76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
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/*
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* jcexpand.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 image edge-expansion routines.
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* These routines are invoked via the edge_expand method.
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*/
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#include "jinclude.h"
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/*
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* Expand an image so that it is a multiple of the MCU dimensions.
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* This is to be accomplished by duplicating the rightmost column
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* and/or bottommost row of pixels. The image has not yet been
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* subsampled, so all components have the same dimensions.
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*/
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METHODDEF void
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edge_expand (compress_info_ptr cinfo,
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long input_cols, int input_rows,
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long output_cols, int output_rows,
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JSAMPIMAGE image_data)
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{
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/* Expand horizontally */
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if (input_cols < output_cols) {
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register JSAMPROW ptr;
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register JSAMPLE pixval;
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register long count;
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register int row;
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short ci;
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long numcols = output_cols - input_cols;
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for (ci = 0; ci < cinfo->num_components; ci++) {
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for (row = 0; row < input_rows; row++) {
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ptr = image_data[ci][row] + (input_cols-1);
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pixval = GETJSAMPLE(*ptr++);
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for (count = numcols; count > 0; count--)
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*ptr++ = pixval;
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}
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}
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}
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/* Expand vertically */
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/* This happens only once at the bottom of the image, */
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/* so it needn't be super-efficient */
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if (input_rows < output_rows) {
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register int row;
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short ci;
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JSAMPARRAY this_component;
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for (ci = 0; ci < cinfo->num_components; ci++) {
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this_component = image_data[ci];
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for (row = input_rows; row < output_rows; row++) {
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jcopy_sample_rows(this_component, input_rows-1, this_component, row,
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1, output_cols);
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}
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}
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}
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}
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/*
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* The method selection routine for edge expansion.
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*/
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GLOBAL void
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jselexpand (compress_info_ptr cinfo)
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{
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/* just one implementation for now */
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cinfo->methods->edge_expand = edge_expand;
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}
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