nuclear@26: /*
nuclear@26:  * jdsample.c
nuclear@26:  *
nuclear@26:  * Copyright (C) 1991-1996, Thomas G. Lane.
nuclear@26:  * This file is part of the Independent JPEG Group's software.
nuclear@26:  * For conditions of distribution and use, see the accompanying README file.
nuclear@26:  *
nuclear@26:  * This file contains upsampling routines.
nuclear@26:  *
nuclear@26:  * Upsampling input data is counted in "row groups".  A row group
nuclear@26:  * is defined to be (v_samp_factor * DCT_scaled_size / min_DCT_scaled_size)
nuclear@26:  * sample rows of each component.  Upsampling will normally produce
nuclear@26:  * max_v_samp_factor pixel rows from each row group (but this could vary
nuclear@26:  * if the upsampler is applying a scale factor of its own).
nuclear@26:  *
nuclear@26:  * An excellent reference for image resampling is
nuclear@26:  *   Digital Image Warping, George Wolberg, 1990.
nuclear@26:  *   Pub. by IEEE Computer Society Press, Los Alamitos, CA. ISBN 0-8186-8944-7.
nuclear@26:  */
nuclear@26: 
nuclear@26: #define JPEG_INTERNALS
nuclear@26: #include "jinclude.h"
nuclear@26: #include "jpeglib.h"
nuclear@26: 
nuclear@26: 
nuclear@26: /* Pointer to routine to upsample a single component */
nuclear@26: typedef JMETHOD(void, upsample1_ptr,
nuclear@26: 		(j_decompress_ptr cinfo, jpeg_component_info * compptr,
nuclear@26: 		 JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr));
nuclear@26: 
nuclear@26: /* Private subobject */
nuclear@26: 
nuclear@26: typedef struct {
nuclear@26:   struct jpeg_upsampler pub;	/* public fields */
nuclear@26: 
nuclear@26:   /* Color conversion buffer.  When using separate upsampling and color
nuclear@26:    * conversion steps, this buffer holds one upsampled row group until it
nuclear@26:    * has been color converted and output.
nuclear@26:    * Note: we do not allocate any storage for component(s) which are full-size,
nuclear@26:    * ie do not need rescaling.  The corresponding entry of color_buf[] is
nuclear@26:    * simply set to point to the input data array, thereby avoiding copying.
nuclear@26:    */
nuclear@26:   JSAMPARRAY color_buf[MAX_COMPONENTS];
nuclear@26: 
nuclear@26:   /* Per-component upsampling method pointers */
nuclear@26:   upsample1_ptr methods[MAX_COMPONENTS];
nuclear@26: 
nuclear@26:   int next_row_out;		/* counts rows emitted from color_buf */
nuclear@26:   JDIMENSION rows_to_go;	/* counts rows remaining in image */
nuclear@26: 
nuclear@26:   /* Height of an input row group for each component. */
nuclear@26:   int rowgroup_height[MAX_COMPONENTS];
nuclear@26: 
nuclear@26:   /* These arrays save pixel expansion factors so that int_expand need not
nuclear@26:    * recompute them each time.  They are unused for other upsampling methods.
nuclear@26:    */
nuclear@26:   UINT8 h_expand[MAX_COMPONENTS];
nuclear@26:   UINT8 v_expand[MAX_COMPONENTS];
nuclear@26: } my_upsampler;
nuclear@26: 
nuclear@26: typedef my_upsampler * my_upsample_ptr;
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Initialize for an upsampling pass.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: start_pass_upsample (j_decompress_ptr cinfo)
nuclear@26: {
nuclear@26:   my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
nuclear@26: 
nuclear@26:   /* Mark the conversion buffer empty */
nuclear@26:   upsample->next_row_out = cinfo->max_v_samp_factor;
nuclear@26:   /* Initialize total-height counter for detecting bottom of image */
nuclear@26:   upsample->rows_to_go = cinfo->output_height;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Control routine to do upsampling (and color conversion).
nuclear@26:  *
nuclear@26:  * In this version we upsample each component independently.
nuclear@26:  * We upsample one row group into the conversion buffer, then apply
nuclear@26:  * color conversion a row at a time.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: sep_upsample (j_decompress_ptr cinfo,
nuclear@26: 	      JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
nuclear@26: 	      JDIMENSION in_row_groups_avail,
nuclear@26: 	      JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
nuclear@26: 	      JDIMENSION out_rows_avail)
nuclear@26: {
nuclear@26:   my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
nuclear@26:   int ci;
nuclear@26:   jpeg_component_info * compptr;
nuclear@26:   JDIMENSION num_rows;
nuclear@26: 
nuclear@26:   /* Fill the conversion buffer, if it's empty */
nuclear@26:   if (upsample->next_row_out >= cinfo->max_v_samp_factor) {
nuclear@26:     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@26: 	 ci++, compptr++) {
nuclear@26:       /* Invoke per-component upsample method.  Notice we pass a POINTER
nuclear@26:        * to color_buf[ci], so that fullsize_upsample can change it.
nuclear@26:        */
nuclear@26:       (*upsample->methods[ci]) (cinfo, compptr,
nuclear@26: 	input_buf[ci] + (*in_row_group_ctr * upsample->rowgroup_height[ci]),
nuclear@26: 	upsample->color_buf + ci);
nuclear@26:     }
nuclear@26:     upsample->next_row_out = 0;
nuclear@26:   }
nuclear@26: 
nuclear@26:   /* Color-convert and emit rows */
nuclear@26: 
nuclear@26:   /* How many we have in the buffer: */
nuclear@26:   num_rows = (JDIMENSION) (cinfo->max_v_samp_factor - upsample->next_row_out);
nuclear@26:   /* Not more than the distance to the end of the image.  Need this test
nuclear@26:    * in case the image height is not a multiple of max_v_samp_factor:
nuclear@26:    */
nuclear@26:   if (num_rows > upsample->rows_to_go) 
nuclear@26:     num_rows = upsample->rows_to_go;
nuclear@26:   /* And not more than what the client can accept: */
nuclear@26:   out_rows_avail -= *out_row_ctr;
nuclear@26:   if (num_rows > out_rows_avail)
nuclear@26:     num_rows = out_rows_avail;
nuclear@26: 
nuclear@26:   (*cinfo->cconvert->color_convert) (cinfo, upsample->color_buf,
nuclear@26: 				     (JDIMENSION) upsample->next_row_out,
nuclear@26: 				     output_buf + *out_row_ctr,
nuclear@26: 				     (int) num_rows);
nuclear@26: 
nuclear@26:   /* Adjust counts */
nuclear@26:   *out_row_ctr += num_rows;
nuclear@26:   upsample->rows_to_go -= num_rows;
nuclear@26:   upsample->next_row_out += num_rows;
nuclear@26:   /* When the buffer is emptied, declare this input row group consumed */
nuclear@26:   if (upsample->next_row_out >= cinfo->max_v_samp_factor)
nuclear@26:     (*in_row_group_ctr)++;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * These are the routines invoked by sep_upsample to upsample pixel values
nuclear@26:  * of a single component.  One row group is processed per call.
nuclear@26:  */
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * For full-size components, we just make color_buf[ci] point at the
nuclear@26:  * input buffer, and thus avoid copying any data.  Note that this is
nuclear@26:  * safe only because sep_upsample doesn't declare the input row group
nuclear@26:  * "consumed" until we are done color converting and emitting it.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: fullsize_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
nuclear@26: 		   JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
nuclear@26: {
nuclear@26:   *output_data_ptr = input_data;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * This is a no-op version used for "uninteresting" components.
nuclear@26:  * These components will not be referenced by color conversion.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: noop_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
nuclear@26: 	       JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
nuclear@26: {
nuclear@26:   *output_data_ptr = NULL;	/* safety check */
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * This version handles any integral sampling ratios.
nuclear@26:  * This is not used for typical JPEG files, so it need not be fast.
nuclear@26:  * Nor, for that matter, is it particularly accurate: the algorithm is
nuclear@26:  * simple replication of the input pixel onto the corresponding output
nuclear@26:  * pixels.  The hi-falutin sampling literature refers to this as a
nuclear@26:  * "box filter".  A box filter tends to introduce visible artifacts,
nuclear@26:  * so if you are actually going to use 3:1 or 4:1 sampling ratios
nuclear@26:  * you would be well advised to improve this code.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: int_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
nuclear@26: 	      JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
nuclear@26: {
nuclear@26:   my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
nuclear@26:   JSAMPARRAY output_data = *output_data_ptr;
nuclear@26:   register JSAMPROW inptr, outptr;
nuclear@26:   register JSAMPLE invalue;
nuclear@26:   register int h;
nuclear@26:   JSAMPROW outend;
nuclear@26:   int h_expand, v_expand;
nuclear@26:   int inrow, outrow;
nuclear@26: 
nuclear@26:   h_expand = upsample->h_expand[compptr->component_index];
nuclear@26:   v_expand = upsample->v_expand[compptr->component_index];
nuclear@26: 
nuclear@26:   inrow = outrow = 0;
nuclear@26:   while (outrow < cinfo->max_v_samp_factor) {
nuclear@26:     /* Generate one output row with proper horizontal expansion */
nuclear@26:     inptr = input_data[inrow];
nuclear@26:     outptr = output_data[outrow];
nuclear@26:     outend = outptr + cinfo->output_width;
nuclear@26:     while (outptr < outend) {
nuclear@26:       invalue = *inptr++;	/* don't need GETJSAMPLE() here */
nuclear@26:       for (h = h_expand; h > 0; h--) {
nuclear@26: 	*outptr++ = invalue;
nuclear@26:       }
nuclear@26:     }
nuclear@26:     /* Generate any additional output rows by duplicating the first one */
nuclear@26:     if (v_expand > 1) {
nuclear@26:       jcopy_sample_rows(output_data, outrow, output_data, outrow+1,
nuclear@26: 			v_expand-1, cinfo->output_width);
nuclear@26:     }
nuclear@26:     inrow++;
nuclear@26:     outrow += v_expand;
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Fast processing for the common case of 2:1 horizontal and 1:1 vertical.
nuclear@26:  * It's still a box filter.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: h2v1_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
nuclear@26: 	       JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
nuclear@26: {
nuclear@26:   JSAMPARRAY output_data = *output_data_ptr;
nuclear@26:   register JSAMPROW inptr, outptr;
nuclear@26:   register JSAMPLE invalue;
nuclear@26:   JSAMPROW outend;
nuclear@26:   int inrow;
nuclear@26: 
nuclear@26:   for (inrow = 0; inrow < cinfo->max_v_samp_factor; inrow++) {
nuclear@26:     inptr = input_data[inrow];
nuclear@26:     outptr = output_data[inrow];
nuclear@26:     outend = outptr + cinfo->output_width;
nuclear@26:     while (outptr < outend) {
nuclear@26:       invalue = *inptr++;	/* don't need GETJSAMPLE() here */
nuclear@26:       *outptr++ = invalue;
nuclear@26:       *outptr++ = invalue;
nuclear@26:     }
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Fast processing for the common case of 2:1 horizontal and 2:1 vertical.
nuclear@26:  * It's still a box filter.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: h2v2_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
nuclear@26: 	       JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
nuclear@26: {
nuclear@26:   JSAMPARRAY output_data = *output_data_ptr;
nuclear@26:   register JSAMPROW inptr, outptr;
nuclear@26:   register JSAMPLE invalue;
nuclear@26:   JSAMPROW outend;
nuclear@26:   int inrow, outrow;
nuclear@26: 
nuclear@26:   inrow = outrow = 0;
nuclear@26:   while (outrow < cinfo->max_v_samp_factor) {
nuclear@26:     inptr = input_data[inrow];
nuclear@26:     outptr = output_data[outrow];
nuclear@26:     outend = outptr + cinfo->output_width;
nuclear@26:     while (outptr < outend) {
nuclear@26:       invalue = *inptr++;	/* don't need GETJSAMPLE() here */
nuclear@26:       *outptr++ = invalue;
nuclear@26:       *outptr++ = invalue;
nuclear@26:     }
nuclear@26:     jcopy_sample_rows(output_data, outrow, output_data, outrow+1,
nuclear@26: 		      1, cinfo->output_width);
nuclear@26:     inrow++;
nuclear@26:     outrow += 2;
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Fancy processing for the common case of 2:1 horizontal and 1:1 vertical.
nuclear@26:  *
nuclear@26:  * The upsampling algorithm is linear interpolation between pixel centers,
nuclear@26:  * also known as a "triangle filter".  This is a good compromise between
nuclear@26:  * speed and visual quality.  The centers of the output pixels are 1/4 and 3/4
nuclear@26:  * of the way between input pixel centers.
nuclear@26:  *
nuclear@26:  * A note about the "bias" calculations: when rounding fractional values to
nuclear@26:  * integer, we do not want to always round 0.5 up to the next integer.
nuclear@26:  * If we did that, we'd introduce a noticeable bias towards larger values.
nuclear@26:  * Instead, this code is arranged so that 0.5 will be rounded up or down at
nuclear@26:  * alternate pixel locations (a simple ordered dither pattern).
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: h2v1_fancy_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
nuclear@26: 		     JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
nuclear@26: {
nuclear@26:   JSAMPARRAY output_data = *output_data_ptr;
nuclear@26:   register JSAMPROW inptr, outptr;
nuclear@26:   register int invalue;
nuclear@26:   register JDIMENSION colctr;
nuclear@26:   int inrow;
nuclear@26: 
nuclear@26:   for (inrow = 0; inrow < cinfo->max_v_samp_factor; inrow++) {
nuclear@26:     inptr = input_data[inrow];
nuclear@26:     outptr = output_data[inrow];
nuclear@26:     /* Special case for first column */
nuclear@26:     invalue = GETJSAMPLE(*inptr++);
nuclear@26:     *outptr++ = (JSAMPLE) invalue;
nuclear@26:     *outptr++ = (JSAMPLE) ((invalue * 3 + GETJSAMPLE(*inptr) + 2) >> 2);
nuclear@26: 
nuclear@26:     for (colctr = compptr->downsampled_width - 2; colctr > 0; colctr--) {
nuclear@26:       /* General case: 3/4 * nearer pixel + 1/4 * further pixel */
nuclear@26:       invalue = GETJSAMPLE(*inptr++) * 3;
nuclear@26:       *outptr++ = (JSAMPLE) ((invalue + GETJSAMPLE(inptr[-2]) + 1) >> 2);
nuclear@26:       *outptr++ = (JSAMPLE) ((invalue + GETJSAMPLE(*inptr) + 2) >> 2);
nuclear@26:     }
nuclear@26: 
nuclear@26:     /* Special case for last column */
nuclear@26:     invalue = GETJSAMPLE(*inptr);
nuclear@26:     *outptr++ = (JSAMPLE) ((invalue * 3 + GETJSAMPLE(inptr[-1]) + 1) >> 2);
nuclear@26:     *outptr++ = (JSAMPLE) invalue;
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Fancy processing for the common case of 2:1 horizontal and 2:1 vertical.
nuclear@26:  * Again a triangle filter; see comments for h2v1 case, above.
nuclear@26:  *
nuclear@26:  * It is OK for us to reference the adjacent input rows because we demanded
nuclear@26:  * context from the main buffer controller (see initialization code).
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: h2v2_fancy_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
nuclear@26: 		     JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
nuclear@26: {
nuclear@26:   JSAMPARRAY output_data = *output_data_ptr;
nuclear@26:   register JSAMPROW inptr0, inptr1, outptr;
nuclear@26: #if BITS_IN_JSAMPLE == 8
nuclear@26:   register int thiscolsum, lastcolsum, nextcolsum;
nuclear@26: #else
nuclear@26:   register INT32 thiscolsum, lastcolsum, nextcolsum;
nuclear@26: #endif
nuclear@26:   register JDIMENSION colctr;
nuclear@26:   int inrow, outrow, v;
nuclear@26: 
nuclear@26:   inrow = outrow = 0;
nuclear@26:   while (outrow < cinfo->max_v_samp_factor) {
nuclear@26:     for (v = 0; v < 2; v++) {
nuclear@26:       /* inptr0 points to nearest input row, inptr1 points to next nearest */
nuclear@26:       inptr0 = input_data[inrow];
nuclear@26:       if (v == 0)		/* next nearest is row above */
nuclear@26: 	inptr1 = input_data[inrow-1];
nuclear@26:       else			/* next nearest is row below */
nuclear@26: 	inptr1 = input_data[inrow+1];
nuclear@26:       outptr = output_data[outrow++];
nuclear@26: 
nuclear@26:       /* Special case for first column */
nuclear@26:       thiscolsum = GETJSAMPLE(*inptr0++) * 3 + GETJSAMPLE(*inptr1++);
nuclear@26:       nextcolsum = GETJSAMPLE(*inptr0++) * 3 + GETJSAMPLE(*inptr1++);
nuclear@26:       *outptr++ = (JSAMPLE) ((thiscolsum * 4 + 8) >> 4);
nuclear@26:       *outptr++ = (JSAMPLE) ((thiscolsum * 3 + nextcolsum + 7) >> 4);
nuclear@26:       lastcolsum = thiscolsum; thiscolsum = nextcolsum;
nuclear@26: 
nuclear@26:       for (colctr = compptr->downsampled_width - 2; colctr > 0; colctr--) {
nuclear@26: 	/* General case: 3/4 * nearer pixel + 1/4 * further pixel in each */
nuclear@26: 	/* dimension, thus 9/16, 3/16, 3/16, 1/16 overall */
nuclear@26: 	nextcolsum = GETJSAMPLE(*inptr0++) * 3 + GETJSAMPLE(*inptr1++);
nuclear@26: 	*outptr++ = (JSAMPLE) ((thiscolsum * 3 + lastcolsum + 8) >> 4);
nuclear@26: 	*outptr++ = (JSAMPLE) ((thiscolsum * 3 + nextcolsum + 7) >> 4);
nuclear@26: 	lastcolsum = thiscolsum; thiscolsum = nextcolsum;
nuclear@26:       }
nuclear@26: 
nuclear@26:       /* Special case for last column */
nuclear@26:       *outptr++ = (JSAMPLE) ((thiscolsum * 3 + lastcolsum + 8) >> 4);
nuclear@26:       *outptr++ = (JSAMPLE) ((thiscolsum * 4 + 7) >> 4);
nuclear@26:     }
nuclear@26:     inrow++;
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Module initialization routine for upsampling.
nuclear@26:  */
nuclear@26: 
nuclear@26: GLOBAL(void)
nuclear@26: jinit_upsampler (j_decompress_ptr cinfo)
nuclear@26: {
nuclear@26:   my_upsample_ptr upsample;
nuclear@26:   int ci;
nuclear@26:   jpeg_component_info * compptr;
nuclear@26:   boolean need_buffer, do_fancy;
nuclear@26:   int h_in_group, v_in_group, h_out_group, v_out_group;
nuclear@26: 
nuclear@26:   upsample = (my_upsample_ptr)
nuclear@26:     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@26: 				SIZEOF(my_upsampler));
nuclear@26:   cinfo->upsample = (struct jpeg_upsampler *) upsample;
nuclear@26:   upsample->pub.start_pass = start_pass_upsample;
nuclear@26:   upsample->pub.upsample = sep_upsample;
nuclear@26:   upsample->pub.need_context_rows = FALSE; /* until we find out differently */
nuclear@26: 
nuclear@26:   if (cinfo->CCIR601_sampling)	/* this isn't supported */
nuclear@26:     ERREXIT(cinfo, JERR_CCIR601_NOTIMPL);
nuclear@26: 
nuclear@26:   /* jdmainct.c doesn't support context rows when min_DCT_scaled_size = 1,
nuclear@26:    * so don't ask for it.
nuclear@26:    */
nuclear@26:   do_fancy = cinfo->do_fancy_upsampling && cinfo->min_DCT_scaled_size > 1;
nuclear@26: 
nuclear@26:   /* Verify we can handle the sampling factors, select per-component methods,
nuclear@26:    * and create storage as needed.
nuclear@26:    */
nuclear@26:   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@26:        ci++, compptr++) {
nuclear@26:     /* Compute size of an "input group" after IDCT scaling.  This many samples
nuclear@26:      * are to be converted to max_h_samp_factor * max_v_samp_factor pixels.
nuclear@26:      */
nuclear@26:     h_in_group = (compptr->h_samp_factor * compptr->DCT_scaled_size) /
nuclear@26: 		 cinfo->min_DCT_scaled_size;
nuclear@26:     v_in_group = (compptr->v_samp_factor * compptr->DCT_scaled_size) /
nuclear@26: 		 cinfo->min_DCT_scaled_size;
nuclear@26:     h_out_group = cinfo->max_h_samp_factor;
nuclear@26:     v_out_group = cinfo->max_v_samp_factor;
nuclear@26:     upsample->rowgroup_height[ci] = v_in_group; /* save for use later */
nuclear@26:     need_buffer = TRUE;
nuclear@26:     if (! compptr->component_needed) {
nuclear@26:       /* Don't bother to upsample an uninteresting component. */
nuclear@26:       upsample->methods[ci] = noop_upsample;
nuclear@26:       need_buffer = FALSE;
nuclear@26:     } else if (h_in_group == h_out_group && v_in_group == v_out_group) {
nuclear@26:       /* Fullsize components can be processed without any work. */
nuclear@26:       upsample->methods[ci] = fullsize_upsample;
nuclear@26:       need_buffer = FALSE;
nuclear@26:     } else if (h_in_group * 2 == h_out_group &&
nuclear@26: 	       v_in_group == v_out_group) {
nuclear@26:       /* Special cases for 2h1v upsampling */
nuclear@26:       if (do_fancy && compptr->downsampled_width > 2)
nuclear@26: 	upsample->methods[ci] = h2v1_fancy_upsample;
nuclear@26:       else
nuclear@26: 	upsample->methods[ci] = h2v1_upsample;
nuclear@26:     } else if (h_in_group * 2 == h_out_group &&
nuclear@26: 	       v_in_group * 2 == v_out_group) {
nuclear@26:       /* Special cases for 2h2v upsampling */
nuclear@26:       if (do_fancy && compptr->downsampled_width > 2) {
nuclear@26: 	upsample->methods[ci] = h2v2_fancy_upsample;
nuclear@26: 	upsample->pub.need_context_rows = TRUE;
nuclear@26:       } else
nuclear@26: 	upsample->methods[ci] = h2v2_upsample;
nuclear@26:     } else if ((h_out_group % h_in_group) == 0 &&
nuclear@26: 	       (v_out_group % v_in_group) == 0) {
nuclear@26:       /* Generic integral-factors upsampling method */
nuclear@26:       upsample->methods[ci] = int_upsample;
nuclear@26:       upsample->h_expand[ci] = (UINT8) (h_out_group / h_in_group);
nuclear@26:       upsample->v_expand[ci] = (UINT8) (v_out_group / v_in_group);
nuclear@26:     } else
nuclear@26:       ERREXIT(cinfo, JERR_FRACT_SAMPLE_NOTIMPL);
nuclear@26:     if (need_buffer) {
nuclear@26:       upsample->color_buf[ci] = (*cinfo->mem->alloc_sarray)
nuclear@26: 	((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@26: 	 (JDIMENSION) jround_up((long) cinfo->output_width,
nuclear@26: 				(long) cinfo->max_h_samp_factor),
nuclear@26: 	 (JDIMENSION) cinfo->max_v_samp_factor);
nuclear@26:     }
nuclear@26:   }
nuclear@26: }