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