freeimagewrapper.cs

对gif

		/// <param name="flags">Flags to enable or disable plugin-features.</param>
		/// <returns>Returns true on success, false on failure.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="dib"/> or <paramref name="stream"/> is null.</exception>
		/// <exception cref="ArgumentException">
		/// <paramref name="stream"/> cannot write.</exception>
		public static bool SaveToStream(
			FIBITMAP dib,
			Stream stream,
			FREE_IMAGE_FORMAT format,
			FREE_IMAGE_SAVE_FLAGS flags)
		{
			return SaveToStream(
				ref dib,
				stream,
				format,
				flags,
				FREE_IMAGE_COLOR_DEPTH.FICD_AUTO,
				false);
		}

		/// <summary>
		/// Saves a previously loaded FreeImage bitmap to a stream.
		/// The stream must be set to the correct position before calling SaveToStream.
		/// </summary>
		/// <param name="dib">Handle to a FreeImage bitmap.</param>
		/// <param name="stream">The stream to write to.</param>
		/// <param name="format">Format of the image.</param>
		/// <param name="flags">Flags to enable or disable plugin-features.</param>
		/// <param name="unloadSource">When true the structure will be unloaded on success.</param>
		/// <returns>Returns true on success, false on failure.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="dib"/> or <paramref name="stream"/> is null.</exception>
		/// <exception cref="ArgumentException">
		/// <paramref name="stream"/> cannot write.</exception>
		public static bool SaveToStream(
			ref FIBITMAP dib,
			Stream stream,
			FREE_IMAGE_FORMAT format,
			FREE_IMAGE_SAVE_FLAGS flags,
			bool unloadSource)
		{
			return SaveToStream(
				ref dib, stream,
				format,
				flags,
				FREE_IMAGE_COLOR_DEPTH.FICD_AUTO,
				unloadSource);
		}

		/// <summary>
		/// Saves a previously loaded FreeImage bitmap to a stream.
		/// The stream must be set to the correct position before calling SaveToStream.
		/// </summary>
		/// <param name="dib">Handle to a FreeImage bitmap.</param>
		/// <param name="stream">The stream to write to.</param>
		/// <param name="format">Format of the image.</param>
		/// <param name="flags">Flags to enable or disable plugin-features.</param>
		/// <param name="colorDepth">The new color depth of the bitmap.
		/// Set to <see cref="FREE_IMAGE_COLOR_DEPTH.FICD_AUTO"/> if SaveToStream should
		/// take the best suitable color depth.
		/// If a color depth is selected that the provided format cannot write an
		/// error-message will be thrown.</param>
		/// <returns>Returns true on success, false on failure.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="dib"/> or <paramref name="stream"/> is null.</exception>
		/// <exception cref="ArgumentException">
		/// <paramref name="stream"/> cannot write.</exception>
		public static bool SaveToStream(
			FIBITMAP dib,
			Stream stream,
			FREE_IMAGE_FORMAT format,
			FREE_IMAGE_SAVE_FLAGS flags,
			FREE_IMAGE_COLOR_DEPTH colorDepth)
		{
			return SaveToStream(
				ref dib,
				stream,
				format,
				flags,
				colorDepth,
				false);
		}

		/// <summary>
		/// Saves a previously loaded FreeImage bitmap to a stream.
		/// The stream must be set to the correct position before calling SaveToStream.
		/// </summary>
		/// <param name="dib">Handle to a FreeImage bitmap.</param>
		/// <param name="stream">The stream to write to.</param>
		/// <param name="format">Format of the image.</param>
		/// <param name="flags">Flags to enable or disable plugin-features.</param>
		/// <param name="colorDepth">The new color depth of the bitmap.
		/// Set to <see cref="FREE_IMAGE_COLOR_DEPTH.FICD_AUTO"/> if SaveToStream should
		/// take the best suitable color depth.
		/// If a color depth is selected that the provided format cannot write an
		/// error-message will be thrown.</param>
		/// <param name="unloadSource">When true the structure will be unloaded on success.</param>
		/// <returns>Returns true on success, false on failure.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="dib"/> or <paramref name="stream"/> is null.</exception>
		/// <exception cref="ArgumentException">
		/// <paramref name="stream"/> cannot write.</exception>
		public static bool SaveToStream(
			ref FIBITMAP dib,
			Stream stream,
			FREE_IMAGE_FORMAT format,
			FREE_IMAGE_SAVE_FLAGS flags,
			FREE_IMAGE_COLOR_DEPTH colorDepth,
			bool unloadSource)
		{
			if (dib.IsNull)
			{
				throw new ArgumentNullException("dib");
			}
			if (stream == null)
			{
				throw new ArgumentNullException("stream");
			}
			if (!stream.CanWrite)
			{
				throw new ArgumentException("stream is not capable of writing.");
			}
			if ((!FIFSupportsWriting(format)) || (!FIFSupportsExportType(format, FREE_IMAGE_TYPE.FIT_BITMAP)))
			{
				return false;
			}

			FIBITMAP dibToSave = PrepareBitmapColorDepth(dib, format, colorDepth);
			bool result = false;

			try
			{
				// Create a 'FreeImageIO' structure for calling 'SaveToHandle'
				FreeImageIO io = FreeImageStreamIO.io;

				using (fi_handle handle = new fi_handle(stream))
				{
					result = SaveToHandle(format, dibToSave, ref io, handle, flags);
				}
			}
			catch
			{
				// Always unload a temporary created bitmap.
				if (dibToSave != dib)
				{
					UnloadEx(ref dibToSave);
				}
				// On success unload the bitmap
				if (result && unloadSource)
				{
					UnloadEx(ref dib);
				}
			}

			return result;
		}

		#endregion

		#region Plugin functions

		/// <summary>
		/// Checks if an extension is valid for a certain format.
		/// </summary>
		/// <param name="fif">The desired format.</param>
		/// <param name="extension">The desired extension.</param>
		/// <returns>True if the extension is valid for the given format, false otherwise.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="extension"/> is null.</exception>
		public static bool IsExtensionValidForFIF(FREE_IMAGE_FORMAT fif, string extension)
		{
			return IsExtensionValidForFIF(fif, extension, StringComparison.CurrentCulture);
		}

		/// <summary>
		/// Checks if an extension is valid for a certain format.
		/// </summary>
		/// <param name="fif">The desired format.</param>
		/// <param name="extension">The desired extension.</param>
		/// <param name="comparisonType">The string comparison type.</param>
		/// <returns>True if the extension is valid for the given format, false otherwise.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="extension"/> is null.</exception>
		public static bool IsExtensionValidForFIF(FREE_IMAGE_FORMAT fif, string extension, StringComparison comparisonType)
		{
			if (extension == null)
			{
				throw new ArgumentNullException("extension");
			}
			bool result = false;
			// Split up the string and compare each with the given extension
			string tempList = GetFIFExtensionList(fif);
			if (tempList != null)
			{
				string[] extensionList = tempList.Split(',');
				foreach (string ext in extensionList)
				{
					if (extension.Equals(ext, comparisonType))
					{
						result = true;
						break;
					}
				}
			}
			return result;
		}

		/// <summary>
		/// Checks if a filename is valid for a certain format.
		/// </summary>
		/// <param name="fif">The desired format.</param>
		/// <param name="filename">The desired filename.</param>
		/// <returns>True if the filename is valid for the given format, false otherwise.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="filename"/> is null.</exception>
		public static bool IsFilenameValidForFIF(FREE_IMAGE_FORMAT fif, string filename)
		{
			return IsFilenameValidForFIF(fif, filename, StringComparison.CurrentCulture);
		}

		/// <summary>
		/// Checks if a filename is valid for a certain format.
		/// </summary>
		/// <param name="fif">The desired format.</param>
		/// <param name="filename">The desired filename.</param>
		/// <param name="comparisonType">The string comparison type.</param>
		/// <returns>True if the filename is valid for the given format, false otherwise.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="filename"/> is null.</exception>
		public static bool IsFilenameValidForFIF(FREE_IMAGE_FORMAT fif, string filename, StringComparison comparisonType)
		{
			if (filename == null)
			{
				throw new ArgumentNullException("filename");
			}
			bool result = false;
			// Extract the filenames extension if it exists
			int position = filename.LastIndexOf('.');
			if (position >= 0)
			{
				result = IsExtensionValidForFIF(fif, filename.Substring(position + 1), comparisonType);
			}
			return result;
		}

		/// <summary>
		/// This function returns the primary (main or most commonly used?) extension of a certain
		/// image format (fif). This is done by returning the first of all possible extensions
		/// returned by GetFIFExtensionList().
		/// That assumes, that the plugin returns the extensions in ordered form.</summary>
		/// <param name="fif">The image format to obtain the primary extension for.</param>
		/// <returns>The primary extension of the specified image format.</returns>
		public static string GetPrimaryExtensionFromFIF(FREE_IMAGE_FORMAT fif)
		{
			string result = null;
			string extensions = GetFIFExtensionList(fif);
			if (extensions != null)
			{
				int position = extensions.IndexOf(',');
				if (position < 0)
				{
					result = extensions;
				}
				else
				{
					result = extensions.Substring(0, position);
				}
			}
			return result;
		}

		#endregion

		#region Multipage functions

		/// <summary>
		/// Loads a FreeImage multi-paged bitmap.
		/// </summary>
		/// <param name="filename">The complete name of the file to load.</param>
		/// <returns>Handle to a FreeImage multi-paged bitmap.</returns>
		/// <exception cref="FileNotFoundException">
		/// <paramref name="filename"/> does not exists while opening.</exception>
		public static FIMULTIBITMAP OpenMultiBitmapEx(
			string filename)
		{
			FREE_IMAGE_FORMAT format = FREE_IMAGE_FORMAT.FIF_UNKNOWN;
			return OpenMultiBitmapEx(
				filename,
				ref format,
				FREE_IMAGE_LOAD_FLAGS.DEFAULT,
				false,
				false,
				false);
		}

		/// <summary>
		/// Loads a FreeImage multi-paged bitmap.
		/// </summary>
		/// <param name="filename">The complete name of the file to load.</param>
		/// <param name="keep_cache_in_memory">When true performance is increased at the cost of memory.</param>
		/// <returns>Handle to a FreeImage multi-paged bitmap.</returns>
		/// <exception cref="FileNotFoundException">
		/// <paramref name="filename"/> does not exists while opening.</exception>
		public static FIMULTIBITMAP OpenMultiBitmapEx(
			string filename,
			bool keep_cache_in_memory)
		{
			FREE_IMAGE_FORMAT format = FREE_IMAGE_FORMAT.FIF_UNKNOWN;
			return OpenMultiBitmapEx(
				filename,
				ref format,
				FREE_IMAGE_LOAD_FLAGS.DEFAULT,
				false,
				false,
				keep_cache_in_memory);
		}

		/// <summary>
		/// Loads a FreeImage multi-paged bitmap.
		/// </summary>
		/// <param name="filename">The complete name of the file to load.</param>
		/// <param name="read_only">When true the bitmap will be loaded read only.</param>
		/// <param name="keep_cache_in_memory">When true performance is increased at the cost of memory.</param>
		/// <returns>Handle to a FreeImage multi-paged bitmap.</returns>
		/// <exception cref="FileNotFoundException">
		/// <paramref name="filename"/> does not exists while opening.</exception>
		public static FIMULTIBITMAP OpenMultiBitmapEx(
			string filename,
			bool read_only,
			bool keep_cache_in_memory)
		{
			FREE_IMAGE_FORMAT format = FREE_IMAGE_FORMAT.FIF_UNKNOWN;
			return OpenMultiBitmapEx(
				filename,
				ref format,
				FREE_IMAGE_LOAD_FLAGS.DEFAULT,
				false,
				read_only,
				keep_cache_in_memory);
		}

		/// <summary>
		/// Loads a FreeImage multi-paged bitmap.
		/// </summary>
		/// <param name="filename">The complete name of the file to load.</param>
		/// <param name="create_new">When true a new bitmap is created.</param>
		/// <param name="read_only">When true the bitmap will be loaded read only.</param>
		/// <param name="keep_cache_in_memory">When true performance is increased at the cost of memory.</param>
		/// <returns>Handle to a FreeImage multi-paged bitmap.</returns>
		/// <exception cref="FileNotFoundException">
		/// <paramref name="filename"/> does not exists while opening.</exception>
		public static FIMULTIBITMAP OpenMultiBitmapEx(