/// <summary>
/// Builds the Stroke Descriptor for this stroke based on Packet Layout and Extended Properties
/// For details on how this is strored please refer to the spec.
/// </summary>
internal static void BuildStrokeDescriptor(
Stroke stroke,
GuidList guidList,
StrokeCollectionSerializer.StrokeLookupEntry strokeLookupEntry,
out StrokeDescriptor strokeDescriptor,
out MetricBlock metricBlock)
{
// Initialize the metric block for this stroke
metricBlock = new MetricBlock();
// Clear any existing template
strokeDescriptor = new StrokeDescriptor();
// Uninitialized variable passed in AddMetricEntry
MetricEntryType metricEntryType;
StylusPointDescription stylusPointDescription = stroke.StylusPoints.Description;
KnownTagCache.KnownTagIndex tag = guidList.FindTag(KnownIds.X, true);
metricEntryType = metricBlock.AddMetricEntry(stylusPointDescription.GetPropertyInfo(StylusPointProperties.X), tag);
tag = guidList.FindTag(KnownIds.Y, true);
metricEntryType = metricBlock.AddMetricEntry(stylusPointDescription.GetPropertyInfo(StylusPointProperties.Y), tag);
ReadOnlyCollection<StylusPointPropertyInfo> propertyInfos
= stylusPointDescription.GetStylusPointProperties();
int i = 0; //i is defined out of the for loop so we can use it later for buttons
for (i = 2/*past x,y*/; i < propertyInfos.Count; i++)
{
if (i == StylusPointDescription.RequiredPressureIndex/*2*/ &&
!strokeLookupEntry.StorePressure)
{
//
// don't store pressure information
//
continue;
}
StylusPointPropertyInfo propertyInfo = propertyInfos[i];
if (propertyInfo.IsButton)
{
//we don't serialize buttons
break;
}
tag = guidList.FindTag(propertyInfo.Id, true);
strokeDescriptor.Template.Add(tag);
strokeDescriptor.Size += SerializationHelper.VarSize((uint)tag);
// Create the MetricEntry for this property if necessary
metricEntryType = metricBlock.AddMetricEntry(propertyInfo, tag);
}
/*
we drop button data on the floor. See Windows OS Bugs 1413460 for details
int buttonCount = stylusPointDescription.ButtonCount;
// Now write the button tags in the Template
if (buttonCount > 0)
{
// First write the TAG_BUTTONS
strokeDescriptor.Template.Add(KnownTagCache.KnownTagIndex.Buttons);
strokeDescriptor.Size += SerializationHelper.VarSize((uint)KnownTagCache.KnownTagIndex.Buttons);
// Next write the i of buttons
strokeDescriptor.Template.Add((KnownTagCache.KnownTagIndex)buttonCount);
strokeDescriptor.Size += SerializationHelper.VarSize((uint)buttonCount);
//we broke above on i when it was a button, it still
//points to the first button
for (; i < propertyInfos.Count; i++)
{
StylusPointPropertyInfo propertyInfo = propertyInfos[i];
tag = guidList.FindTag(propertyInfo.Id, false);
strokeDescriptor.Template.Add(tag);
strokeDescriptor.Size += SerializationHelper.VarSize((uint)tag);
}
}
*/
// Now write the extended properties in the template
if (stroke.ExtendedProperties.Count > 0)
{
strokeDescriptor.Template.Add(KnownTagCache.KnownTagIndex.StrokePropertyList);
strokeDescriptor.Size += SerializationHelper.VarSize((uint)KnownTagCache.KnownTagIndex.StrokePropertyList);
// Now write the tags corresponding to each extended properties of the stroke
for (int x = 0; x < stroke.ExtendedProperties.Count; x++)
{
tag = guidList.FindTag(stroke.ExtendedProperties[(int)x].Id, false);
strokeDescriptor.Template.Add(tag);
strokeDescriptor.Size += SerializationHelper.VarSize((uint)tag);
}
}
}
/// <summary>
/// Saves the packets into a stream of bytes
/// </summary>
/// <param name="stroke">Stroke to save</param>
/// <param name="stream">null to calculate size only</param>
/// <param name="strokeLookupEntry"></param>
#endif
static uint SavePackets(
Stroke stroke,
Stream stream,
#if OLD_ISF
Compressor compressor,
#endif
StrokeCollectionSerializer.StrokeLookupEntry strokeLookupEntry)
{
// First write or calculate how many points are there
uint pointCount = (uint)stroke.StylusPoints.Count;
uint localBytesWritten = (stream != null) ? SerializationHelper.Encode(stream, pointCount) : SerializationHelper.VarSize(pointCount);
byte compressionAlgorithm;
int[][] outputArrays = strokeLookupEntry.ISFReadyStrokeData;
//We don't serialize button data, see Windows OS Bugs 1413460 for details
//int valuesPerPoint = stroke.StylusPoints.Description.GetOutputArrayLengthPerPoint();
//int buttonCount = stroke.StylusPoints.Description.ButtonCount;
ReadOnlyCollection<StylusPointPropertyInfo> propertyInfos
= stroke.StylusPoints.Description.GetStylusPointProperties();
int i = 0;
for (; i < propertyInfos.Count; i++)
{
StylusPointPropertyInfo propertyInfo = propertyInfos[i];
if (i == 2 && !strokeLookupEntry.StorePressure)
{
//
// only store pressure if we need to
//
continue;
}
if (propertyInfo.IsButton)
{
//
// we're at the buttons, handle this below
//
break;
}
compressionAlgorithm = strokeLookupEntry.CompressionData;
localBytesWritten += SavePacketPropertyData(outputArrays[i],
stream,
#if OLD_ISF
compressor,
#endif
propertyInfo.Id,
ref compressionAlgorithm);
}
/*
We don't serialize button data, see Windows OS Bugs 1413460 for details
// Now write all button data. Button data is stored as if it is another packet property
// with size (cbuttoncount + 7)/8 bytes and corresponding guids are stored in the packet
// description. Button data is only stored if buttons are present in the description and there
// are packets in the stroke
if (buttonCount > 0 && pointCount > 0)
{
Debug.Assert(i == valuesPerPoint - 1);
BitStreamWriter bitWriter = new BitStreamWriter();
//
// Get the array of button data (i is still pointing at it)
//
int[] buttonData = outputArrays[i];
for (int x = 0; x < pointCount; x++)
{
//
// each int in the button data array contains buttonCount number
// of bits that need to be written to the BitStreamWriter
// the BitStreamWriter takes bytes at a time. We always write the most
// signifigant bits first
//
int uncompactedButtonDataForPoint = buttonData[x];
// calculate the number of full bytes used for buttons per packet
// Example: 10 buttons would require 1 full byte
// but 8 would require
int fullBytesForButtonsPerPacket = buttonCount / Native.BitsPerByte;
// calculate the number of bits that spill beyond the full byte boundary
// Example: 10 buttons would require 2 extra bits (8 fit in a full byte)
int bitsToWrite = buttonCount % Native.BitsPerByte;
for (; fullBytesForButtonsPerPacket >= 0; fullBytesForButtonsPerPacket--)
{
byte byteOfButtonData =
Convert.ToByte(uncompactedButtonDataForPoint >> (fullBytesForButtonsPerPacket * Native.BitsPerByte));
//
// write 8 or less bytes to the bitwriter
// checking for 0 handles the case where we're writing 8, 16 or 24 bytes
// and bitsToWrite is initialize to zero
//
if (bitsToWrite > 0)
{
bitWriter.Write(byteOfButtonData, bitsToWrite);
}
if (fullBytesForButtonsPerPacket > 0)
{
bitsToWrite = Native.BitsPerByte;
}
}
}
// retrieve the button bytes
byte[] packedButtonData = bitWriter.ToBytes();
if (packedButtonData.Length !=
((buttonCount * pointCount + 7) / Native.BitsPerByte))
{
throw new ArgumentException(StrokeCollectionSerializer.ISFDebugMessage("Packed button length not equal to expected length"));
}
// write out the packed button data to the output stream
stream.Write(packedButtonData, 0, packedButtonData.Length);
localBytesWritten += (uint)packedButtonData.Length;
}
*/
return localBytesWritten;
}
/// <summary>
/// Returns an array of bytes of the saved stroke
/// </summary>
/// <param name="stroke">Stroke to save</param>
/// <param name="stream">null to calculate only the size</param>
/// <param name="compressionAlgorithm"></param>
/// <param name="guidList"></param>
/// <param name="strokeLookupEntry"></param>
#endif
internal static uint EncodeStroke(
Stroke stroke,
Stream stream,
#if OLD_ISF
Compressor compressor,
#endif
byte compressionAlgorithm,
GuidList guidList,
StrokeCollectionSerializer.StrokeLookupEntry strokeLookupEntry)
{
uint cbWrite = SavePackets( stroke,
stream,
#if OLD_ISF
compressor,
#endif
strokeLookupEntry);
if (stroke.ExtendedProperties.Count > 0)
cbWrite += ExtendedPropertySerializer.EncodeAsISF(stroke.ExtendedProperties, stream, guidList, compressionAlgorithm, false);
return cbWrite;
}