gifextensions.cs

gif图像处理 包括对多帧gif动画的缩放

#region Copyright & License
/*-------------------------New BSD License ------------------
 Copyright (c) 2008, jillzhang
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

* Neither the name of jillzhang nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */
#endregion

using System;
using System.Collections.Generic;
using System.Text;

namespace Jillzhang.GifUtility
{
    #region 类GifExtensions
    /// <summary>
    /// 扩展块中的一些常量
    /// </summary>
    internal class GifExtensions
    {
        /// <summary>
        /// Extension Introducer - 标识这是一个扩展块，固定值0x21
        /// </summary>          
        internal const byte ExtensionIntroducer = 0x21;

        /// <summary>
        /// lock Terminator - 标识注释块结束，固定值0
        /// </summary>
        internal const byte Terminator = 0;


        /// <summary>
        /// Application Extension Label - 标识这是一个应用程序扩展块，固定值0xFF 
        /// </summary>
        internal const byte ApplicationExtensionLabel = 0xFF;


        /// <summary>
        /// Comment Label - 标识这是一个注释块，固定值0xFE
        /// </summary>
        internal const byte CommentLabel = 0xFE;


        /// <summary>
        /// 图象标识符开始，固定值为','
        /// </summary>
        internal const byte ImageDescriptorLabel = 0x2C;

        /// <summary>
        /// Plain Text Label - 标识这是一个图形文本扩展块，固定值0x01
        /// </summary>
        internal const byte PlainTextLabel = 0x01;

        /// <summary>
        /// Graphic Control Label - 标识这是一个图形控制扩展块，固定值0xF9
        /// </summary>
        internal const byte GraphicControlLabel = 0xF9;

        /// <summary>
        /// 图像的标示
        /// </summary>
        internal const byte ImageLabel = 0x2C;

        /// <summary>
        /// 文件结尾
        /// </summary>
        internal const byte EndIntroducer = 0x3B;
    }
    #endregion
}