text: /*
   * Copyright (C) 2001-2011 Michael Niedermayer <michaelni@gmx.at>
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #ifndef SWSCALE_SWSCALE_H
  #define SWSCALE_SWSCALE_H
  
  /**
   * @file
   * @ingroup libsws
   * external API header
   */
  
  #include <stdint.h>
  
  #include "libavutil/avutil.h"
  #include "libavutil/log.h"
  #include "libavutil/pixfmt.h"
  #include "version.h"
  
  /**
   * @defgroup libsws Color conversion and scaling
   * @{
   *
   * Return the LIBSWSCALE_VERSION_INT constant.
   */
  unsigned swscale_version(void);
  
  /**
   * Return the libswscale build-time configuration.
   */
  const char *swscale_configuration(void);
  
  /**
   * Return the libswscale license.
   */
  const char *swscale_license(void);
  
  /* values for the flags, the stuff on the command line is different */
  #define SWS_FAST_BILINEAR     1
  #define SWS_BILINEAR          2
  #define SWS_BICUBIC           4
  #define SWS_X                 8
  #define SWS_POINT          0x10
  #define SWS_AREA           0x20
  #define SWS_BICUBLIN       0x40
  #define SWS_GAUSS          0x80
  #define SWS_SINC          0x100
  #define SWS_LANCZOS       0x200
  #define SWS_SPLINE        0x400
  
  #define SWS_SRC_V_CHR_DROP_MASK     0x30000
  #define SWS_SRC_V_CHR_DROP_SHIFT    16
  
  #define SWS_PARAM_DEFAULT           123456
  
  #define SWS_PRINT_INFO              0x1000
  
  //the following 3 flags are not completely implemented
  //internal chrominace subsampling info
  #define SWS_FULL_CHR_H_INT    0x2000
  //input subsampling info
  #define SWS_FULL_CHR_H_INP    0x4000
  #define SWS_DIRECT_BGR        0x8000
  #define SWS_ACCURATE_RND      0x40000
  #define SWS_BITEXACT          0x80000
  #define SWS_ERROR_DIFFUSION  0x800000
  
  #define SWS_MAX_REDUCE_CUTOFF 0.002
  
  #define SWS_CS_ITU709         1
  #define SWS_CS_FCC            4
  #define SWS_CS_ITU601         5
  #define SWS_CS_ITU624         5
  #define SWS_CS_SMPTE170M      5
  #define SWS_CS_SMPTE240M      7
  #define SWS_CS_DEFAULT        5
  
  /**
   * Return a pointer to yuv<->rgb coefficients for the given colorspace
   * suitable for sws_setColorspaceDetails().
   *
   * @param colorspace One of the SWS_CS_* macros. If invalid,
   * SWS_CS_DEFAULT is used.
   */
  const int *sws_getCoefficients(int colorspace);
  
  // when used for filters they must have an odd number of elements
  // coeffs cannot be shared between vectors
  typedef struct SwsVector {
      double *coeff;              ///< pointer to the list of coefficients
      int length;                 ///< number of coefficients in the vector
  } SwsVector;
  
  // vectors can be shared
  typedef struct SwsFilter {
      SwsVector *lumH;
      SwsVector *lumV;
      SwsVector *chrH;
      SwsVector *chrV;
  } SwsFilter;
  
  struct SwsContext;
  
  /**
   * Return a positive value if pix_fmt is a supported input format, 0
   * otherwise.
   */
  int sws_isSupportedInput(enum AVPixelFormat pix_fmt);
  
  /**
   * Return a positive value if pix_fmt is a supported output format, 0
   * otherwise.
   */
  int sws_isSupportedOutput(enum AVPixelFormat pix_fmt);
  
  /**
   * @param[in]  pix_fmt the pixel format
   * @return a positive value if an endianness conversion for pix_fmt is
   * supported, 0 otherwise.
   */
  int sws_isSupportedEndiannessConversion(enum AVPixelFormat pix_fmt);
  
  /**
   * Allocate an empty SwsContext. This must be filled and passed to
   * sws_init_context(). For filling see AVOptions, options.c and
   * sws_setColorspaceDetails().
   */
  struct SwsContext *sws_alloc_context(void);
  
  /**
   * Initialize the swscaler context sws_context.
   *
   * @return zero or positive value on success, a negative value on
   * error
   */
  av_warn_unused_result
  int sws_init_context(struct SwsContext *sws_context, SwsFilter *srcFilter, SwsFilter *dstFilter);
  
  /**
   * Free the swscaler context swsContext.
   * If swsContext is NULL, then does nothing.
   */
  void sws_freeContext(struct SwsContext *swsContext);
  
  /**
   * Allocate and return an SwsContext. You need it to perform
   * scaling/conversion operations using sws_scale().
   *
   * @param srcW the width of the source image
   * @param srcH the height of the source image
   * @param srcFormat the source image format
   * @param dstW the width of the destination image
   * @param dstH the height of the destination image
   * @param dstFormat the destination image format
   * @param flags specify which algorithm and options to use for rescaling
   * @param param extra parameters to tune the used scaler
   *              For SWS_BICUBIC param[0] and [1] tune the shape of the basis
   *              function, param[0] tunes f(1) and param[1] f´(1)
   *              For SWS_GAUSS param[0] tunes the exponent and thus cutoff
   *              frequency
   *              For SWS_LANCZOS param[0] tunes the width of the window function
   * @return a pointer to an allocated context, or NULL in case of error
   * @note this function is to be removed after a saner alternative is
   *       written
   */
  struct SwsContext *sws_getContext(int srcW, int srcH, enum AVPixelFormat srcFormat,
                                    int dstW, int dstH, enum AVPixelFormat dstFormat,
                                    int flags, SwsFilter *srcFilter,
                                    SwsFilter *dstFilter, const double *param);
  
  /**
   * Scale the image slice in srcSlice and put the resulting scaled
   * slice in the image in dst. A slice is a sequence of consecutive
   * rows in an image.
   *
   * Slices have to be provided in sequential order, either in
   * top-bottom or bottom-top order. If slices are provided in
   * non-sequential order the behavior of the function is undefined.
   *
   * @param c         the scaling context previously created with
   *                  sws_getContext()
   * @param srcSlice  the array containing the pointers to the planes of
   *                  the source slice
   * @param srcStride the array containing the strides for each plane of
   *                  the source image
   * @param srcSliceY the position in the source image of the slice to
   *                  process, that is the number (counted starting from
   *                  zero) in the image of the first row of the slice
   * @param srcSliceH the height of the source slice, that is the number
   *                  of rows in the slice
   * @param dst       the array containing the pointers to the planes of
   *                  the destination image
   * @param dstStride the array containing the strides for each plane of
   *                  the destination image
   * @return          the height of the output slice
   */
  int sws_scale(struct SwsContext *c, const uint8_t *const srcSlice[],
                const int srcStride[], int srcSliceY, int srcSliceH,
                uint8_t *const dst[], const int dstStride[]);
  
  /**
   * @param dstRange flag indicating the while-black range of the output (1=jpeg / 0=mpeg)
   * @param srcRange flag indicating the while-black range of the input (1=jpeg / 0=mpeg)
   * @param table the yuv2rgb coefficients describing the output yuv space, normally ff_yuv2rgb_coeffs[x]
   * @param inv_table the yuv2rgb coefficients describing the input yuv space, normally ff_yuv2rgb_coeffs[x]
   * @param brightness 16.16 fixed point brightness correction
   * @param contrast 16.16 fixed point contrast correction
   * @param saturation 16.16 fixed point saturation correction
   * @return -1 if not supported
   */
  int sws_setColorspaceDetails(struct SwsContext *c, const int inv_table[4],
                               int srcRange, const int table[4], int dstRange,
                               int brightness, int contrast, int saturation);
  
  /**
   * @return -1 if not supported
   */
  int sws_getColorspaceDetails(struct SwsContext *c, int **inv_table,
                               int *srcRange, int **table, int *dstRange,
                               int *brightness, int *contrast, int *saturation);
  
  /**
   * Allocate and return an uninitialized vector with length coefficients.
   */
  SwsVector *sws_allocVec(int length);
  
  /**
   * Return a normalized Gaussian curve used to filter stuff
   * quality = 3 is high quality, lower is lower quality.
   */
  SwsVector *sws_getGaussianVec(double variance, double quality);
  
  /**
   * Allocate and return a vector with length coefficients, all
   * with the same value c.
   */
  SwsVector *sws_getConstVec(double c, int length);
  
  /**
   * Allocate and return a vector with just one coefficient, with
   * value 1.0.
   */
  SwsVector *sws_getIdentityVec(void);
  
  /**
   * Scale all the coefficients of a by the scalar value.
   */
  void sws_scaleVec(SwsVector *a, double scalar);
  
  /**
   * Scale all the coefficients of a so that their sum equals height.
   */
  void sws_normalizeVec(SwsVector *a, double height);
  void sws_convVec(SwsVector *a, SwsVector *b);
  void sws_addVec(SwsVector *a, SwsVector *b);
  void sws_subVec(SwsVector *a, SwsVector *b);
  void sws_shiftVec(SwsVector *a, int shift);
  
  /**
   * Allocate and return a clone of the vector a, that is a vector
   * with the same coefficients as a.
   */
  SwsVector *sws_cloneVec(SwsVector *a);
  
  /**
   * Print with av_log() a textual representation of the vector a
   * if log_level <= av_log_level.
   */
  void sws_printVec2(SwsVector *a, AVClass *log_ctx, int log_level);
  
  void sws_freeVec(SwsVector *a);
  
  SwsFilter *sws_getDefaultFilter(float lumaGBlur, float chromaGBlur,
                                  float lumaSharpen, float chromaSharpen,
                                  float chromaHShift, float chromaVShift,
                                  int verbose);
  void sws_freeFilter(SwsFilter *filter);
  
  /**
   * Check if context can be reused, otherwise reallocate a new one.
   *
   * If context is NULL, just calls sws_getContext() to get a new
   * context. Otherwise, checks if the parameters are the ones already
   * saved in context. If that is the case, returns the current
   * context. Otherwise, frees context and gets a new context with
   * the new parameters.
   *
   * Be warned that srcFilter and dstFilter are not checked, they
   * are assumed to remain the same.
   */
  struct SwsContext *sws_getCachedContext(struct SwsContext *context,
                                          int srcW, int srcH, enum AVPixelFormat srcFormat,
                                          int dstW, int dstH, enum AVPixelFormat dstFormat,
                                          int flags, SwsFilter *srcFilter,
                                          SwsFilter *dstFilter, const double *param);
  
  /**
   * Convert an 8-bit paletted frame into a frame with a color depth of 32 bits.
   *
   * The output frame will have the same packed format as the palette.
   *
   * @param src        source frame buffer
   * @param dst        destination frame buffer
   * @param num_pixels number of pixels to convert
   * @param palette    array with [256] entries, which must match color arrangement (RGB or BGR) of src
   */
  void sws_convertPalette8ToPacked32(const uint8_t *src, uint8_t *dst, int num_pixels, const uint8_t *palette);
  
  /**
   * Convert an 8-bit paletted frame into a frame with a color depth of 24 bits.
   *
   * With the palette format "ABCD", the destination frame ends up with the format "ABC".
   *
   * @param src        source frame buffer
   * @param dst        destination frame buffer
   * @param num_pixels number of pixels to convert
   * @param palette    array with [256] entries, which must match color arrangement (RGB or BGR) of src
   */
  void sws_convertPalette8ToPacked24(const uint8_t *src, uint8_t *dst, int num_pixels, const uint8_t *palette);
  
  /**
   * Get the AVClass for swsContext. It can be used in combination with
   * AV_OPT_SEARCH_FAKE_OBJ for examining options.
   *
   * @see av_opt_find().
   */
  const AVClass *sws_get_class(void);
  
  /**
   * @}
   */
  
  #endif /* SWSCALE_SWSCALE_H */
  