ExcStatus ReadHeader(
ImageColorSpec& colorSpec,
ImageSamplingGeometry& geometry)
{
int i;
Point origin;
RectSize size;
Rect refgrid;
JERRCODE jerr;
jerr = CJPEGDecoder::ReadHeader(&m_size.width, &m_size.height, &m_nchannels, &m_color, &m_sampling, &m_precision);
if(JPEG_OK != jerr)
return ExcStatusFail;
origin.SetX(0);
origin.SetY(0);
size.SetWidth(m_size.width);
size.SetHeight(m_size.height);
refgrid.SetOrigin(origin);
refgrid.SetSize(size);
geometry.SetRefGridRect(refgrid);
geometry.ReAlloc(m_nchannels);
geometry.SetEnumSampling(j2u_smap[m_sampling]);
colorSpec.ReAlloc(m_nchannels);
colorSpec.SetColorSpecMethod(UIC::Enumerated);
colorSpec.SetComponentToColorMap(UIC::Direct);
colorSpec.SetEnumColorSpace(j2u_cmap[m_color]);
if(m_precision <= 8)
{
for(i = 0; i < m_nchannels; i++)
colorSpec.DataRange()[i].SetAsRange8u((1 << m_precision) - 1);
}
else
{
for(i = 0; i < m_nchannels; i++)
colorSpec.DataRange()[i].SetAsRange16u((1 << m_precision) - 1);
}
return ExcStatusOk;
}
ExcStatus SetParams(
const ImageColorSpec& colorSpec,
const ImageSamplingGeometry& geometry)
{
ImageEnumSampling m_enumSampling;
m_enumSampling = geometry.EnumSampling();
if(JC_YCBCR == m_color && JC_GRAY == u2j_cmap[colorSpec.EnumColorSpace()])
m_nchannels = 1;
m_color = u2j_cmap[colorSpec.EnumColorSpace()];
m_sampling = u2j_smap[m_enumSampling];
m_precision = colorSpec.DataRange()[0].BitDepth() + 1;
m_size.width = geometry.RefGridRect().Width();
m_size.height = geometry.RefGridRect().Height();
return ExcStatusOk;
} // JPEGDecoder::SetParams()