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//---------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// Description: The Fonts class provides font enumeration APIs.
// See spec at http://avalon/text/DesignDocsAndSpecs/Font%20Enumeration%20API.htm
//
//
// History:
// 03/02/2004 : mleonov - Created
// 08/08/2008 : Microsoft - Integrating with DWrite.
//
//---------------------------------------------------------------------------
using System;
using System.Text;
using System.IO;
using System.Globalization;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.Windows;
using MS.Internal;
using MS.Internal.FontCache;
using MS.Internal.FontFace;
using MS.Internal.PresentationCore;
using MS.Internal.Shaping;
using System.Security;
namespace System.Windows.Media
{
/// <summary>
/// The FontEmbeddingManager class provides font enumeration APIs.
/// </summary>
public static class Fonts
{
//------------------------------------------------------
//
// Public Methods
//
//------------------------------------------------------
#region Public Methods
/// <summary>
/// Enumerates font families from an arbitrary location.
/// </summary>
/// <param name="location">An absolute URI of a folder containing fonts or a font file.</param>
/// <returns>Collection of FontFamily objects from the specified folder or file.</returns>
/// <remarks>
/// The specified location must be an absolute file URI or path, and the caller must have
/// FileIOPermission(FileIOPermissionAccess.Read) for the location. Each resulting FontFamily
/// object includes the specified location in its friendly name and has no base URI.
/// </remarks>
public static ICollection<FontFamily> GetFontFamilies(string location)
{
if (location == null)
throw new ArgumentNullException("location");
return GetFontFamilies(null, location);
}
/// <summary>
/// Enumerates font families in the same folder as the specified base URI.
/// </summary>
/// <param name="baseUri">An absolute URI of a folder containing fonts or a resource in that folder.</param>
/// <returns>Collection of FontFamily objects from the specified folder.</returns>
/// <remarks>
/// The caller must have FileIOPermission(FileIOPermissionAccess.Read) for the folder
/// specified by baseUri. Each resulting FontFamily object has the specified Uri as its
/// BaseUri property has a friendly name of the form "./#Family Name".
/// </remarks>
public static ICollection<FontFamily> GetFontFamilies(Uri baseUri)
{
if (baseUri == null)
throw new ArgumentNullException("baseUri");
return GetFontFamilies(baseUri, null);
}
/// <summary>
/// Enumerates font families in the font location specified by a base URI and/or a location string.
/// </summary>
/// <param name="baseUri">Base URI used to determine the font location if the location parameter is not specified
/// or is relative, and the value of the BaseUri property of each FontFamily in the resulting collection. This
/// parameter can be null if the location parameter specifies an absolute location.</param>
/// <param name="location">Optional relative or absolute URI reference. The location is used (with baseUri) to
/// determine the font folder and is exposed as part of the Source property of each FontFamily in the resulting
/// collection. If location is null or empty then "./" is implied, meaning same folder as the base URI.</param>
/// <returns>Collection of FontFamily objects from the specified font location.</returns>
/// <remarks>
/// The caller must have FileIOPermission(FileIOPermissionAccess.Read) for the specified font folder.
/// Each resulting FontFamily object has the specified base Uri as its BaseUri property and includes the
/// specified location as part of the friendly name specified by the Source property.
/// </remarks>
public static ICollection<FontFamily> GetFontFamilies(Uri baseUri, string location)
{
// Both Uri parameters are optional but neither can be relative.
if (baseUri != null && !baseUri.IsAbsoluteUri)
throw new ArgumentException(SR.Get(SRID.UriNotAbsolute), "baseUri");
// Determine the font location from the base URI and location string.
Uri fontLocation;
if (!string.IsNullOrEmpty(location) && Uri.TryCreate(location, UriKind.Absolute, out fontLocation))
{
// absolute location; make sure we support absolute font family references for this scheme
if (!Util.IsSupportedSchemeForAbsoluteFontFamilyUri(fontLocation))
throw new ArgumentException(SR.Get(SRID.InvalidAbsoluteUriInFontFamilyName), "location");
// make sure the absolute location is a valid URI reference rather than a Win32 path as
// we don't support the latter in a font family reference
location = fontLocation.GetComponents(UriComponents.AbsoluteUri, UriFormat.SafeUnescaped);
}
else
{
// relative location; we need a base URI
if (baseUri == null)
throw new ArgumentNullException("baseUri", SR.Get(SRID.NullBaseUriParam, "baseUri", "location"));
// the location part must include a path component, otherwise we'll look in windows fonts and ignore the base URI
if (string.IsNullOrEmpty(location))
location = "./";
else if (Util.IsReferenceToWindowsFonts(location))
location = "./" + location;
fontLocation = new Uri(baseUri, location);
}
// Create the font families.
return CreateFamilyCollection(
fontLocation, // fontLocation
baseUri, // fontFamilyBaseUri
location // fontFamilyLocationReference
);
}
/// <summary>
/// Enumerates typefaces from an arbitrary location.
/// </summary>
/// <param name="location">An absolute URI of a folder containing fonts or a font file.</param>
/// <returns>Collection of Typeface objects from the specified folder or file.</returns>
/// <remarks>
/// The specified location must be an absolute file URI or path, and the caller must have
/// FileIOPermission(FileIOPermissionAccess.Read) for the location. The FontFamily of each
/// resulting Typeface object includes the specified location in its friendly name and has
/// no base URI.
/// </remarks>
public static ICollection<Typeface> GetTypefaces(string location)
{
if (location == null)
throw new ArgumentNullException("location");
return new TypefaceCollection(GetFontFamilies(null, location));
}
/// <summary>
/// Enumerates typefaces in the same folder as the specified base URI.
/// </summary>
/// <param name="baseUri">An absolute URI of a folder containing fonts or a resource in that folder.</param>
/// <returns>Collection of Typeface objects from the specified folder.</returns>
/// <remarks>
/// The caller must have FileIOPermission(FileIOPermissionAccess.Read) for the folder
/// specified by baseUri. The FontFamily of each resulting Typeface object has the specified
/// Uri as its BaseUri property has a friendly name of the form "./#Family Name".
/// </remarks>
public static ICollection<Typeface> GetTypefaces(Uri baseUri)
{
if (baseUri == null)
throw new ArgumentNullException("baseUri");
return new TypefaceCollection(GetFontFamilies(baseUri, null));
}
/// <summary>
/// Enumerates typefaces in the font location specified by a base URI and/or a location string.
/// </summary>
/// <param name="baseUri">Base URI used to determine the font location if the location parameter is not specified
/// or is relative, and the value of the BaseUri property of each FontFamily in the resulting collection. This
/// parameter can be null if the location parameter specifies an absolute location.</param>
/// <param name="location">Optional relative or absolute URI reference. The location is used (with baseUri) to
/// determine the font folder and is exposed as part of the Source property of each FontFamily in the resulting
/// collection. If location is null or empty then "./" is implied, meaning same folder as the base URI.</param>
/// <returns>Collection of Typeface objects from the specified font location.</returns>
/// <remarks>
/// The caller must have FileIOPermission(FileIOPermissionAccess.Read) for the specified font folder.
/// Each resulting FontFamily object has the specified base Uri as its BaseUri property and includes the
/// specified location as part of the friendly name specified by the Source property.
/// </remarks>
public static ICollection<Typeface> GetTypefaces(Uri baseUri, string location)
{
return new TypefaceCollection(GetFontFamilies(baseUri, location));
}
#endregion Public Methods
//------------------------------------------------------
//
// Public Properties
//
//------------------------------------------------------
#region Public Properties
/// <summary>
/// Font families from the default system font location.
/// </summary>
/// <value>Collection of FontFamily objects from the default system font location.</value>
public static ICollection<FontFamily> SystemFontFamilies
{
get
{
return _defaultFontCollection;
}
}
/// <summary>
/// Type faces from the default system font location.
/// </summary>
/// <value>Collection of Typeface objects from the default system font location.</value>
public static ICollection<Typeface> SystemTypefaces
{
get
{
return new TypefaceCollection(_defaultFontCollection);
}
}
#endregion Public Properties
//------------------------------------------------------
//
// Private Methods
//
//------------------------------------------------------
#region Private Methods
/// <summary>
/// This method enumerates the font families in the specified font location and returns the resulting
/// collection of FontFamily objects.
/// </summary>
/// <param name="fontLocation">Absolute URI of file or folder containing font data</param>
/// <param name="fontFamilyBaseUri">Optional base URI, exposed as the BaseUri property of each FontFamily.</param>
/// <param name="fontFamilyLocationReference">Optional location reference, exposed as part of the Source
/// property of each FontFamily.</param>
/// <SecurityNote>
/// SecurityCritical - Calls the critical FamilyCollection constructor; fontLocation may be critical
/// TreatAsSafe - FamilyCollection does security demands for the necessary permissions; fontLocation is
/// not exposed by the resulting FontFamily objects
/// </SecurityNote>
[SecurityCritical,SecurityTreatAsSafe]
private static ICollection<FontFamily> CreateFamilyCollection(
Uri fontLocation,
Uri fontFamilyBaseUri,
string fontFamilyLocationReference
)
{
// Use reference comparison to determine the critical isWindowsFonts value. We want this
// to be true ONLY if we're called internally to enumerate the default family collection.
// See the SecurityNote for the FamilyCollection constructor.
FamilyCollection familyCollection =
object.ReferenceEquals(fontLocation, Util.WindowsFontsUriObject) ?
FamilyCollection.FromWindowsFonts(fontLocation) :
FamilyCollection.FromUri(fontLocation);
FontFamily[] fontFamilyList = familyCollection.GetFontFamilies(fontFamilyBaseUri, fontFamilyLocationReference);
return Array.AsReadOnly<FontFamily>(fontFamilyList);
}
/// <summary>
/// Creates a collection of font families in the Windows Fonts folder.
/// </summary>
/// <remarks>
/// This method is used to initialized the static _defaultFontCollection field. By having this
/// safe wrapper for CreateFamilyCollection we avoid having to create a static initializer and
/// declare it critical.
/// </remarks>
/// <SecurityNote>
/// Critical - This method accesses the critical Util.WindowsFontsUriObject
/// TreatAsSafe - It specifies null as the BaseUri of the resulting FontFamily objects
/// </SecurityNote>
[SecurityCritical, SecurityTreatAsSafe]
private static ICollection<FontFamily> CreateDefaultFamilyCollection()
{
return CreateFamilyCollection(
Util.WindowsFontsUriObject, // fontLocation
null, // fontFamilyBaseUri,
null // fontFamilyLocationReference
);
}
#endregion Private Methods
//------------------------------------------------------
//
// Private Classes
//
//------------------------------------------------------
#region Private Classes
private struct TypefaceCollection : ICollection<Typeface>
{
private IEnumerable<FontFamily> _families;
public TypefaceCollection(IEnumerable<FontFamily> families)
{
_families = families;
}
#region ICollection<Typeface> Members
public void Add(Typeface item)
{
throw new NotSupportedException();
}
public void Clear()
{
throw new NotSupportedException();
}
public bool Contains(Typeface item)
{
foreach (Typeface t in this)
{
if (t.Equals(item))
return true;
}
return false;
}
public void CopyTo(Typeface[] 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 (Typeface t in this)
{
array[arrayIndex++] = t;
}
}
public int Count
{
get
{
int count = 0;
foreach (Typeface t in this)
{
++count;
}
return count;
}
}
public bool IsReadOnly
{
get
{
return true;
}
}
public bool Remove(Typeface item)
{
throw new NotSupportedException();
}
#endregion
#region IEnumerable<Typeface> Members
public IEnumerator<Typeface> GetEnumerator()
{
foreach (FontFamily family in _families)
{
foreach (Typeface typeface in family.GetTypefaces())
{
yield return typeface;
}
}
}
#endregion
#region IEnumerable Members
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{
return ((IEnumerable<Typeface>)this).GetEnumerator();
}
#endregion
}
#endregion Private Classes
//------------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
#region Private Fields
private static readonly ICollection<FontFamily> _defaultFontCollection = CreateDefaultFamilyCollection();
#endregion Private Fields
}
}
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