diff options
author | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2015-11-06 07:14:47 +0100 |
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committer | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2015-11-06 07:14:47 +0100 |
commit | d479dd1aab1c1cb907932c6595b0ef33523fc797 (patch) | |
tree | ad7d454b9edaae3d8892d84cd8f8ef5c2697b79b /jpeg/jcsample.c | |
parent | 9491825ddff7a294d1f49061bae7044e426aeb2e (diff) |
Imported Upstream version 1.8.3upstream/1.8.3
Diffstat (limited to 'jpeg/jcsample.c')
-rwxr-xr-x | jpeg/jcsample.c | 545 |
1 files changed, 0 insertions, 545 deletions
diff --git a/jpeg/jcsample.c b/jpeg/jcsample.c deleted file mode 100755 index 4d36f85..0000000 --- a/jpeg/jcsample.c +++ /dev/null @@ -1,545 +0,0 @@ -/* - * 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 -} |