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<html><!-- Created using the cpp_pretty_printer from the dlib C++ library. See http://dlib.net for updates. --><head><title>dlib C++ Library - jdsample.c</title></head><body bgcolor='white'><pre>
<font color='#009900'>/*
* jdsample.c
*
* Copyright (C) 1991-1996, Thomas G. Lane.
* Modified 2002-2008 by Guido Vollbeding.
* 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_v_scaled_size / min_DCT_v_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.
*/</font>
<font color='#0000FF'>#define</font> JPEG_INTERNALS
<font color='#0000FF'>#include</font> "<a style='text-decoration:none' href='jinclude.h.html'>jinclude.h</a>"
<font color='#0000FF'>#include</font> "<a style='text-decoration:none' href='jpeglib.h.html'>jpeglib.h</a>"
<font color='#009900'>/* Pointer to routine to upsample a single component */</font>
<font color='#0000FF'>typedef</font> <b><a name='JMETHOD'></a>JMETHOD</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font>, upsample1_ptr,
<font face='Lucida Console'>(</font>j_decompress_ptr cinfo, jpeg_component_info <font color='#5555FF'>*</font> compptr,
JSAMPARRAY input_data, JSAMPARRAY <font color='#5555FF'>*</font> output_data_ptr<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>;
<font color='#009900'>/* Private subobject */</font>
<font color='#0000FF'>typedef</font> <font color='#0000FF'>struct</font> <b>{</b>
<font color='#0000FF'>struct</font> jpeg_upsampler pub; <font color='#009900'>/* public fields */</font>
<font color='#009900'>/* 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.
*/</font>
JSAMPARRAY color_buf[MAX_COMPONENTS];
<font color='#009900'>/* Per-component upsampling method pointers */</font>
upsample1_ptr methods[MAX_COMPONENTS];
<font color='#0000FF'><u>int</u></font> next_row_out; <font color='#009900'>/* counts rows emitted from color_buf */</font>
JDIMENSION rows_to_go; <font color='#009900'>/* counts rows remaining in image */</font>
<font color='#009900'>/* Height of an input row group for each component. */</font>
<font color='#0000FF'><u>int</u></font> rowgroup_height[MAX_COMPONENTS];
<font color='#009900'>/* These arrays save pixel expansion factors so that int_expand need not
* recompute them each time. They are unused for other upsampling methods.
*/</font>
UINT8 h_expand[MAX_COMPONENTS];
UINT8 v_expand[MAX_COMPONENTS];
<b>}</b> my_upsampler;
<font color='#0000FF'>typedef</font> my_upsampler <font color='#5555FF'>*</font> my_upsample_ptr;
<font color='#009900'>/*
* Initialize for an upsampling pass.
*/</font>
<b><a name='METHODDEF'></a>METHODDEF</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='start_pass_upsample'></a>start_pass_upsample</b> <font face='Lucida Console'>(</font>j_decompress_ptr cinfo<font face='Lucida Console'>)</font>
<b>{</b>
my_upsample_ptr upsample <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>my_upsample_ptr<font face='Lucida Console'>)</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>upsample;
<font color='#009900'>/* Mark the conversion buffer empty */</font>
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_row_out <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor;
<font color='#009900'>/* Initialize total-height counter for detecting bottom of image */</font>
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>rows_to_go <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>output_height;
<b>}</b>
<font color='#009900'>/*
* 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.
*/</font>
<b><a name='METHODDEF'></a>METHODDEF</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='sep_upsample'></a>sep_upsample</b> <font face='Lucida Console'>(</font>j_decompress_ptr cinfo,
JSAMPIMAGE input_buf, JDIMENSION <font color='#5555FF'>*</font>in_row_group_ctr,
JDIMENSION in_row_groups_avail,
JSAMPARRAY output_buf, JDIMENSION <font color='#5555FF'>*</font>out_row_ctr,
JDIMENSION out_rows_avail<font face='Lucida Console'>)</font>
<b>{</b>
my_upsample_ptr upsample <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>my_upsample_ptr<font face='Lucida Console'>)</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>upsample;
<font color='#0000FF'><u>int</u></font> ci;
jpeg_component_info <font color='#5555FF'>*</font> compptr;
JDIMENSION num_rows;
<font color='#009900'>/* Fill the conversion buffer, if it's empty */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_row_out <font color='#5555FF'>></font><font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor<font face='Lucida Console'>)</font> <b>{</b>
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>ci <font color='#5555FF'>=</font> <font color='#979000'>0</font>, compptr <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>comp_info; ci <font color='#5555FF'><</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>num_components;
ci<font color='#5555FF'>+</font><font color='#5555FF'>+</font>, compptr<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* Invoke per-component upsample method. Notice we pass a POINTER
* to color_buf[ci], so that fullsize_upsample can change it.
*/</font>
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>methods[ci]<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>cinfo, compptr,
input_buf[ci] <font color='#5555FF'>+</font> <font face='Lucida Console'>(</font><font color='#5555FF'>*</font>in_row_group_ctr <font color='#5555FF'>*</font> upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>rowgroup_height[ci]<font face='Lucida Console'>)</font>,
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_buf <font color='#5555FF'>+</font> ci<font face='Lucida Console'>)</font>;
<b>}</b>
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_row_out <font color='#5555FF'>=</font> <font color='#979000'>0</font>;
<b>}</b>
<font color='#009900'>/* Color-convert and emit rows */</font>
<font color='#009900'>/* How many we have in the buffer: */</font>
num_rows <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor <font color='#5555FF'>-</font> upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_row_out<font face='Lucida Console'>)</font>;
<font color='#009900'>/* 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:
*/</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>num_rows <font color='#5555FF'>></font> upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>rows_to_go<font face='Lucida Console'>)</font>
num_rows <font color='#5555FF'>=</font> upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>rows_to_go;
<font color='#009900'>/* And not more than what the client can accept: */</font>
out_rows_avail <font color='#5555FF'>-</font><font color='#5555FF'>=</font> <font color='#5555FF'>*</font>out_row_ctr;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>num_rows <font color='#5555FF'>></font> out_rows_avail<font face='Lucida Console'>)</font>
num_rows <font color='#5555FF'>=</font> out_rows_avail;
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>cconvert<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_convert<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>cinfo, upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_buf,
<font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_row_out,
output_buf <font color='#5555FF'>+</font> <font color='#5555FF'>*</font>out_row_ctr,
<font face='Lucida Console'>(</font><font color='#0000FF'><u>int</u></font><font face='Lucida Console'>)</font> num_rows<font face='Lucida Console'>)</font>;
<font color='#009900'>/* Adjust counts */</font>
<font color='#5555FF'>*</font>out_row_ctr <font color='#5555FF'>+</font><font color='#5555FF'>=</font> num_rows;
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>rows_to_go <font color='#5555FF'>-</font><font color='#5555FF'>=</font> num_rows;
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_row_out <font color='#5555FF'>+</font><font color='#5555FF'>=</font> num_rows;
<font color='#009900'>/* When the buffer is emptied, declare this input row group consumed */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_row_out <font color='#5555FF'>></font><font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor<font face='Lucida Console'>)</font>
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>in_row_group_ctr<font face='Lucida Console'>)</font><font color='#5555FF'>+</font><font color='#5555FF'>+</font>;
<b>}</b>
<font color='#009900'>/*
* These are the routines invoked by sep_upsample to upsample pixel values
* of a single component. One row group is processed per call.
*/</font>
<font color='#009900'>/*
* 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.
*/</font>
<b><a name='METHODDEF'></a>METHODDEF</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='fullsize_upsample'></a>fullsize_upsample</b> <font face='Lucida Console'>(</font>j_decompress_ptr cinfo, jpeg_component_info <font color='#5555FF'>*</font> compptr,
JSAMPARRAY input_data, JSAMPARRAY <font color='#5555FF'>*</font> output_data_ptr<font face='Lucida Console'>)</font>
<b>{</b>
<font color='#5555FF'>*</font>output_data_ptr <font color='#5555FF'>=</font> input_data;
<b>}</b>
<font color='#009900'>/*
* This is a no-op version used for "uninteresting" components.
* These components will not be referenced by color conversion.
*/</font>
<b><a name='METHODDEF'></a>METHODDEF</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='noop_upsample'></a>noop_upsample</b> <font face='Lucida Console'>(</font>j_decompress_ptr cinfo, jpeg_component_info <font color='#5555FF'>*</font> compptr,
JSAMPARRAY input_data, JSAMPARRAY <font color='#5555FF'>*</font> output_data_ptr<font face='Lucida Console'>)</font>
<b>{</b>
<font color='#5555FF'>*</font>output_data_ptr <font color='#5555FF'>=</font> NULL; <font color='#009900'>/* safety check */</font>
<b>}</b>
<font color='#009900'>/*
* 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.
*/</font>
<b><a name='METHODDEF'></a>METHODDEF</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='int_upsample'></a>int_upsample</b> <font face='Lucida Console'>(</font>j_decompress_ptr cinfo, jpeg_component_info <font color='#5555FF'>*</font> compptr,
JSAMPARRAY input_data, JSAMPARRAY <font color='#5555FF'>*</font> output_data_ptr<font face='Lucida Console'>)</font>
<b>{</b>
my_upsample_ptr upsample <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>my_upsample_ptr<font face='Lucida Console'>)</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>upsample;
JSAMPARRAY output_data <font color='#5555FF'>=</font> <font color='#5555FF'>*</font>output_data_ptr;
<font color='#0000FF'>register</font> JSAMPROW inptr, outptr;
<font color='#0000FF'>register</font> JSAMPLE invalue;
<font color='#0000FF'>register</font> <font color='#0000FF'><u>int</u></font> h;
JSAMPROW outend;
<font color='#0000FF'><u>int</u></font> h_expand, v_expand;
<font color='#0000FF'><u>int</u></font> inrow, outrow;
h_expand <font color='#5555FF'>=</font> upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>h_expand[compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>component_index];
v_expand <font color='#5555FF'>=</font> upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>v_expand[compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>component_index];
inrow <font color='#5555FF'>=</font> outrow <font color='#5555FF'>=</font> <font color='#979000'>0</font>;
<font color='#0000FF'>while</font> <font face='Lucida Console'>(</font>outrow <font color='#5555FF'><</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor<font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* Generate one output row with proper horizontal expansion */</font>
inptr <font color='#5555FF'>=</font> input_data[inrow];
outptr <font color='#5555FF'>=</font> output_data[outrow];
outend <font color='#5555FF'>=</font> outptr <font color='#5555FF'>+</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>output_width;
<font color='#0000FF'>while</font> <font face='Lucida Console'>(</font>outptr <font color='#5555FF'><</font> outend<font face='Lucida Console'>)</font> <b>{</b>
invalue <font color='#5555FF'>=</font> <font color='#5555FF'>*</font>inptr<font color='#5555FF'>+</font><font color='#5555FF'>+</font>; <font color='#009900'>/* don't need GETJSAMPLE() here */</font>
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>h <font color='#5555FF'>=</font> h_expand; h <font color='#5555FF'>></font> <font color='#979000'>0</font>; h<font color='#5555FF'>-</font><font color='#5555FF'>-</font><font face='Lucida Console'>)</font> <b>{</b>
<font color='#5555FF'>*</font>outptr<font color='#5555FF'>+</font><font color='#5555FF'>+</font> <font color='#5555FF'>=</font> invalue;
<b>}</b>
<b>}</b>
<font color='#009900'>/* Generate any additional output rows by duplicating the first one */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>v_expand <font color='#5555FF'>></font> <font color='#979000'>1</font><font face='Lucida Console'>)</font> <b>{</b>
<font color='#BB00BB'>jcopy_sample_rows</font><font face='Lucida Console'>(</font>output_data, outrow, output_data, outrow<font color='#5555FF'>+</font><font color='#979000'>1</font>,
v_expand<font color='#5555FF'>-</font><font color='#979000'>1</font>, cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>output_width<font face='Lucida Console'>)</font>;
<b>}</b>
inrow<font color='#5555FF'>+</font><font color='#5555FF'>+</font>;
outrow <font color='#5555FF'>+</font><font color='#5555FF'>=</font> v_expand;
<b>}</b>
<b>}</b>
<font color='#009900'>/*
* Fast processing for the common case of 2:1 horizontal and 1:1 vertical.
* It's still a box filter.
*/</font>
<b><a name='METHODDEF'></a>METHODDEF</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='h2v1_upsample'></a>h2v1_upsample</b> <font face='Lucida Console'>(</font>j_decompress_ptr cinfo, jpeg_component_info <font color='#5555FF'>*</font> compptr,
JSAMPARRAY input_data, JSAMPARRAY <font color='#5555FF'>*</font> output_data_ptr<font face='Lucida Console'>)</font>
<b>{</b>
JSAMPARRAY output_data <font color='#5555FF'>=</font> <font color='#5555FF'>*</font>output_data_ptr;
<font color='#0000FF'>register</font> JSAMPROW inptr, outptr;
<font color='#0000FF'>register</font> JSAMPLE invalue;
JSAMPROW outend;
<font color='#0000FF'><u>int</u></font> outrow;
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>outrow <font color='#5555FF'>=</font> <font color='#979000'>0</font>; outrow <font color='#5555FF'><</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor; outrow<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font> <b>{</b>
inptr <font color='#5555FF'>=</font> input_data[outrow];
outptr <font color='#5555FF'>=</font> output_data[outrow];
outend <font color='#5555FF'>=</font> outptr <font color='#5555FF'>+</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>output_width;
<font color='#0000FF'>while</font> <font face='Lucida Console'>(</font>outptr <font color='#5555FF'><</font> outend<font face='Lucida Console'>)</font> <b>{</b>
invalue <font color='#5555FF'>=</font> <font color='#5555FF'>*</font>inptr<font color='#5555FF'>+</font><font color='#5555FF'>+</font>; <font color='#009900'>/* don't need GETJSAMPLE() here */</font>
<font color='#5555FF'>*</font>outptr<font color='#5555FF'>+</font><font color='#5555FF'>+</font> <font color='#5555FF'>=</font> invalue;
<font color='#5555FF'>*</font>outptr<font color='#5555FF'>+</font><font color='#5555FF'>+</font> <font color='#5555FF'>=</font> invalue;
<b>}</b>
<b>}</b>
<b>}</b>
<font color='#009900'>/*
* Fast processing for the common case of 2:1 horizontal and 2:1 vertical.
* It's still a box filter.
*/</font>
<b><a name='METHODDEF'></a>METHODDEF</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='h2v2_upsample'></a>h2v2_upsample</b> <font face='Lucida Console'>(</font>j_decompress_ptr cinfo, jpeg_component_info <font color='#5555FF'>*</font> compptr,
JSAMPARRAY input_data, JSAMPARRAY <font color='#5555FF'>*</font> output_data_ptr<font face='Lucida Console'>)</font>
<b>{</b>
JSAMPARRAY output_data <font color='#5555FF'>=</font> <font color='#5555FF'>*</font>output_data_ptr;
<font color='#0000FF'>register</font> JSAMPROW inptr, outptr;
<font color='#0000FF'>register</font> JSAMPLE invalue;
JSAMPROW outend;
<font color='#0000FF'><u>int</u></font> inrow, outrow;
inrow <font color='#5555FF'>=</font> outrow <font color='#5555FF'>=</font> <font color='#979000'>0</font>;
<font color='#0000FF'>while</font> <font face='Lucida Console'>(</font>outrow <font color='#5555FF'><</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor<font face='Lucida Console'>)</font> <b>{</b>
inptr <font color='#5555FF'>=</font> input_data[inrow];
outptr <font color='#5555FF'>=</font> output_data[outrow];
outend <font color='#5555FF'>=</font> outptr <font color='#5555FF'>+</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>output_width;
<font color='#0000FF'>while</font> <font face='Lucida Console'>(</font>outptr <font color='#5555FF'><</font> outend<font face='Lucida Console'>)</font> <b>{</b>
invalue <font color='#5555FF'>=</font> <font color='#5555FF'>*</font>inptr<font color='#5555FF'>+</font><font color='#5555FF'>+</font>; <font color='#009900'>/* don't need GETJSAMPLE() here */</font>
<font color='#5555FF'>*</font>outptr<font color='#5555FF'>+</font><font color='#5555FF'>+</font> <font color='#5555FF'>=</font> invalue;
<font color='#5555FF'>*</font>outptr<font color='#5555FF'>+</font><font color='#5555FF'>+</font> <font color='#5555FF'>=</font> invalue;
<b>}</b>
<font color='#BB00BB'>jcopy_sample_rows</font><font face='Lucida Console'>(</font>output_data, outrow, output_data, outrow<font color='#5555FF'>+</font><font color='#979000'>1</font>,
<font color='#979000'>1</font>, cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>output_width<font face='Lucida Console'>)</font>;
inrow<font color='#5555FF'>+</font><font color='#5555FF'>+</font>;
outrow <font color='#5555FF'>+</font><font color='#5555FF'>=</font> <font color='#979000'>2</font>;
<b>}</b>
<b>}</b>
<font color='#009900'>/*
* Module initialization routine for upsampling.
*/</font>
<b><a name='GLOBAL'></a>GLOBAL</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='jinit_upsampler'></a>jinit_upsampler</b> <font face='Lucida Console'>(</font>j_decompress_ptr cinfo<font face='Lucida Console'>)</font>
<b>{</b>
my_upsample_ptr upsample;
<font color='#0000FF'><u>int</u></font> ci;
jpeg_component_info <font color='#5555FF'>*</font> compptr;
boolean need_buffer;
<font color='#0000FF'><u>int</u></font> h_in_group, v_in_group, h_out_group, v_out_group;
upsample <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>my_upsample_ptr<font face='Lucida Console'>)</font>
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>mem<font color='#5555FF'>-</font><font color='#5555FF'>></font>alloc_small<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font><font face='Lucida Console'>(</font>j_common_ptr<font face='Lucida Console'>)</font> cinfo, JPOOL_IMAGE,
<font color='#BB00BB'>SIZEOF</font><font face='Lucida Console'>(</font>my_upsampler<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>;
cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>upsample <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'>struct</font> jpeg_upsampler <font color='#5555FF'>*</font><font face='Lucida Console'>)</font> upsample;
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>pub.start_pass <font color='#5555FF'>=</font> start_pass_upsample;
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>pub.upsample <font color='#5555FF'>=</font> sep_upsample;
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>pub.need_context_rows <font color='#5555FF'>=</font> FALSE; <font color='#009900'>/* until we find out differently */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>CCIR601_sampling<font face='Lucida Console'>)</font> <font color='#009900'>/* this isn't supported */</font>
<font color='#BB00BB'>ERREXIT</font><font face='Lucida Console'>(</font>cinfo, JERR_CCIR601_NOTIMPL<font face='Lucida Console'>)</font>;
<font color='#009900'>/* Verify we can handle the sampling factors, select per-component methods,
* and create storage as needed.
*/</font>
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>ci <font color='#5555FF'>=</font> <font color='#979000'>0</font>, compptr <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>comp_info; ci <font color='#5555FF'><</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>num_components;
ci<font color='#5555FF'>+</font><font color='#5555FF'>+</font>, compptr<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* 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.
*/</font>
h_in_group <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>h_samp_factor <font color='#5555FF'>*</font> compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>DCT_h_scaled_size<font face='Lucida Console'>)</font> <font color='#5555FF'>/</font>
cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>min_DCT_h_scaled_size;
v_in_group <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>v_samp_factor <font color='#5555FF'>*</font> compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>DCT_v_scaled_size<font face='Lucida Console'>)</font> <font color='#5555FF'>/</font>
cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>min_DCT_v_scaled_size;
h_out_group <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_h_samp_factor;
v_out_group <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor;
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>rowgroup_height[ci] <font color='#5555FF'>=</font> v_in_group; <font color='#009900'>/* save for use later */</font>
need_buffer <font color='#5555FF'>=</font> TRUE;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font><font color='#5555FF'>!</font> compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>component_needed<font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* Don't bother to upsample an uninteresting component. */</font>
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>methods[ci] <font color='#5555FF'>=</font> noop_upsample;
need_buffer <font color='#5555FF'>=</font> FALSE;
<b>}</b> <font color='#0000FF'>else</font> <font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>h_in_group <font color='#5555FF'>=</font><font color='#5555FF'>=</font> h_out_group <font color='#5555FF'>&</font><font color='#5555FF'>&</font> v_in_group <font color='#5555FF'>=</font><font color='#5555FF'>=</font> v_out_group<font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* Fullsize components can be processed without any work. */</font>
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>methods[ci] <font color='#5555FF'>=</font> fullsize_upsample;
need_buffer <font color='#5555FF'>=</font> FALSE;
<b>}</b> <font color='#0000FF'>else</font> <font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>h_in_group <font color='#5555FF'>*</font> <font color='#979000'>2</font> <font color='#5555FF'>=</font><font color='#5555FF'>=</font> h_out_group <font color='#5555FF'>&</font><font color='#5555FF'>&</font>
v_in_group <font color='#5555FF'>=</font><font color='#5555FF'>=</font> v_out_group<font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* Special case for 2h1v upsampling */</font>
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>methods[ci] <font color='#5555FF'>=</font> h2v1_upsample;
<b>}</b> <font color='#0000FF'>else</font> <font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>h_in_group <font color='#5555FF'>*</font> <font color='#979000'>2</font> <font color='#5555FF'>=</font><font color='#5555FF'>=</font> h_out_group <font color='#5555FF'>&</font><font color='#5555FF'>&</font>
v_in_group <font color='#5555FF'>*</font> <font color='#979000'>2</font> <font color='#5555FF'>=</font><font color='#5555FF'>=</font> v_out_group<font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* Special case for 2h2v upsampling */</font>
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>methods[ci] <font color='#5555FF'>=</font> h2v2_upsample;
<b>}</b> <font color='#0000FF'>else</font> <font color='#0000FF'>if</font> <font face='Lucida Console'>(</font><font face='Lucida Console'>(</font>h_out_group <font color='#5555FF'>%</font> h_in_group<font face='Lucida Console'>)</font> <font color='#5555FF'>=</font><font color='#5555FF'>=</font> <font color='#979000'>0</font> <font color='#5555FF'>&</font><font color='#5555FF'>&</font>
<font face='Lucida Console'>(</font>v_out_group <font color='#5555FF'>%</font> v_in_group<font face='Lucida Console'>)</font> <font color='#5555FF'>=</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* Generic integral-factors upsampling method */</font>
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>methods[ci] <font color='#5555FF'>=</font> int_upsample;
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>h_expand[ci] <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>UINT8<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>h_out_group <font color='#5555FF'>/</font> h_in_group<font face='Lucida Console'>)</font>;
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>v_expand[ci] <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>UINT8<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>v_out_group <font color='#5555FF'>/</font> v_in_group<font face='Lucida Console'>)</font>;
<b>}</b> <font color='#0000FF'>else</font>
<font color='#BB00BB'>ERREXIT</font><font face='Lucida Console'>(</font>cinfo, JERR_FRACT_SAMPLE_NOTIMPL<font face='Lucida Console'>)</font>;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>need_buffer<font face='Lucida Console'>)</font> <b>{</b>
upsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_buf[ci] <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#5555FF'>*</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>mem<font color='#5555FF'>-</font><font color='#5555FF'>></font>alloc_sarray<font face='Lucida Console'>)</font>
<font face='Lucida Console'>(</font><font face='Lucida Console'>(</font>j_common_ptr<font face='Lucida Console'>)</font> cinfo, JPOOL_IMAGE,
<font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> <font color='#BB00BB'>jround_up</font><font face='Lucida Console'>(</font><font face='Lucida Console'>(</font><font color='#0000FF'><u>long</u></font><font face='Lucida Console'>)</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>output_width,
<font face='Lucida Console'>(</font><font color='#0000FF'><u>long</u></font><font face='Lucida Console'>)</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_h_samp_factor<font face='Lucida Console'>)</font>,
<font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor<font face='Lucida Console'>)</font>;
<b>}</b>
<b>}</b>
<b>}</b>
</pre></body></html> |