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Scope IME display attribute enumeration to the edited ranges #11872

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Scope IME display attribute enumeration to the edited ranges #11872

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997746f
Scope IME display attribute enumeration to the edited ranges
akon47 Aug 27, 2026
11639ab
Scope the enumeration to compositions and changed ranges
akon47 Sep 4, 2026
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213 changes: 164 additions & 49 deletions ...sentationFramework/System/Windows/Documents/TextServicesDisplayAttributePropertyRanges.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -77,13 +77,6 @@ internal override void OnEndEdit(UnsafeNativeMethods.ITfContext context,
{
Guid displayAttributeGuid;
UnsafeNativeMethods.ITfProperty displayAttributeProperty;
UnsafeNativeMethods.IEnumTfRanges attributeRangeEnumerator;
UnsafeNativeMethods.ITfRange[] attributeRanges;
int fetched;
int guidAtom;
TextServicesDisplayAttribute displayAttribute;
ITextPointer start;
ITextPointer end;

//
// Remove any existing display attribute highlights.
Expand Down Expand Up @@ -111,25 +104,166 @@ internal override void OnEndEdit(UnsafeNativeMethods.ITfContext context,
// Get the DisplayAttributeProperty.
displayAttributeGuid = Guid;
context.GetProperty(ref displayAttributeGuid, out displayAttributeProperty);
// Get a range enumerator for the property.
if (displayAttributeProperty.EnumRanges(ecReadOnly, out attributeRangeEnumerator, null) == NativeMethods.S_OK)

//
// Enumerate the display attribute property only where display attributes
// can currently be, instead of over the whole document.
//
// Passing null as the target range of EnumRanges enumerates the property
// across the entire document. The property keeps a range for every run the
// input method has composed, so on a long document this is a COM round trip
// per historical range, on every keystroke. Measured with the Windows 11
// Korean TSF IME on a 1,200 character document, a single OnEndEdit
// enumerated 1,077 ranges of which exactly one carried an attribute, and
// blocked the UI thread for roughly three seconds.
//
// Display attributes are decorations the input method places on text it is
// composing, so they can only be (a) inside an active composition or
// (b) on a range this edit just changed (which also covers ranges an ending
// composition just cleared). Enumerating the smallest span that covers both
// finds every range the whole-document scan would find - for any IME,
// including ones whose composition holds several attribute ranges at once,
// such as Japanese clause conversion, and edits that touch only some of
// them - while keeping the cost proportional to the composition rather than
// to the document.
//
if (TryGetAttributeScanWindow(context, ecReadOnly, editRecord, out int scanStart, out int scanEnd))
{
attributeRanges = new UnsafeNativeMethods.ITfRange[1];
context.GetStart(ecReadOnly, out UnsafeNativeMethods.ITfRange scanRange);
((UnsafeNativeMethods.ITfRangeACP)scanRange).SetExtent(scanStart, scanEnd - scanStart);

// Walk each range.
while (attributeRangeEnumerator.Next(1, attributeRanges, out fetched) == NativeMethods.S_OK)
{
// Get a DisplayAttribute for this range.
guidAtom = GetInt32Value(ecReadOnly, displayAttributeProperty, attributeRanges[0]);
displayAttribute = GetDisplayAttribute(guidAtom);
AddAttributeRanges(ecReadOnly, displayAttributeProperty, scanRange);

if (displayAttribute != null && !displayAttribute.IsEmptyAttribute())
{
// Set a matching highlight for the attribute range.
ConvertToTextPosition(attributeRanges[0], out start, out end);
Marshal.ReleaseComObject(scanRange);
}

#if UNUSED_IME_HIGHLIGHT_LAYER
if (_highlightLayer != null)
{
this.TextStore.TextContainer.Highlights.AddLayer(_highlightLayer);
}
#endif

if (start != null)
if (_compositionAdorner != null)
{
// Update the layout to get the acurated rectangle from calling GetRectangleFromTextPosition
this.TextStore.RenderScope.UpdateLayout();

// Invalidate the composition adorner to render the composition attribute ranges.
_compositionAdorner.InvalidateAdorner();
}

Marshal.ReleaseComObject(displayAttributeProperty);
}

/// <summary>
/// Computes the smallest ACP span covering every active composition and
/// every range whose display attribute this edit changed. Returns false
/// when there is nothing to scan.
/// </summary>
private bool TryGetAttributeScanWindow(
UnsafeNativeMethods.ITfContext context,
int ecReadOnly,
UnsafeNativeMethods.ITfEditRecord editRecord,
out int scanStart,
out int scanEnd)
{
scanStart = int.MaxValue;
scanEnd = int.MinValue;
int fetched;

// (a) Active compositions.
if (context is UnsafeNativeMethods.ITfContextComposition contextComposition)
{
contextComposition.EnumCompositions(out UnsafeNativeMethods.IEnumITfCompositionView compositionEnumerator);
if (compositionEnumerator != null)
{
UnsafeNativeMethods.ITfCompositionView[] views = new UnsafeNativeMethods.ITfCompositionView[1];
while (compositionEnumerator.Next(1, views, out fetched) == NativeMethods.S_OK && fetched == 1)
{
views[0].GetRange(out UnsafeNativeMethods.ITfRange compositionRange);
if (compositionRange != null)
{
ExtendScanWindow(compositionRange, ref scanStart, ref scanEnd);
Marshal.ReleaseComObject(compositionRange);
}
Marshal.ReleaseComObject(views[0]);
}
Marshal.ReleaseComObject(compositionEnumerator);
}
}

// (b) Ranges whose display attribute changed in this edit.
UnsafeNativeMethods.IEnumTfRanges updatedRanges = GetPropertyUpdate(editRecord);
if (updatedRanges != null)
{
UnsafeNativeMethods.ITfRange[] updated = new UnsafeNativeMethods.ITfRange[1];
while (updatedRanges.Next(1, updated, out fetched) == NativeMethods.S_OK && fetched == 1)
{
ExtendScanWindow(updated[0], ref scanStart, ref scanEnd);
Marshal.ReleaseComObject(updated[0]);
}
Marshal.ReleaseComObject(updatedRanges);
}

return scanStart <= scanEnd;
}

private static void ExtendScanWindow(UnsafeNativeMethods.ITfRange range, ref int scanStart, ref int scanEnd)
{
((UnsafeNativeMethods.ITfRangeACP)range).GetExtent(out int start, out int count);

// Cicero can report a negative length; ConvertToTextPosition guards the same way.
if (count < 0)
{
return;
}

if (start < scanStart)
{
scanStart = start;
}
if (start + count > scanEnd)
{
scanEnd = start + count;
}
}

/// <summary>
/// Adds every display attribute range found inside targetRange to the
/// composition adorner.
/// </summary>
private void AddAttributeRanges(
int ecReadOnly,
UnsafeNativeMethods.ITfProperty displayAttributeProperty,
UnsafeNativeMethods.ITfRange targetRange)
{
UnsafeNativeMethods.IEnumTfRanges attributeRangeEnumerator;

if (displayAttributeProperty.EnumRanges(ecReadOnly, out attributeRangeEnumerator, targetRange) != NativeMethods.S_OK)
{
return;
}

UnsafeNativeMethods.ITfRange[] attributeRanges = new UnsafeNativeMethods.ITfRange[1];
int fetched;

// Walk each range.
while (attributeRangeEnumerator.Next(1, attributeRanges, out fetched) == NativeMethods.S_OK)
{
// Get a DisplayAttribute for this range.
int guidAtom = GetInt32Value(ecReadOnly, displayAttributeProperty, attributeRanges[0]);
TextServicesDisplayAttribute displayAttribute = GetDisplayAttribute(guidAtom);

if (displayAttribute != null && !displayAttribute.IsEmptyAttribute())
{
// Set a matching highlight for the attribute range.
ITextPointer start;
ITextPointer end;
ConvertToTextPosition(attributeRanges[0], out start, out end);

if (start != null)
{
#if UNUSED_IME_HIGHLIGHT_LAYER
// Demand create the highlight layer.
if (_highlightLayer == null)
Expand All @@ -138,45 +272,26 @@ internal override void OnEndEdit(UnsafeNativeMethods.ITfContext context,
}
#endif

if (_compositionAdorner == null)
{
_compositionAdorner = new CompositionAdorner(this.TextStore.TextView);
_compositionAdorner.Initialize(this.TextStore.TextView);
}
if (_compositionAdorner == null)
{
_compositionAdorner = new CompositionAdorner(this.TextStore.TextView);
_compositionAdorner.Initialize(this.TextStore.TextView);
}

#if UNUSED_IME_HIGHLIGHT_LAYER
// Need to pass the foreground and background color of the composition
_highlightLayer.Add(start, end, /*TextDecorationCollection:*/null);
#endif

// Add the attribute range into CompositionAdorner.
_compositionAdorner.AddAttributeRange(start, end, displayAttribute);
}
// Add the attribute range into CompositionAdorner.
_compositionAdorner.AddAttributeRange(start, end, displayAttribute);
}

Marshal.ReleaseComObject(attributeRanges[0]);
}

#if UNUSED_IME_HIGHLIGHT_LAYER
if (_highlightLayer != null)
{
this.TextStore.TextContainer.Highlights.AddLayer(_highlightLayer);
}
#endif

if (_compositionAdorner != null)
{
// Update the layout to get the acurated rectangle from calling GetRectangleFromTextPosition
this.TextStore.RenderScope.UpdateLayout();

// Invalidate the composition adorner to render the composition attribute ranges.
_compositionAdorner.InvalidateAdorner();
}

Marshal.ReleaseComObject(attributeRangeEnumerator);
Marshal.ReleaseComObject(attributeRanges[0]);
}

Marshal.ReleaseComObject(displayAttributeProperty);
Marshal.ReleaseComObject(attributeRangeEnumerator);
}

// Callback from TextServicesProperty.OnLayoutUpdated.
Expand Down
6 changes: 4 additions & 2 deletions ...tNet.Wpf/src/PresentationFramework/System/Windows/Documents/TextServicesPropertyRanges.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -147,8 +147,10 @@ protected static Object GetValue(int ecReadOnly, UnsafeNativeMethods.ITfProperty
/// <summary>
/// Get ranges that the property is changed.
/// </summary>
private UnsafeNativeMethods.IEnumTfRanges GetPropertyUpdate(
UnsafeNativeMethods.ITfEditRecord editRecord)
// Promoted from private to protected so TextServicesDisplayAttributePropertyRanges
// can reuse it to scope its enumeration to the ranges an edit actually changed.
protected UnsafeNativeMethods.IEnumTfRanges GetPropertyUpdate(
UnsafeNativeMethods.ITfEditRecord editRecord)
{
UnsafeNativeMethods.IEnumTfRanges ranges;

Expand Down