/**
* im_lab_morph:
* @in: input image
* @out: output image
* @mask: cast correction table
* @L_offset: L adjustment
* @L_scale: L adjustment
* @a_scale: a scale
* @b_scale: b scale
*
* Morph an image in CIELAB colour space. Useful for certain types of gamut
* mapping, or correction of greyscales on some printers.
*
* We perform three adjustments:
*
* <itemizedlist>
* <listitem>
* <para>
* <emphasis>cast</emphasis>
*
* Pass in @mask containing CIELAB readings for a neutral greyscale. For
* example:
*
* <tgroup cols='3' align='left' colsep='1' rowsep='1'>
* <tbody>
* <row>
* <entry>3</entry>
* <entry>4</entry>
* </row>
* <row>
* <entry>14.23</entry>
* <entry>4.8</entry>
* <entry>-3.95</entry>
* </row>
* <row>
* <entry>18.74</entry>
* <entry>2.76</entry>
* <entry>-2.62</entry>
* </row>
* <row>
* <entry>23.46</entry>
* <entry>1.4</entry>
* <entry>-1.95</entry>
* </row>
* <row>
* <entry>27.53</entry>
* <entry>1.76</entry>
* <entry>-2.01</entry>
* </row>
* </tbody>
* </tgroup>
*
* Interpolation from this makes cast corrector. The top and tail are
* interpolated towards [0, 0, 0] and [100, 0, 0], intermediate values are
* interpolated along straight lines fitted between the specified points.
* Rows may be in any order (ie. they need not be sorted on L*).
*
* Each pixel is displaced in a/b by the amount specified for that L in the
* table.
* </para>
* </listitem>
* <listitem>
* <para>
* <emphasis>L*</emphasis>
*
* Pass in scale and offset for L. L' = (L + offset) * scale.
* </para>
* </listitem>
* <listitem>
* <para>
* <emphasis>saturation</emphasis>
*
* scale a and b by these amounts, eg. 1.5 increases saturation.
* </para>
* </listitem>
* </itemizedlist>
*
* Find the top two by generating and printing a greyscale. Find the bottom
* by printing a Macbeth and looking at a/b spread
*
* Returns: 0 on success, -1 on error.
*/
int
im_lab_morph( IMAGE *in, IMAGE *out,
DOUBLEMASK *mask,
double L_offset, double L_scale,
double a_scale, double b_scale )
{
Params *parm;
/* Recurse for coded images.
*/
if( in->Coding == IM_CODING_LABQ ) {
IMAGE *t[2];
if( im_open_local_array( out, t, 2, "im_lab_morph", "p" ) ||
im_LabQ2Lab( in, t[0] ) ||
im_lab_morph( t[0], t[1],
mask, L_offset, L_scale, a_scale, b_scale ) ||
im_Lab2LabQ( t[1], out ) )
return( -1 );
return( 0 );
}
if( !(parm = IM_NEW( out, Params )) ||
morph_init( parm,
in, out, L_scale, L_offset, mask, a_scale, b_scale ) )
return( -1 );
return( im__colour_unary( "im_lab_morph", in, out, IM_TYPE_LAB,
(im_wrapone_fn) morph_buffer, parm, NULL ) );
}
static int
morph_vec( im_object *argv )
{
im_mask_object *mo = argv[2];
double L_offset = *((double *) argv[3]);
double L_scale = *((double *) argv[4]);
double a_scale = *((double *) argv[5]);
double b_scale = *((double *) argv[6]);
return( im_lab_morph( argv[0], argv[1],
mo->mask, L_offset, L_scale, a_scale, b_scale ) );
}
/* Morph an image.
*/
int
im_lab_morph( IMAGE *in, IMAGE *out,
DOUBLEMASK *mask,
double L_offset, double L_scale,
double a_scale, double b_scale )
{
Params *parm;
/* Recurse for coded images.
*/
if( in->Coding == IM_CODING_LABQ ) {
IMAGE *t1 = im_open_local( out, "im_lab_morph:1", "p" );
IMAGE *t2 = im_open_local( out, "im_lab_morph:2", "p" );
if( !t1 || !t2 ||
im_LabQ2Lab( in, t1 ) ||
im_lab_morph( t1, t2,
mask, L_offset, L_scale, a_scale, b_scale ) ||
im_Lab2LabQ( t2, out ) )
return( -1 );
return( 0 );
}
if( in->Coding != IM_CODING_NONE ) {
im_errormsg( "im_lab_morph: must be uncoded or IM_CODING_LABQ" );
return( -1 );
}
if( in->BandFmt != IM_BANDFMT_FLOAT && in->BandFmt != IM_BANDFMT_DOUBLE ) {
im_errormsg( "im_lab_morph: must be uncoded float or double" );
return( -1 );
}
if( in->Bands != 3 ) {
im_errormsg( "im_lab_morph: must be 3 bands" );
return( -1 );
}
if( !(parm = IM_NEW( out, Params )) ||
morph_init( parm,
in, out, L_scale, L_offset, mask, a_scale, b_scale ) )
return( -1 );
if( im_cp_desc( out, in ) )
return( -1 );
out->Type = IM_TYPE_LAB;
if( im_wrapone( in, out,
(im_wrapone_fn) morph_buffer, parm, NULL ) )
return( -1 );
return( 0 );
}
VALUE
img_lab_morph(VALUE obj, VALUE mask, VALUE l_offset, VALUE l_scale,
VALUE a_scale, VALUE b_scale)
{
DOUBLEMASK *dmask;
GetImg(obj, data, im);
OutImg(obj, new, data_new, im_new);
mask_arg2mask(mask, NULL, &dmask);
if( im_lab_morph(im, im_new, dmask, NUM2DBL(l_offset),
NUM2DBL(l_scale), NUM2DBL(a_scale), NUM2DBL(b_scale)) )
vips_lib_error();
return new;
}