media/libjpeg/jdsample.h

   1 /*
   2  * jdsample.h
   3  *
   4  * This file was part of the Independent JPEG Group's software:
   5  * Copyright (C) 1991-1996, Thomas G. Lane.
   6  * libjpeg-turbo Modifications:
   7  * Copyright (C) 2022, D. R. Commander.
   8  * For conditions of distribution and use, see the accompanying README.ijg
   9  * file.
  10  */
  11
  12 #define JPEG_INTERNALS
  13 #include "jpeglib.h"
  14 #include "jsamplecomp.h"
  15
  16
  17 /* Pointer to routine to upsample a single component */
  18 typedef void (*upsample1_ptr) (j_decompress_ptr cinfo,
  19                                jpeg_component_info *compptr,
  20                                _JSAMPARRAY input_data,
  21                                _JSAMPARRAY *output_data_ptr);
  22
  23 /* Private subobject */
  24
  25 typedef struct {
  26   struct jpeg_upsampler pub;    /* public fields */
  27
  28   /* Color conversion buffer.  When using separate upsampling and color
  29    * conversion steps, this buffer holds one upsampled row group until it
  30    * has been color converted and output.
  31    * Note: we do not allocate any storage for component(s) which are full-size,
  32    * ie do not need rescaling.  The corresponding entry of color_buf[] is
  33    * simply set to point to the input data array, thereby avoiding copying.
  34    */
  35   _JSAMPARRAY color_buf[MAX_COMPONENTS];
  36
  37   /* Per-component upsampling method pointers */
  38   upsample1_ptr methods[MAX_COMPONENTS];
  39
  40   int next_row_out;             /* counts rows emitted from color_buf */
  41   JDIMENSION rows_to_go;        /* counts rows remaining in image */
  42
  43   /* Height of an input row group for each component. */
  44   int rowgroup_height[MAX_COMPONENTS];
  45
  46   /* These arrays save pixel expansion factors so that int_expand need not
  47    * recompute them each time.  They are unused for other upsampling methods.
  48    */
  49   UINT8 h_expand[MAX_COMPONENTS];
  50   UINT8 v_expand[MAX_COMPONENTS];
  51 } my_upsampler;
  52
  53 typedef my_upsampler *my_upsample_ptr;