152 lines
4.1 KiB
C
152 lines
4.1 KiB
C
/* @(#) Invert a UCHAR image. Very simple new-style VIPS routine. See
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* @(#) im_exptra() for the next level of complexity. This function is not
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* @(#) as quick as it could be - it is intended to be an example rather than
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* @(#) to be useful. This should really be written with im_wrapone().
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* @(#)
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* @(#) int
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* @(#) im_invert( IMAGE *in, IMAGE *out )
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* @(#)
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* @(#) All functions return 0 on success and -1 on error
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* @(#)
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*
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* Copyright: 1990, N. Dessipris.
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*
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* Author: Nicos Dessipris
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* Written on: 12/02/1990
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* Modified on :
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* 7/7/93 JC
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* - memory leaks fixed
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* - adapted for partial v2
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* - ANSIfied
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* 22/2/95 JC
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* - tidied up again
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /*HAVE_CONFIG_H*/
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#include <vips/intl.h>
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#include <stdio.h>
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#include <vips/vips.h>
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#ifdef WITH_DMALLOC
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#include <dmalloc.h>
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#endif /*WITH_DMALLOC*/
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/* Invert a REGION. We are given the REGION we should write to, the REGION we
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* should use for input, and the IMAGE we are processing. On entry to
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* invert_gen(), or points to the memory we should write to and ir is blank.
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*/
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static int
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invert_gen( REGION *or, void *seq, void *a, void *b )
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{
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REGION *ir = (REGION *) seq;
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/* Left, right, top and bottom for the output region.
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*/
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int le = or->valid.left;
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int to = or->valid.top;
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int bo = IM_RECT_BOTTOM( &or->valid );
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int x, y;
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/* Ask for the section of the input image we need to produce this
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* section of the output image.
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*/
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if( im_prepare( ir, &or->valid ) )
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return( -1 );
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/* Loop over output, writing input.
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*/
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for( y = to; y < bo; y++ ) {
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/* Point p and q at the start of the line of pels we must
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* process this loop.
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*/
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PEL *p = (PEL *) IM_REGION_ADDR( ir, le, y );
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PEL *q = (PEL *) IM_REGION_ADDR( or, le, y );
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/* Loop along the line, processing pels.
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* IM_REGION_N_ELEMENTS(region) gives
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* the number of band elements across a region. By looping to
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* IM_REGION_N_ELEMENTS() rather than ir->valid.width, we work
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* for any number of bands.
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*/
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for( x = 0; x < IM_REGION_N_ELEMENTS( or ); x++ )
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q[x] = 255 - p[x];
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}
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return( 0 );
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}
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/* Invert IMAGE in to IMAGE out. Any number of bands, unsigned char pels
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* only. See im_exptra() for an example of a VIPS function which can process
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* any input image type.
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*/
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int
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im_invert( IMAGE *in, IMAGE *out )
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{
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/* Check args.
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*/
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if( in->Coding != IM_CODING_NONE ) {
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im_error( "im_invert", "%s", _( "not uncoded" ) );
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return( -1 );
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}
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if( in->BandFmt != IM_BANDFMT_UCHAR ) {
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im_error( "im_invert", "%s", _( "not UCHAR" ) );
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return( -1 );
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}
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if( im_piocheck( in, out ) )
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return( -1 );
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/* Prepare the output header.
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*/
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if( im_cp_desc( out, in ) )
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return( -1 );
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/* Set demand hints. Like most one-to-one operations, we work best
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* with long, thin strips.
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*/
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if( im_demand_hint( out, IM_THINSTRIP, in, NULL ) )
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return( -1 );
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/* Generate into out. im_start_one() and im_stop_one() are simple
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* convenience functions provided by VIPS which do the necessary
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* region creation and destruction for one-image-in
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* style functions. See im_add(), im_start_many() and im_stop_many()
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* for convenience functions for multiple inputs.
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*/
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if( im_generate( out,
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im_start_one, invert_gen, im_stop_one, in, NULL ) )
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return( -1 );
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return( 0 );
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}
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