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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
//
//
//
// Contents: Implementation of text shapeable symbols for characters
//
// Spec: Text Formatting API.doc
//
//
using System;
using System.Diagnostics;
using System.Globalization;
using System.Collections;
using System.Collections.Generic;
using System.Security;
using System.Windows;
using System.Windows.Markup; // for XmlLanguage
using System.Windows.Media;
using MS.Internal;
using MS.Internal.FontCache;
using MS.Internal.TextFormatting;
using MS.Internal.Shaping;
using MS.Internal.Text.TextInterface;
namespace System.Windows.Media.TextFormatting
{
/// <summary>
/// A specialized TextShapeableSymbols implemented by TextFormatter to represent
/// a collection of glyphs from a physical typeface.
/// </summary>
internal sealed class TextShapeableCharacters : TextShapeableSymbols
{
private CharacterBufferRange _characterBufferRange;
private TextFormattingMode _textFormattingMode;
private bool _isSideways;
private TextRunProperties _properties;
private double _emSize; // after-scaled
private ItemProps _textItem;
private ShapeTypeface _shapeTypeface;
private bool _nullShape;
#region Constructors
/// <summary>
/// Construct a shapeable characters object
/// </summary>
/// <remarks>
/// The shapeTypeface parameter can be null if and only if CheckFastPathNominalGlyphs
/// has previously returned true.
/// </remarks>
internal TextShapeableCharacters(
CharacterBufferRange characterRange,
TextRunProperties properties,
double emSize,
ItemProps textItem,
ShapeTypeface shapeTypeface,
bool nullShape,
TextFormattingMode textFormattingMode,
bool isSideways
)
{
_isSideways = isSideways;
_textFormattingMode = textFormattingMode;
_characterBufferRange = characterRange;
_properties = properties;
_emSize = emSize;
_textItem = textItem;
_shapeTypeface = shapeTypeface;
_nullShape = nullShape;
}
#endregion
#region TextRun implementation
/// <summary>
/// Character reference
/// </summary>
public sealed override CharacterBufferReference CharacterBufferReference
{
get
{
return _characterBufferRange.CharacterBufferReference;
}
}
/// <summary>
/// Character length of the run
/// </summary>
public sealed override int Length
{
get
{
return _characterBufferRange.Length;
}
}
/// <summary>
/// A set of properties shared by every characters in the run
/// </summary>
public sealed override TextRunProperties Properties
{
get
{
return _properties;
}
}
#endregion
#region TextShapeableSymbols implementation
/// <summary>
/// Compute a shaped glyph run object from specified glyph-based info
/// </summary>
internal sealed override GlyphRun ComputeShapedGlyphRun(
Point origin,
char[] characterString,
ushort[] clusterMap,
ushort[] glyphIndices,
IList<double> glyphAdvances,
IList<Point> glyphOffsets,
bool rightToLeft,
bool sideways
)
{
Invariant.Assert(_shapeTypeface != null);
Invariant.Assert(glyphIndices != null);
// Device fonts are only used through the LS non-glyphed code path. Only when a DigitCulture is set
// will a potential device font be ignored and come through shaping.
Invariant.Assert(_shapeTypeface.DeviceFont == null || _textItem.DigitCulture != null);
bool[] caretStops = null;
if ( clusterMap != null
&& (HasExtendedCharacter || NeedsCaretInfo)
)
{
caretStops = new bool[clusterMap.Length + 1];
// caret stops at cluster boundaries, the first and the last entries are always set
caretStops[0] = true;
caretStops[clusterMap.Length] = true;
ushort lastGlyph = clusterMap[0];
for (int i = 1; i < clusterMap.Length; i++)
{
ushort glyph = clusterMap[i];
if (glyph != lastGlyph)
{
caretStops[i] = true;
lastGlyph = glyph;
}
}
}
return GlyphRun.TryCreate(
_shapeTypeface.GlyphTypeface,
(rightToLeft ? 1 : 0),
sideways,
_emSize,
(float)_properties.PixelsPerDip,
glyphIndices,
origin,
glyphAdvances,
glyphOffsets,
characterString,
null,
clusterMap,
caretStops,
XmlLanguage.GetLanguage(CultureMapper.GetSpecificCulture(_properties.CultureInfo).IetfLanguageTag),
_textFormattingMode
);
}
private GlyphTypeface GetGlyphTypeface(out bool nullFont)
{
GlyphTypeface glyphTypeface;
if (_shapeTypeface == null)
{
// We're in the optimized path where the GlyphTypeface depends only
// on the Typeface, not on the particular input characters.
Typeface typeface = _properties.Typeface;
// Get the GlyphTypeface.
glyphTypeface = typeface.TryGetGlyphTypeface();
// If Typeface does not specify *any* valid font family, then we use
// the GlyphTypeface for Arial but only to display missing glyphs.
nullFont = typeface.NullFont;
}
else
{
// Font linking has mapped the input to a specific GlyphTypeface.
glyphTypeface = _shapeTypeface.GlyphTypeface;
// If font linking could not find *any* physical font family, then we
// use the GlyphTypeface for Arial but only to display missing glyphs.
nullFont = _nullShape;
}
Invariant.Assert(glyphTypeface != null);
return glyphTypeface;
}
/// <summary>
/// Compute unshaped glyph run object from the specified character-based info
/// </summary>
internal sealed override GlyphRun ComputeUnshapedGlyphRun(
Point origin,
char[] characterString,
IList<double> characterAdvances
)
{
bool nullFont;
GlyphTypeface glyphTypeface = GetGlyphTypeface(out nullFont);
Invariant.Assert(glyphTypeface != null);
return glyphTypeface.ComputeUnshapedGlyphRun(
origin,
new CharacterBufferRange(
characterString,
0, // offsetToFirstChar
characterString.Length
),
characterAdvances,
_emSize,
(float)_properties.PixelsPerDip,
_properties.FontHintingEmSize,
nullFont,
CultureMapper.GetSpecificCulture(_properties.CultureInfo),
(_shapeTypeface == null || _shapeTypeface.DeviceFont == null) ? null : _shapeTypeface.DeviceFont.Name,
_textFormattingMode
);
}
/// <summary>
/// Draw glyph run to the drawing surface
/// </summary>
internal sealed override void Draw(
DrawingContext drawingContext,
Brush foregroundBrush,
GlyphRun glyphRun
)
{
ArgumentNullException.ThrowIfNull(drawingContext);
glyphRun.EmitBackground(drawingContext, _properties.BackgroundBrush);
drawingContext.DrawGlyphRun(
foregroundBrush != null ? foregroundBrush : _properties.ForegroundBrush,
glyphRun
);
}
internal override double EmSize
{
get
{
return _emSize;
}
}
internal override MS.Internal.Text.TextInterface.ItemProps ItemProps
{
get
{
return _textItem;
}
}
/// <summary>
/// Get advance widths of unshaped characters
/// </summary>
internal sealed override unsafe void GetAdvanceWidthsUnshaped(
char* characterString,
int characterLength,
double scalingFactor,
int* advanceWidthsUnshaped
)
{
if (!IsShapingRequired)
{
if ( (_shapeTypeface != null)
&& (_shapeTypeface.DeviceFont != null))
{
// Use device font to compute advance widths
_shapeTypeface.DeviceFont.GetAdvanceWidths(
characterString,
characterLength,
_emSize * scalingFactor,
advanceWidthsUnshaped
);
}
else
{
bool nullFont;
GlyphTypeface glyphTypeface = GetGlyphTypeface(out nullFont);
Invariant.Assert(glyphTypeface != null);
glyphTypeface.GetAdvanceWidthsUnshaped(
characterString,
characterLength,
_emSize,
(float)_properties.PixelsPerDip,
scalingFactor,
advanceWidthsUnshaped,
nullFont,
_textFormattingMode,
_isSideways
);
}
}
else
{
GlyphTypeface glyphTypeface = _shapeTypeface.GlyphTypeface;
Invariant.Assert(glyphTypeface != null);
Invariant.Assert(characterLength > 0);
CharacterBufferRange newBuffer = new CharacterBufferRange(characterString, characterLength);
MS.Internal.Text.TextInterface.GlyphMetrics[] glyphMetrics = BufferCache.GetGlyphMetrics(characterLength);
glyphTypeface.GetGlyphMetricsOptimized(newBuffer,
_emSize,
(float)_properties.PixelsPerDip,
_textFormattingMode,
_isSideways,
glyphMetrics
);
if (_textFormattingMode == TextFormattingMode.Display &&
TextFormatterContext.IsSpecialCharacter(*characterString))
{
// If the run starts with a special character (in
// the LineServices sense), we apply display-mode rounding now,
// as we won't get another chance. This assumes that the characters
// in a run are either all special or all non-special; that assumption
// is valid in the current LS implementation.
double designToEm = _emSize / glyphTypeface.DesignEmHeight;
double pixelsPerDip = _properties.PixelsPerDip;
for (int i = 0; i < characterLength; i++)
{
advanceWidthsUnshaped[i] = (int)Math.Round(TextFormatterImp.RoundDipForDisplayMode(glyphMetrics[i].AdvanceWidth * designToEm, pixelsPerDip) * scalingFactor);
}
}
else
{
// For the normal case, rounding is applied later on when LS
// invokes the callback GetGlyphPositions, so that adjustments
// due to justification and shaping are taken into account.
double designToEm = _emSize * scalingFactor / glyphTypeface.DesignEmHeight;
for (int i = 0; i < characterLength; i++)
{
advanceWidthsUnshaped[i] = (int)Math.Round(glyphMetrics[i].AdvanceWidth * designToEm);
}
}
BufferCache.ReleaseGlyphMetrics(glyphMetrics);
}
}
/// <summary>
/// This is needed to decide whether we should pass a max cluster size to LS.
/// We pass a max cluster size to LS to perform line breaking correctly.
/// Passing a max cluster size larger than necessary will have impact on perf.
/// </summary>
internal sealed override bool NeedsMaxClusterSize
{
get
{
// We will need to pass a max cluster size to LS if:
// 1) the script is not Latin (hence more likely to formed into ligature)
// 2) or the run contains combining mark or extended characters
if (!_textItem.IsLatin ||
_textItem.HasCombiningMark ||
_textItem.HasExtendedCharacter
)
{
return true;
}
return false;
}
}
/// <summary>
/// Return value indicates whether two runs can shape together
/// </summary>
internal sealed override bool CanShapeTogether(
TextShapeableSymbols shapeable
)
{
TextShapeableCharacters charShape = shapeable as TextShapeableCharacters;
if (charShape == null)
return false;
return
_shapeTypeface.Equals(charShape._shapeTypeface)
// Extended characters need to be shaped by surrogate shaper. They cannot be shaped together with non-exteneded characters.
&& (_textItem.HasExtendedCharacter) == (charShape._textItem.HasExtendedCharacter)
&& _emSize == charShape._emSize
&& (
_properties.CultureInfo == null ?
charShape._properties.CultureInfo == null
: _properties.CultureInfo.Equals(charShape._properties.CultureInfo)
)
&& _nullShape == charShape._nullShape
&& (_textItem.CanShapeTogether(charShape._textItem));
}
/// <summary>
/// Indicate whether run cannot be treated as simple characters because shaping is required.
///
/// The following cases use simple rendering without shaping:
/// o No _shapeTypeface. This happens in very simple rendering cases.
/// o Non-Unicode (i.e. symbol) fonts.
/// o When using a device font.
///
/// Note that the presence of a device font in _shapeTypeface.DeviceFont implies use of
/// a device font in all cases except where digit substitution applies. This special
/// case occurs because the cached result per codepoint of TypefaceMap must include the device font
/// for non-western digits in order to support device font rendering of the non-Western
/// digit Unicode codepoints. The device font is not used however when the non-Western digits
/// are displayed as a result of digit substitution from backing store Western digits.
/// </summary>
internal sealed override bool IsShapingRequired
{
get
{
return
(_shapeTypeface != null) // Can't use shaping without a shape typeface
&& ( (_shapeTypeface.DeviceFont == null) // Can't use shaping when rendering with a device font
|| (_textItem.DigitCulture != null)) // -- unless substituting digits
&& (!IsSymbol); // Can't use shaping for symbol (non-Unicode) fonts
}
}
/// <summary>
/// A Boolean value indicates whether additional info is required for caret positioning
/// </summary>
internal sealed override bool NeedsCaretInfo
{
get
{
return (_textItem.HasCombiningMark)
|| (_textItem.NeedsCaretInfo);
}
}
/// <summary>
/// A Boolean value indicates whether run has extended character
/// </summary>
internal sealed override bool HasExtendedCharacter
{
get
{
return _textItem.HasExtendedCharacter;
}
}
/// <summary>
/// Run height
/// </summary>
internal sealed override double Height
{
get
{
return _properties.Typeface.LineSpacing(_properties.FontRenderingEmSize, 1, _properties.PixelsPerDip, _textFormattingMode);
}
}
/// <summary>
/// Distance from top to baseline
/// </summary>
internal sealed override double Baseline
{
get
{
return _properties.Typeface.Baseline(_properties.FontRenderingEmSize, 1, _properties.PixelsPerDip, _textFormattingMode);
}
}
/// <summary>
/// Distance from baseline to underline position relative to TextRunProperties.FontRenderingEmSize
/// </summary>
internal sealed override double UnderlinePosition
{
get
{
return _properties.Typeface.UnderlinePosition;
}
}
/// <summary>
/// Underline thickness relative to TextRunProperties.FontRenderingEmSize
/// </summary>
internal sealed override double UnderlineThickness
{
get
{
return _properties.Typeface.UnderlineThickness;
}
}
/// <summary>
/// Distance from baseline to strike-through position relative to TextRunProperties.FontRenderingEmSize
/// </summary>
internal sealed override double StrikethroughPosition
{
get
{
return _properties.Typeface.StrikethroughPosition;
}
}
/// <summary>
/// strike-through thickness relative to TextRunProperties.FontRenderingEmSize
/// </summary>
internal sealed override double StrikethroughThickness
{
get
{
return _properties.Typeface.StrikethroughThickness;
}
}
#endregion
/// <summary>
/// Whether all characters in this run are non-Unicode character (symbol)
/// </summary>
internal bool IsSymbol
{
get
{
if (_shapeTypeface != null)
return _shapeTypeface.GlyphTypeface.Symbol;
return _properties.Typeface.Symbol;
}
}
internal override GlyphTypeface GlyphTypeFace
{
get
{
if (_shapeTypeface != null)
return _shapeTypeface.GlyphTypeface;
return _properties.Typeface.TryGetGlyphTypeface();
}
}
/// <summary>
/// Returns maximum possible cluster size for the run. Normally, this
/// is 8 characters, but Indic scripts require this to be 15.
/// </summary>
internal const ushort DefaultMaxClusterSize = 8;
private const ushort IndicMaxClusterSize = 15;
internal sealed override ushort MaxClusterSize
{
get
{
if (_textItem.IsIndic)
{
return IndicMaxClusterSize;
}
return DefaultMaxClusterSize;
}
}
}
}
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