/// <summary>
/// Creates a substring of this rich text.
/// </summary>
public RichText Substring(int offset, int length)
{
if (offset == 0 && length == this.Length)
{
return(this);
}
string newText = text.Substring(offset, length);
RichTextModel model = ToRichTextModel();
OffsetChangeMap map = new OffsetChangeMap(2);
map.Add(new OffsetChangeMapEntry(offset + length, text.Length - offset - length, 0));
map.Add(new OffsetChangeMapEntry(0, offset, 0));
model.UpdateOffsets(map);
return(new RichText(newText, model));
}
public static OffsetChangeMap ToOffsetChangeMap(this IEnumerable<Edit> edits)
{
var map = new OffsetChangeMap();
int diff = 0;
foreach (var edit in edits) {
Debug.Assert(edit.EditType != ChangeType.None && edit.EditType != ChangeType.Unsaved);
int offset = edit.BeginA + diff;
int removalLength = edit.EndA - edit.BeginA;
int insertionLength = edit.EndB - edit.BeginB;
diff += (insertionLength - removalLength);
map.Add(new OffsetChangeMapEntry(offset, removalLength, insertionLength));
}
return map;
}
public static OffsetChangeMap ToOffsetChangeMap(this IEnumerable <Edit> edits)
{
var map = new OffsetChangeMap();
int diff = 0;
foreach (var edit in edits)
{
Debug.Assert(edit.EditType != ChangeType.None && edit.EditType != ChangeType.Unsaved);
int offset = edit.BeginA + diff;
int removalLength = edit.EndA - edit.BeginA;
int insertionLength = edit.EndB - edit.BeginB;
diff += (insertionLength - removalLength);
map.Add(new OffsetChangeMapEntry(offset, removalLength, insertionLength));
}
return(map);
}
/// <summary>
/// Replaces text.
/// </summary>
/// <param name="offset">The starting offset of the text to be replaced.</param>
/// <param name="length">The length of the text to be replaced.</param>
/// <param name="text">The new text.</param>
/// <param name="offsetChangeMappingType">The offsetChangeMappingType determines how offsets inside the old text are mapped to the new text.
/// This affects how the anchors and segments inside the replaced region behave.</param>
public void Replace(int offset, int length, string text, OffsetChangeMappingType offsetChangeMappingType)
{
if (text == null)
throw new ArgumentNullException("text");
// Please see OffsetChangeMappingType XML comments for details on how these modes work.
switch (offsetChangeMappingType) {
case OffsetChangeMappingType.Normal:
Replace(offset, length, text, null);
break;
case OffsetChangeMappingType.KeepAnchorBeforeInsertion:
Replace(offset, length, text, OffsetChangeMap.FromSingleElement(
new OffsetChangeMapEntry(offset, length, text.Length, false, true)));
break;
case OffsetChangeMappingType.RemoveAndInsert:
if (length == 0 || text.Length == 0) {
// only insertion or only removal?
// OffsetChangeMappingType doesn't matter, just use Normal.
Replace(offset, length, text, null);
} else {
OffsetChangeMap map = new OffsetChangeMap(2);
map.Add(new OffsetChangeMapEntry(offset, length, 0));
map.Add(new OffsetChangeMapEntry(offset, 0, text.Length));
map.Freeze();
Replace(offset, length, text, map);
}
break;
case OffsetChangeMappingType.CharacterReplace:
if (length == 0 || text.Length == 0) {
// only insertion or only removal?
// OffsetChangeMappingType doesn't matter, just use Normal.
Replace(offset, length, text, null);
} else if (text.Length > length) {
// look at OffsetChangeMappingType.CharacterReplace XML comments on why we need to replace
// the last character
OffsetChangeMapEntry entry = new OffsetChangeMapEntry(offset + length - 1, 1, 1 + text.Length - length);
Replace(offset, length, text, OffsetChangeMap.FromSingleElement(entry));
} else if (text.Length < length) {
OffsetChangeMapEntry entry = new OffsetChangeMapEntry(offset + text.Length, length - text.Length, 0, true, false);
Replace(offset, length, text, OffsetChangeMap.FromSingleElement(entry));
} else {
Replace(offset, length, text, OffsetChangeMap.Empty);
}
break;
default:
throw new ArgumentOutOfRangeException("offsetChangeMappingType", offsetChangeMappingType, "Invalid enum value");
}
}
/// <summary>
/// Creates a substring of this rich text.
/// </summary>
public RichText Substring(int offset, int length)
{
if (offset == 0 && length == this.Length)
return this;
string newText = text.Substring(offset, length);
RichTextModel model = ToRichTextModel();
OffsetChangeMap map = new OffsetChangeMap(2);
map.Add(new OffsetChangeMapEntry(offset + length, text.Length - offset - length, 0));
map.Add(new OffsetChangeMapEntry(0, offset, 0));
model.UpdateOffsets(map);
return new RichText(newText, model);
}