// Deletes a specified run of content.
//
// On exit,
// symbolsRemoved <== count of symbols actually removed.
// removeStartIndex <== offset of first symbol affected by the edit.
//
// removeStartIndex is always <= endPosition.Offset, but it does not necessarily
// match the position of the logically removed content. In some rare cases
// a scoping element may be removed, meaning we have two or more runs of
// removed content, and removeStartIndex + symbolsRemoved < the offset of
// the last position affected by the operation.
private void RemoveContent(ITextPointer startPosition, ITextPointer endPosition, out int symbolsRemoved, out int removeStartIndex)
{
symbolsRemoved = 0;
removeStartIndex = startPosition.Offset;
if (startPosition.CompareTo(endPosition) == 0)
return;
TextContainer container = (TextContainer)startPosition.TextContainer;
symbolsRemoved = container.SymbolCount;
if (startPosition is TextPointer)
{
_minSymbolsRemovedIndex = Int32.MaxValue;
}
startPosition.DeleteContentToPosition(endPosition);
if (startPosition is TextPointer)
{
removeStartIndex = _minSymbolsRemovedIndex;
}
symbolsRemoved = symbolsRemoved - container.SymbolCount;
}
/// <summary>
/// Deletes a content covered by two positions assuming that
/// the content crosses only paragraph-mergeable boundaries (if at all) -
/// Paragraphs, Sections, Lists, ListItems, but not harder structural
/// elements like Tables, TableCells, TableRows, Floaters, Figures.
/// </summary>
/// <param name="start">
/// Position indicating a beginning of deleted content.
/// </param>
/// <param name="end">
/// Position indicating an end of deleted content.
/// </param>
internal static void DeleteParagraphContent(ITextPointer start, ITextPointer end)
{
// Parameters validation
Invariant.Assert(start != null, "null check: start");
Invariant.Assert(end != null, "null check: end");
Invariant.Assert(start.CompareTo(end) <= 0, "expecting: start <= end");
if (!(start is TextPointer))
{
// Abstract text container. We can only use basic abstract functionality here:
start.DeleteContentToPosition(end);
return;
}
TextPointer startPosition = (TextPointer)start;
TextPointer endPosition = (TextPointer)end;
// Delete all equi-scoped content in the given range
DeleteEquiScopedContent(startPosition, endPosition); // delete content runs from start to root
DeleteEquiScopedContent(endPosition, startPosition); // delete contentruns from end to root
// Merge crossed elements
if (startPosition.CompareTo(endPosition) < 0)
{
if (TextPointerBase.IsAfterLastParagraph(endPosition))
{
// This means that end position is after the last paragraph of a text container.
// When the last paragraph is empty (and selection crosses its end boundary)
// we need to delete it.
// When last paragraph is not empty, we have to leave it as is.
while (startPosition.GetPointerContext(LogicalDirection.Backward) == TextPointerContext.ElementStart &&
startPosition.GetPointerContext(LogicalDirection.Forward) == TextPointerContext.ElementEnd)
{
//
TextElement parent = (TextElement)startPosition.Parent;
if (parent is Inline || TextSchema.AllowsParagraphMerging(parent.GetType()))
{
parent.RepositionWithContent(null);
}
else
{
break;
}
}
}
else
{
Block firstParagraphOrBlockUIContainer = startPosition.ParagraphOrBlockUIContainer;
Block secondParagraphOrBlockUIContainer = endPosition.ParagraphOrBlockUIContainer;
// If startPosition and/or endPosition is parented by an empty ListItem, create an implicit paragraph in it.
// This will enable the following code to merge paragraphs in list items.
if (firstParagraphOrBlockUIContainer == null && TextPointerBase.IsInEmptyListItem(startPosition))
{
startPosition = TextRangeEditTables.EnsureInsertionPosition(startPosition);
firstParagraphOrBlockUIContainer = startPosition.Paragraph;
Invariant.Assert(firstParagraphOrBlockUIContainer != null, "EnsureInsertionPosition must create a paragraph inside list item - 1");
}
if (secondParagraphOrBlockUIContainer == null && TextPointerBase.IsInEmptyListItem(endPosition))
{
endPosition = TextRangeEditTables.EnsureInsertionPosition(endPosition);
secondParagraphOrBlockUIContainer = endPosition.Paragraph;
Invariant.Assert(secondParagraphOrBlockUIContainer != null, "EnsureInsertionPosition must create a paragraph inside list item - 2");
}
if (firstParagraphOrBlockUIContainer != null && secondParagraphOrBlockUIContainer != null)
{
TextRangeEditLists.MergeParagraphs(firstParagraphOrBlockUIContainer, secondParagraphOrBlockUIContainer);
}
else
{
// When crossing BlockUIContainer boundaries we need to clear
// any empty BlockUIContainers and empty adjacent paragraphs
MergeEmptyParagraphsAndBlockUIContainers(startPosition, endPosition);
}
}
}
// Remove empty formatting elements
MergeFormattingInlines(startPosition);
MergeFormattingInlines(endPosition);
// Check for remaining empty BlockUICOntainer or empty Hyperlink elements
if (startPosition.Parent is BlockUIContainer && ((BlockUIContainer)startPosition.Parent).IsEmpty)
{
((BlockUIContainer)startPosition.Parent).Reposition(null, null);
}
else if (startPosition.Parent is Hyperlink && ((Hyperlink)startPosition.Parent).IsEmpty)
{
((Hyperlink)startPosition.Parent).Reposition(null, null);
// After deleting an empty hyperlink, we might have inlines to merge.
MergeFormattingInlines(startPosition);
}
//
}
