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