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Diffstat (limited to 'src/3rdparty/libwebp/src/utils/rescaler.h')
-rw-r--r-- | src/3rdparty/libwebp/src/utils/rescaler.h | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/src/3rdparty/libwebp/src/utils/rescaler.h b/src/3rdparty/libwebp/src/utils/rescaler.h new file mode 100644 index 0000000..68e49ce --- /dev/null +++ b/src/3rdparty/libwebp/src/utils/rescaler.h @@ -0,0 +1,84 @@ +// Copyright 2012 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. +// ----------------------------------------------------------------------------- +// +// Rescaling functions +// +// Author: Skal (pascal.massimino@gmail.com) + +#ifndef WEBP_UTILS_RESCALER_H_ +#define WEBP_UTILS_RESCALER_H_ + +#ifdef __cplusplus +extern "C" { +#endif + +#include "../webp/types.h" + +// Structure used for on-the-fly rescaling +typedef struct { + int x_expand; // true if we're expanding in the x direction + int num_channels; // bytes to jump between pixels + int fy_scale, fx_scale; // fixed-point scaling factor + int64_t fxy_scale; // '' + // we need hpel-precise add/sub increments, for the downsampled U/V planes. + int y_accum; // vertical accumulator + int y_add, y_sub; // vertical increments (add ~= src, sub ~= dst) + int x_add, x_sub; // horizontal increments (add ~= src, sub ~= dst) + int src_width, src_height; // source dimensions + int dst_width, dst_height; // destination dimensions + uint8_t* dst; + int dst_stride; + int32_t* irow, *frow; // work buffer +} WebPRescaler; + +// Initialize a rescaler given scratch area 'work' and dimensions of src & dst. +void WebPRescalerInit(WebPRescaler* const rescaler, + int src_width, int src_height, + uint8_t* const dst, + int dst_width, int dst_height, int dst_stride, + int num_channels, + int x_add, int x_sub, + int y_add, int y_sub, + int32_t* const work); + +// Returns the number of input lines needed next to produce one output line, +// considering that the maximum available input lines are 'max_num_lines'. +int WebPRescaleNeededLines(const WebPRescaler* const rescaler, + int max_num_lines); + +// Import a row of data and save its contribution in the rescaler. +// 'channel' denotes the channel number to be imported. +void WebPRescalerImportRow(WebPRescaler* const rescaler, + const uint8_t* const src, int channel); + +// Import multiple rows over all channels, until at least one row is ready to +// be exported. Returns the actual number of lines that were imported. +int WebPRescalerImport(WebPRescaler* const rescaler, int num_rows, + const uint8_t* src, int src_stride); + +// Return true if there is pending output rows ready. +static WEBP_INLINE +int WebPRescalerHasPendingOutput(const WebPRescaler* const rescaler) { + return (rescaler->y_accum <= 0); +} + +// Export one row from rescaler. Returns the pointer where output was written, +// or NULL if no row was pending. +uint8_t* WebPRescalerExportRow(WebPRescaler* const rescaler); + +// Export as many rows as possible. Return the numbers of rows written. +int WebPRescalerExport(WebPRescaler* const rescaler); + +//------------------------------------------------------------------------------ + +#ifdef __cplusplus +} // extern "C" +#endif + +#endif /* WEBP_UTILS_RESCALER_H_ */ |