46 lines
1.6 KiB
C
46 lines
1.6 KiB
C
// Copyright 2013 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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// Utilities for processing transparent channel.
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//
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// Author: Skal (pascal.massimino@gmail.com)
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#ifndef WEBP_UTILS_ALPHA_PROCESSING_H_
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#define WEBP_UTILS_ALPHA_PROCESSING_H_
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#include "../webp/types.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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// Pre-Multiply operation transforms x into x * A / 255 (where x=Y,R,G or B).
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// Un-Multiply operation transforms x into x * 255 / A.
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// Pre-Multiply or Un-Multiply (if 'inverse' is true) argb values in a row.
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void WebPMultARGBRow(uint32_t* const ptr, int width, int inverse);
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// Same a WebPMultARGBRow(), but for several rows.
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void WebPMultARGBRows(uint8_t* ptr, int stride, int width, int num_rows,
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int inverse);
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// Same for a row of single values, with side alpha values.
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void WebPMultRow(uint8_t* const ptr, const uint8_t* const alpha,
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int width, int inverse);
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// Same a WebPMultRow(), but for several 'num_rows' rows.
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void WebPMultRows(uint8_t* ptr, int stride,
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const uint8_t* alpha, int alpha_stride,
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int width, int num_rows, int inverse);
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#ifdef __cplusplus
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} // extern "C"
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#endif
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#endif // WEBP_UTILS_ALPHA_PROCESSING_H_
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