WSHCommon/Common/Library/SharpFont-master/SharpFont/Cache/ImageCache.cs

#region MIT License
/*Copyright (c) 2012 Robert Rouhani <robert.rouhani@gmail.com>

SharpFont based on Tao.FreeType, Copyright (c) 2003-2007 Tao Framework Team

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.*/
#endregion

using System;

namespace SharpFont.Cache
{
	/// <summary>
	/// A handle to an glyph image cache object. They are designed to hold many distinct glyph images while not
	/// exceeding a certain memory threshold.
	/// </summary>
	public class ImageCache
	{
		#region Fields

		private IntPtr reference;
		private Manager parentManager;

		#endregion

		#region Constructors

		/// <summary>
		/// Initializes a new instance of the <see cref="ImageCache"/> class.
		/// </summary>
		/// <param name="manager">The parent manager for the image cache.</param>
		public ImageCache(Manager manager)
		{
			if (manager == null)
				throw new ArgumentNullException("manager");

			IntPtr cacheRef;
			Error err = FT.FTC_ImageCache_New(manager.Reference, out cacheRef);

			if (err != Error.Ok)
				throw new FreeTypeException(err);

			parentManager = manager;
			Reference = cacheRef;
		}

		#endregion

		#region Properties

		internal IntPtr Reference
		{
			get
			{
				if (parentManager.IsDisposed)
					throw new ObjectDisposedException("Reference", "Cannot access a disposed object.");

				return reference;
			}

			set
			{
				if (parentManager.IsDisposed)
					throw new ObjectDisposedException("Reference", "Cannot access a disposed object.");

				reference = value;
			}
		}

		#endregion

		#region Methods

		/// <summary>
		/// Retrieve a given glyph image from a glyph image cache.
		/// </summary>
		/// <remarks><para>
		/// The returned glyph is owned and managed by the glyph image cache. Never try to transform or discard it
		/// manually! You can however create a copy with <see cref="Glyph.Copy"/> and modify the new one.
		/// </para><para>
		/// If ‘node’ is not NULL, it receives the address of the cache node containing the glyph image,
		/// after increasing its reference count. This ensures that the node (as well as the <see cref="Glyph"/>) will
		/// always be kept in the cache until you call <see cref="Node.Unref"/> to ‘release’ it.
		/// </para><para>
		/// If ‘node’ is NULL, the cache node is left unchanged, which means that the <see cref="Glyph"/>
		/// could be flushed out of the cache on the next call to one of the caching sub-system APIs. Don't assume that
		/// it is persistent!
		/// </para></remarks>
		/// <param name="type">A pointer to a glyph image type descriptor.</param>
		/// <param name="gIndex">The glyph index to retrieve.</param>
		/// <param name="node">
		/// Used to return the address of of the corresponding cache node after incrementing its reference count (see
		/// note below).
		/// </param>
		/// <returns>The corresponding <see cref="Glyph"/> object. 0 in case of failure.</returns>
		[CLSCompliant(false)]
		public Glyph Lookup(ImageType type, uint gIndex, out Node node)
		{
			if (parentManager.IsDisposed)
				throw new ObjectDisposedException("Reference", "Cannot access a disposed object.");

			IntPtr glyphRef, nodeRef;
			Error err = FT.FTC_ImageCache_Lookup(Reference, type.Reference, gIndex, out glyphRef, out nodeRef);

			if (err != Error.Ok)
				throw new FreeTypeException(err);

			node = new Node(nodeRef);
			return new Glyph(glyphRef, null);
		}

		/// <summary>
		/// A variant of <see cref="ImageCache.Lookup"/> that uses a <see cref="Scaler"/> to specify the face ID and its
		/// size.
		/// </summary>
		/// <remarks><para>
		/// The returned glyph is owned and managed by the glyph image cache. Never try to transform or discard it
		/// manually! You can however create a copy with <see cref="Glyph.Copy"/> and modify the new one.
		/// </para><para>
		/// If ‘node’ is not NULL, it receives the address of the cache node containing the glyph image,
		/// after increasing its reference count. This ensures that the node (as well as the <see cref="Glyph"/>) will
		/// always be kept in the cache until you call <see cref="Node.Unref"/> to ‘release’ it.
		/// </para><para>
		/// If ‘node’ is NULL, the cache node is left unchanged, which means that the <see cref="Glyph"/>
		/// could be flushed out of the cache on the next call to one of the caching sub-system APIs. Don't assume that
		/// it is persistent!
		/// </para><para>
		/// Calls to <see cref="Face.SetCharSize"/> and friends have no effect on cached glyphs; you should always use
		/// the FreeType cache API instead.
		/// </para></remarks>
		/// <param name="scaler">A pointer to a scaler descriptor.</param>
		/// <param name="loadFlags">The corresponding load flags.</param>
		/// <param name="gIndex">The glyph index to retrieve.</param>
		/// <param name="node">
		/// Used to return the address of of the corresponding cache node after incrementing its reference count (see
		/// note below).
		/// </param>
		/// <returns>The corresponding <see cref="Glyph"/> object. 0 in case of failure.</returns>
		[CLSCompliant(false)]
		public Glyph LookupScaler(Scaler scaler, LoadFlags loadFlags, uint gIndex, out Node node)
		{
			if (parentManager.IsDisposed)
				throw new ObjectDisposedException("Reference", "Cannot access a disposed object.");

			IntPtr glyphRef, nodeRef;
			Error err = FT.FTC_ImageCache_LookupScaler(Reference, scaler.Reference, loadFlags, gIndex, out glyphRef, out nodeRef);

			if (err != Error.Ok)
				throw new FreeTypeException(err);

			node = new Node(nodeRef);
			return new Glyph(glyphRef, null);
		}

		#endregion
	}
}