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* jdsample.h
* This file was part of the Independent JPEG Group's software:
* Copyright (C) 1991-1996, Thomas G. Lane.
* For conditions of distribution and use, see the accompanying README.ijg
* file.
#include "jpeglib.h"
/* Pointer to routine to upsample a single component */
typedef void (*upsample1_ptr) (j_decompress_ptr cinfo,
jpeg_component_info *compptr,
JSAMPARRAY input_data,
JSAMPARRAY *output_data_ptr);
/* Private subobject */
typedef struct {
struct jpeg_upsampler pub; /* public fields */
/* Color conversion buffer. When using separate upsampling and color
* conversion steps, this buffer holds one upsampled row group until it
* has been color converted and output.
* Note: we do not allocate any storage for component(s) which are full-size,
* ie do not need rescaling. The corresponding entry of color_buf[] is
* simply set to point to the input data array, thereby avoiding copying.
/* Per-component upsampling method pointers */
upsample1_ptr methods[MAX_COMPONENTS];
int next_row_out; /* counts rows emitted from color_buf */
JDIMENSION rows_to_go; /* counts rows remaining in image */
/* Height of an input row group for each component. */
int rowgroup_height[MAX_COMPONENTS];
/* These arrays save pixel expansion factors so that int_expand need not
* recompute them each time. They are unused for other upsampling methods.
} my_upsampler;
typedef my_upsampler *my_upsample_ptr;