godot/thirdparty/libwebp/src/utils/rescaler_utils.h

// 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 ([email protected])

#ifndef WEBP_UTILS_RESCALER_UTILS_H_
#define WEBP_UTILS_RESCALER_UTILS_H_

#ifdef __cplusplus
extern "C" {
#endif

#include "src/webp/types.h"

#define WEBP_RESCALER_RFIX …
#define WEBP_RESCALER_ONE …
#define WEBP_RESCALER_FRAC(x, y) …

// Structure used for on-the-fly rescaling
rescaler_t;   // type for side-buffer
WebPRescaler;
struct WebPRescaler { … };

// Initialize a rescaler given scratch area 'work' and dimensions of src & dst.
// Returns false in case of error.
int 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,
                     rescaler_t* const work);

// If either 'scaled_width' or 'scaled_height' (but not both) is 0 the value
// will be calculated preserving the aspect ratio, otherwise the values are
// left unmodified. Returns true on success, false if either value is 0 after
// performing the scaling calculation.
int WebPRescalerGetScaledDimensions(int src_width, int src_height,
                                    int* const scaled_width,
                                    int* const scaled_height);

// 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 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);

// Export as many rows as possible. Return the numbers of rows written.
int WebPRescalerExport(WebPRescaler* const rescaler);

// Return true if input is finished
static WEBP_INLINE
int WebPRescalerInputDone(const WebPRescaler* const rescaler) { … }
// Return true if output is finished
static WEBP_INLINE
int WebPRescalerOutputDone(const WebPRescaler* const rescaler) { … }

// Return true if there are pending output rows ready.
static WEBP_INLINE
int WebPRescalerHasPendingOutput(const WebPRescaler* const rescaler) { … }

//------------------------------------------------------------------------------

#ifdef __cplusplus
}    // extern "C"
#endif

#endif  // WEBP_UTILS_RESCALER_UTILS_H_