| /* im_invert.c |
| * |
| * Copyright: 1990, N. Dessipris. |
| * |
| * Author: Nicos Dessipris |
| * Written on: 12/02/1990 |
| * Modified on : |
| * 7/7/93 JC |
| * - memory leaks fixed |
| * - adapted for partial v2 |
| * - ANSIfied |
| * 22/2/95 JC |
| * - tidied up again |
| * 2/9/09 |
| * - gtk-doc comment |
| */ |
| |
| /* |
| |
| 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 <vips/vips.h> |
| |
| #ifdef WITH_DMALLOC |
| #include <dmalloc.h> |
| #endif /*WITH_DMALLOC*/ |
| |
| /* Invert a REGION. We are given the REGION we should write to, the REGION we |
| * should use for input, and the IMAGE we are processing. On entry to |
| * invert_gen(), or points to the memory we should write to and ir is blank. |
| */ |
| static int |
| invert_gen( REGION *or, void *seq, void *a, void *b ) |
| { |
| REGION *ir = (REGION *) seq; |
| |
| /* Left, right, top and bottom for the output region. |
| */ |
| int le = or->valid.left; |
| int to = or->valid.top; |
| int bo = IM_RECT_BOTTOM( &or->valid ); |
| |
| int x, y; |
| |
| /* Ask for the section of the input image we need to produce this |
| * section of the output image. |
| */ |
| if( im_prepare( ir, &or->valid ) ) |
| return( -1 ); |
| |
| /* Loop over output. |
| */ |
| for( y = to; y < bo; y++ ) { |
| /* Point p and q at the start of the line of pels we must |
| * process this loop. |
| */ |
| PEL *p = (PEL *) IM_REGION_ADDR( ir, le, y ); |
| PEL *q = (PEL *) IM_REGION_ADDR( or, le, y ); |
| |
| /* Loop along the line, processing pels. |
| * IM_REGION_N_ELEMENTS(region) gives |
| * the number of band elements across a region. By looping to |
| * IM_REGION_N_ELEMENTS() rather than ir->valid.width, we work |
| * for any number of bands. |
| */ |
| for( x = 0; x < IM_REGION_N_ELEMENTS( or ); x++ ) |
| q[x] = 255 - p[x]; |
| } |
| |
| return( 0 ); |
| } |
| |
| /** |
| * im_invert: |
| * @in: input #IMAGE |
| * @out: output #IMAGE |
| * |
| * this operation calculates (255 - @in). |
| * The operation works on uchar images only. The input can have any no of |
| * channels. |
| * |
| * This is not a generally useful program -- it is included as an example of |
| * a very simple new-style IO function. |
| * See im_exptra() for an example of a VIPS function which can process |
| * any input image type. |
| * |
| * See also: im_exptra(), im_lintra(). |
| * |
| * Returns: 0 on success, -1 on error |
| */ |
| int |
| im_invert( IMAGE *in, IMAGE *out ) |
| { |
| /* Check args. |
| */ |
| if( im_check_uncoded( "im_invert", in ) || |
| im_check_format( "im_invert", in, IM_BANDFMT_UCHAR ) || |
| im_piocheck( in, out ) ) |
| return( -1 ); |
| |
| /* Prepare the output header. |
| */ |
| if( im_cp_desc( out, in ) ) |
| return( -1 ); |
| |
| /* Set demand hints. Like most one-to-one operations, we work best |
| * with long, thin strips. |
| */ |
| if( im_demand_hint( out, IM_THINSTRIP, in, NULL ) ) |
| return( -1 ); |
| |
| /* Generate into out. im_start_one() and im_stop_one() are simple |
| * convenience functions provided by VIPS which do the necessary |
| * region creation and destruction for one-image-in |
| * style functions. See im_add(), im_start_many() and im_stop_many() |
| * for convenience functions for multiple inputs. |
| */ |
| if( im_generate( out, |
| im_start_one, invert_gen, im_stop_one, in, NULL ) ) |
| return( -1 ); |
| |
| return( 0 ); |
| } |