sRGB2XYZ.c \
+	sRGB2scRGB.c \
+	scRGB2XYZ.c \
+	XYZ2scRGB.c \
+	scRGB2sRGB.c 
 
 INCLUDES = -I${top_srcdir}/libvips/include @VIPS_CFLAGS@ @VIPS_INCLUDES@ 

libvips/colour/XYZ2sRGB.c

@@ -85,10 +85,12 @@ vips_XYZ2sRGB_line_8( VipsPel *q, float *p, int width )
 		float Y = p[1];
 		float Z = p[2];
 
+		float R, G, B;
 		int r, g, b;
 		int or;
 
-		vips_col_XYZ2sRGB_8( X, Y, Z, &r, &g, &b, &or );
+		vips_col_XYZ2scRGB( X, Y, Z, &R, &G, &B );
+		vips_col_scRGB2sRGB_8( R, G, B, &r, &g, &b, &or );
 
 		p += 3;
 
@@ -110,10 +112,12 @@ vips_XYZ2sRGB_line_16( unsigned short *q, float *p, int width )
 		float Y = p[1];
 		float Z = p[2];
 
+		float R, G, B;
 		int r, g, b;
 		int or;
 
-		vips_col_XYZ2sRGB_16( X, Y, Z, &r, &g, &b, &or );
+		vips_col_XYZ2scRGB( X, Y, Z, &R, &G, &B );
+		vips_col_scRGB2sRGB_16( R, G, B, &r, &g, &b, &or );
 
 		p += 3;
 

libvips/colour/XYZ2scRGB.c

@@ -0,0 +1,118 @@
+/* Turn XYZ to scRGB colourspace. 
+ *
+ * 11/12/12
+ * 	- from Yxy2XYZ.c
+ */
+
+/*
+
+    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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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 <math.h>
+
+#include <vips/vips.h>
+
+#include "colour.h"
+
+typedef VipsColourSpace VipsXYZ2scRGB;
+typedef VipsColourSpaceClass VipsXYZ2scRGBClass;
+
+G_DEFINE_TYPE( VipsXYZ2scRGB, vips_XYZ2scRGB, VIPS_TYPE_COLOUR_SPACE );
+
+void
+vips_XYZ2scRGB_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
+{
+	float *p = (float *) in[0];
+	float *q = (float *) out;
+
+	int i;
+
+	for( i = 0; i < width; i++ ) {
+		float X = p[0];
+		float Y = p[1];
+		float Z = p[2];
+
+		float R, G, B;
+
+		p += 3;
+
+		vips_col_XYZ2scRGB( X, Y, Z, &R, &G, &B );
+
+		q[0] = R;
+		q[1] = G;
+		q[2] = B;
+
+		q += 3;
+	}
+}
+
+static void
+vips_XYZ2scRGB_class_init( VipsXYZ2scRGBClass *class )
+{
+	VipsObjectClass *object_class = (VipsObjectClass *) class;
+	VipsColourClass *colour_class = VIPS_COLOUR_CLASS( class );
+
+	object_class->nickname = "XYZ2scRGB";
+	object_class->description = _( "transform XYZ to scRGB" );
+
+	colour_class->process_line = vips_XYZ2scRGB_line;
+}
+
+static void
+vips_XYZ2scRGB_init( VipsXYZ2scRGB *XYZ2scRGB )
+{
+	VipsColour *colour = VIPS_COLOUR( XYZ2scRGB );
+
+	colour->interpretation = VIPS_INTERPRETATION_scRGB;
+}
+
+/**
+ * vips_XYZ2scRGB:
+ * @in: input image
+ * @out: output image
+ *
+ * Turn XYZ to Yxy.
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int
+vips_XYZ2scRGB( VipsImage *in, VipsImage **out, ... )
+{
+	va_list ap;
+	int result;
+
+	va_start( ap, out );
+	result = vips_call_split( "XYZ2scRGB", ap, in, out );
+	va_end( ap );
+
+	return( result );
+}
+

libvips/colour/colour.c

@@ -798,6 +798,10 @@ vips_colour_operation_init( void )
 	extern GType vips_LabQ2sRGB_get_type( void ); 
 	extern GType vips_XYZ2sRGB_get_type( void ); 
 	extern GType vips_sRGB2XYZ_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 ); 
@@ -827,6 +831,10 @@ vips_colour_operation_init( void )
 	vips_LabQ2sRGB_get_type();
 	vips_XYZ2sRGB_get_type();
 	vips_sRGB2XYZ_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();

libvips/colour/sRGB2XYZ.c

@@ -10,7 +10,7 @@
  * 	- redone as a class
  * 	- sRGB only, support for other RGBs is now via lcms
  * 6/11/12
- * 	- add 15-bit sRGB import
+ * 	- add 16-bit sRGB import
  */
 
 /*
@@ -67,11 +67,14 @@ vips_sRGB2XYZ_line_8( float *q, VipsPel *p, int width )
 		int r = p[0];
 		int g = p[1];
 		int b = p[2];
+
+		float R, G, B;
 		float X, Y, Z;
 
 		p += 3;
 
-		vips_col_sRGB2XYZ_8( r, g, b, &X, &Y, &Z );
+		vips_col_sRGB2scRGB_8( r, g, b, &R, &G, &B );
+		vips_col_scRGB2XYZ( R, G, B, &X, &Y, &Z );
 
 		q[0] = X;
 		q[1] = Y;
@@ -92,11 +95,14 @@ vips_sRGB2XYZ_line_16( float *q, unsigned short *p, int width )
 		int r = p[0];
 		int g = p[1];
 		int b = p[2];
+
+		float R, G, B;
 		float X, Y, Z;
 
 		p += 3;
 
-		vips_col_sRGB2XYZ_16( r, g, b, &X, &Y, &Z );
+		vips_col_sRGB2scRGB_16( r, g, b, &R, &G, &B );
+		vips_col_scRGB2XYZ( R, G, B, &X, &Y, &Z );
 
 		q[0] = X;
 		q[1] = Y;

libvips/colour/sRGB2scRGB.c

@@ -0,0 +1,186 @@
+/* Turn displayable rgb files to scRGB.
+ *
+ * 11/12/12
+ * 	- from sRGB2XYZ.c
+ */
+
+/*
+
+    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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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 <math.h>
+
+#include <vips/vips.h>
+
+#include "colour.h"
+
+typedef VipsColourCode VipssRGB2scRGB;
+typedef VipsColourCodeClass VipssRGB2scRGBClass;
+
+G_DEFINE_TYPE( VipssRGB2scRGB, vips_sRGB2scRGB, VIPS_TYPE_COLOUR_CODE );
+
+/* Convert a buffer of 8-bit pixels.
+ */
+static void
+vips_sRGB2scRGB_line_8( float *q, VipsPel *p, int width )
+{
+	int i;
+
+	for( i = 0; i < width; i++ ) {
+		int r = p[0];
+		int g = p[1];
+		int b = p[2];
+
+		float R, G, B;
+
+		p += 3;
+
+		vips_col_sRGB2scRGB_8( r, g, b, &R, &G, &B );
+
+		q[0] = R;
+		q[1] = G;
+		q[2] = B;
+
+		q += 3;
+	}
+}
+
+/* Convert a buffer of 16-bit pixels.
+ */
+static void
+vips_sRGB2scRGB_line_16( float *q, unsigned short *p, int width )
+{
+	int i;
+
+	for( i = 0; i < width; i++ ) {
+		int r = p[0];
+		int g = p[1];
+		int b = p[2];
+
+		float R, G, B;
+
+		p += 3;
+
+		vips_col_sRGB2scRGB_16( r, g, b, &R, &G, &B );
+
+		q[0] = R;
+		q[1] = G;
+		q[2] = B;
+
+		q += 3;
+	}
+}
+
+static void
+vips_sRGB2scRGB_line( VipsColour *colour, 
+	VipsPel *out, VipsPel **in, int width )
+{
+	if( colour->in[0]->BandFmt == VIPS_FORMAT_UCHAR )
+		vips_sRGB2scRGB_line_8( (float *) out, 
+			(VipsPel *) in[0], width );
+	else
+		vips_sRGB2scRGB_line_16( (float *) out, 
+			(unsigned short *) in[0], width );
+}
+
+static int
+vips_sRGB2scRGB_build( VipsObject *object )
+{
+	VipsColourCode *code = (VipsColourCode *) object;
+
+	if( code->in ) 
+		code->input_format = 
+			code->in->BandFmt == VIPS_FORMAT_USHORT ? 
+			VIPS_FORMAT_USHORT : VIPS_FORMAT_UCHAR;
+
+	if( VIPS_OBJECT_CLASS( vips_sRGB2scRGB_parent_class )->
+		build( object ) )
+		return( -1 );
+
+	return( 0 );
+}
+
+static void
+vips_sRGB2scRGB_class_init( VipssRGB2scRGBClass *class )
+{
+	VipsObjectClass *object_class = (VipsObjectClass *) class;
+	VipsColourClass *colour_class = VIPS_COLOUR_CLASS( class );
+
+	object_class->nickname = "sRGB2scRGB";
+	object_class->description = _( "convert an sRGB image to scRGB" );
+	object_class->build = vips_sRGB2scRGB_build;
+
+	colour_class->process_line = vips_sRGB2scRGB_line;
+}
+
+static void
+vips_sRGB2scRGB_init( VipssRGB2scRGB *sRGB2scRGB )
+{
+	VipsColour *colour = VIPS_COLOUR( sRGB2scRGB );
+	VipsColourCode *code = VIPS_COLOUR_CODE( sRGB2scRGB );
+
+	colour->coding = VIPS_CODING_NONE;
+	colour->interpretation = VIPS_INTERPRETATION_scRGB;
+	colour->format = VIPS_FORMAT_FLOAT;
+	colour->bands = 3;
+
+	code->input_coding = VIPS_CODING_NONE;
+	code->input_bands = 3;
+
+	/* The default. This can get changed above ^^ if we see a 
+	 * 16-bit input.
+	 */
+	code->input_format = VIPS_FORMAT_UCHAR;
+}
+
+/**
+ * vips_sRGB2scRGB:
+ * @in: input image
+ * @out: output image
+ *
+ * Convert an sRGB image to scRGB.
+ *
+ * See also: vips_sRGB2XYZ(), vips_rad2float().
+ *
+ * Returns: 0 on success, -1 on error.
+ */
+int
+vips_sRGB2scRGB( VipsImage *in, VipsImage **out, ... )
+{
+	va_list ap;
+	int result;
+
+	va_start( ap, out );
+	result = vips_call_split( "sRGB2scRGB", ap, in, out );
+	va_end( ap );
+
+	return( result );
+}

libvips/colour/scRGB2XYZ.c

@@ -0,0 +1,123 @@
+/* Turn scRGB to XYZ colourspace. 
+ *
+ * Modified:
+ * 29/5/02 JC
+ *	- from lab2xyz
+ * 2/11/09
+ * 	- gtkdoc
+ * 	- cleanups
+ * 20/9/12
+ * 	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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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 <math.h>
+
+#include <vips/vips.h>
+
+#include "colour.h"
+
+typedef VipsColourSpace VipsscRGB2XYZ;
+typedef VipsColourSpaceClass VipsscRGB2XYZClass;
+
+G_DEFINE_TYPE( VipsscRGB2XYZ, vips_scRGB2XYZ, VIPS_TYPE_COLOUR_SPACE );
+
+void
+vips_scRGB2XYZ_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
+{
+	float *p = (float *) in[0];
+	float *q = (float *) out;
+
+	int i;
+
+	for( i = 0; i < width; i++ ) {
+		float R = p[0];
+		float G = p[1];
+		float B = p[2];
+
+		float X, Y, Z;
+
+		p += 3;
+
+		vips_col_scRGB2XYZ( R, G, B, &X, &Y, &Z );
+
+		q[0] = X;
+		q[1] = Y;
+		q[2] = Z;
+		q += 3;
+	}
+}
+
+static void
+vips_scRGB2XYZ_class_init( VipsscRGB2XYZClass *class )
+{
+	VipsObjectClass *object_class = (VipsObjectClass *) class;
+	VipsColourClass *colour_class = VIPS_COLOUR_CLASS( class );
+
+	object_class->nickname = "scRGB2XYZ";
+	object_class->description = _( "transform scRGB to XYZ" );
+
+	colour_class->process_line = vips_scRGB2XYZ_line;
+}
+
+static void
+vips_scRGB2XYZ_init( VipsscRGB2XYZ *scRGB2XYZ )
+{
+	VipsColour *colour = VIPS_COLOUR( scRGB2XYZ );
+
+	colour->interpretation = VIPS_INTERPRETATION_XYZ;
+}
+
+/**
+ * vips_scRGB2XYZ:
+ * @in: input image
+ * @out: output image
+ *
+ * Turn XYZ to scRGB.
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int
+vips_scRGB2XYZ( VipsImage *in, VipsImage **out, ... )
+{
+	va_list ap;
+	int result;
+
+	va_start( ap, out );
+	result = vips_call_split( "scRGB2XYZ", ap, in, out );
+	va_end( ap );
+
+	return( result );
+}
+

libvips/colour/scRGB2sRGB.c

@@ -0,0 +1,222 @@
+/* Turn scRGB files into displayable rgb.
+ *
+ * 11/12/12
+ * 	- from XYZ2sRGB.c
+ */
+
+/*
+
+    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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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 <math.h>
+
+#include <vips/vips.h>
+
+#include "colour.h"
+
+typedef struct _VipsscRGB2sRGB {
+	VipsColourCode parent_instance;
+	
+	int depth;
+} VipsscRGB2sRGB;
+
+typedef VipsColourCodeClass VipsscRGB2sRGBClass;
+
+G_DEFINE_TYPE( VipsscRGB2sRGB, vips_scRGB2sRGB, VIPS_TYPE_COLOUR_CODE );
+
+/* Process a buffer of data.
+ */
+static void
+vips_scRGB2sRGB_line_8( VipsPel *q, float *p, int width )
+{
+	int i;
+
+	for( i = 0; i < width; i++ ) {
+		float R = p[0];
+		float G = p[1];
+		float B = p[2];
+
+		int r, g, b;
+		int or;
+
+		vips_col_scRGB2sRGB_8( R, G, B, &r, &g, &b, &or );
+
+		p += 3;
+
+		q[0] = r;
+		q[1] = g;
+		q[2] = b;
+
+		q += 3;
+	}
+}
+
+static void
+vips_scRGB2sRGB_line_16( unsigned short *q, float *p, int width )
+{
+	int i;
+
+	for( i = 0; i < width; i++ ) {
+		float R = p[0];
+		float G = p[1];
+		float B = p[2];
+
+		int r, g, b;
+		int or;
+
+		vips_col_scRGB2sRGB_16( R, G, B, &r, &g, &b, &or );
+
+		p += 3;
+
+		q[0] = r;
+		q[1] = g;
+		q[2] = b;
+
+		q += 3;
+	}
+}
+
+static void
+vips_scRGB2sRGB_line( VipsColour *colour, 
+	VipsPel *out, VipsPel **in, int width )
+{
+	VipsscRGB2sRGB *scRGB2sRGB = (VipsscRGB2sRGB *) colour;
+
+	if( scRGB2sRGB->depth == 16 ) 
+		vips_scRGB2sRGB_line_16( (unsigned short *) out, 
+			(float *) in[0], width );
+	else
+		vips_scRGB2sRGB_line_8( (VipsPel *) out, 
+			(float *) in[0], width );
+}
+
+static int
+vips_scRGB2sRGB_build( VipsObject *object )
+{
+	VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object ); 
+	VipsscRGB2sRGB *scRGB2sRGB = (VipsscRGB2sRGB *) object;
+	VipsColour *colour = VIPS_COLOUR( scRGB2sRGB );
+
+	switch( scRGB2sRGB->depth ) { 
+	case 16:
+		colour->interpretation = VIPS_INTERPRETATION_RGB16;
+		colour->format = VIPS_FORMAT_USHORT;
+		break;
+
+	case 8:
+		colour->interpretation = VIPS_INTERPRETATION_sRGB;
+		colour->format = VIPS_FORMAT_UCHAR;
+		break;
+
+	default:
+		vips_error( class->nickname, 
+			"%s", _( "depth must be 8 or 16" ) );
+		return( -1 );
+	}
+
+	if( VIPS_OBJECT_CLASS( vips_scRGB2sRGB_parent_class )->build( object ) )
+		return( -1 );
+
+	return( 0 );
+}
+
+static void
+vips_scRGB2sRGB_class_init( VipsscRGB2sRGBClass *class )
+{
+	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
+	VipsObjectClass *object_class = (VipsObjectClass *) class;
+	VipsColourClass *colour_class = VIPS_COLOUR_CLASS( class );
+
+	gobject_class->set_property = vips_object_set_property;
+	gobject_class->get_property = vips_object_get_property;
+
+	object_class->nickname = "scRGB2sRGB";
+	object_class->description = _( "convert an scRGB image to sRGB" ); 
+	object_class->build = vips_scRGB2sRGB_build;
+
+	colour_class->process_line = vips_scRGB2sRGB_line;
+
+	VIPS_ARG_INT( class, "depth", 130, 
+		_( "Depth" ),
+		_( "Output device space depth in bits" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT, 
+		G_STRUCT_OFFSET( VipsscRGB2sRGB, depth ),
+		8, 16, 8 );
+}
+
+static void
+vips_scRGB2sRGB_init( VipsscRGB2sRGB *scRGB2sRGB )
+{
+	VipsColour *colour = VIPS_COLOUR( scRGB2sRGB );
+	VipsColourCode *code = VIPS_COLOUR_CODE( scRGB2sRGB );
+
+	/* Just the default, can be overridden, see above.
+	 */
+	colour->coding = VIPS_CODING_NONE;
+	colour->interpretation = VIPS_INTERPRETATION_sRGB;
+	colour->format = VIPS_FORMAT_UCHAR;
+	colour->bands = 3;
+
+	code->input_coding = VIPS_CODING_NONE;
+	code->input_bands = 3;
+	code->input_format = VIPS_FORMAT_FLOAT;
+
+	scRGB2sRGB->depth = 8;
+}
+
+/**
+ * vips_scRGB2sRGB:
+ * @in: input image
+ * @out: output image
+ *
+ * Optional arguments:
+ *
+ * @depth: depth of output image in bits
+ *
+ * Convert an scRGB image to sRGB. Set @depth to 16 to get 16-bit output.
+ *
+ * See also: im_LabS2LabQ(), im_scRGB2sRGB(), im_rad2float().
+ *
+ * Returns: 0 on success, -1 on error.
+ */
+int
+vips_scRGB2sRGB( VipsImage *in, VipsImage **out, ... )
+{
+	va_list ap;
+	int result;
+
+	va_start( ap, out );
+	result = vips_call_split( "scRGB2sRGB", ap, in, out );
+	va_end( ap );
+
+	return( result );
+}
+

libvips/include/vips/colour.h

@@ -141,10 +141,21 @@ int vips_Lab2XYZ( VipsImage *in, VipsImage **out, ... )
 	__attribute__((sentinel));
 int vips_XYZ2Lab( VipsImage *in, VipsImage **out, ... )
 	__attribute__((sentinel));
+
+int vips_XYZ2scRGB( VipsImage *in, VipsImage **out, ... )
+	__attribute__((sentinel));
+int vips_scRGB2sRGB( VipsImage *in, VipsImage **out, ... )
+	__attribute__((sentinel));
 int vips_XYZ2sRGB( VipsImage *in, VipsImage **out, ... )
 	__attribute__((sentinel));
+
 int vips_sRGB2XYZ( VipsImage *in, VipsImage **out, ... )
 	__attribute__((sentinel));
+int vips_sRGB2scRGB( VipsImage *in, VipsImage **out, ... )
+	__attribute__((sentinel));
+int vips_scRGB2XYZ( VipsImage *in, VipsImage **out, ... )
+	__attribute__((sentinel));
+
 int vips_LCh2CMC( VipsImage *in, VipsImage **out, ... )
 	__attribute__((sentinel));
 int vips_CMC2LCh( VipsImage *in, VipsImage **out, ... )
@@ -193,13 +204,20 @@ float vips_col_Lcmc2L( float Lcmc );
 float vips_col_Ccmc2C( float Ccmc );
 float vips_col_Chcmc2h( float C, float hcmc );
 
-int vips_col_XYZ2sRGB_8( float X, float Y, float Z, 
+int vips_col_sRGB2scRGB_8( int r, int g, int b, float *R, float *G, float *B );
-	int *r, int *g, int *b, int *or_ret );
+int vips_col_sRGB2scRGB_16( int r, int g, int b, float *R, float *G, float *B );
-int vips_col_sRGB2XYZ_8( int r, int g, int b, float *X, float *Y, float *Z );
 
-int vips_col_XYZ2sRGB_16( float X, float Y, float Z, 
+int vips_col_scRGB2XYZ( float R, float G, float B, 
-	int *r, int *g, int *b, int *or_ret );
+	float *X, float *Y, float *Z );
-int vips_col_sRGB2XYZ_16( int r, int g, int b, float *X, float *Y, float *Z );
+int vips_col_XYZ2scRGB( float X, float Y, float Z, 
+	float *R, float *G, float *B );
+
+int vips_col_scRGB2sRGB_8( float R, float G, float B, 
+	int *r, int *g, int *b, 
+	int *or_ret );
+int vips_col_scRGB2sRGB_16( float R, float G, float B, 
+	int *r, int *g, int *b, 
+	int *or_ret );
 
 float vips_pythagoras( float L1, float a1, float b1, 
 	float L2, float a2, float b2 );

libvips/include/vips/image.h

@@ -122,6 +122,7 @@ typedef enum {
  * @VIPS_INTERPRETATION_LCH: pixels are in CIE LCh space
  * @VIPS_INTERPRETATION_LABS: CIE LAB coded as three signed 16-bit values
  * @VIPS_INTERPRETATION_sRGB: pixels are sRGB
+ * @VIPS_INTERPRETATION_scRGB: pixels are scRGB
  * @VIPS_INTERPRETATION_YXY: pixels are CIE Yxy
  * @VIPS_INTERPRETATION_RGB16: generic 16-bit RGB
  * @VIPS_INTERPRETATION_GREY16: generic 16-bit mono
@@ -156,7 +157,8 @@ typedef enum {
 	VIPS_INTERPRETATION_FOURIER = 24,
 	VIPS_INTERPRETATION_RGB16 = 25,
 	VIPS_INTERPRETATION_GREY16 = 26,
-	VIPS_INTERPRETATION_ARRAY = 27
+	VIPS_INTERPRETATION_ARRAY = 27,
+	VIPS_INTERPRETATION_scRGB = 28
 } VipsInterpretation;
 
 /**

libvips/iofuncs/enumtypes.c

@@ -493,6 +493,7 @@ vips_interpretation_get_type( void )
 			{VIPS_INTERPRETATION_RGB16, "VIPS_INTERPRETATION_RGB16", "rgb16"},
 			{VIPS_INTERPRETATION_GREY16, "VIPS_INTERPRETATION_GREY16", "grey16"},
 			{VIPS_INTERPRETATION_ARRAY, "VIPS_INTERPRETATION_ARRAY", "array"},
+			{VIPS_INTERPRETATION_scRGB, "VIPS_INTERPRETATION_scRGB", "scrgb"},
 			{0, NULL, NULL}
 		};
 		

libvips/iofuncs/image.c

@@ -457,7 +457,7 @@ vips_image_sanity( VipsObject *object, VipsBuf *buf )
 				image->Coding != VIPS_CODING_NONE && 
 				image->Coding != VIPS_CODING_LABQ &&
 				image->Coding != VIPS_CODING_RAD) ||
-			image->Type > VIPS_INTERPRETATION_ARRAY ||
+			image->Type > VIPS_INTERPRETATION_scRGB ||
 			image->dtype > VIPS_IMAGE_PARTIAL || 
 			image->dhint > VIPS_DEMAND_STYLE_ANY ) 
 			vips_buf_appends( buf, "bad enum\n" );