private int m_next_row; /* index of next row to fill/empty in strip */
/// <summary>
/// Initialize postprocessing controller.
/// </summary>
public jpeg_d_post_controller(jpeg_decompress_struct cinfo, bool need_full_buffer)
{
m_cinfo = cinfo;
/* Create the quantization buffer, if needed */
if (cinfo.m_quantize_colors)
{
/* The buffer strip height is max_v_samp_factor, which is typically
* an efficient number of rows for upsampling to return.
* (In the presence of output rescaling, we might want to be smarter?)
*/
m_strip_height = cinfo.m_max_v_samp_factor;
if (need_full_buffer)
{
/* Two-pass color quantization: need full-image storage. */
/* We round up the number of rows to a multiple of the strip height. */
m_whole_image = jpeg_common_struct.CreateSamplesArray(
cinfo.m_output_width * cinfo.m_out_color_components,
JpegUtils.jround_up(cinfo.m_output_height, m_strip_height));
m_whole_image.ErrorProcessor = cinfo;
}
else
{
/* One-pass color quantization: just make a strip buffer. */
m_buffer = jpeg_common_struct.AllocJpegSamples(
cinfo.m_output_width * cinfo.m_out_color_components, m_strip_height);
}
}
}
public my_upsampler(jpeg_decompress_struct cinfo)
{
m_cinfo = cinfo;
m_need_context_rows = false; /* until we find out differently */
if (cinfo.m_CCIR601_sampling) /* this isn't supported */
{
cinfo.ERREXIT(J_MESSAGE_CODE.JERR_CCIR601_NOTIMPL);
}
/* Verify we can handle the sampling factors, select per-component methods,
* and create storage as needed.
*/
for (int ci = 0; ci < cinfo.m_num_components; ci++)
{
jpeg_component_info componentInfo = 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.
*/
int h_in_group = (componentInfo.H_samp_factor * componentInfo.DCT_h_scaled_size) / cinfo.min_DCT_h_scaled_size;
int v_in_group = (componentInfo.V_samp_factor * componentInfo.DCT_v_scaled_size) / cinfo.min_DCT_v_scaled_size;
int h_out_group = cinfo.m_max_h_samp_factor;
int v_out_group = cinfo.m_max_v_samp_factor;
/* save for use later */
m_rowgroup_height[ci] = v_in_group;
if (!componentInfo.component_needed)
{
/* Don't bother to upsample an uninteresting component. */
m_upsampleMethods[ci] = ComponentUpsampler.noop_upsampler;
continue; /* don't need to allocate buffer */
}
if (h_in_group == h_out_group && v_in_group == v_out_group)
{
/* Fullsize components can be processed without any work. */
m_upsampleMethods[ci] = ComponentUpsampler.fullsize_upsampler;
continue; /* don't need to allocate buffer */
}
if (h_in_group * 2 == h_out_group && v_in_group == v_out_group)
{
/* Special case for 2h1v upsampling */
m_upsampleMethods[ci] = ComponentUpsampler.h2v1_upsampler;
}
else if (h_in_group * 2 == h_out_group && v_in_group * 2 == v_out_group)
{
/* Special case for 2h2v upsampling */
m_upsampleMethods[ci] = ComponentUpsampler.h2v2_upsampler;
}
else if ((h_out_group % h_in_group) == 0 && (v_out_group % v_in_group) == 0)
{
/* Generic integral-factors upsampling method */
m_upsampleMethods[ci] = ComponentUpsampler.int_upsampler;
m_h_expand[ci] = (byte)(h_out_group / h_in_group);
m_v_expand[ci] = (byte)(v_out_group / v_in_group);
}
else
{
cinfo.ERREXIT(J_MESSAGE_CODE.JERR_FRACT_SAMPLE_NOTIMPL);
}
ComponentBuffer cb = new ComponentBuffer();
cb.SetBuffer(jpeg_common_struct.AllocJpegSamples(
JpegUtils.jround_up(cinfo.m_output_width,
cinfo.m_max_h_samp_factor), cinfo.m_max_v_samp_factor));
m_color_buf[ci] = cb;
}
}
