libvips/libsrc/conversion/im_rot180.c

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2007-08-29 18:23:50 +02:00
/* @(#) rotates an image 180 degrees
* @(#) Usage:
* @(#) im_rot180(in, out)
* @(#) IMAGE *in, *out;
* @(#)
* @(#) Returns 0 on sucess and -1 on error
* @(#)
* Copyright: 1991, N. Dessipris
* Written on: 28/10/91
* Updated on: 2/4/92, J.Cupitt
* bugs in im_la90rot fixed, now works for any type.
* 19/7/93 JC
* - IM_CODING_LABQ allowed now
* 15/11/94 JC
* - name changed
* - memory leaks fixed
* 8/2/95 JC
* - oops! memory allocation problem fixed
* 18/5/95 JC
* - IM_MAXLINES increased
* 13/8/96 JC
* - rewritten for partials
* - adapted from im_rot90
* 14/4/04
* - sets Xoffset / Yoffset
*/
/*
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 <stdlib.h>
#include <string.h>
#include <vips/vips.h>
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
/* Rotate a small piece.
*/
static int
rot180_gen( REGION *or, REGION *ir, IMAGE *in )
{
/* Output area.
*/
Rect *r = &or->valid;
int le = r->left;
int ri = IM_RECT_RIGHT(r);
int to = r->top;
int bo = IM_RECT_BOTTOM(r);
int x, y;
/* Pixel geometry.
*/
int ps;
/* Find the area of the input image we need.
*/
Rect need;
need.left = in->Xsize - ri;
need.top = in->Ysize - bo;
need.width = r->width;
need.height = r->height;
if( im_prepare( ir, &need ) )
return( -1 );
/* Find PEL size and line skip for ir.
*/
ps = IM_IMAGE_SIZEOF_PEL( in );
/* Rotate the bit we now have.
*/
for( y = to; y < bo; y++ ) {
/* Start of this output line.
*/
PEL *q = (PEL *) IM_REGION_ADDR( or, le, y );
/* Corresponding position in ir.
*/
PEL *p = (PEL *) IM_REGION_ADDR( ir,
need.left + need.width - 1,
need.top + need.height - (y - to) - 1 );
/* Blap across!
*/
for( x = le; x < ri; x++ ) {
memcpy( q, p, ps );
q += ps;
p -= ps;
}
}
return( 0 );
}
int
im_rot180( IMAGE *in, IMAGE *out )
{
/* Make output image.
*/
if( im_piocheck( in, out ) )
return( -1 );
if( in->Coding != IM_CODING_NONE && in->Coding != IM_CODING_LABQ ) {
im_error( "im_rot180", _( "uncoded or IM_CODING_LABQ only" ) );
return( -1 );
}
if( im_cp_desc( out, in ) )
return( -1 );
/* We are fastest with thinstrip.
*/
if( im_demand_hint( out, IM_THINSTRIP, in, NULL ) )
return( -1 );
/* Generate!
*/
if( im_generate( out,
im_start_one, rot180_gen, im_stop_one, in, NULL ) )
return( -1 );
out->Xoffset = in->Xsize;
out->Yoffset = in->Ysize;
return( 0 );
}