139 lines
3.8 KiB
C
139 lines
3.8 KiB
C
/* @(#) creates a sinewave with horfreq cycles per horizontal direction and
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* @(#) verfreq cycles per vertical direction
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* @(#) If horfreq and verfreq are integers the resultant image is periodical
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* @(#) and therfore the Fourier transform doesnot present spikes
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* @(#) Image should have been set by a call to im_setbuf() or im_openout()
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* @(#)
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* @(#) Usage: int im_sines(image, xsize, ysize, horfreq, verfreq)
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* @(#) IMAGE *image;
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* @(#) int xsize, ysize;
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* @(#) double horfreq, verfreq;
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* @(#)
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* @(#) Returns 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: 02/02/1990
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* Modified on:
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* 22/7/93 JC
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* - externs removed
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* - im_outcheck() added
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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 <stdlib.h>
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#include <math.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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int
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im_sines( IMAGE *image, int xsize, int ysize, double horfreq, double verfreq )
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{
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int x, y;
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float *line, *cpline;
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int size;
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double cons, factor;
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double theta_rad, costheta, sintheta, ysintheta;
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/* Check input args */
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if( im_outcheck( image ) )
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return( -1 );
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if ( xsize <= 0 || ysize <= 0 )
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{ im_errormsg("im_sines: wrong sizes"); return(-1); }
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/* Set now image properly */
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im_initdesc(image, xsize, ysize, 1, IM_BBITS_FLOAT, IM_BANDFMT_FLOAT,
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IM_CODING_NONE, IM_TYPE_B_W, 1.0, 1.0, 0, 0);
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/* Set up image checking whether the output is a buffer or a file */
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if (im_setupout( image ) == -1 )
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{ im_errormsg("im_sines: im_setupout failed"); return(-1); }
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/* Create data */
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size = image->Xsize;
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if ( (line=(float *)calloc((unsigned)size, sizeof(float))) == NULL )
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{ im_errormsg("im_sines: calloc failed"); return(-1); }
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/* make angle in rad */
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if (horfreq == 0)
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theta_rad = IM_PI/2.0;
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else
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theta_rad = atan(verfreq/horfreq);
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costheta = cos(theta_rad); sintheta = sin(theta_rad);
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factor = sqrt ((double)(horfreq*horfreq + verfreq*verfreq));
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cons = factor * IM_PI * 2.0/(double)image->Xsize;
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/* There is a bug (rounding error ?) for horfreq=0,
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*so do this calculation independantly */
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if ( horfreq != 0 )
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{
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for (y=0; y<image->Ysize; y++)
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{
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ysintheta = y * sintheta;
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cpline = line;
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for (x=0; x<image->Xsize; x++)
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*cpline++ =
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(float)(cos(cons*(x*costheta-ysintheta)));
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if ( im_writeline( y, image, (PEL *)line ) == -1 )
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{
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im_errormsg("im_sines: im_writeline failed");
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free ( (char *)line );
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return( -1 );
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}
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}
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}
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else
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{
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for (y=0; y<image->Ysize; y++)
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{
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cpline = line;
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ysintheta = cos (- cons * y * sintheta);
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for (x=0; x<image->Xsize; x++)
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*cpline++ = (float)ysintheta;
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if ( im_writeline( y, image, (PEL *)line ) == -1 )
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{
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im_errormsg("im_sines: im_writeline failed");
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free ( (char *)line );
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return( -1 );
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}
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}
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}
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free ( (char *)line );
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return(0);
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}
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