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; } }