include/filters/GP_Linear.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    Linear filters.
  26
  27  */
  28
  29 #ifndef FILTERS_GP_LINEAR_H
  30 #define FILTERS_GP_LINEAR_H
  31
  32 #include "GP_Filter.h"
  33
  34 /*
  35  * Gaussian blur
  36  *
  37  * The sigma parameters defines the blur radii in horizontal and vertical
  38  * direction.
  39  *
  40  * Internaly this is implemented as separable linear filter (calls vertical and
  41  * horizontal convolution with generated gaussian kernel).
  42  *
  43  * This variant could work in-place so it's perectly okay to call
  44  *
  45  * GP_FilterGaussianBlur_Raw(context, context, ...);
  46  */
  47 int GP_FilterGaussianBlur_Raw(const GP_Context *src, GP_Context *dst,
  48                               float sigma_x, float sigma_y,
  49                               GP_ProgressCallback *callback);
  50 /*
  51  * Gaussian blur.
  52  *
  53  * If dst is NULL, new bitmap is allocated.
  54  *
  55  * This variant could work in-place.
  56  *
  57  * Returns pointer to destination bitmap or NULL if allocation failed.
  58  */
  59 GP_Context *GP_FilterGaussianBlur(const GP_Context *src, GP_Context *dst,
  60                                   float sigma_x, float sigma_y,
  61                                   GP_ProgressCallback *callback);
  62
  63 /*
  64  * Linear convolution.
  65  *
  66  * The kernel is array of kw * kh floats and is indexed as two directional
  67  * array.
  68  *
  69  * To define 3x3 average filter
  70  *
  71  * kernel[] = {
  72  *      1, 1, 1,
  73  *      1, 1, 1,
  74  *      1, 1, 1,
  75  * };
  76  *
  77  * kw = kh = 3
  78  *
  79  * kern_div = 9
  80  *
  81  * This function works also in-place.
  82  */
  83 int GP_FilterLinearConvolution_Raw(const GP_Context *src, GP_Context *dst,
  84                                    float kernel[], uint32_t kw, uint32_t kh,
  85                                    float kern_div, GP_ProgressCallback *callback);
  86
  87 /*
  88  * Special cases for convolution only in horizontal/vertical direction.
  89  *
  90  * These are about 10-30% faster than the generic implementation (depending on
  91  * the kernel size, bigger kernel == more savings).
  92  *
  93  * These are two are a base for bilinear filters.
  94  *
  95  * Both works also in-place.
  96  */
  97 int GP_FilterHLinearConvolution_Raw(const GP_Context *src, GP_Context *dst,
  98                                     float kernel[], uint32_t kw, float kern_div,
  99                                     GP_ProgressCallback *callback);
 100
 101 int GP_FilterVLinearConvolution_Raw(const GP_Context *src, GP_Context *dst,
 102                                     float kernel[], uint32_t kh, float kern_div,
 103                                     GP_ProgressCallback *callback);
 104
 105 /*
 106  * Applies both horizontal and vertical convolution and takes care of the
 107  * correct progress callback (both horizontal and vertical kernels are expected
 108  * to be similar in size).
 109  */
 110 int GP_FilterVHLinearConvolution_Raw(const GP_Context *src, GP_Context *dst,
 111                                      float hkernel[], uint32_t kw, float hkern_div,
 112                                      float vkernel[], uint32_t kh, float vkern_div,
 113                                      GP_ProgressCallback *callback);
 114
 115 #endif /* FILTERS_GP_LINEAR_H */