internal LineRecord(int offset, TextBoxLine line)
{
_offset = offset;
_length = line.Length;
_contentLength = line.ContentLength;
_width = line.Width;
}
// Helper for IncrementalMeasureLinesAfterInsert, IncrementalMeasureLinesAfterDelete.
// Formats the line preceding the first directly affected line after a TextContainer change.
// In general this line might grow as content in the following line is absorbed.
private void FormatFirstIncrementalLine(int lineIndex, double constraintWidth, LineProperties lineProperties, TextBoxLine line,
out int lineOffset, out bool endOfParagraph)
{
int originalEndOffset = _lineMetrics[lineIndex].EndOffset;
lineOffset = _lineMetrics[lineIndex].Offset;
using (line)
{
line.Format(lineOffset, constraintWidth, constraintWidth, lineProperties, _cache.TextRunCache, _cache.TextFormatter);
_lineMetrics[lineIndex] = new LineRecord(lineOffset, line);
lineOffset += line.Length;
endOfParagraph = line.EndOfParagraph;
}
// Don't clear the cached Visual unless something changed.
if (originalEndOffset != _lineMetrics[lineIndex].EndOffset)
{
ClearLineVisual(lineIndex);
}
}
// Helper for IncrementalMeasureLinesAfterInsert, IncrementalMeasureLinesAfterDelete.
// Formats line until we hit a synchronization point, a position where we know
// following lines could not be affected by the change.
private void SyncLineMetrics(DirtyTextRange range, double constraintWidth, LineProperties lineProperties, TextBoxLine line,
bool endOfParagraph, int lineIndex, int lineOffset)
{
bool offsetSyncOk = (range.PositionsAdded == 0 || range.PositionsRemoved == 0);
int lastCoveredCharOffset = range.StartIndex + Math.Max(range.PositionsAdded, range.PositionsRemoved);
// Keep updating lines until we find a synchronized position.
while (!endOfParagraph &&
(lineIndex == _lineMetrics.Count ||
!offsetSyncOk ||
lineOffset != _lineMetrics[lineIndex].Offset))
{
if (lineIndex < _lineMetrics.Count &&
lineOffset >= _lineMetrics[lineIndex].EndOffset)
{
// If the current line offset starts past the current line metric offset,
// remove the metric. This happens when the previous line
// frees up enough space to completely consume the following line.
// We can't simply replace the record without potentially missing our
// [....] position.
_lineMetrics.RemoveAt(lineIndex); //
RemoveLineVisualRange(lineIndex, 1);
}
else
{
using (line)
{
line.Format(lineOffset, constraintWidth, constraintWidth, lineProperties, _cache.TextRunCache, _cache.TextFormatter);
LineRecord record = new LineRecord(lineOffset, line);
if (lineIndex == _lineMetrics.Count ||
lineOffset + line.Length <= _lineMetrics[lineIndex].Offset)
{
// The new line preceeds the old line, insert a new record.
//
_lineMetrics.Insert(lineIndex, record);
AddLineVisualPlaceholder(lineIndex);
}
else
{
// We expect to be colliding with the old line directly.
// If we extend past it, we're in danger of needlessly
// re-formatting the entire doc (ie, we miss the real
// [....] position and don't stop until EndOfParagraph).
Invariant.Assert(lineOffset < _lineMetrics[lineIndex].EndOffset);
_lineMetrics[lineIndex] = record;
ClearLineVisual(lineIndex);
// If this line ends past the invalidated region, and it
// has a hard line break, it's safe to synchronize on the next
// line metric with a matching start offset.
offsetSyncOk |= lastCoveredCharOffset <= record.EndOffset && line.HasLineBreak;
}
lineIndex++;
lineOffset += line.Length;
endOfParagraph = line.EndOfParagraph;
}
}
}
// Remove any trailing lines that got absorbed into the new last line.
if (endOfParagraph && lineIndex < _lineMetrics.Count)
{
int count = _lineMetrics.Count - lineIndex;
_lineMetrics.RemoveRange(lineIndex, count);
RemoveLineVisualRange(lineIndex, count);
}
}
// Measures content invalidated due to a TextContainer change.
private void IncrementalMeasureLinesAfterDelete(double constraintWidth, LineProperties lineProperties, DirtyTextRange range, ref Size desiredSize)
{
int delta = range.PositionsAdded - range.PositionsRemoved;
Invariant.Assert(delta < 0);
int firstLineIndex = GetLineIndexFromOffset(range.StartIndex);
// Clip the scope of the affected lines to the region of the document
// we've already inspected. Clipping happens when background layout
// has not yet completed but an incremental update happens.
int endOffset = range.StartIndex + -delta - 1;
if (endOffset > _lineMetrics[_lineMetrics.Count - 1].EndOffset)
{
Invariant.Assert(this.IsBackgroundLayoutPending);
endOffset = _lineMetrics[_lineMetrics.Count - 1].EndOffset;
if (range.StartIndex == endOffset)
{
// Nothing left to do until background layout runs.
return;
}
}
int lastLineIndex = GetLineIndexFromOffset(endOffset);
// Increment the offsets of all following lines.
//
for (int i = lastLineIndex + 1; i < _lineMetrics.Count; i++)
{
_lineMetrics[i].Offset += delta;
}
TextBoxLine line = new TextBoxLine(this);
int lineIndex = firstLineIndex;
int lineOffset;
bool endOfParagraph;
// We need to re-format the previous line, because if someone inserted
// a hard break, the first directly affected line might now be shorter
// and mergeable with its predecessor.
if (lineIndex > 0) //
{
FormatFirstIncrementalLine(lineIndex - 1, constraintWidth, lineProperties, line, out lineOffset, out endOfParagraph);
}
else
{
lineOffset = _lineMetrics[lineIndex].Offset;
endOfParagraph = false;
}
//
// Update the first affected line. If it's completely covered, remove it entirely below.
if (!endOfParagraph &&
(range.StartIndex > lineOffset || range.StartIndex + -delta < _lineMetrics[lineIndex].EndOffset))
{
// Only part of the line is covered, reformat it.
using (line)
{
line.Format(lineOffset, constraintWidth, constraintWidth, lineProperties, _cache.TextRunCache, _cache.TextFormatter);
_lineMetrics[lineIndex] = new LineRecord(lineOffset, line);
lineOffset += line.Length;
endOfParagraph = line.EndOfParagraph;
}
ClearLineVisual(lineIndex);
lineIndex++;
}
// Remove all the following lines that are completely covered.
//
_lineMetrics.RemoveRange(lineIndex, lastLineIndex - lineIndex + 1);
RemoveLineVisualRange(lineIndex, lastLineIndex - lineIndex + 1);
// Recalc the following lines not directly affected as needed.
SyncLineMetrics(range, constraintWidth, lineProperties, line, endOfParagraph, lineIndex, lineOffset);
desiredSize = BruteForceCalculateDesiredSize();
}
// Measures content invalidated due to a TextContainer change.
private void IncrementalMeasureLinesAfterInsert(double constraintWidth, LineProperties lineProperties, DirtyTextRange range, ref Size desiredSize)
{
int delta = range.PositionsAdded - range.PositionsRemoved;
Invariant.Assert(delta >= 0);
int lineIndex = GetLineIndexFromOffset(range.StartIndex, LogicalDirection.Forward);
if (delta > 0)
{
// Increment of the offsets of all following lines.
//
for (int i = lineIndex + 1; i < _lineMetrics.Count; i++)
{
_lineMetrics[i].Offset += delta;
}
}
TextBoxLine line = new TextBoxLine(this);
int lineOffset;
bool endOfParagraph = false;
// We need to re-format the previous line, because if someone inserted
// a hard break, the first directly affected line might now be shorter
// and mergeable with its predecessor.
if (lineIndex > 0) //
{
FormatFirstIncrementalLine(lineIndex - 1, constraintWidth, lineProperties, line, out lineOffset, out endOfParagraph);
}
else
{
lineOffset = _lineMetrics[lineIndex].Offset;
}
// Format the line directly affected by the change.
// If endOfParagraph == true, then the line was absorbed into its
// predessor (because its new content is thinner, or because the
// TextWrapping property changed).
if (!endOfParagraph)
{
using (line)
{
line.Format(lineOffset, constraintWidth, constraintWidth, lineProperties, _cache.TextRunCache, _cache.TextFormatter);
_lineMetrics[lineIndex] = new LineRecord(lineOffset, line);
lineOffset += line.Length;
endOfParagraph = line.EndOfParagraph;
}
ClearLineVisual(lineIndex);
lineIndex++;
}
// Recalc the following lines not directly affected as needed.
SyncLineMetrics(range, constraintWidth, lineProperties, line, endOfParagraph, lineIndex, lineOffset);
desiredSize = BruteForceCalculateDesiredSize();
}
// Performs one iteration of background measure.
// Background measure always works at the end of the current
// line metrics array -- invalidations to prevoiusly examined
// content is handled by incremental layout, synchronously.
//
// Returns the full content size, omitting any unanalyzed content
// at the document end.
private Size FullMeasureTick(double constraintWidth, LineProperties lineProperties)
{
Size desiredSize;
TextBoxLine line = new TextBoxLine(this);
int lineOffset;
bool endOfParagraph;
// Find the next position for this iteration.
if (_lineMetrics.Count == 0)
{
desiredSize = new Size();
lineOffset = 0;
}
else
{
desiredSize = _contentSize;
lineOffset = _lineMetrics[_lineMetrics.Count - 1].EndOffset;
}
// Calculate a stop time.
// We limit work to just a few milliseconds per iteration
// to avoid blocking the thread.
DateTime stopTime;
if ((ScrollBarVisibility)((Control)_host).GetValue(ScrollViewer.VerticalScrollBarVisibilityProperty) == ScrollBarVisibility.Auto)
{
// Workaround for bug 1766924.
// When VerticalScrollBarVisiblity == Auto, there's a problem with
// our interaction with ScrollViewer. Disable background layout to
// mitigate the problem until we can take a real fix in v.next.
//
stopTime = DateTime.MaxValue;
}
else
{
stopTime = DateTime.Now.AddMilliseconds(_maxMeasureTimeMs);
}
// Format lines until we hit the end of document or run out of time.
do
{
using (line)
{
line.Format(lineOffset, constraintWidth, constraintWidth, lineProperties, _cache.TextRunCache, _cache.TextFormatter);
// This is a loop invariant, but has negligable cost.
//
_lineHeight = lineProperties.CalcLineAdvance(line.Height);
_lineMetrics.Add(new LineRecord(lineOffset, line));
// Desired width is always max of calculated line widths.
// Desired height is sum of all line heights.
desiredSize.Width = Math.Max(desiredSize.Width, line.Width);
desiredSize.Height += _lineHeight;
lineOffset += line.Length;
endOfParagraph = line.EndOfParagraph;
}
}
while (!endOfParagraph && DateTime.Now < stopTime);
if (!endOfParagraph)
{
// Ran out of time. Defer to background layout.
SetFlags(true, Flags.BackgroundLayoutPending);
this.Dispatcher.BeginInvoke(DispatcherPriority.Background, new DispatcherOperationCallback(OnBackgroundMeasure), null);
}
else
{
// Finished the entire document. Stop background layout.
SetFlags(false, Flags.BackgroundLayoutPending);
}
return desiredSize;
}
// Updates line visuals on an ArrangeOverride call.
private void ArrangeVisuals(Size arrangeSize)
{
Invariant.Assert(_dirtyList == null); // We should never see pending incremental updates during arrange.
//
// Initialize state.
//
if (_visualChildren == null)
{
_visualChildren = new List<TextBoxLineDrawingVisual>(1) ;
}
EnsureCache();
LineProperties lineProperties = _cache.LineProperties;
TextBoxLine line = new TextBoxLine(this);
//
// Calculate the current viewport extent, in lines.
// We won't do any work for lines that aren't visible.
//
int firstLineIndex;
int lastLineIndex;
GetVisibleLines(out firstLineIndex, out lastLineIndex);
SetViewportLines(firstLineIndex, lastLineIndex);
double width = GetWrappingWidth(arrangeSize.Width);
double horizontalOffset = GetTextAlignmentCorrection(lineProperties.TextAlignment, width);
double verticalOffset = this.VerticalAlignmentOffset;
if (_scrollData != null)
{
horizontalOffset -= _scrollData.HorizontalOffset;
verticalOffset -= _scrollData.VerticalOffset;
}
// Remove invalidated lines from the visual tree.
DetachDiscardedVisualChildren();
//
// Iterate across the visible lines.
// If we have a cached visual, simply update its current offset.
// Otherwise, allocate and render a new visual.
//
double formatWidth = GetWrappingWidth(_previousConstraint.Width);
for (int lineIndex = firstLineIndex; lineIndex <= lastLineIndex; lineIndex++)
{
TextBoxLineDrawingVisual lineVisual = GetLineVisual(lineIndex);
if (lineVisual == null)
{
LineRecord metrics = _lineMetrics[lineIndex];
using (line)
{
line.Format(metrics.Offset, formatWidth, width, lineProperties, _cache.TextRunCache, _cache.TextFormatter);
// We should be in [....] with current metrics, unless background layout is pending.
if (!this.IsBackgroundLayoutPending)
{
Invariant.Assert(metrics.Length == line.Length, "Line is out of [....] with metrics!");
}
lineVisual = line.CreateVisual();
}
SetLineVisual(lineIndex, lineVisual);
AttachVisualChild(lineVisual);
}
lineVisual.Offset = new Vector(horizontalOffset, verticalOffset + lineIndex * _lineHeight);
}
}
// Returns a formatted TextBoxLine at the specified index.
// Caller must Dispose the TextBoxLine.
// This method is expensive.
private TextBoxLine GetFormattedLine(int lineIndex, out LineProperties lineProperties)
{
TextBoxLine line = new TextBoxLine(this);
LineRecord metrics = _lineMetrics[lineIndex];
lineProperties = GetLineProperties();
Control hostControl = (Control)_host;
TextFormattingMode textFormattingMode = TextOptions.GetTextFormattingMode(hostControl);
TextFormatter formatter = TextFormatter.FromCurrentDispatcher(textFormattingMode);
double width = GetWrappingWidth(this.RenderSize.Width);
double formatWidth = GetWrappingWidth(_previousConstraint.Width);
line.Format(metrics.Offset, formatWidth, width, lineProperties, new TextRunCache(), formatter);
Invariant.Assert(metrics.Length == line.Length, "Line is out of [....] with metrics!");
return line;
}
