/// <summary>
/// Adding multiple strokes (which can't be erased individually because there are no Guids)
/// Specifically, this is for student submission overlays.
/// There are also some CP3 scenarios such as when the instructor opens a CP3 file that has pre-existing ink.
/// </summary>
/// <param name="ink"></param>
public void AddInk(Microsoft.Ink.Ink newInk)
{
if ((newInk != null) && (newInk.Strokes.Count > 0))
{
//separate transparent and opaque strokes
List <int> transparentStrokes = new List <int>();
List <int> opaqueStrokes = new List <int>();
//iterate over strokes, adding the ink ids to the correct list
foreach (Microsoft.Ink.Stroke s in newInk.Strokes)
{
if ((s.DrawingAttributes.Transparency != 0) && (s.DrawingAttributes.Transparency != 255))
{
transparentStrokes.Add(s.Id);
}
else
{
opaqueStrokes.Add(s.Id);
}
}
//Add transparent strokes to transparentInk.
if (transparentStrokes.Count > 0)
{
Microsoft.Ink.Strokes tStrokes = newInk.CreateStrokes((int[])transparentStrokes.ToArray());
if (transparentInk == null)
{
transparentInk = new Microsoft.Ink.Ink();
}
transparentInk.AddStrokesAtRectangle(tStrokes, tStrokes.GetBoundingBox());
dirtyBit = true;
}
//Add opaque strokes to opaqueInk.
if (opaqueStrokes.Count > 0)
{
Microsoft.Ink.Strokes oStrokes = newInk.CreateStrokes((int[])opaqueStrokes.ToArray());
if (opaqueInk == null)
{
opaqueInk = new Microsoft.Ink.Ink();
}
opaqueInk.AddStrokesAtRectangle(oStrokes, oStrokes.GetBoundingBox());
dirtyBit = true;
}
}
}
private void addTransparentInkOverlay(Image img, double size)
{
//Ink transparency is in the range 0-255 with 0==opaque and 255==invisible.
//In practice CP sets transparency to 160, but we should be prepared for
//arbitrary values.
//We have no assurance that individual strokes won't have different transparencies, so we'll
//do each stroke as a separate overlay.
if ((transparentInk != null) && (transparentInk.Strokes.Count > 0))
{
foreach (Microsoft.Ink.Stroke s in transparentInk.Strokes)
{
Microsoft.Ink.Strokes strokes = transparentInk.CreateStrokes(new int[] { s.Id });
addTransparentStroke(img, strokes, size);
}
}
}