transform.h

/* Affine transforms.
*/

/*

Copyright (C) 1991-2003 The National Gallery

This program 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

*/

#ifndef VIPS_TRANSFORM_H
#define VIPS_TRANSFORM_H

#ifdef __cplusplus
extern “C” {
#endif /__cplusplus/

/* Params for an affine transformation.
/
typedef struct {
/
Area of input we can use. This can be smaller than the real input
* image: we expand the input to add extra pixels for interpolation.
*/
VipsRect iarea;

/* The area of the output we’ve been asked to generate. left/top can
* be negative.
*/
VipsRect oarea;

/* The transform.
*/
double a, b, c, d;
double idx, idy;
double odx, ody;

double ia, ib, ic, id; /* Inverse of matrix abcd */
} VipsTransformation;

void vips__transform_init( VipsTransformation *trn );
int vips__transform_calc_inverse( VipsTransformation *trn );
int vips__transform_isidentity( const VipsTransformation *trn );
int vips__transform_add( const VipsTransformation *in1,
const VipsTransformation *in2,
VipsTransformation *out );
void vips__transform_print( const VipsTransformation *trn );

void vips__transform_forward_point( const VipsTransformation *trn,
const double x, const double y, double *ox, double *oy );
void vips__transform_invert_point( const VipsTransformation *trn,
const double x, const double y, double *ox, double *oy );
void vips__transform_forward_rect( const VipsTransformation *trn,
const VipsRect *in, VipsRect *out );
void vips__transform_invert_rect( const VipsTransformation *trn,
const VipsRect *in, VipsRect *out );

void vips__transform_set_area( VipsTransformation * );

int vips__affine( VipsImage *in, VipsImage *out, VipsTransformation *trn );

#ifdef __cplusplus
}
#endif /__cplusplus/

#endif /VIPS_TRANSFORM_H/