freeimagewrapper.cs

对gif

			string filename,
			bool create_new,
			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,
				create_new,
				read_only,
				keep_cache_in_memory);
		}

		/// <summary>
		/// Loads a FreeImage multi-paged bitmap.
		/// In case the loading format is <see cref="FREE_IMAGE_FORMAT.FIF_UNKNOWN"/> the files real
		/// format is being analysed. If no plugin can read the file, format remains
		/// <see cref="FREE_IMAGE_FORMAT.FIF_UNKNOWN"/> and 0 is returned.
		/// </summary>
		/// <param name="filename">The complete name of the file to load.</param>
		/// <param name="format">Format of the image. If the format is unknown use
		/// <see cref="FREE_IMAGE_FORMAT.FIF_UNKNOWN"/>.
		/// In case a suitable format was found by LoadEx it will be returned in format.</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(
			string filename,
			ref FREE_IMAGE_FORMAT format,
			bool create_new,
			bool read_only,
			bool keep_cache_in_memory)
		{
			return OpenMultiBitmapEx(
				filename,
				ref format,
				FREE_IMAGE_LOAD_FLAGS.DEFAULT,
				create_new,
				read_only,
				keep_cache_in_memory);
		}

		/// <summary>
		/// Loads a FreeImage multi-paged bitmap.
		/// In case the loading format is <see cref="FREE_IMAGE_FORMAT.FIF_UNKNOWN"/> the files
		/// real format is being analysed. If no plugin can read the file, format remains
		/// <see cref="FREE_IMAGE_FORMAT.FIF_UNKNOWN"/> and 0 is returned.
		/// Load flags can be provided by the flags parameter.
		/// </summary>
		/// <param name="filename">The complete name of the file to load.</param>
		/// <param name="format">Format of the image. If the format is unknown use 
		/// <see cref="FREE_IMAGE_FORMAT.FIF_UNKNOWN"/>.
		/// In case a suitable format was found by LoadEx it will be returned in format.</param>
		/// <param name="flags">Flags to enable or disable plugin-features.</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(
			string filename,
			ref FREE_IMAGE_FORMAT format,
			FREE_IMAGE_LOAD_FLAGS flags,
			bool create_new,
			bool read_only,
			bool keep_cache_in_memory)
		{
			if (!File.Exists(filename) && !create_new)
			{
				throw new FileNotFoundException(filename + " could not be found.");
			}
			if (format == FREE_IMAGE_FORMAT.FIF_UNKNOWN)
			{
				// Check if a plugin can read the data
				format = GetFileType(filename, 0);
			}
			FIMULTIBITMAP dib = 0;
			if (FIFSupportsReading(format))
			{
				dib = OpenMultiBitmap(format, filename, create_new, read_only, keep_cache_in_memory, flags);
			}
			return dib;
		}

		/// <summary>
		/// Closes a previously opened multi-page bitmap and, when the bitmap was not opened read-only,
		/// applies any changes made to it.
		/// On success the handle will be reset to null.
		/// </summary>
		/// <param name="dib">Handle to a FreeImage multi-paged bitmap.</param>
		/// <returns>Returns true on success, false on failure.</returns>
		public static bool CloseMultiBitmapEx(ref FIMULTIBITMAP dib)
		{
			return CloseMultiBitmapEx(ref dib, FREE_IMAGE_SAVE_FLAGS.DEFAULT);
		}

		/// <summary>
		/// Closes a previously opened multi-page bitmap and, when the bitmap was not opened read-only,
		/// applies any changes made to it.
		/// On success the handle will be reset to null.
		/// </summary>
		/// <param name="dib">Handle to a FreeImage multi-paged bitmap.</param>
		/// <param name="flags">Flags to enable or disable plugin-features.</param>
		/// <returns>Returns true on success, false on failure.</returns>
		public static bool CloseMultiBitmapEx(ref FIMULTIBITMAP dib, FREE_IMAGE_SAVE_FLAGS flags)
		{
			bool result = false;
			if (!dib.IsNull)
			{
				if (CloseMultiBitmap(dib, flags))
				{
					dib = 0;
					result = true;
				}
			}
			return result;
		}

		/// <summary>
		/// Retrieves the number of pages that are locked in a multi-paged bitmap.
		/// </summary>
		/// <param name="dib">Handle to a FreeImage multi-paged bitmap.</param>
		/// <returns>Number of locked pages.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="dib"/> is null.</exception>
		public static int GetLockedPageCount(FIMULTIBITMAP dib)
		{
			if (dib.IsNull)
			{
				throw new ArgumentNullException("dib");
			}
			int result = 0;
			GetLockedPageNumbers(dib, null, ref result);
			return result;
		}

		/// <summary>
		/// Retrieves a list locked pages of a multi-paged bitmap.
		/// </summary>
		/// <param name="dib">Handle to a FreeImage multi-paged bitmap.</param>
		/// <returns>List containing the indexes of the locked pages.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="dib"/> is null.</exception>
		public static int[] GetLockedPages(FIMULTIBITMAP dib)
		{
			if (dib.IsNull)
			{
				throw new ArgumentNullException("dib");
			}
			// Get the number of pages and create an array to save the information
			int count = 0;
			int[] result = null;
			// Get count
			if (GetLockedPageNumbers(dib, result, ref count))
			{
				result = new int[count];
				// Fill array
				if (!GetLockedPageNumbers(dib, result, ref count))
				{
					result = null;
				}
			}
			return result;
		}

		/// <summary>
		/// Loads a FreeImage multi-paged bitmap from a stream and returns the
		/// FreeImage memory stream used as temporary buffer.
		/// The bitmap can not be modified by calling
		/// <see cref="FreeImage.AppendPage(FIMULTIBITMAP,FIBITMAP)"/>,
		/// <see cref="FreeImage.InsertPage(FIMULTIBITMAP,Int32,FIBITMAP)"/>,
		/// <see cref="FreeImage.MovePage(FIMULTIBITMAP,Int32,Int32)"/> or
		/// <see cref="FreeImage.DeletePage(FIMULTIBITMAP,Int32)"/>.
		/// </summary>
		/// <param name="stream">The stream to read from.</param>
		/// <param name="format">Format of the image.</param>
		/// <param name="flags">Flags to enable or disable plugin-features.</param>
		/// <param name="memory">The temporary memory buffer used to load the bitmap.</param>
		/// <returns>Handle to a FreeImage multi-paged bitmap.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="stream"/> is null.</exception>
		/// <exception cref="ArgumentException">
		/// <paramref name="stream"/> can not read.</exception>
		public static FIMULTIBITMAP LoadMultiBitmapFromStream(
			Stream stream,
			FREE_IMAGE_FORMAT format,
			FREE_IMAGE_LOAD_FLAGS flags,
			out FIMEMORY memory)
		{
			if (stream == null)
			{
				throw new ArgumentNullException("stream");
			}
			if (!stream.CanRead)
			{
				throw new ArgumentException("stream");
			}
			const int blockSize = 1024;
			int bytesRead;
			byte[] buffer = new byte[blockSize];

			stream = stream.CanSeek ? stream : new StreamWrapper(stream, true);
			memory = OpenMemory(IntPtr.Zero, 0);

			do
			{
				bytesRead = stream.Read(buffer, 0, blockSize);
				WriteMemory(buffer, (uint)blockSize, (uint)1, memory);
			}
			while (bytesRead == blockSize);

			return LoadMultiBitmapFromMemory(format, memory, flags);
		}

		#endregion

		#region Filetype functions

		/// <summary>
		/// Orders FreeImage to analyze the bitmap signature.
		/// In case the stream is not seekable, the stream will have been used
		/// and must be recreated for loading.
		/// </summary>
		/// <param name="stream">Name of the stream to analyze.</param>
		/// <returns>Type of the bitmap.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="stream"/> is null.</exception>
		/// <exception cref="ArgumentException">
		/// <paramref name="stream"/> can not read.</exception>
		public static FREE_IMAGE_FORMAT GetFileTypeFromStream(Stream stream)
		{
			if (stream == null)
			{
				throw new ArgumentNullException("stream");
			}
			if (!stream.CanRead)
			{
				throw new ArgumentException("stream is not capable of reading.");
			}
			// Wrap the stream if it cannot seek
			stream = (stream.CanSeek) ? stream : new StreamWrapper(stream, true);
			// Create a 'FreeImageIO' structure for the stream
			FreeImageIO io = FreeImageStreamIO.io;
			using (fi_handle handle = new fi_handle(stream))
			{
				return GetFileTypeFromHandle(ref io, handle, 0);
			}
		}

		#endregion

		#region Pixel access functions

		/// <summary>
		/// Retrieves an hBitmap for a FreeImage bitmap.
		/// Call FreeHbitmap(IntPtr) to free the handle.
		/// </summary>
		/// <param name="dib">Handle to a FreeImage bitmap.</param>
		/// <param name="hdc">A reference device context.
		/// Use IntPtr.Zero if no reference is available.</param>
		/// <param name="unload">When true dib will be unloaded if the function succeeded.</param>
		/// <returns>The hBitmap for the FreeImage bitmap.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="dib"/> is null.</exception>
		public static unsafe IntPtr GetHbitmap(FIBITMAP dib, IntPtr hdc, bool unload)
		{
			if (dib.IsNull)
			{
				throw new ArgumentNullException("dib");
			}
			IntPtr hBitmap = IntPtr.Zero;
			bool release = false;
			IntPtr ppvBits = IntPtr.Zero;
			// Check if we have destination
			if (release = (hdc == IntPtr.Zero))
			{
				// We don't so request dc
				hdc = GetDC(IntPtr.Zero);
			}
			if (hdc != IntPtr.Zero)
			{
				// Get pointer to the infoheader of the bitmap
				IntPtr info = GetInfo(dib);
				// Create a bitmap in the dc
				hBitmap = CreateDIBSection(hdc, info, DIB_RGB_COLORS, out ppvBits, IntPtr.Zero, 0);
				if (hBitmap != IntPtr.Zero && ppvBits != IntPtr.Zero)
				{
					// Copy the data into the dc
					CopyMemory(
						ppvBits,
						GetBits(dib),
						(GetHeight(dib) * GetPitch(dib)));
					// Success: we unload the bitmap
					if (unload)
					{
						Unload(dib);
					}
				}
				// We have to release the dc
				if (release)
				{
					ReleaseDC(IntPtr.Zero, hdc);
				}
			}
			return hBitmap;
		}

		/// <summary>
		/// Returns an HBITMAP created by the <c>CreateDIBitmap()</c> function which in turn
		/// has always the same color depth as the reference DC, which may be provided
		/// through <paramref name="hdc"/>. The desktop DC will be used,
		/// if <c>IntPtr.Zero</c> DC is specified.
		/// Call <see cref="FreeImage.FreeHbitmap(IntPtr)"/> to free the handle.
		/// </summary>
		/// <param name="dib">Handle to a FreeImage bitmap.</param>
		/// <param name="hdc">Handle to a device context.</param>
		/// <param name="unload">When true the structure will be unloaded on success.
		/// If the function failed and returned false, the bitmap was not unloaded.</param>
		/// <returns>If the function succeeds, the return value is a handle to the
		/// compatible bitmap. If the function fails, the return value is <see cref="IntPtr.Zero"/>.</returns>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="dib"/> is null.</exception>
		public static IntPtr GetBitmapForDevice(FIBITMAP dib, IntPtr hdc, bool unload)
		{
			if (dib.IsNull)
			{
				throw new ArgumentNullException("dib");
			}
			IntPtr hbitmap = IntPtr.Zero;
			bool release = false;
			if (release = (hdc == IntPtr.Zero))
			{
				hdc = GetDC(IntPtr.Zero);
			}
			if (hdc != IntPtr.Zero)
			{
				hbitmap = CreateDIBitmap(
					hdc,
					GetInfoHeader(dib),
					CBM_INIT,
					GetBits(dib),
					GetInfo(dib),
					DIB_RGB_COLORS);
				if (unload)
				{