ResourceFontLoader.cs

// Copyright (c) 2010-2013 SharpDX - Alexandre Mutel
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
using System.Collections.Generic;
using SharpDX;
using SharpDX.DirectWrite;

namespace CustomFont
{
    /// <summary>
    /// ResourceFont main loader. This classes implements FontCollectionLoader and FontFileLoader.
    /// It reads all fonts embedded as resource in the current assembly and expose them.
    /// </summary>
    public partial class ResourceFontLoader : CallbackBase, FontCollectionLoader, FontFileLoader
    {
        private readonly List<ResourceFontFileStream> _fontStreams = new List<ResourceFontFileStream>();
        private readonly List<ResourceFontFileEnumerator> _enumerators = new List<ResourceFontFileEnumerator>();
        private readonly DataStream _keyStream;
        private readonly Factory _factory;

        /// <summary>
        /// Initializes a new instance of the <see cref="ResourceFontLoader"/> class.
        /// </summary>
        /// <param name="factory">The factory.</param>
        public ResourceFontLoader(Factory factory)
        {
            _factory = factory;
            foreach (var name in typeof(ResourceFontLoader).Assembly.GetManifestResourceNames())
            {
                if (name.EndsWith(".ttf"))
                {
                    var fontBytes = Utilities.ReadStream(typeof (ResourceFontLoader).Assembly.GetManifestResourceStream(name));
                    var stream = new DataStream(fontBytes.Length, true, true);
                    stream.Write(fontBytes, 0, fontBytes.Length);
                    stream.Position = 0;
                    _fontStreams.Add(new ResourceFontFileStream(stream));
                }
            }

            // Build a Key storage that stores the index of the font
            _keyStream = new DataStream(sizeof(int) * _fontStreams.Count, true, true);
            for (int i = 0; i < _fontStreams.Count; i++ )
                _keyStream.Write((int)i);
            _keyStream.Position = 0;

            // Register the 
            _factory.RegisterFontFileLoader(this);
            _factory.RegisterFontCollectionLoader(this);
        }


        /// <summary>
        /// Gets the key used to identify the FontCollection as well as storing index for fonts.
        /// </summary>
        /// <value>The key.</value>
        public DataStream Key
        {
            get
            {
                return _keyStream;
            }
        }

        /// <summary>
        /// Creates a font file enumerator object that encapsulates a collection of font files. The font system calls back to this interface to create a font collection.
        /// </summary>
        /// <param name="factory">Pointer to the <see cref="SharpDX.DirectWrite.Factory"/> object that was used to create the current font collection.</param>
        /// <param name="collectionKey">A font collection key that uniquely identifies the collection of font files within the scope of the font collection loader being used. The buffer allocated for this key must be at least  the size, in bytes, specified by collectionKeySize.</param>
        /// <returns>
        /// a reference to the newly created font file enumerator.
        /// </returns>
        /// <unmanaged>HRESULT IDWriteFontCollectionLoader::CreateEnumeratorFromKey([None] IDWriteFactory* factory,[In, Buffer] const void* collectionKey,[None] int collectionKeySize,[Out] IDWriteFontFileEnumerator** fontFileEnumerator)</unmanaged>
        FontFileEnumerator FontCollectionLoader.CreateEnumeratorFromKey(Factory factory, DataPointer collectionKey)
        {
            var enumerator = new ResourceFontFileEnumerator(factory, this, collectionKey);
            _enumerators.Add(enumerator);

            return enumerator;
        }

        /// <summary>
        /// Creates a font file stream object that encapsulates an open file resource.
        /// </summary>
        /// <param name="fontFileReferenceKey">A reference to a font file reference key that uniquely identifies the font file resource within the scope of the font loader being used. The buffer allocated for this key must at least be the size, in bytes, specified by  fontFileReferenceKeySize.</param>
        /// <returns>
        /// a reference to the newly created <see cref="SharpDX.DirectWrite.FontFileStream"/> object.
        /// </returns>
        /// <remarks>
        /// The resource is closed when the last reference to fontFileStream is released.
        /// </remarks>
        /// <unmanaged>HRESULT IDWriteFontFileLoader::CreateStreamFromKey([In, Buffer] const void* fontFileReferenceKey,[None] int fontFileReferenceKeySize,[Out] IDWriteFontFileStream** fontFileStream)</unmanaged>
        FontFileStream FontFileLoader.CreateStreamFromKey(DataPointer fontFileReferenceKey)
        {
            var index = Utilities.Read<int>(fontFileReferenceKey.Pointer);
            return _fontStreams[index];
        }

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                _factory.UnregisterFontFileLoader(this);
                _factory.UnregisterFontCollectionLoader(this);
            }

            base.Dispose(disposing);
        }
    }
}