libjpeg update

git-svn-id: http://svn.miranda-ng.org/main/trunk@5843 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c

1 files changed, 545 insertions, 545 deletions

diff --git a/plugins/AdvaImg/src/LibJPEG/jcsample.c b/plugins/AdvaImg/src/LibJPEG/jcsample.c
index 4d36f85f35..1aef8a6fc7 100644
--- a/plugins/AdvaImg/src/LibJPEG/jcsample.c
+++ b/plugins/AdvaImg/src/LibJPEG/jcsample.c
@@ -1,545 +1,545 @@
-/*
- * 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];
-
-  /* Height of an output row group for each component. */
-  int rowgroup_height[MAX_COMPONENTS];
-
-  /* These arrays save pixel expansion factors so that int_downsample need not
-   * recompute them each time.  They are unused for other downsampling methods.
-   */
-  UINT8 h_expand[MAX_COMPONENTS];
-  UINT8 v_expand[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 * downsample->rowgroup_height[ci]);
-    (*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)
-{
-  my_downsample_ptr downsample = (my_downsample_ptr) cinfo->downsample;
-  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 * compptr->DCT_h_scaled_size;
-  JSAMPROW inptr, outptr;
-  INT32 outvalue;
-
-  h_expand = downsample->h_expand[compptr->component_index];
-  v_expand = downsample->v_expand[compptr->component_index];
-  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 = outrow = 0;
-  while (inrow < cinfo->max_v_samp_factor) {
-    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;
-    outrow++;
-  }
-}
-
-
-/*
- * 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 * compptr->DCT_h_scaled_size);
-}
-
-
-/*
- * 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 inrow;
-  JDIMENSION outcol;
-  JDIMENSION output_cols = compptr->width_in_blocks * compptr->DCT_h_scaled_size;
-  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 (inrow = 0; inrow < cinfo->max_v_samp_factor; inrow++) {
-    outptr = output_data[inrow];
-    inptr = input_data[inrow];
-    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 * compptr->DCT_h_scaled_size;
-  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 = outrow = 0;
-  while (inrow < cinfo->max_v_samp_factor) {
-    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;
-    outrow++;
-  }
-}
-
-
-#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 * compptr->DCT_h_scaled_size;
-  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 = outrow = 0;
-  while (inrow < cinfo->max_v_samp_factor) {
-    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;
-    outrow++;
-  }
-}
-
-
-/*
- * 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 inrow;
-  JDIMENSION colctr;
-  JDIMENSION output_cols = compptr->width_in_blocks * compptr->DCT_h_scaled_size;
-  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 (inrow = 0; inrow < cinfo->max_v_samp_factor; inrow++) {
-    outptr = output_data[inrow];
-    inptr = input_data[inrow];
-    above_ptr = input_data[inrow-1];
-    below_ptr = input_data[inrow+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;
-  int h_in_group, v_in_group, h_out_group, v_out_group;
-
-  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++) {
-    /* Compute size of an "output group" for DCT scaling.  This many samples
-     * are to be converted from max_h_samp_factor * max_v_samp_factor pixels.
-     */
-    h_out_group = (compptr->h_samp_factor * compptr->DCT_h_scaled_size) /
-		  cinfo->min_DCT_h_scaled_size;
-    v_out_group = (compptr->v_samp_factor * compptr->DCT_v_scaled_size) /
-		  cinfo->min_DCT_v_scaled_size;
-    h_in_group = cinfo->max_h_samp_factor;
-    v_in_group = cinfo->max_v_samp_factor;
-    downsample->rowgroup_height[ci] = v_out_group; /* save for use later */
-    if (h_in_group == h_out_group && v_in_group == v_out_group) {
-#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 (h_in_group == h_out_group * 2 &&
-	       v_in_group == v_out_group) {
-      smoothok = FALSE;
-      downsample->methods[ci] = h2v1_downsample;
-    } else if (h_in_group == h_out_group * 2 &&
-	       v_in_group == v_out_group * 2) {
-#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 ((h_in_group % h_out_group) == 0 &&
-	       (v_in_group % v_out_group) == 0) {
-      smoothok = FALSE;
-      downsample->methods[ci] = int_downsample;
-      downsample->h_expand[ci] = (UINT8) (h_in_group / h_out_group);
-      downsample->v_expand[ci] = (UINT8) (v_in_group / v_out_group);
-    } else
-      ERREXIT(cinfo, JERR_FRACT_SAMPLE_NOTIMPL);
-  }
-
-#ifdef INPUT_SMOOTHING_SUPPORTED
-  if (cinfo->smoothing_factor && !smoothok)
-    TRACEMS(cinfo, 0, JTRC_SMOOTH_NOTIMPL);
-#endif
-}
+/*

+ * 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];

+

+  /* Height of an output row group for each component. */

+  int rowgroup_height[MAX_COMPONENTS];

+

+  /* These arrays save pixel expansion factors so that int_downsample need not

+   * recompute them each time.  They are unused for other downsampling methods.

+   */

+  UINT8 h_expand[MAX_COMPONENTS];

+  UINT8 v_expand[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 * downsample->rowgroup_height[ci]);

+    (*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)

+{

+  my_downsample_ptr downsample = (my_downsample_ptr) cinfo->downsample;

+  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 * compptr->DCT_h_scaled_size;

+  JSAMPROW inptr, outptr;

+  INT32 outvalue;

+

+  h_expand = downsample->h_expand[compptr->component_index];

+  v_expand = downsample->v_expand[compptr->component_index];

+  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 = outrow = 0;

+  while (inrow < cinfo->max_v_samp_factor) {

+    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;

+    outrow++;

+  }

+}

+

+

+/*

+ * 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 * compptr->DCT_h_scaled_size);

+}

+

+

+/*

+ * 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 inrow;

+  JDIMENSION outcol;

+  JDIMENSION output_cols = compptr->width_in_blocks * compptr->DCT_h_scaled_size;

+  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 (inrow = 0; inrow < cinfo->max_v_samp_factor; inrow++) {

+    outptr = output_data[inrow];

+    inptr = input_data[inrow];

+    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 * compptr->DCT_h_scaled_size;

+  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 = outrow = 0;

+  while (inrow < cinfo->max_v_samp_factor) {

+    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;

+    outrow++;

+  }

+}

+

+

+#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 * compptr->DCT_h_scaled_size;

+  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 = outrow = 0;

+  while (inrow < cinfo->max_v_samp_factor) {

+    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;

+    outrow++;

+  }

+}

+

+

+/*

+ * 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 inrow;

+  JDIMENSION colctr;

+  JDIMENSION output_cols = compptr->width_in_blocks * compptr->DCT_h_scaled_size;

+  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 (inrow = 0; inrow < cinfo->max_v_samp_factor; inrow++) {

+    outptr = output_data[inrow];

+    inptr = input_data[inrow];

+    above_ptr = input_data[inrow-1];

+    below_ptr = input_data[inrow+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;

+  int h_in_group, v_in_group, h_out_group, v_out_group;

+

+  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++) {

+    /* Compute size of an "output group" for DCT scaling.  This many samples

+     * are to be converted from max_h_samp_factor * max_v_samp_factor pixels.

+     */

+    h_out_group = (compptr->h_samp_factor * compptr->DCT_h_scaled_size) /

+		  cinfo->min_DCT_h_scaled_size;

+    v_out_group = (compptr->v_samp_factor * compptr->DCT_v_scaled_size) /

+		  cinfo->min_DCT_v_scaled_size;

+    h_in_group = cinfo->max_h_samp_factor;

+    v_in_group = cinfo->max_v_samp_factor;

+    downsample->rowgroup_height[ci] = v_out_group; /* save for use later */

+    if (h_in_group == h_out_group && v_in_group == v_out_group) {

+#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 (h_in_group == h_out_group * 2 &&

+	       v_in_group == v_out_group) {

+      smoothok = FALSE;

+      downsample->methods[ci] = h2v1_downsample;

+    } else if (h_in_group == h_out_group * 2 &&

+	       v_in_group == v_out_group * 2) {

+#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 ((h_in_group % h_out_group) == 0 &&

+	       (v_in_group % v_out_group) == 0) {

+      smoothok = FALSE;

+      downsample->methods[ci] = int_downsample;

+      downsample->h_expand[ci] = (UINT8) (h_in_group / h_out_group);

+      downsample->v_expand[ci] = (UINT8) (v_in_group / v_out_group);

+    } else

+      ERREXIT(cinfo, JERR_FRACT_SAMPLE_NOTIMPL);

+  }

+

+#ifdef INPUT_SMOOTHING_SUPPORTED

+  if (cinfo->smoothing_factor && !smoothok)

+    TRACEMS(cinfo, 0, JTRC_SMOOTH_NOTIMPL);

+#endif

+}