60 lines
2.0 KiB
C
60 lines
2.0 KiB
C
// Copyright 2011 Google Inc. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the COPYING file in the root of the source
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// tree. An additional intellectual property rights grant can be found
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// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
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// -----------------------------------------------------------------------------
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//
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// Spatial prediction using various filters
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//
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// Author: Urvang (urvang@google.com)
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#ifndef WEBP_UTILS_FILTERS_H_
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#define WEBP_UTILS_FILTERS_H_
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#include "../webp/types.h"
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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// Filters.
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typedef enum {
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WEBP_FILTER_NONE = 0,
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WEBP_FILTER_HORIZONTAL,
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WEBP_FILTER_VERTICAL,
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WEBP_FILTER_GRADIENT,
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WEBP_FILTER_LAST = WEBP_FILTER_GRADIENT + 1, // end marker
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WEBP_FILTER_BEST,
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WEBP_FILTER_FAST
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} WEBP_FILTER_TYPE;
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typedef void (*WebPFilterFunc)(const uint8_t* in, int width, int height,
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int stride, uint8_t* out);
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typedef void (*WebPUnfilterFunc)(int width, int height, int stride,
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int row, int num_rows, uint8_t* data);
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// Filter the given data using the given predictor.
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// 'in' corresponds to a 2-dimensional pixel array of size (stride * height)
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// in raster order.
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// 'stride' is number of bytes per scan line (with possible padding).
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// 'out' should be pre-allocated.
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extern const WebPFilterFunc WebPFilters[WEBP_FILTER_LAST];
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// In-place reconstruct the original data from the given filtered data.
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// The reconstruction will be done for 'num_rows' rows starting from 'row'
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// (assuming rows upto 'row - 1' are already reconstructed).
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extern const WebPUnfilterFunc WebPUnfilters[WEBP_FILTER_LAST];
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// Fast estimate of a potentially good filter.
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WEBP_FILTER_TYPE EstimateBestFilter(const uint8_t* data,
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int width, int height, int stride);
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#if defined(__cplusplus) || defined(c_plusplus)
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} // extern "C"
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#endif
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#endif /* WEBP_UTILS_FILTERS_H_ */
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