// Initialize for an upsampling pass.
static void start_pass_upsample(jpeg_decompress cinfo)
{
my_upsampler upsample = (my_upsampler)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.
static void sep_upsample(jpeg_decompress cinfo, byte[][][] input_buf, ref uint in_row_group_ctr, uint in_row_groups_avail, byte[][] output_buf, uint output_buf_offset, ref uint out_row_ctr, uint out_rows_avail)
{
my_upsampler upsample = (my_upsampler)cinfo.upsample;
// Fill the conversion buffer, if it's empty
if (upsample.next_row_out >= cinfo.max_v_samp_factor)
{
for (int ci = 0; ci < cinfo.num_components; ci++)
{
jpeg_component_info compptr = cinfo.comp_info[ci];
// 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], (int)(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:
uint num_rows = (uint)(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, (uint)upsample.next_row_out, output_buf, output_buf_offset + out_row_ctr, (int)num_rows);
// Adjust counts
out_row_ctr += num_rows;
upsample.rows_to_go -= num_rows;
upsample.next_row_out += (int)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++;
}
}
// 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.
static void int_upsample(jpeg_decompress cinfo, jpeg_component_info compptr, byte[][] input_data, int input_data_offset, byte[][][] output_data_ptr, int output_data_offset)
{
my_upsampler upsample = (my_upsampler)cinfo.upsample;
byte[][] output_data = output_data_ptr[output_data_offset];
int h_expand = upsample.h_expand[compptr.component_index];
int v_expand = upsample.v_expand[compptr.component_index];
int outrow = 0;
uint outend = cinfo.output_width;
while (outrow < cinfo.max_v_samp_factor)
{
// Generate one output row with proper horizontal expansion
byte[] inptr = input_data[input_data_offset];
uint inptr_ind = 0;
byte[] outptr = output_data[outrow];
uint outptr_ind = 0;
while (outptr_ind < outend)
{
byte invalue = inptr[inptr_ind++];
for (int h = h_expand; h > 0; h--)
{
outptr[outptr_ind++] = 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);
}
input_data_offset++;
outrow += v_expand;
}
}
// Module initialization routine for upsampling.
public static void jinit_upsampler(jpeg_decompress cinfo)
{
my_upsampler upsample = null;
bool need_buffer;
int h_in_group, v_in_group, h_out_group, v_out_group;
try
{
upsample = new my_upsampler();
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
cinfo.upsample = upsample;
upsample.start_pass = start_pass_upsample;
upsample.upsample = sep_upsample;
#if UPSCALING_CONTEXT
upsample.need_context_rows = false; // until we find out differently
#endif
if (cinfo.CCIR601_sampling)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_CCIR601_NOTIMPL); // this isn't supported
}
// jdmainct.cs doesn't support context rows when min_DCT_scaled_size = 1,
// so don't ask for it.
bool 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 (int ci = 0; ci < cinfo.num_components; ci++)
{
jpeg_component_info compptr = cinfo.comp_info[ci];
// 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 = (int)(compptr.h_samp_factor * compptr.DCT_scaled_size) / cinfo.min_DCT_scaled_size;
v_in_group = (int)(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;
upsample.color_buf[ci] = new byte[cinfo.max_v_samp_factor][];
}
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 UPSCALING_CONTEXT
if (do_fancy && compptr.downsampled_width > 2)
{
upsample.methods[ci] = h2v2_fancy_upsample;
upsample.need_context_rows = true;
compptr.doContext = true;
}
else
#endif
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] = (byte)(h_out_group / h_in_group);
upsample.v_expand[ci] = (byte)(v_out_group / v_in_group);
}
else
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_FRACT_SAMPLE_NOTIMPL);
}
if (need_buffer)
{
upsample.color_buf[ci] = alloc_sarray(cinfo, (uint)jround_up((int)cinfo.output_width, (int)cinfo.max_h_samp_factor), (uint)cinfo.max_v_samp_factor);
}
}
}
// Module initialization routine for upsampling.
public static void jinit_upsampler(jpeg_decompress cinfo)
{
my_upsampler upsample=null;
bool need_buffer;
int h_in_group, v_in_group, h_out_group, v_out_group;
try
{
upsample=new my_upsampler();
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
cinfo.upsample=upsample;
upsample.start_pass=start_pass_upsample;
upsample.upsample=sep_upsample;
#if UPSCALING_CONTEXT
upsample.need_context_rows=false; // until we find out differently
#endif
if(cinfo.CCIR601_sampling) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_CCIR601_NOTIMPL); // this isn't supported
// jdmainct.cs doesn't support context rows when min_DCT_scaled_size = 1,
// so don't ask for it.
bool 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(int ci=0; ci<cinfo.num_components; ci++)
{
jpeg_component_info compptr=cinfo.comp_info[ci];
// 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=(int)(compptr.h_samp_factor*compptr.DCT_scaled_size)/cinfo.min_DCT_scaled_size;
v_in_group=(int)(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;
upsample.color_buf[ci]=new byte[cinfo.max_v_samp_factor][];
}
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 UPSCALING_CONTEXT
if(do_fancy&&compptr.downsampled_width>2)
{
upsample.methods[ci]=h2v2_fancy_upsample;
upsample.need_context_rows=true;
compptr.doContext=true;
}
else
#endif
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]=(byte)(h_out_group/h_in_group);
upsample.v_expand[ci]=(byte)(v_out_group/v_in_group);
}
else ERREXIT(cinfo, J_MESSAGE_CODE.JERR_FRACT_SAMPLE_NOTIMPL);
if(need_buffer)
{
upsample.color_buf[ci]=alloc_sarray(cinfo, (uint)jround_up((int)cinfo.output_width, (int)cinfo.max_h_samp_factor), (uint)cinfo.max_v_samp_factor);
}
}
}