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//---------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// Description: The FontFaceLayoutInfo class
//
// History:
// 07/23/2003 : mleonov - Big rewrite to change cache structure
// 08/08/2008 : Microsoft - Integrating with DWrite.
//
//---------------------------------------------------------------------------
using System;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Security;
using System.ComponentModel;
using System.Collections;
using System.Collections.Generic;
using System.Security.Permissions;
using System.Windows;
using System.Windows.Media;
using System.Runtime.InteropServices;
using MS.Win32;
using MS.Utility;
using MS.Internal;
using MS.Internal.FontFace;
using MS.Internal.Shaping;
using MS.Internal.PresentationCore;
namespace MS.Internal.FontCache
{
[FriendAccessAllowed]
internal sealed class FontFaceLayoutInfo
{
private FontTechnology _fontTechnology;
private TypographyAvailabilities _typographyAvailabilities;
private FontEmbeddingRight _embeddingRights;
private bool _embeddingRightsInitialized;
private bool _gsubInitialized;
private bool _gposInitialized;
private bool _gdefInitialized;
private bool _fontTechnologyInitialized;
private bool _typographyAvailabilitiesInitialized;
private byte[] _gsubCache;
private byte[] _gposCache;
private byte[] _gsub;
private byte[] _gpos;
private byte[] _gdef;
Text.TextInterface.Font _font;
ushort _blankGlyphIndex;
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
#region Constructors
/// <SecurityNote>
/// Critical - Calls into the critical CreateOpenTypeLayoutCache.
/// </SecurityNote>
[SecurityCritical]
internal FontFaceLayoutInfo(Text.TextInterface.Font font)
{
_fontTechnologyInitialized = false;
_typographyAvailabilitiesInitialized = false;
_gsubInitialized = false;
_gposInitialized = false;
_gdefInitialized = false;
_embeddingRightsInitialized = false;
_gsubCache = null;
_gposCache = null;
_gsub = null;
_gpos = null;
_gdef = null;
_font = font;
_cmap = new IntMap(_font);
_cmap.TryGetValue(' ', out _blankGlyphIndex);
}
#endregion Constructors
internal IntMap CharacterMap
{
get
{
return _cmap;
}
}
internal ushort BlankGlyph
{
get
{
return _blankGlyphIndex;
}
}
/// <SecurityNote>
/// Critical: This calls into critical DesignUnitsPerEm.
/// TreatAsSafe: This data is safe to expose.
/// </SecurityNote>
internal ushort DesignEmHeight
{
[SecurityCritical, SecurityTreatAsSafe]
get
{
return _font.Metrics.DesignUnitsPerEm;
}
}
private static class Os2EmbeddingFlags
{
public const ushort RestrictedLicense = 0x0002;
public const ushort PreviewAndPrint = 0x0004;
public const ushort Editable = 0x0008;
// The font is installable if all bits in the InstallableMask are set to zero.
public const ushort InstallableMask = RestrictedLicense | PreviewAndPrint | Editable;
public const ushort NoSubsetting = 0x0100;
public const ushort BitmapOnly = 0x0200;
}
/// <summary>
/// Analyzes os/2 fsType value and construct FontEmbeddingRight enum value from it.
/// </summary>
/// <SecurityNote>
/// Critical: This code writes critical information into FontFaceLayoutInfo.
/// TreatAsSafe: It does this only using font data and not user defined parameters.
/// </SecurityNote>
internal FontEmbeddingRight EmbeddingRights
{
[SecurityCritical, SecurityTreatAsSafe]
get
{
if (!_embeddingRightsInitialized)
{
// If there is no os/2 table, default to restricted font.
// This is the precedence that has been set by T2Embed, Word, etc.
// No one has complained about this because these fonts are generally lower in quality and are less likely to be embedded.
FontEmbeddingRight rights = FontEmbeddingRight.RestrictedLicense;
ushort fsType;
bool success;
MS.Internal.Text.TextInterface.FontFace fontFace = _font.GetFontFace();
try
{
success = fontFace.ReadFontEmbeddingRights(out fsType);
}
finally
{
fontFace.Release();
}
if (success)
{
// Start with the most restrictive flags.
// In case a font uses conflicting flags,
// expose the least restrictive combination in order to be compatible with existing applications.
if ((fsType & Os2EmbeddingFlags.InstallableMask) == 0)
{
// The font is installable if all bits in the InstallableMask are set to zero.
switch (fsType & (Os2EmbeddingFlags.NoSubsetting | Os2EmbeddingFlags.BitmapOnly))
{
case 0:
rights = FontEmbeddingRight.Installable;
break;
case Os2EmbeddingFlags.NoSubsetting:
rights = FontEmbeddingRight.InstallableButNoSubsetting;
break;
case Os2EmbeddingFlags.BitmapOnly:
rights = FontEmbeddingRight.InstallableButWithBitmapsOnly;
break;
case Os2EmbeddingFlags.NoSubsetting | Os2EmbeddingFlags.BitmapOnly:
rights = FontEmbeddingRight.InstallableButNoSubsettingAndWithBitmapsOnly;
break;
}
}
else if ((fsType & Os2EmbeddingFlags.Editable) != 0)
{
switch (fsType & (Os2EmbeddingFlags.NoSubsetting | Os2EmbeddingFlags.BitmapOnly))
{
case 0:
rights = FontEmbeddingRight.Editable;
break;
case Os2EmbeddingFlags.NoSubsetting:
rights = FontEmbeddingRight.EditableButNoSubsetting;
break;
case Os2EmbeddingFlags.BitmapOnly:
rights = FontEmbeddingRight.EditableButWithBitmapsOnly;
break;
case Os2EmbeddingFlags.NoSubsetting | Os2EmbeddingFlags.BitmapOnly:
rights = FontEmbeddingRight.EditableButNoSubsettingAndWithBitmapsOnly;
break;
}
}
else if ((fsType & Os2EmbeddingFlags.PreviewAndPrint) != 0)
{
switch (fsType & (Os2EmbeddingFlags.NoSubsetting | Os2EmbeddingFlags.BitmapOnly))
{
case 0:
rights = FontEmbeddingRight.PreviewAndPrint;
break;
case Os2EmbeddingFlags.NoSubsetting:
rights = FontEmbeddingRight.PreviewAndPrintButNoSubsetting;
break;
case Os2EmbeddingFlags.BitmapOnly:
rights = FontEmbeddingRight.PreviewAndPrintButWithBitmapsOnly;
break;
case Os2EmbeddingFlags.NoSubsetting | Os2EmbeddingFlags.BitmapOnly:
rights = FontEmbeddingRight.PreviewAndPrintButNoSubsettingAndWithBitmapsOnly;
break;
}
}
else
{
// Otherwise, the font either has Os2EmbeddingFlags.RestrictedLicense set, or
// it has a reserved bit 0 set, which is invalid per specification.
// Either way, rights should remain FontEmbeddingRight.RestrictedLicense.
}
}
_embeddingRights = rights;
_embeddingRightsInitialized = true;
}
return _embeddingRights;
}
}
internal FontTechnology FontTechnology
{
get
{
if (!_fontTechnologyInitialized)
{
ComputeFontTechnology();
_fontTechnologyInitialized = true;
}
return _fontTechnology;
}
}
/// <SecurityNote>
/// Critical - calls critical method ComputeTypographyAvailabilities
/// </SecurityNote>
internal TypographyAvailabilities TypographyAvailabilities
{
[SecurityCritical, SecurityTreatAsSafe]
get
{
if (!_typographyAvailabilitiesInitialized)
{
ComputeTypographyAvailabilities();
_typographyAvailabilitiesInitialized = true;
}
return _typographyAvailabilities;
}
}
/// <SecurityNote>
/// Critical: This calls into critical GlyphCount.
/// TreatAsSafe: This data is safe to expose.
/// </SecurityNote>
internal ushort GlyphCount
{
[SecurityCritical, SecurityTreatAsSafe]
get
{
ushort glyphCount;
MS.Internal.Text.TextInterface.FontFace fontFace = _font.GetFontFace();
try
{
glyphCount = fontFace.GlyphCount;
}
finally
{
fontFace.Release();
}
return glyphCount;
}
}
/// <SecurityNote>
/// Critical - calls critical method TryGetFontTable, returns critical info.
/// </SecurityNote>
[SecurityCritical]
private byte[] GetFontTable(Text.TextInterface.OpenTypeTableTag openTypeTableTag)
{
byte[] table;
MS.Internal.Text.TextInterface.FontFace fontFace = _font.GetFontFace();
try
{
if (!fontFace.TryGetFontTable(openTypeTableTag, out table))
{
table = null;
}
}
finally
{
fontFace.Release();
}
return table;
}
// OpenType support
/// <SecurityNote>
/// Critical - calls critical method GetFontTable
/// </SecurityNote>
[SecurityCritical]
internal byte[] Gsub()
{
if (!_gsubInitialized)
{
_gsub = GetFontTable(Text.TextInterface.OpenTypeTableTag.TTO_GSUB);
_gsubInitialized = true;
}
return _gsub;
}
/// <SecurityNote>
/// Critical - calls critical method GetFontTable
/// </SecurityNote>
[SecurityCritical]
internal byte[] Gpos()
{
if (!_gposInitialized)
{
_gpos = GetFontTable(Text.TextInterface.OpenTypeTableTag.TTO_GPOS);
_gposInitialized = true;
}
return _gpos;
}
/// <SecurityNote>
/// Critical - calls critical method GetFontTable
/// </SecurityNote>
[SecurityCritical]
internal byte[] Gdef()
{
if (!_gdefInitialized)
{
_gdef = GetFontTable(Text.TextInterface.OpenTypeTableTag.TTO_GDEF);
_gdefInitialized = true;
}
return _gdef;
}
/// <SecurityNote>
/// Critical: Calls unsafe code
/// </SecurityNote>
[SecurityCritical]
internal byte[] GetTableCache(OpenTypeTags tableTag)
{
switch (tableTag)
{
case OpenTypeTags.GSUB:
if (Gsub() != null)
{
return _gsubCache;
}
break;
case OpenTypeTags.GPOS:
if (Gpos() != null)
{
return _gposCache;
}
break;
default:
throw new NotSupportedException();
}
return null;
}
internal byte[] AllocateTableCache(OpenTypeTags tableTag, int size)
{
switch (tableTag)
{
case OpenTypeTags.GSUB:
{
_gsubCache = new byte[size];
return _gsubCache;
}
case OpenTypeTags.GPOS:
{
_gposCache = new byte[size];
return _gposCache;
}
default:
{
throw new NotSupportedException();
}
}
}
/// <SecurityNote>
/// Critical: This calls into critical Type.
/// TreatAsSafe: Does not expose any critical data.
/// </SecurityNote>
[SecurityCritical, SecurityTreatAsSafe]
private void ComputeFontTechnology()
{
MS.Internal.Text.TextInterface.FontFace fontFace = _font.GetFontFace();
try
{
if (fontFace.Type == Text.TextInterface.FontFaceType.TrueTypeCollection)
{
_fontTechnology = FontTechnology.TrueTypeCollection;
}
else if (fontFace.Type == Text.TextInterface.FontFaceType.CFF)
{
_fontTechnology = FontTechnology.PostscriptOpenType;
}
else
{
_fontTechnology = FontTechnology.TrueType;
}
}
finally
{
fontFace.Release();
}
}
/// <summary>
/// Computes the typography availabilities.
/// It checks the presence of a set of required features in the font
/// for ranges of unicode code points and set the corresponding bits
/// in the TypographyAvailabilities enum. TypographyAvailabilities enum is
/// used to determind whether fast path can be used to format the input.
/// </summary>
/// <SecurityNote>
/// Critical - calls critical code (OpenType layout table access)
/// Also uses pointers
/// </SecurityNote>
[SecurityCritical, SecurityTreatAsSafe]
private void ComputeTypographyAvailabilities()
{
int glyphBitsLength = (GlyphCount + 31) >> 5;
uint[] glyphBits = BufferCache.GetUInts(glyphBitsLength);
Array.Clear(glyphBits, 0, glyphBitsLength);
ushort minGlyphId = 65535;
ushort maxGlyphId = 0;
WritingSystem[] complexScripts;
TypographyAvailabilities typography = TypographyAvailabilities.None;
GsubGposTables GsubGpos = new GsubGposTables(this);
// preparing the glyph bits. When the bit is set, it means the corresponding
// glyph needs to be checked against.
for (int i = 0; i < fastTextRanges.Length; i++)
{
uint[] codepoints = fastTextRanges[i].GetFullRange();
ushort[] glyphIndices = BufferCache.GetUShorts(codepoints.Length);
unsafe
{
fixed (uint *pCodepoints = &codepoints[0])
{
fixed (ushort *pGlyphIndices = &glyphIndices[0])
{
CharacterMap.TryGetValues(pCodepoints, checked((uint)codepoints.Length), pGlyphIndices);
}
}
}
for (int j = 0; j < codepoints.Length; j++)
{
ushort glyphId = glyphIndices[j];
if (glyphId != 0)
{
glyphBits[glyphId >> 5] |= (uint)(1 << (glyphId % 32));
if (glyphId > maxGlyphId) maxGlyphId = glyphId;
if (glyphId < minGlyphId) minGlyphId = glyphId;
}
}
BufferCache.ReleaseUShorts(glyphIndices);
}
//
// Step 1: call OpenType layout engine to test presence of
// 'locl' feature. Based on the returned writing systems, set
// FastTextMajorLanguageLocalizedFormAvailable bit and
// FastTextExtraLanguageLocalizedFormAvailable bit
//
OpenTypeLayoutResult result;
unsafe
{
result = OpenTypeLayout.GetComplexLanguageList(
GsubGpos,
LoclFeature,
glyphBits,
minGlyphId,
maxGlyphId,
out complexScripts
);
}
if (result != OpenTypeLayoutResult.Success)
{
// The check failed. We abort and don't keep partial results that are not reliable
_typographyAvailabilities = TypographyAvailabilities.None;
return;
}
else if (complexScripts != null)
{
// This is the bits for localized form we would want to set
// if both bits for localized form were set, we can end the loop earlier
TypographyAvailabilities loclBitsTest =
TypographyAvailabilities.FastTextMajorLanguageLocalizedFormAvailable
| TypographyAvailabilities.FastTextExtraLanguageLocalizedFormAvailable;
for (int i = 0; i < complexScripts.Length && typography != loclBitsTest; i++)
{
if (MajorLanguages.Contains((ScriptTags)complexScripts[i].scriptTag, (LanguageTags)complexScripts[i].langSysTag))
{
typography |= TypographyAvailabilities.FastTextMajorLanguageLocalizedFormAvailable;
}
else
{
typography |= TypographyAvailabilities.FastTextExtraLanguageLocalizedFormAvailable;
}
}
}
//
// step 2: continue to find out whether there is common features availabe
// in the font for the unicode ranges and set the FastTextTypographyAvailable bit
//
unsafe
{
result = OpenTypeLayout.GetComplexLanguageList(
GsubGpos,
RequiredTypographyFeatures,
glyphBits,
minGlyphId,
maxGlyphId,
out complexScripts
);
}
if (result != OpenTypeLayoutResult.Success)
{
// The check failed. We abort and don't keep partial results that are not reliable
_typographyAvailabilities = TypographyAvailabilities.None;
return;
}
else if (complexScripts != null)
{
typography |= TypographyAvailabilities.FastTextTypographyAvailable;
}
//
// Step 3: call OpenType layout engine to find out if there is any feature present for
// ideographs. Because there are many ideographs to check for, an alternative is to
// check for all scripts with the required features in the font by setting all
// glyph bits to 1, then see whether CJKIdeograph is in the returned list.
//
for (int i = 0; i < glyphBitsLength; i++)
{
glyphBits[i] = 0xFFFFFFFF;
}
unsafe
{
result = OpenTypeLayout.GetComplexLanguageList(
GsubGpos,
RequiredFeatures,
glyphBits,
minGlyphId,
maxGlyphId,
out complexScripts
);
}
if (result != OpenTypeLayoutResult.Success)
{
// The check failed. We abort and don't keep partial results that are not reliable
_typographyAvailabilities = TypographyAvailabilities.None;
return;
}
else if (complexScripts != null)
{
for (int i = 0; i < complexScripts.Length; i++)
{
if (complexScripts[i].scriptTag == (uint)ScriptTags.CJKIdeographic)
{
typography |= TypographyAvailabilities.IdeoTypographyAvailable;
}
else
{
typography |= TypographyAvailabilities.Available;
}
}
}
if (typography != TypographyAvailabilities.None)
{
// if any of the bits were set, set TypographyAvailabilities.Avaialble bit
// as well to indicate some lookup is available.
typography |= TypographyAvailabilities.Available;
}
_typographyAvailabilities = typography;
// Note: we don't worry about calling ReleaseUInts in case of early out for a failure
// above. Releasing glyphBits is a performance optimization that is not necessary
// for correctness, and not interesting in the rare failure case.
BufferCache.ReleaseUInts(glyphBits);
}
#region IntMap
/// <summary>
/// IntMap represents mapping from UTF32 code points to glyph indices.
/// The IDictionary part is eventually returned from public APIs and is made read-only.
/// Internal methods are used by the font driver to create the cmap.
/// </summary>
internal sealed class IntMap : IDictionary<int, ushort>
{
private Text.TextInterface.Font _font;
private Dictionary<int, ushort> _cmap;
internal IntMap(Text.TextInterface.Font font)
{
_font = font;
_cmap = null;
}
private Dictionary<int, ushort> CMap
{
get
{
if (_cmap == null)
{
lock (this)
{
if (_cmap == null)
{
_cmap = new Dictionary<int, ushort>();
ushort glyphIndex;
for (int codePoint = 0; codePoint <= FontFamilyMap.LastUnicodeScalar; ++codePoint)
{
if (TryGetValue(codePoint, out glyphIndex))
{
_cmap.Add(codePoint, glyphIndex);
}
}
}
}
}
return _cmap;
}
}
#region IDictionary<int,ushort> Members
public void Add(int key, ushort value)
{
throw new NotSupportedException();
}
/// <SecurityNote>
/// Critical: This calls into critical HasCharacter.
/// TreatAsSafe: This data is safe to expose.
/// </SecurityNote>
[SecurityCritical,SecurityTreatAsSafe]
public bool ContainsKey(int key)
{
return _font.HasCharacter(checked((uint)key));
}
public ICollection<int> Keys
{
get
{
return CMap.Keys;
}
}
public bool Remove(int key)
{
throw new NotSupportedException();
}
/// <SecurityNote>
/// Critical: This code calls into an unsafe block and calls critical GetArrayOfGlyphIndices.
/// TreatAsSafe: Creates its own known-sized buffers to pass into critical code and
/// does not modify or return any critical data.
/// </SecurityNote>
[SecurityCritical,SecurityTreatAsSafe]
public bool TryGetValue(int key, out ushort value)
{
ushort localValue;
unsafe
{
uint uKey = checked((uint)key);
uint *pKey = &uKey;
MS.Internal.Text.TextInterface.FontFace fontFace = _font.GetFontFace();
try
{
fontFace.GetArrayOfGlyphIndices(pKey, 1, &localValue);
}
finally
{
fontFace.Release();
}
value = localValue;
}
// if a glyph is not present, index 0 is returned
return (value != 0);
}
/// <SecurityNote>
/// Critical: This code calls critical GetArrayOfGlyphIndices.
/// </SecurityNote>
[SecurityCritical]
internal unsafe void TryGetValues(uint *pKeys, uint characterCount, ushort *pIndices)
{
MS.Internal.Text.TextInterface.FontFace fontFace = _font.GetFontFace();
try
{
fontFace.GetArrayOfGlyphIndices(pKeys, characterCount, pIndices);
}
finally
{
fontFace.Release();
}
}
public ICollection<ushort> Values
{
get
{
return CMap.Values;
}
}
ushort IDictionary<int, ushort>.this[int i]
{
get
{
ushort glyphIndex;
if (!TryGetValue(i, out glyphIndex))
throw new KeyNotFoundException();
return glyphIndex;
}
set
{
throw new NotSupportedException();
}
}
#endregion
#region ICollection<KeyValuePair<int,ushort>> Members
public void Add(KeyValuePair<int, ushort> item)
{
throw new NotSupportedException();
}
public void Clear()
{
throw new NotSupportedException();
}
public bool Contains(KeyValuePair<int, ushort> item)
{
return ContainsKey(item.Key);
}
public void CopyTo(KeyValuePair<int, ushort>[] array, int arrayIndex)
{
if (array == null)
{
throw new ArgumentNullException("array");
}
if (array.Rank != 1)
{
throw new ArgumentException(SR.Get(SRID.Collection_BadRank));
}
// The extra "arrayIndex >= array.Length" check in because even if _collection.Count
// is 0 the index is not allowed to be equal or greater than the length
// (from the MSDN ICollection docs)
if (arrayIndex < 0 || arrayIndex >= array.Length || (arrayIndex + Count) > array.Length)
{
throw new ArgumentOutOfRangeException("arrayIndex");
}
foreach (KeyValuePair<int, ushort> pair in this)
array[arrayIndex++] = pair;
}
public int Count
{
get { return CMap.Count; }
}
public bool IsReadOnly
{
get { return true; }
}
public bool Remove(KeyValuePair<int, ushort> item)
{
throw new NotSupportedException();
}
#endregion
#region IEnumerable<KeyValuePair<int,ushort>> Members
public IEnumerator<KeyValuePair<int, ushort>> GetEnumerator()
{
return CMap.GetEnumerator();
}
#endregion
#region IEnumerable Members
IEnumerator IEnumerable.GetEnumerator()
{
return ((IEnumerable<KeyValuePair<int, ushort>>)this).GetEnumerator();
}
#endregion
}
#endregion
//------------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
#region Private Fields
private IntMap _cmap;
// 'locl' feature which is language sensitive
private static readonly uint[] LoclFeature = new uint[]
{
(uint)OpenTypeTags.locl
};
// common features for fast text
// They are insensitive to languages
private static readonly uint[] RequiredTypographyFeatures = new uint[]
{
(uint)OpenTypeTags.ccmp,
(uint)OpenTypeTags.rlig,
(uint)OpenTypeTags.liga,
(uint)OpenTypeTags.clig,
(uint)OpenTypeTags.calt,
(uint)OpenTypeTags.kern,
(uint)OpenTypeTags.mark,
(uint)OpenTypeTags.mkmk
};
// All required features
private static readonly uint[] RequiredFeatures = new uint[]
{
(uint)OpenTypeTags.locl,
(uint)OpenTypeTags.ccmp,
(uint)OpenTypeTags.rlig,
(uint)OpenTypeTags.liga,
(uint)OpenTypeTags.clig,
(uint)OpenTypeTags.calt,
(uint)OpenTypeTags.kern,
(uint)OpenTypeTags.mark,
(uint)OpenTypeTags.mkmk
};
private static readonly UnicodeRange[] fastTextRanges = new UnicodeRange[]
{
new UnicodeRange(0x20 , 0x7e ), // basic latin
new UnicodeRange(0xA1 , 0xFF ), // latin-1 supplement,
new UnicodeRange(0x0100, 0x17F ), // latin extended-A
new UnicodeRange(0x0180, 0x024F), // latin extended-B
new UnicodeRange(0x1E00, 0x1EFF), // latin extended additional (Vietnamese precomposed)
new UnicodeRange(0x3040, 0x3098), // hiragana
new UnicodeRange(0x309B, 0x309F), // hiragana
new UnicodeRange(0x30A0, 0x30FF) // kana
};
#endregion Private Fields
}
/// <summary>
/// An implementation of IOpenTypeFont which only provides GSUB and GPOS tables
/// It is used by OTLS API to determine the optimizable script.
/// </summary>
/// <remarks>
/// OTLS API always accepts IOpenTypeFont as input parameter. To be consistent, we
/// implement this IOpenTypeFont just for OpenTypeLayout.GetComplexLanguangeList(..) method.
/// </remarks>
internal sealed class GsubGposTables : IOpenTypeFont
{
/// <SecurityNote>
/// Critical: Gsub() and Gpos() return pointers
/// </SecurityNote>
[SecurityCritical]
internal GsubGposTables(FontFaceLayoutInfo layout)
{
_layout = layout;
_gsubTable = new FontTable(_layout.Gsub());
_gposTable = new FontTable(_layout.Gpos());
}
/// <summary>
/// Returns font table data
/// </summary>
public FontTable GetFontTable(OpenTypeTags TableTag)
{
switch (TableTag)
{
case OpenTypeTags.GSUB:
{
return _gsubTable;
}
case OpenTypeTags.GPOS:
{
return _gposTable;
}
default:
{
throw new NotSupportedException();
}
}
}
/// <summary>
/// Returns glyph coordinate
/// </summary>
public LayoutOffset GetGlyphPointCoord(ushort Glyph, ushort PointIndex)
{
throw new NotSupportedException();
}
/// <summary>
/// Returns cache for layout table. If cache not found, return null Checked pointer
/// </summary>
/// <SecurityNote>
/// Critical: Calls critical code
/// </SecurityNote>
[SecurityCritical]
public byte[] GetTableCache(OpenTypeTags tableTag)
{
return _layout.GetTableCache(tableTag);
}
/// <summary>
/// Allocate space for layout table cache.
/// </summary>
/// <SecurityNote>
/// Critical: Calls critical code
/// </SecurityNote>
[SecurityCritical]
public byte[] AllocateTableCache(OpenTypeTags tableTag, int size)
{
return _layout.AllocateTableCache(tableTag, size);
}
private FontTable _gsubTable;
private FontTable _gposTable;
private FontFaceLayoutInfo _layout;
}
/// <summary>
/// A unicode range identified by a pair of first and last unicode code point
/// </summary>
internal struct UnicodeRange
{
internal UnicodeRange(int first, int last)
{
firstChar = first;
lastChar = last;
}
//
// In order to get the glyph indices of all of the fast ranges efficiently,
// it's necessary for us to pass a full array to TextInterface components
// containing all the codepoints we want glyph indices for.
// Generate such an array here on demand
//
internal uint[] GetFullRange()
{
int smaller = Math.Min(lastChar, firstChar);
int larger = Math.Max(lastChar, firstChar);
int arrayLength = larger - smaller + 1;
uint[] unicodeArray = new uint[arrayLength];
for (int i = 0; i < arrayLength; i++)
{
unicodeArray[i] = checked((uint)(smaller + i));
}
return unicodeArray;
}
internal int firstChar;
internal int lastChar;
}
/// <summary>
/// Major language targetted for optimization
/// </summary>
internal static class MajorLanguages
{
/// <summary>
/// check if input script and langSys is considered a major language.
/// </summary>
/// <returns> true if it is a major language </returns>
internal static bool Contains(ScriptTags script, LanguageTags langSys)
{
for (int i = 0; i < majorLanguages.Length; i++)
{
if (script == majorLanguages[i].Script &&
(langSys == LanguageTags.Default || langSys == majorLanguages[i].LangSys))
{
return true;
}
}
return false;
}
/// <summary>
/// check if input culture is considered a major language.
/// </summary>
/// <returns> true if it is a major language </returns>
internal static bool Contains(CultureInfo culture)
{
if (culture == null) return false;
// explicitly check for InvariantCulture. We don't need to check for its parent.
if (culture == CultureInfo.InvariantCulture) return true;
for (int i = 0; i < majorLanguages.Length; i++)
{
if (majorLanguages[i].Culture.Equals(culture)
|| majorLanguages[i].Culture.Equals(culture.Parent)
)
{
return true;
}
}
return false;
}
// major languages
private static readonly MajorLanguageDesc[] majorLanguages = new MajorLanguageDesc[]
{
new MajorLanguageDesc(new CultureInfo("en"), ScriptTags.Latin, LanguageTags.English), // English neutral culture
new MajorLanguageDesc(new CultureInfo("de"), ScriptTags.Latin, LanguageTags.German), // German neutral culture
new MajorLanguageDesc(new CultureInfo("ja"), ScriptTags.CJKIdeographic, LanguageTags.Japanese), // Japanese neutral culture
new MajorLanguageDesc(new CultureInfo("ja"), ScriptTags.Hiragana, LanguageTags.Japanese) // Japanese neutral culture
};
private struct MajorLanguageDesc
{
internal MajorLanguageDesc(CultureInfo culture, ScriptTags script, LanguageTags langSys)
{
Culture = culture;
Script = script;
LangSys = langSys;
}
internal readonly CultureInfo Culture;
internal readonly ScriptTags Script;
internal readonly LanguageTags LangSys;
}
}
/// <summary>
/// An enum flag indicating the availabilities of various open type
/// look ups.
/// </summary>
/// <remarks>
/// The enum is used to determine whether fast path is applicable.
/// Ideo refers to Ideographs
/// FastText refers to Other optimizable text
/// We keep a minimum set of flags here to allow us reliably optimize
/// the most common inputs. It is not to prevent under-optimization for
/// all cases.
/// </remarks>
[Flags]
internal enum TypographyAvailabilities
{
/// <summary>
/// No required OpenType typography features is available
/// </summary>
None = 0,
/// <summary>
/// There are some lookup available for required typography
/// features
/// </summary>
Available = 1,
/// <summary>
/// There are some lookup available for required typography features
/// for Ideographic script.
/// </summary>
IdeoTypographyAvailable = 2,
/// <summary>
/// There are lookup available for required typography features
/// for fast text
/// </summary>
FastTextTypographyAvailable = 4,
/// <summary>
/// There are localized form available for major Ui lanaguages for fast text
/// </summary>
/// <seealso> MajorLanguages class</seealso>
FastTextMajorLanguageLocalizedFormAvailable = 8,
/// <summary>
/// There are localized form for non major Ui language available for fast text
/// </summary>
FastTextExtraLanguageLocalizedFormAvailable = 16,
}
}
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