include/filters/GP_Convolution.h

   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 /*
  24
  25   Convolution filters.
  26
  27  */
  28
  29 #ifndef FILTERS_GP_CONVOLUTION_H
  30 #define FILTERS_GP_CONVOLUTION_H
  31
  32 #include "GP_Filter.h"
  33 #include "GP_Linear.h"
  34
  35 /*
  36  * 2D convolution kernel.
  37  *
  38  * The kernel array size must be w * h.
  39  *
  40  * The div is used to divide the resulting value which is commonly used for
  41  * normalization.
  42  *
  43  * Example box smoothing filter kernel initialization:
  44  *
  45  * float box_filter[] = {
  46  *      1, 1, 1,
  47  *      1, 1, 1,
  48  *      1, 1, 1,
  49  * };
  50  *
  51  * GP_FilterKernel2D box_kernel = {
  52  *      .w = 3,
  53  *      .h = 3,
  54  *      .div = 9,
  55  *      .kernel = box_filter,
  56  * };
  57  */
  58 typedef struct GP_FilterKernel2D {
  59         unsigned int w;
  60         unsigned int h;
  61         float div;
  62         float *kernel;
  63 } GP_FilterKernel2D;
  64
  65 /*
  66  * Extended convolution filter.
  67  *
  68  * Works on rectangle in src defined by x_src, y_src, w_src and h_src.
  69  *
  70  * The result is stored into dst strating from x_dst and y_dst.
  71  *
  72  */
  73 int GP_FilterConvolutionEx(const GP_Pixmap *src,
  74                            GP_Coord x_src, GP_Coord y_src,
  75                            GP_Size w_src, GP_Coord h_src,
  76                            GP_Pixmap *dst,
  77                            GP_Coord x_dst, GP_Coord y_dst,
  78                            const GP_FilterKernel2D *kernel,
  79                            GP_ProgressCallback *callback);
  80
  81 /*
  82  * Extended convolution filter.
  83  *
  84  * Works on rectangle in src defined by x_src, y_src, w_src and h_src.
  85  *
  86  * Allocates pixmap of a w_src x h_src.
  87  */
  88 GP_Pixmap *GP_FilterConvolutionExAlloc(const GP_Pixmap *src,
  89                                         GP_Coord x_src, GP_Coord y_src,
  90                                         GP_Size w_src, GP_Size h_src,
  91                                         const GP_FilterKernel2D *kernel,
  92                                         GP_ProgressCallback *callback);
  93
  94
  95 static inline int GP_FilterConvolution(const GP_Pixmap *src, GP_Pixmap *dst,
  96                                        const GP_FilterKernel2D *kernel,
  97                                        GP_ProgressCallback *callback)
  98 {
  99         return GP_FilterConvolutionEx(src, 0, 0, dst->w, dst->h, dst, 0, 0,
 100                                       kernel, callback);
 101 }
 102
 103 static inline GP_Pixmap *GP_FilterConvolutionAlloc(const GP_Pixmap *src,
 104                                                     const GP_FilterKernel2D *kernel,
 105                                                     GP_ProgressCallback *callback)
 106 {
 107         return GP_FilterConvolutionExAlloc(src, 0, 0, src->w, src->h,
 108                                            kernel, callback);
 109 }
 110
 111 /*
 112  * Prints a kernel into the stdout.
 113  */
 114 static inline void GP_FilterKernel2DPrint(const GP_FilterKernel2D *kernel)
 115 {
 116         GP_FilterKernelPrint_Raw(kernel->kernel, kernel->w, kernel->h,
 117                                  kernel->div);
 118 }
 119
 120 #endif /* FILTERS_GP_CONVOLUTION_H */