wrlib/convolve.c

   1 /*
   2  * Raster graphics library
   3  *
   4  * Copyright (c) 1997-2003 Alfredo K. Kojima
   5  *
   6  *  This library is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU Library General Public
   8  *  License as published by the Free Software Foundation; either
   9  *  version 2 of the License, or (at your option) any later version.
  10  *
  11  *  This library is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *  Library General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU Library General Public
  17  *  License along with this library; if not, write to the Free
  18  *  Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
  19  *  MA 02110-1301, USA.
  20  */
  21
  22 #include <config.h>
  23
  24 #include <stdlib.h>
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <X11/Xlib.h>
  28
  29 #include "wraster.h"
  30 #include "wr_i18n.h"
  31
  32
  33 /*
  34  *----------------------------------------------------------------------
  35  * RBlurImage--
  36  *      Apply 3x3 1 1 1 low pass, convolution mask to image.
  37  *                1 2 1
  38  *                1 1 1 /10
  39  *----------------------------------------------------------------------
  40  */
  41 int RBlurImage(RImage * image)
  42 {
  43         register int x, y;
  44         register int tmp;
  45         unsigned char *ptr, *nptr;
  46         unsigned char *pptr = NULL, *tmpp;
  47         int ch = image->format == RRGBAFormat ? 4 : 3;
  48
  49         pptr = malloc(image->width * ch);
  50         if (!pptr) {
  51                 RErrorCode = RERR_NOMEMORY;
  52                 return False;
  53         }
  54 #define MASK(prev, cur, next, ch)\
  55     (*(prev-ch) + *prev + *(prev+ch)\
  56     +*(cur-ch) + 2 * *cur + *(cur+ch)\
  57     +*(next-ch) + *next + *(next+ch)) / 10
  58
  59         memcpy(pptr, image->data, image->width * ch);
  60
  61         ptr = image->data;
  62         nptr = ptr + image->width * ch;
  63         tmpp = pptr;
  64
  65         if (ch == 3) {
  66                 ptr += 3;
  67                 nptr += 3;
  68                 pptr += 3;
  69
  70                 for (y = 1; y < image->height - 1; y++) {
  71
  72                         for (x = 1; x < image->width - 1; x++) {
  73                                 tmp = *ptr;
  74                                 *ptr = MASK(pptr, ptr, nptr, 3);
  75                                 *pptr = tmp;
  76                                 ptr++;
  77                                 nptr++;
  78                                 pptr++;
  79
  80                                 tmp = *ptr;
  81                                 *ptr = MASK(pptr, ptr, nptr, 3);
  82                                 *pptr = tmp;
  83                                 ptr++;
  84                                 nptr++;
  85                                 pptr++;
  86
  87                                 tmp = *ptr;
  88                                 *ptr = MASK(pptr, ptr, nptr, 3);
  89                                 *pptr = tmp;
  90                                 ptr++;
  91                                 nptr++;
  92                                 pptr++;
  93                         }
  94                         pptr = tmpp;
  95                         ptr += 6;
  96                         nptr += 6;
  97                         pptr += 6;
  98                 }
  99         } else {
 100                 ptr += 4;
 101                 nptr += 4;
 102                 pptr += 4;
 103
 104                 for (y = 1; y < image->height - 1; y++) {
 105                         for (x = 1; x < image->width - 1; x++) {
 106                                 tmp = *ptr;
 107                                 *ptr = MASK(pptr, ptr, nptr, 4);
 108                                 *pptr = tmp;
 109                                 ptr++;
 110                                 nptr++;
 111                                 pptr++;
 112
 113                                 tmp = *ptr;
 114                                 *ptr = MASK(pptr, ptr, nptr, 4);
 115                                 *pptr = tmp;
 116                                 ptr++;
 117                                 nptr++;
 118                                 pptr++;
 119
 120                                 tmp = *ptr;
 121                                 *ptr = MASK(pptr, ptr, nptr, 4);
 122                                 *pptr = tmp;
 123                                 ptr++;
 124                                 nptr++;
 125                                 pptr++;
 126
 127                                 tmp = *ptr;
 128                                 *ptr = MASK(pptr, ptr, nptr, 4);
 129                                 *pptr = tmp;
 130                                 ptr++;
 131                                 nptr++;
 132                                 pptr++;
 133                         }
 134                         pptr = tmpp;
 135                         ptr += 8;
 136                         nptr += 8;
 137                         pptr += 8;
 138                 }
 139         }
 140
 141         free(tmpp);
 142
 143         return True;
 144 }
 145