/// <summary>
/// Emit a SOF marker
/// </summary>
private void emit_sof(JPEG_MARKER code)
{
emit_marker(code);
emit_2bytes(3 * m_cinfo.m_num_components + 2 + 5 + 1); /* length */
/* Make sure image isn't bigger than SOF field can handle */
if (m_cinfo.m_image_height > 65535 || m_cinfo.m_image_width > 65535)
m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_IMAGE_TOO_BIG, 65535);
emit_byte(m_cinfo.m_data_precision);
emit_2bytes(m_cinfo.m_image_height);
emit_2bytes(m_cinfo.m_image_width);
emit_byte(m_cinfo.m_num_components);
for (int ci = 0; ci < m_cinfo.m_num_components; ci++)
{
jpeg_component_info componentInfo = m_cinfo.Component_info[ci];
emit_byte(componentInfo.Component_id);
emit_byte((componentInfo.H_samp_factor << 4) + componentInfo.V_samp_factor);
emit_byte(componentInfo.Quant_tbl_no);
}
}
// Emit a SOF marker
static void emit_sof(jpeg_compress cinfo, JPEG_MARKER code)
{
emit_marker(cinfo, code);
emit_2bytes(cinfo, 3*cinfo.num_components+2+5+1); // length
// Make sure image isn't bigger than SOF field can handle
if(cinfo.image_height>65535||cinfo.image_width>65535) ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_IMAGE_TOO_BIG, 65535);
emit_byte(cinfo, cinfo.data_precision);
emit_2bytes(cinfo, (int)cinfo.image_height);
emit_2bytes(cinfo, (int)cinfo.image_width);
emit_byte(cinfo, cinfo.num_components);
for(int ci=0; ci<cinfo.num_components; ci++)
{
emit_byte(cinfo, cinfo.comp_info[ci].component_id);
emit_byte(cinfo, (cinfo.comp_info[ci].h_samp_factor<<4)+cinfo.comp_info[ci].v_samp_factor);
emit_byte(cinfo, cinfo.comp_info[ci].quant_tbl_no);
}
}
//////////////////////////////////////////////////////////////////////////
// Basic output routines.
//
// Note that we do not support suspension while writing a marker.
// Therefore, an application using suspension must ensure that there is
// enough buffer space for the initial markers (typ. 600-700 bytes) before
// calling jpeg_start_compress, and enough space to write the trailing EOI
// (a few bytes) before calling jpeg_finish_compress. Multipass compression
// modes are not supported at all with suspension, so those two are the only
// points where markers will be written.
/// <summary>
/// Emit a marker code
/// </summary>
private void emit_marker(JPEG_MARKER mark)
{
emit_byte(0xFF);
emit_byte((int)mark);
}
// Emit a marker code
static void emit_marker(jpeg_compress cinfo, JPEG_MARKER mark)
{
emit_byte(cinfo, 0xFF);
emit_byte(cinfo, (int)mark);
}