/*+
−
 * jcsample.c+
−
 *+
−
 * Copyright (C) 1991-1996, 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 downsampling routines.+
−
 *+
−
 * Downsampling input data is counted in "row groups".  A row group+
−
 * is defined to be max_v_samp_factor pixel rows of each component,+
−
 * from which the downsampler produces v_samp_factor sample rows.+
−
 * A single row group is processed in each call to the downsampler module.+
−
 *+
−
 * The downsampler is responsible for edge-expansion of its output data+
−
 * to fill an integral number of DCT blocks horizontally.  The source buffer+
−
 * may be modified if it is helpful for this purpose (the source buffer is+
−
 * allocated wide enough to correspond to the desired output width).+
−
 * The caller (the prep controller) is responsible for vertical padding.+
−
 *+
−
 * The downsampler may request "context rows" by setting need_context_rows+
−
 * during startup.  In this case, the input arrays will contain at least+
−
 * one row group's worth of pixels above and below the passed-in data;+
−
 * the caller will create dummy rows at image top and bottom by replicating+
−
 * the first or last real pixel row.+
−
 *+
−
 * An excellent reference for image resampling is+
−
 *   Digital Image Warping, George Wolberg, 1990.+
−
 *   Pub. by IEEE Computer Society Press, Los Alamitos, CA. ISBN 0-8186-8944-7.+
−
 *+
−
 * The downsampling algorithm used here is a simple average of the source+
−
 * pixels covered by the output pixel.  The hi-falutin sampling literature+
−
 * refers to this as a "box filter".  In general the characteristics of a box+
−
 * filter are not very good, but for the specific cases we normally use (1:1+
−
 * and 2:1 ratios) the box is equivalent to a "triangle filter" which is not+
−
 * nearly so bad.  If you intend to use other sampling ratios, you'd be well+
−
 * advised to improve this code.+
−
 *+
−
 * A simple input-smoothing capability is provided.  This is mainly intended+
−
 * for cleaning up color-dithered GIF input files (if you find it inadequate,+
−
 * we suggest using an external filtering program such as pnmconvol).  When+
−
 * enabled, each input pixel P is replaced by a weighted sum of itself and its+
−
 * eight neighbors.  P's weight is 1-8*SF and each neighbor's weight is SF,+
−
 * where SF = (smoothing_factor / 1024).+
−
 * Currently, smoothing is only supported for 2h2v sampling factors.+
−
 */+
−
+
−
#define JPEG_INTERNALS+
−
#include "jinclude.h"+
−
#include "jpeglib.h"+
−
+
−
+
−
/* Pointer to routine to downsample a single component */+
−
typedef JMETHOD(void, downsample1_ptr,+
−
		(j_compress_ptr cinfo, jpeg_component_info * compptr,+
−
		 JSAMPARRAY input_data, JSAMPARRAY output_data));+
−
+
−
/* Private subobject */+
−
+
−
typedef struct {+
−
  struct jpeg_downsampler pub;	/* public fields */+
−
+
−
  /* Downsampling method pointers, one per component */+
−
  downsample1_ptr methods[MAX_COMPONENTS];+
−
} my_downsampler;+
−
+
−
typedef my_downsampler * my_downsample_ptr;+
−
+
−
+
−
/*+
−
 * Initialize for a downsampling pass.+
−
 */+
−
+
−
METHODDEF(void)+
−
start_pass_downsample (j_compress_ptr cinfo)+
−
{+
−
  /* no work for now */+
−
}+
−
+
−
+
−
/*+
−
 * Expand a component horizontally from width input_cols to width output_cols,+
−
 * by duplicating the rightmost samples.+
−
 */+
−
+
−
LOCAL(void)+
−
expand_right_edge (JSAMPARRAY image_data, int num_rows,+
−
		   JDIMENSION input_cols, JDIMENSION output_cols)+
−
{+
−
  register JSAMPROW ptr;+
−
  register JSAMPLE pixval;+
−
  register int count;+
−
  int row;+
−
  int numcols = (int) (output_cols - input_cols);+
−
+
−
  if (numcols > 0) {+
−
    for (row = 0; row < num_rows; row++) {+
−
      ptr = image_data[row] + input_cols;+
−
      pixval = ptr[-1];		/* don't need GETJSAMPLE() here */+
−
      for (count = numcols; count > 0; count--)+
−
	*ptr++ = pixval;+
−
    }+
−
  }+
−
}+
−
+
−
+
−
/*+
−
 * Do downsampling for a whole row group (all components).+
−
 *+
−
 * In this version we simply downsample each component independently.+
−
 */+
−
+
−
METHODDEF(void)+
−
sep_downsample (j_compress_ptr cinfo,+
−
		JSAMPIMAGE input_buf, JDIMENSION in_row_index,+
−
		JSAMPIMAGE output_buf, JDIMENSION out_row_group_index)+
−
{+
−
  my_downsample_ptr downsample = (my_downsample_ptr) cinfo->downsample;+
−
  int ci;+
−
  jpeg_component_info * compptr;+
−
  JSAMPARRAY in_ptr, out_ptr;+
−
+
−
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;+
−
       ci++, compptr++) {+
−
    in_ptr = input_buf[ci] + in_row_index;+
−
    out_ptr = output_buf[ci] + (out_row_group_index * compptr->v_samp_factor);+
−
    (*downsample->methods[ci]) (cinfo, compptr, in_ptr, out_ptr);+
−
  }+
−
}+
−
+
−
+
−
/*+
−
 * Downsample pixel values of a single component.+
−
 * One row group is processed per call.+
−
 * This version handles arbitrary integral sampling ratios, without smoothing.+
−
 * Note that this version is not actually used for customary sampling ratios.+
−
 */+
−
+
−
METHODDEF(void)+
−
int_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,+
−
		JSAMPARRAY input_data, JSAMPARRAY output_data)+
−
{+
−
  int inrow, outrow, h_expand, v_expand, numpix, numpix2, h, v;+
−
  JDIMENSION outcol, outcol_h;	/* outcol_h == outcol*h_expand */+
−
  JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;+
−
  JSAMPROW inptr, outptr;+
−
  INT32 outvalue;+
−
+
−
  h_expand = cinfo->max_h_samp_factor / compptr->h_samp_factor;+
−
  v_expand = cinfo->max_v_samp_factor / compptr->v_samp_factor;+
−
  numpix = h_expand * v_expand;+
−
  numpix2 = numpix/2;+
−
+
−
  /* Expand input data enough to let all the output samples be generated+
−
   * by the standard loop.  Special-casing padded output would be more+
−
   * efficient.+
−
   */+
−
  expand_right_edge(input_data, cinfo->max_v_samp_factor,+
−
		    cinfo->image_width, output_cols * h_expand);+
−
+
−
  inrow = 0;+
−
  for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {+
−
    outptr = output_data[outrow];+
−
    for (outcol = 0, outcol_h = 0; outcol < output_cols;+
−
	 outcol++, outcol_h += h_expand) {+
−
      outvalue = 0;+
−
      for (v = 0; v < v_expand; v++) {+
−
	inptr = input_data[inrow+v] + outcol_h;+
−
	for (h = 0; h < h_expand; h++) {+
−
	  outvalue += (INT32) GETJSAMPLE(*inptr++);+
−
	}+
−
      }+
−
      *outptr++ = (JSAMPLE) ((outvalue + numpix2) / numpix);+
−
    }+
−
    inrow += v_expand;+
−
  }+
−
}+
−
+
−
+
−
/*+
−
 * Downsample pixel values of a single component.+
−
 * This version handles the special case of a full-size component,+
−
 * without smoothing.+
−
 */+
−
+
−
METHODDEF(void)+
−
fullsize_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,+
−
		     JSAMPARRAY input_data, JSAMPARRAY output_data)+
−
{+
−
  /* Copy the data */+
−
  jcopy_sample_rows(input_data, 0, output_data, 0,+
−
		    cinfo->max_v_samp_factor, cinfo->image_width);+
−
  /* Edge-expand */+
−
  expand_right_edge(output_data, cinfo->max_v_samp_factor,+
−
		    cinfo->image_width, compptr->width_in_blocks * DCTSIZE);+
−
}+
−
+
−
+
−
/*+
−
 * Downsample pixel values of a single component.+
−
 * This version handles the common case of 2:1 horizontal and 1:1 vertical,+
−
 * without smoothing.+
−
 *+
−
 * A note about the "bias" calculations: when rounding fractional values to+
−
 * integer, we do not want to always round 0.5 up to the next integer.+
−
 * If we did that, we'd introduce a noticeable bias towards larger values.+
−
 * Instead, this code is arranged so that 0.5 will be rounded up or down at+
−
 * alternate pixel locations (a simple ordered dither pattern).+
−
 */+
−
+
−
METHODDEF(void)+
−
h2v1_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,+
−
		 JSAMPARRAY input_data, JSAMPARRAY output_data)+
−
{+
−
  int outrow;+
−
  JDIMENSION outcol;+
−
  JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;+
−
  register JSAMPROW inptr, outptr;+
−
  register int bias;+
−
+
−
  /* Expand input data enough to let all the output samples be generated+
−
   * by the standard loop.  Special-casing padded output would be more+
−
   * efficient.+
−
   */+
−
  expand_right_edge(input_data, cinfo->max_v_samp_factor,+
−
		    cinfo->image_width, output_cols * 2);+
−
+
−
  for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {+
−
    outptr = output_data[outrow];+
−
    inptr = input_data[outrow];+
−
    bias = 0;			/* bias = 0,1,0,1,... for successive samples */+
−
    for (outcol = 0; outcol < output_cols; outcol++) {+
−
      *outptr++ = (JSAMPLE) ((GETJSAMPLE(*inptr) + GETJSAMPLE(inptr[1])+
−
			      + bias) >> 1);+
−
      bias ^= 1;		/* 0=>1, 1=>0 */+
−
      inptr += 2;+
−
    }+
−
  }+
−
}+
−
+
−
+
−
/*+
−
 * Downsample pixel values of a single component.+
−
 * This version handles the standard case of 2:1 horizontal and 2:1 vertical,+
−
 * without smoothing.+
−
 */+
−
+
−
METHODDEF(void)+
−
h2v2_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,+
−
		 JSAMPARRAY input_data, JSAMPARRAY output_data)+
−
{+
−
  int inrow, outrow;+
−
  JDIMENSION outcol;+
−
  JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;+
−
  register JSAMPROW inptr0, inptr1, outptr;+
−
  register int bias;+
−
+
−
  /* Expand input data enough to let all the output samples be generated+
−
   * by the standard loop.  Special-casing padded output would be more+
−
   * efficient.+
−
   */+
−
  expand_right_edge(input_data, cinfo->max_v_samp_factor,+
−
		    cinfo->image_width, output_cols * 2);+
−
+
−
  inrow = 0;+
−
  for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {+
−
    outptr = output_data[outrow];+
−
    inptr0 = input_data[inrow];+
−
    inptr1 = input_data[inrow+1];+
−
    bias = 1;			/* bias = 1,2,1,2,... for successive samples */+
−
    for (outcol = 0; outcol < output_cols; outcol++) {+
−
      *outptr++ = (JSAMPLE) ((GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) ++
−
			      GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1])+
−
			      + bias) >> 2);+
−
      bias ^= 3;		/* 1=>2, 2=>1 */+
−
      inptr0 += 2; inptr1 += 2;+
−
    }+
−
    inrow += 2;+
−
  }+
−
}+
−
+
−
+
−
#ifdef INPUT_SMOOTHING_SUPPORTED+
−
+
−
/*+
−
 * Downsample pixel values of a single component.+
−
 * This version handles the standard case of 2:1 horizontal and 2:1 vertical,+
−
 * with smoothing.  One row of context is required.+
−
 */+
−
+
−
METHODDEF(void)+
−
h2v2_smooth_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,+
−
			JSAMPARRAY input_data, JSAMPARRAY output_data)+
−
{+
−
  int inrow, outrow;+
−
  JDIMENSION colctr;+
−
  JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;+
−
  register JSAMPROW inptr0, inptr1, above_ptr, below_ptr, outptr;+
−
  INT32 membersum, neighsum, memberscale, neighscale;+
−
+
−
  /* Expand input data enough to let all the output samples be generated+
−
   * by the standard loop.  Special-casing padded output would be more+
−
   * efficient.+
−
   */+
−
  expand_right_edge(input_data - 1, cinfo->max_v_samp_factor + 2,+
−
		    cinfo->image_width, output_cols * 2);+
−
+
−
  /* We don't bother to form the individual "smoothed" input pixel values;+
−
   * we can directly compute the output which is the average of the four+
−
   * smoothed values.  Each of the four member pixels contributes a fraction+
−
   * (1-8*SF) to its own smoothed image and a fraction SF to each of the three+
−
   * other smoothed pixels, therefore a total fraction (1-5*SF)/4 to the final+
−
   * output.  The four corner-adjacent neighbor pixels contribute a fraction+
−
   * SF to just one smoothed pixel, or SF/4 to the final output; while the+
−
   * eight edge-adjacent neighbors contribute SF to each of two smoothed+
−
   * pixels, or SF/2 overall.  In order to use integer arithmetic, these+
−
   * factors are scaled by 2^16 = 65536.+
−
   * Also recall that SF = smoothing_factor / 1024.+
−
   */+
−
+
−
  memberscale = 16384 - cinfo->smoothing_factor * 80; /* scaled (1-5*SF)/4 */+
−
  neighscale = cinfo->smoothing_factor * 16; /* scaled SF/4 */+
−
+
−
  inrow = 0;+
−
  for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {+
−
    outptr = output_data[outrow];+
−
    inptr0 = input_data[inrow];+
−
    inptr1 = input_data[inrow+1];+
−
    above_ptr = input_data[inrow-1];+
−
    below_ptr = input_data[inrow+2];+
−
+
−
    /* Special case for first column: pretend column -1 is same as column 0 */+
−
    membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) ++
−
		GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);+
−
    neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) ++
−
	       GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) ++
−
	       GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[2]) ++
−
	       GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[2]);+
−
    neighsum += neighsum;+
−
    neighsum += GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[2]) ++
−
		GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[2]);+
−
    membersum = membersum * memberscale + neighsum * neighscale;+
−
    *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);+
−
    inptr0 += 2; inptr1 += 2; above_ptr += 2; below_ptr += 2;+
−
+
−
    for (colctr = output_cols - 2; colctr > 0; colctr--) {+
−
      /* sum of pixels directly mapped to this output element */+
−
      membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) ++
−
		  GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);+
−
      /* sum of edge-neighbor pixels */+
−
      neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) ++
−
		 GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) ++
−
		 GETJSAMPLE(inptr0[-1]) + GETJSAMPLE(inptr0[2]) ++
−
		 GETJSAMPLE(inptr1[-1]) + GETJSAMPLE(inptr1[2]);+
−
      /* The edge-neighbors count twice as much as corner-neighbors */+
−
      neighsum += neighsum;+
−
      /* Add in the corner-neighbors */+
−
      neighsum += GETJSAMPLE(above_ptr[-1]) + GETJSAMPLE(above_ptr[2]) ++
−
		  GETJSAMPLE(below_ptr[-1]) + GETJSAMPLE(below_ptr[2]);+
−
      /* form final output scaled up by 2^16 */+
−
      membersum = membersum * memberscale + neighsum * neighscale;+
−
      /* round, descale and output it */+
−
      *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);+
−
      inptr0 += 2; inptr1 += 2; above_ptr += 2; below_ptr += 2;+
−
    }+
−
+
−
    /* Special case for last column */+
−
    membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) ++
−
		GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);+
−
    neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) ++
−
	       GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) ++
−
	       GETJSAMPLE(inptr0[-1]) + GETJSAMPLE(inptr0[1]) ++
−
	       GETJSAMPLE(inptr1[-1]) + GETJSAMPLE(inptr1[1]);+
−
    neighsum += neighsum;+
−
    neighsum += GETJSAMPLE(above_ptr[-1]) + GETJSAMPLE(above_ptr[1]) ++
−
		GETJSAMPLE(below_ptr[-1]) + GETJSAMPLE(below_ptr[1]);+
−
    membersum = membersum * memberscale + neighsum * neighscale;+
−
    *outptr = (JSAMPLE) ((membersum + 32768) >> 16);+
−
+
−
    inrow += 2;+
−
  }+
−
}+
−
+
−
+
−
/*+
−
 * Downsample pixel values of a single component.+
−
 * This version handles the special case of a full-size component,+
−
 * with smoothing.  One row of context is required.+
−
 */+
−
+
−
METHODDEF(void)+
−
fullsize_smooth_downsample (j_compress_ptr cinfo, jpeg_component_info *compptr,+
−
			    JSAMPARRAY input_data, JSAMPARRAY output_data)+
−
{+
−
  int outrow;+
−
  JDIMENSION colctr;+
−
  JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;+
−
  register JSAMPROW inptr, above_ptr, below_ptr, outptr;+
−
  INT32 membersum, neighsum, memberscale, neighscale;+
−
  int colsum, lastcolsum, nextcolsum;+
−
+
−
  /* Expand input data enough to let all the output samples be generated+
−
   * by the standard loop.  Special-casing padded output would be more+
−
   * efficient.+
−
   */+
−
  expand_right_edge(input_data - 1, cinfo->max_v_samp_factor + 2,+
−
		    cinfo->image_width, output_cols);+
−
+
−
  /* Each of the eight neighbor pixels contributes a fraction SF to the+
−
   * smoothed pixel, while the main pixel contributes (1-8*SF).  In order+
−
   * to use integer arithmetic, these factors are multiplied by 2^16 = 65536.+
−
   * Also recall that SF = smoothing_factor / 1024.+
−
   */+
−
+
−
  memberscale = 65536L - cinfo->smoothing_factor * 512L; /* scaled 1-8*SF */+
−
  neighscale = cinfo->smoothing_factor * 64; /* scaled SF */+
−
+
−
  for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {+
−
    outptr = output_data[outrow];+
−
    inptr = input_data[outrow];+
−
    above_ptr = input_data[outrow-1];+
−
    below_ptr = input_data[outrow+1];+
−
+
−
    /* Special case for first column */+
−
    colsum = GETJSAMPLE(*above_ptr++) + GETJSAMPLE(*below_ptr++) ++
−
	     GETJSAMPLE(*inptr);+
−
    membersum = GETJSAMPLE(*inptr++);+
−
    nextcolsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(*below_ptr) ++
−
		 GETJSAMPLE(*inptr);+
−
    neighsum = colsum + (colsum - membersum) + nextcolsum;+
−
    membersum = membersum * memberscale + neighsum * neighscale;+
−
    *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);+
−
    lastcolsum = colsum; colsum = nextcolsum;+
−
+
−
    for (colctr = output_cols - 2; colctr > 0; colctr--) {+
−
      membersum = GETJSAMPLE(*inptr++);+
−
      above_ptr++; below_ptr++;+
−
      nextcolsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(*below_ptr) ++
−
		   GETJSAMPLE(*inptr);+
−
      neighsum = lastcolsum + (colsum - membersum) + nextcolsum;+
−
      membersum = membersum * memberscale + neighsum * neighscale;+
−
      *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);+
−
      lastcolsum = colsum; colsum = nextcolsum;+
−
    }+
−
+
−
    /* Special case for last column */+
−
    membersum = GETJSAMPLE(*inptr);+
−
    neighsum = lastcolsum + (colsum - membersum) + colsum;+
−
    membersum = membersum * memberscale + neighsum * neighscale;+
−
    *outptr = (JSAMPLE) ((membersum + 32768) >> 16);+
−
+
−
  }+
−
}+
−
+
−
#endif /* INPUT_SMOOTHING_SUPPORTED */+
−
+
−
+
−
/*+
−
 * Module initialization routine for downsampling.+
−
 * Note that we must select a routine for each component.+
−
 */+
−
+
−
GLOBAL(void)+
−
jinit_downsampler (j_compress_ptr cinfo)+
−
{+
−
  my_downsample_ptr downsample;+
−
  int ci;+
−
  jpeg_component_info * compptr;+
−
  boolean smoothok = TRUE;+
−
+
−
  downsample = (my_downsample_ptr)+
−
    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,+
−
				SIZEOF(my_downsampler));+
−
  cinfo->downsample = (struct jpeg_downsampler *) downsample;+
−
  downsample->pub.start_pass = start_pass_downsample;+
−
  downsample->pub.downsample = sep_downsample;+
−
  downsample->pub.need_context_rows = FALSE;+
−
+
−
  if (cinfo->CCIR601_sampling)+
−
    ERREXIT(cinfo, JERR_CCIR601_NOTIMPL);+
−
+
−
  /* Verify we can handle the sampling factors, and set up method pointers */+
−
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;+
−
       ci++, compptr++) {+
−
    if (compptr->h_samp_factor == cinfo->max_h_samp_factor &&+
−
	compptr->v_samp_factor == cinfo->max_v_samp_factor) {+
−
#ifdef INPUT_SMOOTHING_SUPPORTED+
−
      if (cinfo->smoothing_factor) {+
−
	downsample->methods[ci] = fullsize_smooth_downsample;+
−
	downsample->pub.need_context_rows = TRUE;+
−
      } else+
−
#endif+
−
	downsample->methods[ci] = fullsize_downsample;+
−
    } else if (compptr->h_samp_factor * 2 == cinfo->max_h_samp_factor &&+
−
	       compptr->v_samp_factor == cinfo->max_v_samp_factor) {+
−
      smoothok = FALSE;+
−
      downsample->methods[ci] = h2v1_downsample;+
−
    } else if (compptr->h_samp_factor * 2 == cinfo->max_h_samp_factor &&+
−
	       compptr->v_samp_factor * 2 == cinfo->max_v_samp_factor) {+
−
#ifdef INPUT_SMOOTHING_SUPPORTED+
−
      if (cinfo->smoothing_factor) {+
−
	downsample->methods[ci] = h2v2_smooth_downsample;+
−
	downsample->pub.need_context_rows = TRUE;+
−
      } else+
−
#endif+
−
	downsample->methods[ci] = h2v2_downsample;+
−
    } else if ((cinfo->max_h_samp_factor % compptr->h_samp_factor) == 0 &&+
−
	       (cinfo->max_v_samp_factor % compptr->v_samp_factor) == 0) {+
−
      smoothok = FALSE;+
−
      downsample->methods[ci] = int_downsample;+
−
    } else+
−
      ERREXIT(cinfo, JERR_FRACT_SAMPLE_NOTIMPL);+
−
  }+
−
+
−
#ifdef INPUT_SMOOTHING_SUPPORTED+
−
  if (cinfo->smoothing_factor && !smoothok)+
−
    TRACEMS(cinfo, 0, JTRC_SMOOTH_NOTIMPL);+
−
#endif+
−
}+
−