src/SDL2/external/libwebp-0.3.0/src/utils/filters.h

   1 // Copyright 2011 Google Inc. All Rights Reserved.
   2 //
   3 // This code is licensed under the same terms as WebM:
   4 //  Software License Agreement:  http://www.webmproject.org/license/software/
   5 //  Additional IP Rights Grant:  http://www.webmproject.org/license/additional/
   6 // -----------------------------------------------------------------------------
   7 //
   8 // Spatial prediction using various filters
   9 //
  10 // Author: Urvang (urvang@google.com)
  11
  12 #ifndef WEBP_UTILS_FILTERS_H_
  13 #define WEBP_UTILS_FILTERS_H_
  14
  15 #include "../webp/types.h"
  16
  17 #if defined(__cplusplus) || defined(c_plusplus)
  18 extern "C" {
  19 #endif
  20
  21 // Filters.
  22 typedef enum {
  23   WEBP_FILTER_NONE = 0,
  24   WEBP_FILTER_HORIZONTAL,
  25   WEBP_FILTER_VERTICAL,
  26   WEBP_FILTER_GRADIENT,
  27   WEBP_FILTER_LAST = WEBP_FILTER_GRADIENT + 1,  // end marker
  28   WEBP_FILTER_BEST,
  29   WEBP_FILTER_FAST
  30 } WEBP_FILTER_TYPE;
  31
  32 typedef void (*WebPFilterFunc)(const uint8_t* in, int width, int height,
  33                                int stride, uint8_t* out);
  34 typedef void (*WebPUnfilterFunc)(int width, int height, int stride,
  35                                  uint8_t* data);
  36
  37 // Filter the given data using the given predictor.
  38 // 'in' corresponds to a 2-dimensional pixel array of size (stride * height)
  39 // in raster order.
  40 // 'stride' is number of bytes per scan line (with possible padding).
  41 // 'out' should be pre-allocated.
  42 extern const WebPFilterFunc WebPFilters[WEBP_FILTER_LAST];
  43
  44 // In-place reconstruct the original data from the given filtered data.
  45 extern const WebPUnfilterFunc WebPUnfilters[WEBP_FILTER_LAST];
  46
  47 // Fast estimate of a potentially good filter.
  48 extern WEBP_FILTER_TYPE EstimateBestFilter(const uint8_t* data,
  49                                            int width, int height, int stride);
  50
  51 #if defined(__cplusplus) || defined(c_plusplus)
  52 }    // extern "C"
  53 #endif
  54
  55 #endif  /* WEBP_UTILS_FILTERS_H_ */