134 lines
3.6 KiB
C
134 lines
3.6 KiB
C
/*
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* jdsample.c
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*
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* Copyright (C) 1991, Thomas G. Lane.
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* This file is part of the Independent JPEG Group's software.
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* For conditions of distribution and use, see the accompanying README file.
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*
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* This file contains un-subsampling routines.
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* These routines are invoked via the unsubsample and
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* unsubsample_init/term methods.
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*/
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#include "jinclude.h"
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/*
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* Initialize for un-subsampling a scan.
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*/
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METHODDEF void
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unsubsample_init (decompress_info_ptr cinfo)
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{
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/* no work for now */
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}
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/*
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* Un-subsample pixel values of a single component.
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* This version only handles integral sampling ratios.
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*/
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METHODDEF void
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unsubsample (decompress_info_ptr cinfo, int which_component,
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long input_cols, int input_rows,
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long output_cols, int output_rows,
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JSAMPARRAY above, JSAMPARRAY input_data, JSAMPARRAY below,
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JSAMPARRAY output_data)
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{
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jpeg_component_info * compptr = cinfo->cur_comp_info[which_component];
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short h_expand, v_expand, h, v;
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int inrow, outrow;
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long incol;
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JSAMPROW inptr, outptr;
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JSAMPLE invalue;
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/* TEMP FOR DEBUGGING PIPELINE CONTROLLER */
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if (input_rows != compptr->v_samp_factor ||
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output_rows != cinfo->max_v_samp_factor ||
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(input_cols % compptr->h_samp_factor) != 0 ||
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(output_cols % cinfo->max_h_samp_factor) != 0 ||
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output_cols*compptr->h_samp_factor != input_cols*cinfo->max_h_samp_factor)
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ERREXIT(cinfo->emethods, "Bogus unsubsample parameters");
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h_expand = cinfo->max_h_samp_factor / compptr->h_samp_factor;
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v_expand = cinfo->max_v_samp_factor / compptr->v_samp_factor;
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outrow = 0;
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for (inrow = 0; inrow < input_rows; inrow++) {
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for (v = 0; v < v_expand; v++) {
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inptr = input_data[inrow];
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outptr = output_data[outrow++];
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for (incol = 0; incol < input_cols; incol++) {
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invalue = GETJSAMPLE(*inptr++);
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for (h = 0; h < h_expand; h++) {
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*outptr++ = invalue;
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}
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}
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}
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}
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}
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/*
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* Un-subsample pixel values of a single component.
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* This version handles the special case of a full-size component.
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*/
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METHODDEF void
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fullsize_unsubsample (decompress_info_ptr cinfo, int which_component,
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long input_cols, int input_rows,
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long output_cols, int output_rows,
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JSAMPARRAY above, JSAMPARRAY input_data, JSAMPARRAY below,
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JSAMPARRAY output_data)
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{
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if (input_cols != output_cols || input_rows != output_rows) /* DEBUG */
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ERREXIT(cinfo->emethods, "Pipeline controller messed up");
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jcopy_sample_rows(input_data, 0, output_data, 0, output_rows, output_cols);
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}
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/*
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* Clean up after a scan.
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*/
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METHODDEF void
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unsubsample_term (decompress_info_ptr cinfo)
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{
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/* no work for now */
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}
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/*
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* The method selection routine for unsubsampling.
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* Note that we must select a routine for each component.
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*/
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GLOBAL void
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jselunsubsample (decompress_info_ptr cinfo)
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{
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short ci;
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jpeg_component_info * compptr;
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if (cinfo->CCIR601_sampling)
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ERREXIT(cinfo->emethods, "CCIR601 subsampling not implemented yet");
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for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
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compptr = cinfo->cur_comp_info[ci];
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if (compptr->h_samp_factor == cinfo->max_h_samp_factor &&
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compptr->v_samp_factor == cinfo->max_v_samp_factor)
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cinfo->methods->unsubsample[ci] = fullsize_unsubsample;
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else if ((cinfo->max_h_samp_factor % compptr->h_samp_factor) == 0 &&
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(cinfo->max_v_samp_factor % compptr->v_samp_factor) == 0)
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cinfo->methods->unsubsample[ci] = unsubsample;
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else
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ERREXIT(cinfo->emethods, "Fractional subsampling not implemented yet");
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}
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cinfo->methods->unsubsample_init = unsubsample_init;
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cinfo->methods->unsubsample_term = unsubsample_term;
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}
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