/// <summary>
/// Extracts aMetadata
/// </summary>
/// <param name="aMetadata">where to add aMetadata</param>
/// <returns>the aMetadata found</returns>
public override Metadata Extract(Metadata aMetadata)
{
if (base.data == null)
{
return aMetadata;
}
AbstractDirectory lcDirectory = aMetadata.GetDirectory("com.drew.metadata.jpeg.JpegCommentDirectory");
string comment = Utils.Decode(base.data, true);
lcDirectory.SetObject(JpegCommentDirectory.TAG_JPEG_COMMENT,comment);
return aMetadata;
}
/// <summary>
/// Extracts aMetadata
/// </summary>
/// <param name="aMetadata">where to add aMetadata</param>
/// <returns>the aMetadata found</returns>
public override Metadata Extract(Metadata aMetadata)
{
if (base.data == null)
{
return aMetadata;
}
AbstractDirectory lcDirectory = aMetadata.GetDirectory("com.drew.metadata.jpeg.JpegDirectory");
try
{
// data precision
int dataPrecision =
base.Get16Bits(JpegDirectory.TAG_JPEG_DATA_PRECISION);
lcDirectory.SetObject(
JpegDirectory.TAG_JPEG_DATA_PRECISION,
dataPrecision);
// process height
int height = base.Get32Bits(JpegDirectory.TAG_JPEG_IMAGE_HEIGHT);
lcDirectory.SetObject(JpegDirectory.TAG_JPEG_IMAGE_HEIGHT, height);
// process width
int width = base.Get32Bits(JpegDirectory.TAG_JPEG_IMAGE_WIDTH);
lcDirectory.SetObject(JpegDirectory.TAG_JPEG_IMAGE_WIDTH, width);
// number of components
int numberOfComponents =
base.Get16Bits(JpegDirectory.TAG_JPEG_NUMBER_OF_COMPONENTS);
lcDirectory.SetObject(
JpegDirectory.TAG_JPEG_NUMBER_OF_COMPONENTS,
numberOfComponents);
// for each component, there are three bytes of data:
// 1 - Component ID: 1 = Y, 2 = Cb, 3 = Cr, 4 = I, 5 = Q
// 2 - Sampling factors: bit 0-3 vertical, 4-7 horizontal
// 3 - Quantization table number
int offset = 6;
for (int i = 0; i < numberOfComponents; i++)
{
int componentId = base.Get16Bits(offset++);
int samplingFactorByte = base.Get16Bits(offset++);
int quantizationTableNumber = base.Get16Bits(offset++);
JpegComponent lcJpegComponent =
new JpegComponent(
componentId,
samplingFactorByte,
quantizationTableNumber);
lcDirectory.SetObject(
JpegDirectory.TAG_JPEG_COMPONENT_DATA_1 + i,
lcJpegComponent);
}
}
catch (MetadataException me)
{
lcDirectory.HasError = true;
Trace.TraceError("MetadataException: " + me.Message);
}
return aMetadata;
}
/// <summary>
/// Extracts aMetadata
/// </summary>
/// <param name="aMetadata">where to add aMetadata</param>
/// <returns>the aMetadata found</returns>
public override Metadata Extract(Metadata aMetadata)
{
if (base.data == null)
{
return aMetadata;
}
AbstractDirectory lcDirectory = aMetadata.GetDirectory("com.drew.metadata.iptc.IptcDirectory");
// find start of data
int offset = 0;
try
{
while (offset < base.data.Length - 1 && Get32Bits(offset) != 0x1c02)
{
offset++;
}
}
catch (MetadataException e)
{
lcDirectory.HasError = true;
Trace.TraceError(
"Couldn't find start of Iptc data (invalid segment) ("+e.Message+")");
return aMetadata;
}
// for each tag
while (offset < base.data.Length)
{
// identifies start of a tag
if (base.data[offset] != 0x1c)
{
break;
}
// we need at least five bytes left to read a tag
if ((offset + 5) >= base.data.Length)
{
break;
}
offset++;
int directoryType;
int tagType;
int tagByteCount;
try
{
directoryType = base.data[offset++];
tagType = base.data[offset++];
tagByteCount = Get32Bits(offset);
}
catch (MetadataException e)
{
lcDirectory.HasError = true;
Trace.TraceError(
"Iptc data segment ended mid-way through tag descriptor ("+e.Message+")");
return aMetadata;
}
offset += 2;
if ((offset + tagByteCount) > base.data.Length)
{
lcDirectory.HasError = true;
Trace.TraceError(
"Data for tag extends beyond end of IPTC segment");
break;
}
ProcessTag(lcDirectory, directoryType, tagType, offset, tagByteCount);
offset += tagByteCount;
}
return aMetadata;
}