freeimagewrapper.cs

对gif

// ==========================================================
// FreeImage 3 .NET wrapper
// Original FreeImage 3 functions and .NET compatible derived functions
//
// Design and implementation by
// - Jean-Philippe Goerke ([e-mail])
// - Carsten Klein ([e-mail])
//
// Contributors:
// - David Boland ([e-mail])
//
// Main reference : MSDN Knowlede Base
//
// This file is part of FreeImage 3
//
// COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
// THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
// OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED
// CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT
// THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
// SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL
// PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
// THIS DISCLAIMER.
//
// Use at your own risk!
// ==========================================================

// ==========================================================
// CVS
// $Revision: 1.6 $
// $Date: 2008/06/17 13:50:59 $
// $Id: FreeImageWrapper.cs,v 1.6 2008/06/17 13:50:59 cklein05 Exp $
// ==========================================================

using System;
using System.Collections;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Reflection;
using System.Runtime.InteropServices;
using FreeImageAPI.IO;
using FreeImageAPI.Metadata;

namespace FreeImageAPI
{
	/// <summary>
	/// Static class importing functions from the FreeImage library
	/// and providing additional functions.
	/// </summary>
	public static partial class FreeImage
	{
		#region Constants

		/// <summary>
		/// Array containing all 'FREE_IMAGE_MDMODEL's.
		/// </summary>
		public static readonly FREE_IMAGE_MDMODEL[] FREE_IMAGE_MDMODELS =
			(FREE_IMAGE_MDMODEL[])Enum.GetValues(typeof(FREE_IMAGE_MDMODEL));

		/// <summary>
		/// Saved instance for faster access.
		/// </summary>
		private static readonly ConstructorInfo PropertyItemConstructor =
			typeof(PropertyItem).GetConstructor(
			BindingFlags.NonPublic | BindingFlags.Instance, null, new Type[] { }, null);

		private const int DIB_RGB_COLORS = 0;
		private const int DIB_PAL_COLORS = 1;
		private const int CBM_INIT = 0x4;

		/// <summary>
		/// An uncompressed format.
		/// </summary>
		public const int BI_RGB = 0;

		/// <summary>
		/// A run-length encoded (RLE) format for bitmaps with 8 bpp. The compression format is a 2-byte
		/// format consisting of a count byte followed by a byte containing a color index.
		/// </summary>
		public const int BI_RLE8 = 1;

		/// <summary>
		/// An RLE format for bitmaps with 4 bpp. The compression format is a 2-byte format consisting
		/// of a count byte followed by two word-length color indexes.
		/// </summary>
		public const int BI_RLE4 = 2;

		/// <summary>
		/// Specifies that the bitmap is not compressed and that the color table consists of three
		/// <b>DWORD</b> color masks that specify the red, green, and blue components, respectively,
		/// of each pixel. This is valid when used with 16- and 32-bpp bitmaps.
		/// </summary>
		public const int BI_BITFIELDS = 3;

		/// <summary>
		/// <b>Windows 98/Me, Windows 2000/XP:</b> Indicates that the image is a JPEG image.
		/// </summary>
		public const int BI_JPEG = 4;

		/// <summary>
		/// <b>Windows 98/Me, Windows 2000/XP:</b> Indicates that the image is a PNG image.
		/// </summary>
		public const int BI_PNG = 5;

		#endregion

		#region Callback

		// Callback delegate
		private static OutputMessageFunction outputMessageFunction;
		// Handle to pin the functions address
		private static GCHandle outputMessageHandle;

		static FreeImage()
		{
			// Check if FreeImage.dll is present and cancel setting the callbackfuntion if not
			if (!IsAvailable())
			{
				return;
			}
			// Create a delegate (function pointer) to 'OnMessage'
			outputMessageFunction = new OutputMessageFunction(OnMessage);
			// Pin the object so the garbage collector does not move it around in memory
			outputMessageHandle = GCHandle.Alloc(outputMessageFunction, GCHandleType.Normal);
			// Set the callback
			SetOutputMessage(outputMessageFunction);
		}

		/// <summary>
		/// Internal callback
		/// </summary>
		private static void OnMessage(FREE_IMAGE_FORMAT fif, string message)
		{
			// Invoke the message
			if (Message != null)
			{
				Message.Invoke(fif, message);
			}
		}

		/// <summary>
		/// Internal errors in FreeImage generate a logstring that can be
		/// captured by this event.
		/// </summary>
		public static event OutputMessageFunction Message;

		#endregion

		#region General functions

		/// <summary>
		/// Returns the internal version of this FreeImage 3 .NET wrapper.
		/// </summary>
		/// <returns>The internal version of this FreeImage 3 .NET wrapper.</returns>
		public static string GetWrapperVersion()
		{
			return FREEIMAGE_MAJOR_VERSION + "." + FREEIMAGE_MINOR_VERSION + "." + FREEIMAGE_RELEASE_SERIAL;
		}

		/// <summary>
		/// Returns a value indicating if the FreeImage DLL is available or not.
		/// </summary>
		/// <returns>True, if the FreeImage DLL is available, false otherwise.</returns>
		public static bool IsAvailable()
		{
			try
			{
				// Call a static fast executing function
				GetVersion();
				// No exception thrown, the dll seems to be present
				return true;
			}
			catch (DllNotFoundException)
			{
				return false;
			}
			catch (EntryPointNotFoundException)
			{
				return false;
			}
		}

		#endregion

		#region Bitmap management functions

		/// <summary>
		/// Converts a FreeImage bitmap to a .NET <see cref="System.Drawing.Bitmap"/>.
		/// </summary>
		/// <param name="dib">Handle to a FreeImage bitmap.</param>
		/// <returns>The converted .NET <see cref="System.Drawing.Bitmap"/>.</returns>
		/// <remarks>Copying metadata has been disabled until a proper way
		/// of reading and storing metadata in a .NET bitmap is found.</remarks>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="dib"/> is null.</exception>
		/// <exception cref="ArgumentException">
		/// The image type of <paramref name="dib"/> is not FIT_BITMAP.</exception>
		public static Bitmap GetBitmap(FIBITMAP dib)
		{
			return GetBitmap(dib, true);
		}

		/// <summary>
		/// Converts a FreeImage bitmap to a .NET <see cref="System.Drawing.Bitmap"/>.
		/// </summary>
		/// <param name="dib">Handle to a FreeImage bitmap.</param>
		/// <param name="copyMetadata">When true existing metadata will be copied.</param>
		/// <returns>The converted .NET <see cref="System.Drawing.Bitmap"/>.</returns>
		/// <remarks>Copying metadata has been disabled until a proper way
		/// of reading and storing metadata in a .NET bitmap is found.</remarks>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="dib"/> is null.</exception>
		/// <exception cref="ArgumentException">
		/// The image type of <paramref name="dib"/> is not FIT_BITMAP.</exception>
		internal static Bitmap GetBitmap(FIBITMAP dib, bool copyMetadata)
		{
			if (dib.IsNull)
			{
				throw new ArgumentNullException("dib");
			}
			if (GetImageType(dib) != FREE_IMAGE_TYPE.FIT_BITMAP)
			{
				throw new ArgumentException("Only bitmaps with type of FIT_BITMAP can be converted.");
			}

			PixelFormat format = GetPixelFormat(dib);

			if ((format == PixelFormat.Undefined) && (GetBPP(dib) == 16u))
			{
				throw new ArgumentException("Only 16bit 555 and 565 are supported.");
			}

			int height = (int)GetHeight(dib);
			int width = (int)GetWidth(dib);
			int pitch = (int)GetPitch(dib);

			Bitmap result = new Bitmap(width, height, format);
			BitmapData data;
			// Locking the complete bitmap in writeonly mode
			data = result.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.WriteOnly, format);
			// Writing the bitmap data directly into the new created .NET bitmap.
			ConvertToRawBits(data.Scan0, dib, pitch, GetBPP(dib),
				GetRedMask(dib), GetGreenMask(dib), GetBlueMask(dib), true);
			// Unlock the bitmap
			result.UnlockBits(data);
			// Apply the bitmaps resolution
			result.SetResolution(GetResolutionX(dib), GetResolutionY(dib));
			// Check whether the bitmap has a palette
			if (GetPalette(dib) != IntPtr.Zero)
			{
				// Get the bitmaps palette to apply changes
				ColorPalette palette = result.Palette;
				// Get the orgininal palette
				Color[] colorPalette = new Palette(dib).ColorData;
				// Copy each value
				if (palette.Entries.Length == colorPalette.Length)
				{
					for (int i = 0; i < colorPalette.Length; i++)
					{
						palette.Entries[i] = colorPalette[i];
					}
					// Set the bitmaps palette
					result.Palette = palette;
				}
			}
			// Copy metadata
			if (copyMetadata)
			{
				try
				{
					List<PropertyItem> list = new List<PropertyItem>();
					// Get a list of all types
					FITAG tag;
					FIMETADATA mData;
					foreach (FREE_IMAGE_MDMODEL model in FREE_IMAGE_MDMODELS)
					{
						// Get a unique search handle
						mData = FindFirstMetadata(model, dib, out tag);
						// Check if metadata exists for this type
						if (mData.IsNull) continue;
						do
						{
							PropertyItem propItem = CreatePropertyItem();
							propItem.Len = (int)GetTagLength(tag);
							propItem.Id = (int)GetTagID(tag);
							propItem.Type = (short)GetTagType(tag);
							byte[] buffer = new byte[propItem.Len];

							unsafe
							{
								byte* src = (byte*)GetTagValue(tag);
								fixed (byte* dst = buffer)
								{
									MoveMemory(dst, src, (uint)propItem.Len);
								}
							}

							propItem.Value = buffer;
							list.Add(propItem);
						}
						while (FindNextMetadata(mData, out tag));
						FindCloseMetadata(mData);
					}
					foreach (PropertyItem propItem in list)
					{
						result.SetPropertyItem(propItem);
					}
				}
				catch
				{
				}
			}
			return result;
		}

		/// <summary>
		/// Converts an .NET <see cref="System.Drawing.Bitmap"/> into a FreeImage bitmap.
		/// </summary>
		/// <param name="bitmap">The <see cref="System.Drawing.Bitmap"/> to convert.</param>
		/// <returns>Handle to a FreeImage bitmap.</returns>
		/// <remarks>Copying metadata has been disabled until a proper way
		/// of reading and storing metadata in a .NET bitmap is found.</remarks>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="bitmap"/> is null.</exception>
		/// <exception cref="ArgumentException">
		/// The bitmaps pixelformat is invalid.</exception>
		public static FIBITMAP CreateFromBitmap(Bitmap bitmap)
		{
			return CreateFromBitmap(bitmap, false);
		}

		/// <summary>
		/// Converts an .NET <see cref="System.Drawing.Bitmap"/> into a FreeImage bitmap.
		/// </summary>
		/// <param name="bitmap">The <see cref="System.Drawing.Bitmap"/> to convert.</param>
		/// <param name="copyMetadata">When true existing metadata will be copied.</param>
		/// <returns>Handle to a FreeImage bitmap.</returns>
		/// <remarks>Copying metadata has been disabled until a proper way
		/// of reading and storing metadata in a .NET bitmap is found.</remarks>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="bitmap"/> is null.</exception>
		/// <exception cref="ArgumentException">
		/// The bitmaps pixelformat is invalid.</exception>
		internal static FIBITMAP CreateFromBitmap(Bitmap bitmap, bool copyMetadata)
		{
			if (bitmap == null)
			{
				throw new ArgumentNullException("bitmap");
			}
			uint bpp, red_mask, green_mask, blue_mask;