/libjpeg/jcscale.c
https://code.google.com/p/xee/ · C · 62 lines · 38 code · 14 blank · 10 comment · 2 complexity · a774b925aa1c7d29f97d617615345f51 MD5 · raw file
- /*
- * jcscale.c
- *
- * Copyright (C) 1998, 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 sample downscaling by 2^Pt for lossless JPEG.
- */
- #define JPEG_INTERNALS
- #include "jinclude.h"
- #include "jpeglib.h"
- #include "jlossls.h" /* Private declarations for lossless codec */
- #ifdef C_LOSSLESS_SUPPORTED
- METHODDEF(void)
- simple_downscale(j_compress_ptr cinfo,
- JSAMPROW input_buf, JSAMPROW output_buf, JDIMENSION width)
- {
- j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
- int xindex;
- for (xindex = 0; xindex < width; xindex++)
- output_buf[xindex] = (JSAMPLE) RIGHT_SHIFT(GETJSAMPLE(input_buf[xindex]),
- cinfo->Al);
- }
- METHODDEF(void)
- noscale(j_compress_ptr cinfo,
- JSAMPROW input_buf, JSAMPROW output_buf, JDIMENSION width)
- {
- MEMCOPY(output_buf, input_buf, width * SIZEOF(JSAMPLE));
- return;
- }
- METHODDEF(void)
- scaler_start_pass (j_compress_ptr cinfo)
- {
- j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
- /* Set scaler function based on Pt */
- if (cinfo->Al)
- losslsc->scaler_scale = simple_downscale;
- else
- losslsc->scaler_scale = noscale;
- }
- GLOBAL(void)
- jinit_c_scaler (j_compress_ptr cinfo)
- {
- j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
- losslsc->scaler_start_pass = scaler_start_pass;
- }
- #endif /* C_LOSSLESS_SUPPORTED */