static void scaler_start_pass(jpeg_decompress cinfo)
{
jpeg_lossless_d_codec losslsd = (jpeg_lossless_d_codec)cinfo.coef;
scaler scaler = (scaler)losslsd.scaler_private;
// Downscale by the difference in the input vs. output precision. If the
// output precision >= input precision, then do not downscale.
int downscale = BITS_IN_JSAMPLE < cinfo.data_precision?cinfo.data_precision - BITS_IN_JSAMPLE:0;
scaler.scale_factor = cinfo.Al - downscale;
// Set scaler functions based on scale_factor (positive = left shift)
if (scaler.scale_factor > 0)
{
losslsd.scaler_scale = simple_upscale;
}
else if (scaler.scale_factor < 0)
{
scaler.scale_factor = -scaler.scale_factor;
losslsd.scaler_scale = simple_downscale;
}
else
{
losslsd.scaler_scale = noscale;
}
}
static void simple_downscale(jpeg_decompress cinfo, int[] diff_buf, byte[] output_buf, uint width)
{
jpeg_lossless_d_codec losslsd = (jpeg_lossless_d_codec)cinfo.coef;
scaler scaler = (scaler)losslsd.scaler_private;
int scale_factor = scaler.scale_factor;
for (uint xindex = 0; xindex < width; xindex++)
{
output_buf[xindex] = (byte)(diff_buf[xindex] >> scale_factor);
}
}
static void jinit_d_scaler(jpeg_decompress cinfo)
{
jpeg_lossless_d_codec losslsd = (jpeg_lossless_d_codec)cinfo.coef;
scaler scaler = null;
try
{
scaler = new scaler();
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
losslsd.scaler_private = scaler;
losslsd.scaler_start_pass = scaler_start_pass;
}
static void jinit_d_scaler(jpeg_decompress cinfo)
{
jpeg_lossless_d_codec losslsd=(jpeg_lossless_d_codec)cinfo.coef;
scaler scaler=null;
try
{
scaler=new scaler();
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
losslsd.scaler_private=scaler;
losslsd.scaler_start_pass=scaler_start_pass;
}
