libvips/include/vips/yafrnohalo.h

101 lines
3.6 KiB
C

/* YAFRNOHALO interpolator.
*/
/*
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
*/
#ifndef VIPS_YAFRNOHALO_H
#define VIPS_YAFRNOHALO_H
#ifdef __cplusplus
extern "C" {
#endif /*__cplusplus*/
#define VIPS_TYPE_INTERPOLATE_YAFRNOHALO (vips_interpolate_yafrnohalo_get_type())
#define VIPS_INTERPOLATE_YAFRNOHALO( obj ) \
(G_TYPE_CHECK_INSTANCE_CAST( (obj), \
VIPS_TYPE_INTERPOLATE_YAFRNOHALO, VipsInterpolateYafrnohalo ))
#define VIPS_INTERPOLATE_YAFRNOHALO_CLASS( klass ) \
(G_TYPE_CHECK_CLASS_CAST( (klass), \
VIPS_TYPE_INTERPOLATE_YAFRNOHALO, VipsInterpolateYafrnohaloClass))
#define VIPS_IS_INTERPOLATE_YAFRNOHALO( obj ) \
(G_TYPE_CHECK_INSTANCE_TYPE( (obj), VIPS_TYPE_INTERPOLATE_YAFRNOHALO ))
#define VIPS_IS_INTERPOLATE_YAFRNOHALO_CLASS( klass ) \
(G_TYPE_CHECK_CLASS_TYPE( (klass), VIPS_TYPE_INTERPOLATE_YAFRNOHALO ))
#define VIPS_INTERPOLATE_YAFRNOHALO_GET_CLASS( obj ) \
(G_TYPE_INSTANCE_GET_CLASS( (obj), \
VIPS_TYPE_INTERPOLATE_YAFRNOHALO, VipsInterpolateYafrnohaloClass ))
typedef struct _VipsInterpolateYafrnohalo {
VipsInterpolate parent_object;
/* "sharpening" is a continuous method parameter which is
* proportional to the amount of "diagonal straightening" which the
* nonlinear correction part of the method may add to the underlying
* linear scheme. You may also think of it as a sharpening
* parameter: higher values correspond to more sharpening, and
* negative values lead to strange looking effects.
*
* The default value is sharpening = 4/3 when the scheme being
* "straightened" is bilinear---as is the case here. This value
* fixes key pixel values near the diagonal boundary between two
* monochrome regions (the diagonal boundary pixel values being set
* to the halfway colour).
*
* If resampling seems to add unwanted texture artifacts, push
* sharpening toward 0. It is not generally not recommended to set
* sharpening to a value larger than 2.
*
* In order to simplify interfacing with users, the parameter which
* should be set by the user is normalized so that user_sharpening =
* 1 when sharpening is equal to the recommended value. Consistently
* with the above discussion, values of user_sharpening between 0
* and about 1.5 give good results.
*/
double sharpening;
} VipsInterpolateYafrnohalo;
typedef struct _VipsInterpolateYafrnohaloClass {
VipsInterpolateClass parent_class;
} VipsInterpolateYafrnohaloClass;
GType vips_interpolate_yafrnohalo_get_type( void );
VipsInterpolate *vips_interpolate_yafrnohalo_new( void );
void vips_interpolate_yafrnohalo_set_sharpening( VipsInterpolateYafrnohalo *,
double sharpening );
/* Convenience: return a static default yafrnohalo, so no need to free it.
*/
VipsInterpolate *vips_interpolate_yafrnohalo_static( void );
#ifdef __cplusplus
}
#endif /*__cplusplus*/
#endif /*VIPS_YAFRNOHALO_H*/