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