gifframe.cs

gif图像处理 包括对多帧gif动画的缩放

#region File License
/*----------------------------------------------------------------
// Copyright (C) 2008 jillzhang 版权所有。 
//  
// 文件名：Frame.cs
// 文件功能描述：
// 
// 创建标识：jillzhang 
// 修改标识：
// 修改描述：
//
// 修改标识：
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//----------------------------------------------------------------*/

/*-------------------------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GifFrame
    /// <summary>
    /// Gif文件中可以包含多个图像，每个图像加上图像的一些特征，就组成了帧:GifFrame
    /// </summary>
    internal class GifFrame
    {
        #region private fields
        private ImageDescriptor _imgDes;
        private System.Drawing.Bitmap _img;
        private int _colorSize = 3;
        private byte[] _lct;
        private GraphicEx _graphicEx;
        private byte[] _buffer;        
        #endregion

        #region internal property
        /// <summary>
        /// 该桢的背景色
        /// </summary>
        public Color32 BgColor
        {
            get
            {
                Color32[] act = PaletteHelper.GetColor32s(LocalColorTable);
                return act[GraphicExtension.TranIndex];
            }            
        }
        /// <summary>
        /// 图象标识符(Image Descriptor)
        /// 一个GIF文件内可以包含多幅图象
        /// 一幅图象结束之后紧接着下是一幅图象的标识符，
        /// 图象标识符以0x2C(',')字符开始，
        /// 定义紧接着它的图象的性质，包括图象相对于逻辑屏幕边界的偏移量、
        /// 图象大小以及有无局部颜色列表和颜色列表大小
        /// </summary>
        internal ImageDescriptor ImageDescriptor
        {
            get { return _imgDes; }
            set { _imgDes = value; }
        }
               
        /// <summary>
        /// Gif的调色板
        /// </summary>
        internal Color32[] Palette
        {
            get
            {
                Color32[] act = PaletteHelper.GetColor32s(LocalColorTable);
                if (GraphicExtension != null && GraphicExtension.TransparencyFlag)
                {
                    act[GraphicExtension.TranIndex] = new Color32(0);
                }
                return act;
            }
        }

        /// <summary>
        /// 图像
        /// </summary>
        internal System.Drawing.Bitmap Image
        {
            get { return _img; }
            set { _img = value; }
        }
        
        /// <summary>
        /// 数据位大小
        /// </summary>
        internal int ColorDepth
        {
            get
            {
                return _colorSize;
            }
            set
            {
                _colorSize = value;
            }
        }
        
        /// <summary>
        /// 局部颜色列表(Local Color Table)
        /// 如果上面的局部颜色列表标志置位的话，则需要在这里（紧跟在图象标识符之后）
        /// 定义一个局部颜色列表以供紧接着它的图象使用，注意使用前应线保存原来的颜色列表，
        /// 使用结束之后回复原来保存的全局颜色列表。如果一个GIF文件即没有提供全局颜色列表
        /// 也没有提供局部颜色列表，可以自己创建一个颜色列表，或使用系统的颜色列表。
        /// RGBRGB......
        /// </summary>
        internal byte[] LocalColorTable
        {
            get { return _lct; }
            set { _lct = value; }
        }
        
        /// <summary>
        /// 图形控制扩展(Graphic Control Extension)这一部分是可选的（需要89a版本），
        /// 可以放在一个图象块(包括图象标识符、局部颜色列表和图象数据)或文本扩展块的前面，
        /// 用来控制跟在它后面的第一个图象（或文本）的渲染(Render)形式
        /// </summary>
        internal GraphicEx GraphicExtension
        {
            get { return _graphicEx; }
            set { _graphicEx = value; }
        }

        /// <summary>
        /// 延迟-与下一帧之间的时间间隔
        /// </summary>
        internal short Delay
        {
            get { return _graphicEx.Delay; }
            set { _graphicEx.Delay = value; }
        }
       
        /// <summary>
        /// 这个是经过LZW压缩算法后的数据流
        /// </summary>
        internal byte[] IndexedPixel
        {
            get { return _buffer; }
            set { _buffer = value; }
        }
        #endregion
    }
    #endregion
}