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Diffstat (limited to 'src/main/jni/libwebp/utils/filters.c')
-rw-r--r-- | src/main/jni/libwebp/utils/filters.c | 266 |
1 files changed, 0 insertions, 266 deletions
diff --git a/src/main/jni/libwebp/utils/filters.c b/src/main/jni/libwebp/utils/filters.c deleted file mode 100644 index 2d15bd0e4..000000000 --- a/src/main/jni/libwebp/utils/filters.c +++ /dev/null @@ -1,266 +0,0 @@ -// Copyright 2011 Google Inc. All Rights Reserved. -// -// Use of this source code is governed by a BSD-style license -// that can be found in the COPYING file in the root of the source -// tree. An additional intellectual property rights grant can be found -// in the file PATENTS. All contributing project authors may -// be found in the AUTHORS file in the root of the source tree. -// ----------------------------------------------------------------------------- -// -// Spatial prediction using various filters -// -// Author: Urvang (urvang@google.com) - -#include "./filters.h" -#include <assert.h> -#include <stdlib.h> -#include <string.h> - -//------------------------------------------------------------------------------ -// Helpful macro. - -# define SANITY_CHECK(in, out) \ - assert(in != NULL); \ - assert(out != NULL); \ - assert(width > 0); \ - assert(height > 0); \ - assert(stride >= width); \ - assert(row >= 0 && num_rows > 0 && row + num_rows <= height); \ - (void)height; // Silence unused warning. - -static WEBP_INLINE void PredictLine(const uint8_t* src, const uint8_t* pred, - uint8_t* dst, int length, int inverse) { - int i; - if (inverse) { - for (i = 0; i < length; ++i) dst[i] = src[i] + pred[i]; - } else { - for (i = 0; i < length; ++i) dst[i] = src[i] - pred[i]; - } -} - -//------------------------------------------------------------------------------ -// Horizontal filter. - -static WEBP_INLINE void DoHorizontalFilter(const uint8_t* in, - int width, int height, int stride, - int row, int num_rows, - int inverse, uint8_t* out) { - const uint8_t* preds; - const size_t start_offset = row * stride; - const int last_row = row + num_rows; - SANITY_CHECK(in, out); - in += start_offset; - out += start_offset; - preds = inverse ? out : in; - - if (row == 0) { - // Leftmost pixel is the same as input for topmost scanline. - out[0] = in[0]; - PredictLine(in + 1, preds, out + 1, width - 1, inverse); - row = 1; - preds += stride; - in += stride; - out += stride; - } - - // Filter line-by-line. - while (row < last_row) { - // Leftmost pixel is predicted from above. - PredictLine(in, preds - stride, out, 1, inverse); - PredictLine(in + 1, preds, out + 1, width - 1, inverse); - ++row; - preds += stride; - in += stride; - out += stride; - } -} - -static void HorizontalFilter(const uint8_t* data, int width, int height, - int stride, uint8_t* filtered_data) { - DoHorizontalFilter(data, width, height, stride, 0, height, 0, filtered_data); -} - -static void HorizontalUnfilter(int width, int height, int stride, int row, - int num_rows, uint8_t* data) { - DoHorizontalFilter(data, width, height, stride, row, num_rows, 1, data); -} - -//------------------------------------------------------------------------------ -// Vertical filter. - -static WEBP_INLINE void DoVerticalFilter(const uint8_t* in, - int width, int height, int stride, - int row, int num_rows, - int inverse, uint8_t* out) { - const uint8_t* preds; - const size_t start_offset = row * stride; - const int last_row = row + num_rows; - SANITY_CHECK(in, out); - in += start_offset; - out += start_offset; - preds = inverse ? out : in; - - if (row == 0) { - // Very first top-left pixel is copied. - out[0] = in[0]; - // Rest of top scan-line is left-predicted. - PredictLine(in + 1, preds, out + 1, width - 1, inverse); - row = 1; - in += stride; - out += stride; - } else { - // We are starting from in-between. Make sure 'preds' points to prev row. - preds -= stride; - } - - // Filter line-by-line. - while (row < last_row) { - PredictLine(in, preds, out, width, inverse); - ++row; - preds += stride; - in += stride; - out += stride; - } -} - -static void VerticalFilter(const uint8_t* data, int width, int height, - int stride, uint8_t* filtered_data) { - DoVerticalFilter(data, width, height, stride, 0, height, 0, filtered_data); -} - -static void VerticalUnfilter(int width, int height, int stride, int row, - int num_rows, uint8_t* data) { - DoVerticalFilter(data, width, height, stride, row, num_rows, 1, data); -} - -//------------------------------------------------------------------------------ -// Gradient filter. - -static WEBP_INLINE int GradientPredictor(uint8_t a, uint8_t b, uint8_t c) { - const int g = a + b - c; - return ((g & ~0xff) == 0) ? g : (g < 0) ? 0 : 255; // clip to 8bit -} - -static WEBP_INLINE void DoGradientFilter(const uint8_t* in, - int width, int height, int stride, - int row, int num_rows, - int inverse, uint8_t* out) { - const uint8_t* preds; - const size_t start_offset = row * stride; - const int last_row = row + num_rows; - SANITY_CHECK(in, out); - in += start_offset; - out += start_offset; - preds = inverse ? out : in; - - // left prediction for top scan-line - if (row == 0) { - out[0] = in[0]; - PredictLine(in + 1, preds, out + 1, width - 1, inverse); - row = 1; - preds += stride; - in += stride; - out += stride; - } - - // Filter line-by-line. - while (row < last_row) { - int w; - // leftmost pixel: predict from above. - PredictLine(in, preds - stride, out, 1, inverse); - for (w = 1; w < width; ++w) { - const int pred = GradientPredictor(preds[w - 1], - preds[w - stride], - preds[w - stride - 1]); - out[w] = in[w] + (inverse ? pred : -pred); - } - ++row; - preds += stride; - in += stride; - out += stride; - } -} - -static void GradientFilter(const uint8_t* data, int width, int height, - int stride, uint8_t* filtered_data) { - DoGradientFilter(data, width, height, stride, 0, height, 0, filtered_data); -} - -static void GradientUnfilter(int width, int height, int stride, int row, - int num_rows, uint8_t* data) { - DoGradientFilter(data, width, height, stride, row, num_rows, 1, data); -} - -#undef SANITY_CHECK - -// ----------------------------------------------------------------------------- -// Quick estimate of a potentially interesting filter mode to try. - -#define SMAX 16 -#define SDIFF(a, b) (abs((a) - (b)) >> 4) // Scoring diff, in [0..SMAX) - -WEBP_FILTER_TYPE EstimateBestFilter(const uint8_t* data, - int width, int height, int stride) { - int i, j; - int bins[WEBP_FILTER_LAST][SMAX]; - memset(bins, 0, sizeof(bins)); - - // We only sample every other pixels. That's enough. - for (j = 2; j < height - 1; j += 2) { - const uint8_t* const p = data + j * stride; - int mean = p[0]; - for (i = 2; i < width - 1; i += 2) { - const int diff0 = SDIFF(p[i], mean); - const int diff1 = SDIFF(p[i], p[i - 1]); - const int diff2 = SDIFF(p[i], p[i - width]); - const int grad_pred = - GradientPredictor(p[i - 1], p[i - width], p[i - width - 1]); - const int diff3 = SDIFF(p[i], grad_pred); - bins[WEBP_FILTER_NONE][diff0] = 1; - bins[WEBP_FILTER_HORIZONTAL][diff1] = 1; - bins[WEBP_FILTER_VERTICAL][diff2] = 1; - bins[WEBP_FILTER_GRADIENT][diff3] = 1; - mean = (3 * mean + p[i] + 2) >> 2; - } - } - { - int filter; - WEBP_FILTER_TYPE best_filter = WEBP_FILTER_NONE; - int best_score = 0x7fffffff; - for (filter = WEBP_FILTER_NONE; filter < WEBP_FILTER_LAST; ++filter) { - int score = 0; - for (i = 0; i < SMAX; ++i) { - if (bins[filter][i] > 0) { - score += i; - } - } - if (score < best_score) { - best_score = score; - best_filter = (WEBP_FILTER_TYPE)filter; - } - } - return best_filter; - } -} - -#undef SMAX -#undef SDIFF - -//------------------------------------------------------------------------------ - -const WebPFilterFunc WebPFilters[WEBP_FILTER_LAST] = { - NULL, // WEBP_FILTER_NONE - HorizontalFilter, // WEBP_FILTER_HORIZONTAL - VerticalFilter, // WEBP_FILTER_VERTICAL - GradientFilter // WEBP_FILTER_GRADIENT -}; - -const WebPUnfilterFunc WebPUnfilters[WEBP_FILTER_LAST] = { - NULL, // WEBP_FILTER_NONE - HorizontalUnfilter, // WEBP_FILTER_HORIZONTAL - VerticalUnfilter, // WEBP_FILTER_VERTICAL - GradientUnfilter // WEBP_FILTER_GRADIENT -}; - -//------------------------------------------------------------------------------ - |