libs/filters/GP_Laplace.c

   1 /*****************************************************************************
   2  * This file is part of gfxprim library.                                     *
   3  *                                                                           *
   4  * Gfxprim is free software; you can redistribute it and/or                  *
   5  * modify it under the terms of the GNU Lesser General Public                *
   6  * License as published by the Free Software Foundation; either              *
   7  * version 2.1 of the License, or (at your option) any later version.        *
   8  *                                                                           *
   9  * Gfxprim is distributed in the hope that it will be useful,                *
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU         *
  12  * Lesser General Public License for more details.                           *
  13  *                                                                           *
  14  * You should have received a copy of the GNU Lesser General Public          *
  15  * License along with gfxprim; if not, write to the Free Software            *
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor,                        *
  17  * Boston, MA  02110-1301  USA                                               *
  18  *                                                                           *
  19  * Copyright (C) 2009-2012 Cyril Hrubis <metan@ucw.cz>                       *
  20  *                                                                           *
  21  *****************************************************************************/
  22
  23 #include "core/GP_Debug.h"
  24 #include "core/GP_GetPutPixel.h"
  25
  26 #include "GP_Linear.h"
  27
  28 #include "GP_Laplace.h"
  29
  30 int GP_FilterLaplace(const GP_Pixmap *src, GP_Pixmap *dst,
  31                      GP_ProgressCallback *callback)
  32 {
  33         GP_DEBUG(1, "Laplace filter %ux%u", src->w, src->h);
  34
  35         float kern[9] = {0,  1,  0,
  36                          1, -4,  1,
  37                          0,  1,  0};
  38
  39         if (GP_FilterLinearConvolution_Raw(src, 0, 0, src->w, src->h,
  40                                            dst, 0, 0, kern, 3, 3, 1, callback))
  41                 return 1;
  42
  43         return 0;
  44 }
  45
  46 GP_Pixmap *GP_FilterLaplaceAlloc(const GP_Pixmap *src,
  47                                   GP_ProgressCallback *callback)
  48 {
  49         GP_Pixmap *ret = GP_PixmapCopy(src, 0);
  50
  51         if (ret == NULL)
  52                 return NULL;
  53
  54         if (GP_FilterLaplace(src, ret, callback)) {
  55                 GP_PixmapFree(ret);
  56                 return NULL;
  57         }
  58
  59         return ret;
  60 }
  61
  62
  63 int GP_FilterEdgeSharpening(const GP_Pixmap *src, GP_Pixmap *dst,
  64                             float w, GP_ProgressCallback *callback)
  65 {
  66         /* Identity kernel */
  67         float kern[9] = {0,  0,  0,
  68                          0,  1,  0,
  69                          0,  0,  0};
  70
  71         GP_DEBUG(1, "Laplace Edge Sharpening filter %ux%u w=%f",
  72                  src->w, src->h, w);
  73
  74         /* Create combined kernel */
  75         kern[1] -=  1.00 * w;
  76         kern[3] -=  1.00 * w;
  77         kern[4] -= -4.00 * w;
  78         kern[5] -=  1.00 * w;
  79         kern[7] -=  1.00 * w;
  80
  81         if (GP_FilterLinearConvolution_Raw(src, 0, 0, src->w, src->h,
  82                                            dst, 0, 0,  kern, 3, 3, 1, callback))
  83                 return 1;
  84
  85         return 0;
  86 }
  87
  88 GP_Pixmap *GP_FilterEdgeSharpeningAlloc(const GP_Pixmap *src, float w,
  89                                          GP_ProgressCallback *callback)
  90 {
  91         GP_Pixmap *ret = GP_PixmapCopy(src, 0);
  92
  93         if (ret == NULL)
  94                 return NULL;
  95
  96         if (GP_FilterEdgeSharpening(src, ret, w, callback)) {
  97                 GP_PixmapFree(ret);
  98                 return NULL;
  99         }
 100
 101         return ret;
 102 }