253 lines
6.3 KiB
C
253 lines
6.3 KiB
C
/* affine transforms
|
|
*/
|
|
|
|
/*
|
|
|
|
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 <vips/intl.h>
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <math.h>
|
|
#include <limits.h>
|
|
|
|
#include <vips/vips.h>
|
|
#include <vips/internal.h>
|
|
#include <vips/transform.h>
|
|
|
|
/* Calculate the inverse transformation.
|
|
*/
|
|
int
|
|
vips__transform_calc_inverse( VipsTransformation *trn )
|
|
{
|
|
DOUBLEMASK *msk, *msk2;
|
|
|
|
if( !(msk = im_create_dmaskv( "boink", 2, 2,
|
|
trn->a, trn->b, trn->c, trn->d )) )
|
|
return( -1 );
|
|
if( !(msk2 = im_matinv( msk, "boink2" )) ) {
|
|
(void) im_free_dmask( msk );
|
|
return( -1 );
|
|
}
|
|
trn->ia = msk2->coeff[0];
|
|
trn->ib = msk2->coeff[1];
|
|
trn->ic = msk2->coeff[2];
|
|
trn->id = msk2->coeff[3];
|
|
(void) im_free_dmask( msk );
|
|
(void) im_free_dmask( msk2 );
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
/* Init a VipsTransform.
|
|
*/
|
|
void
|
|
vips__transform_init( VipsTransformation *trn )
|
|
{
|
|
trn->oarea.left = 0;
|
|
trn->oarea.top = 0;
|
|
trn->oarea.width = -1;
|
|
trn->oarea.height = -1;
|
|
trn->iarea.left = 0;
|
|
trn->iarea.top = 0;
|
|
trn->iarea.width = -1;
|
|
trn->iarea.height = -1;
|
|
trn->a = 1.0; /* Identity transform */
|
|
trn->b = 0.0;
|
|
trn->c = 0.0;
|
|
trn->d = 1.0;
|
|
trn->idx = 0.0;
|
|
trn->idy = 0.0;
|
|
trn->odx = 0.0;
|
|
trn->ody = 0.0;
|
|
|
|
(void) vips__transform_calc_inverse( trn );
|
|
}
|
|
|
|
/* Test for transform is identity function.
|
|
*/
|
|
int
|
|
vips__transform_isidentity( const VipsTransformation *trn )
|
|
{
|
|
if( trn->a == 1.0 && trn->b == 0.0 &&
|
|
trn->c == 0.0 && trn->d == 1.0 &&
|
|
trn->idx == 0.0 && trn->idy == 0.0 &&
|
|
trn->odx == 0.0 && trn->ody == 0.0 )
|
|
return( 1 );
|
|
else
|
|
return( 0 );
|
|
}
|
|
|
|
/* Combine two transformations. out can be one of the ins.
|
|
*/
|
|
int
|
|
vips__transform_add( const VipsTransformation *in1,
|
|
const VipsTransformation *in2, VipsTransformation *out )
|
|
{
|
|
out->a = in1->a * in2->a + in1->c * in2->b;
|
|
out->b = in1->b * in2->a + in1->d * in2->b;
|
|
out->c = in1->a * in2->c + in1->c * in2->d;
|
|
out->d = in1->b * in2->c + in1->d * in2->d;
|
|
|
|
// fixme: do idx/idy as well
|
|
|
|
out->odx = in1->odx * in2->a + in1->ody * in2->b + in2->odx;
|
|
out->ody = in1->odx * in2->c + in1->ody * in2->d + in2->ody;
|
|
|
|
if( vips__transform_calc_inverse( out ) )
|
|
return( -1 );
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
void
|
|
vips__transform_print( const VipsTransformation *trn )
|
|
{
|
|
printf( "vips__transform_print:\n" );
|
|
printf( " iarea: left=%d, top=%d, width=%d, height=%d\n",
|
|
trn->iarea.left,
|
|
trn->iarea.top,
|
|
trn->iarea.width,
|
|
trn->iarea.height );
|
|
printf( " oarea: left=%d, top=%d, width=%d, height=%d\n",
|
|
trn->oarea.left,
|
|
trn->oarea.top,
|
|
trn->oarea.width,
|
|
trn->oarea.height );
|
|
printf( " mat: a=%g, b=%g, c=%g, d=%g\n",
|
|
trn->a, trn->b, trn->c, trn->d );
|
|
printf( " off: odx=%g, ody=%g, idx=%g, idy=%g\n",
|
|
trn->odx, trn->ody, trn->idx, trn->idy );
|
|
}
|
|
|
|
/* Map a pixel coordinate through the transform.
|
|
*/
|
|
void
|
|
vips__transform_forward_point( const VipsTransformation *trn,
|
|
double x, double y, /* In input space */
|
|
double *ox, double *oy )/* In output space */
|
|
{
|
|
x += trn->idx;
|
|
y += trn->idy;
|
|
|
|
*ox = trn->a * x + trn->b * y + trn->odx;
|
|
*oy = trn->c * x + trn->d * y + trn->ody;
|
|
}
|
|
|
|
/* Map a pixel coordinate through the inverse transform.
|
|
*/
|
|
void
|
|
vips__transform_invert_point( const VipsTransformation *trn,
|
|
double x, double y, /* In output space */
|
|
double *ox, double *oy )/* In input space */
|
|
{
|
|
x -= trn->odx;
|
|
y -= trn->ody;
|
|
|
|
*ox = trn->ia * x + trn->ib * y - trn->idx;
|
|
*oy = trn->ic * x + trn->id * y - trn->idy;
|
|
}
|
|
|
|
typedef void (*transform_fn)( const VipsTransformation *,
|
|
const double, const double, double*, double* );
|
|
|
|
/* Transform a rect using a point transformer.
|
|
*/
|
|
static void
|
|
transform_rect( const VipsTransformation *trn, transform_fn transform,
|
|
const VipsRect *in, /* In input space */
|
|
VipsRect *out ) /* In output space */
|
|
{
|
|
double x1, y1; /* Map corners */
|
|
double x2, y2;
|
|
double x3, y3;
|
|
double x4, y4;
|
|
double left, right, top, bottom;
|
|
|
|
/* Map input VipsRect.
|
|
*/
|
|
transform( trn, in->left, in->top,
|
|
&x1, &y1 );
|
|
transform( trn, in->left, VIPS_RECT_BOTTOM( in ),
|
|
&x3, &y3 );
|
|
transform( trn, VIPS_RECT_RIGHT( in ), in->top,
|
|
&x2, &y2 );
|
|
transform( trn, VIPS_RECT_RIGHT( in ), VIPS_RECT_BOTTOM( in ),
|
|
&x4, &y4 );
|
|
|
|
/* Find bounding box for these four corners. Round-to-nearest to try
|
|
* to stop rounding errors growing images.
|
|
*/
|
|
left = VIPS_MIN( x1, VIPS_MIN( x2, VIPS_MIN( x3, x4 ) ) );
|
|
right = VIPS_MAX( x1, VIPS_MAX( x2, VIPS_MAX( x3, x4 ) ) );
|
|
top = VIPS_MIN( y1, VIPS_MIN( y2, VIPS_MIN( y3, y4 ) ) );
|
|
bottom = VIPS_MAX( y1, VIPS_MAX( y2, VIPS_MAX( y3, y4 ) ) );
|
|
|
|
out->left = VIPS_RINT( left );
|
|
out->top = VIPS_RINT( top );
|
|
out->width = VIPS_RINT( right - left );
|
|
out->height = VIPS_RINT( bottom - top );
|
|
}
|
|
|
|
/* Given an area in the input image, calculate the bounding box for those
|
|
* pixels in the output image.
|
|
*/
|
|
void
|
|
vips__transform_forward_rect( const VipsTransformation *trn,
|
|
const VipsRect *in, /* In input space */
|
|
VipsRect *out ) /* In output space */
|
|
{
|
|
transform_rect( trn, vips__transform_forward_point, in, out );
|
|
}
|
|
|
|
/* Given an area in the output image, calculate the bounding box for the
|
|
* corresponding pixels in the input image.
|
|
*/
|
|
void
|
|
vips__transform_invert_rect( const VipsTransformation *trn,
|
|
const VipsRect *in, /* In output space */
|
|
VipsRect *out ) /* In input space */
|
|
{
|
|
transform_rect( trn, vips__transform_invert_point, in, out );
|
|
}
|
|
|
|
/* Set output area of trn so that it just holds all of our input pels.
|
|
*/
|
|
void
|
|
vips__transform_set_area( VipsTransformation *trn )
|
|
{
|
|
vips__transform_forward_rect( trn, &trn->iarea, &trn->oarea );
|
|
}
|