private static EncoderParameters GetQualityEncoderParameters(Image image, ImageCodecInfo encoder, int? quality, int? absoluteQuality)
{
if ((absoluteQuality.HasValue || quality.HasValue) && CanSetQuality(encoder))
{
int? _quality = null;
var oldQuality = 0;
try
{
oldQuality = image.GetEncoderParameterList(System.Drawing.Imaging.Encoder.Quality.Guid)
.Param.Select(p => p.NumberOfValues).FirstOrDefault();
}
catch { }
if (absoluteQuality.HasValue)
{
if (oldQuality < absoluteQuality.Value)
{
_quality = absoluteQuality;
}
}
else if (quality.HasValue)
{
if (oldQuality != quality.Value)
{
_quality = quality;
}
}
if (_quality.HasValue)
{
var parameters = new EncoderParameters(1);
parameters.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, _quality.Value);
return parameters;
}
}
return null;
}
