C#制作透明色GIF动画的类

前几天,关注了下GIF的文件结构

发现一个GIF文件大小错很多.发现主要是3个地方的问题.

一是色彩表的问题.GIF有全局色彩表和图形色彩表.

二是GIF图形的大小并不一定是一样的桢1可能是100*100的桢2可能是10*10 比如天空是黑色100*100 星星在是10*10

三是描述区,没什么作用就是描述

图形一样大小不一样的就这两个地方区别大.

用C#来实现下

并没用LZW是通过.NET来实现LZW的.这里只是进行了文件头的更改和合并.

如果你用这个类打开一个GIF 你通过SAVE方法再保存一次描述类会放到图形类的后面.

有兴趣到这里逛逛：http://baidv.taobao.com

使用方式

Zgke.MyImage.ImageGif _Gif = new Zgke.MyImage.ImageGif(20, 32);
int _Temp =(int)'A';
for (int i = 0; i != 26; i++)
{
Bitmap _BitMap = new Bitmap(20, 32);
Graphics _G = Graphics.FromImage(_BitMap);
char T = (char)_Temp;
_G.DrawString(T.ToString(), new Font("宋体", 20), Brushes.Black, 0, 0);
_Gif.AddImage(_BitMap, 1, true, Zgke.MyImage.ImageGif.DisposalMethod.NoDisposalImage);
_G.Dispose();
_Temp++;
_BitMap.Dispose();
}
pictureBox1.Image = _Gif.Image;
_Gif.SaveFile(@"C:\1.gif");

下面是全部的类

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Runtime.InteropServices;
namespace Zgke.MyImage
{
/// <summary>
/// GIF操作类
/// zgke@sina.com
/// QQ:116149
/// </summary>
public class ImageGif
{
private Header m_Header;
private LogicalScreen m_LogicalScreen;
private ColorTable m_GlobalColorTable;
private IList<ExtensionIntroducer> m_ExtensionIntroducer = new List<ExtensionIntroducer>();
private ApplicationExtension m_ApplicationExtension;
private IList<GraphicControlExtension> m_GraphicControlExtension = new List<GraphicControlExtension>();
/// <summary>
/// 当前位置
/// </summary>
private int m_Index = 0;
private bool m_Open = false;
/// <summary>
/// 是否正常打开
/// </summary>
public bool OpenOK { get { return m_Open; } }
/// <summary>
/// 图形数量
/// </summary>
public int ImageCount { get { return m_GraphicControlExtension.Count; } }
/// <summary>
/// 获取GIF图形
/// </summary>
public Image Image
{
get
{
if (m_GraphicControlExtension.Count == 0) return null;
MemoryStream _MemoryImage = new MemoryStream();
_MemoryImage.Position = 0;
byte[] _Temp = m_Header.GetByte();
_MemoryImage.Write(_Temp, 0, _Temp.Length);
_Temp = m_LogicalScreen.GetByte();
_MemoryImage.Write(_Temp, 0, _Temp.Length);
_Temp = m_GlobalColorTable.GetByte();
_MemoryImage.Write(_Temp, 0, _Temp.Length);
_Temp = m_ApplicationExtension.GetByte();
_MemoryImage.Write(_Temp, 0, _Temp.Length);
for (int i = 0; i != m_GraphicControlExtension.Count; i++) //保存图形
{
_Temp = m_GraphicControlExtension[i].GetByte();
_MemoryImage.Write(_Temp, 0, _Temp.Length);
}
for (int i = 0; i != m_ExtensionIntroducer.Count; i++) //保存描述
{
_Temp = m_ExtensionIntroducer[i].GetByte();
_MemoryImage.Write(_Temp, 0, _Temp.Length);
}
_MemoryImage.WriteByte(0x3B);
return Image.FromStream(_MemoryImage);
}
}
/// <summary>
/// 由文件打开
/// </summary>
/// <param name="p_GifFileName"></param>
public ImageGif(string p_GifFileName)
{
System.IO.FileStream _FileStream = new FileStream(p_GifFileName, FileMode.Open);
byte[] _GifByte = new byte[_FileStream.Length];
_FileStream.Read(_GifByte, 0, _GifByte.Length);
_FileStream.Close();
m_Header = new Header(_GifByte, ref m_Index, ref m_Open);
if (m_Open == false) return;
m_LogicalScreen = new LogicalScreen(_GifByte, ref m_Index, ref m_Open);
if (m_Open == false) return;
m_GlobalColorTable = new ColorTable(m_LogicalScreen.GlobalPal, m_LogicalScreen.GlobalColorSize, _GifByte, ref m_Index, ref m_Open);
if (m_Open == false) return;
//固定位置信息读取完成
m_Open = false;
while (true) //不知道有多少个模块一直循环吧
{
#region 判断位置
switch (_GifByte[m_Index])
{
case 0x21:
m_Index += 2; //坐标移动到类别后面取类类别用-1方式少一行代码
switch (_GifByte[m_Index - 1])
{
case 0xFE:
m_ExtensionIntroducer.Add(new ExtensionIntroducer(_GifByte, ref m_Index, ref m_Open));
if (m_Open == false) return; //获取失败每必要继续了直接返回
break;
case 0xFF:
m_ApplicationExtension = new ApplicationExtension(_GifByte, ref m_Index, ref m_Open);
if (m_Open == false) return;
break;
case 0xF9: //图形在这个区 LZW数据
m_GraphicControlExtension.Add(new GraphicControlExtension(_GifByte, ref m_Index, ref m_Open));
if (m_Open == false) return;
break;
default: //找不到类别直接结束
System.Windows.Forms.MessageBox.Show(_GifByte[m_Index - 1].ToString("X02"));
return;
}
break;
case 0x3B:
m_Open = true;
return;
default:
m_Open = false;
System.Windows.Forms.MessageBox.Show(_GifByte[m_Index].ToString("X02"), m_Index.ToString());
return;
}
#endregion
}
}
/// <summary>
/// 建立新的图形
/// </summary>
/// <param name="p_Width"></param>
/// <param name="p_Height"></param>
public ImageGif(ushort p_Width, ushort p_Height)
{
m_Header = new Header();
m_LogicalScreen = new LogicalScreen(p_Width, p_Height);
m_ApplicationExtension = new ApplicationExtension();
m_ExtensionIntroducer.Add(new ExtensionIntroducer("http://blog.csdn.net/zgke")); //这东西可以很多个描述就是描述没发现什么作用
}
#region 添加图形删除插入
/// <summary>
/// 添加一个图形
/// </summary>
/// <param name="Image">图形</param>
/// <param name="p_DelayTime">显示时间</param>
/// <param name="p_UserColorTable">是否使用全局色彩表 true使用 false 不使用</param>
private GraphicControlExtension GetGraphicsControl(Image p_Image, ushort p_DelayTime, bool p_UserColorTable, DisposalMethod p_Disposal)
{
MemoryStream _MemOry = new MemoryStream();
Image _Image = ToImageGif((Bitmap)p_Image, Color.White); //透明的方法可以加到这里
_Image.Save(_MemOry, ImageFormat.Gif); //保存成GIF图形
int _Index = 783; //开始位置781 0x21 0xF9 已经计算
bool _Open = false;
GraphicControlExtension _Graphics = new GraphicControlExtension(_MemOry.GetBuffer(), ref _Index, ref _Open);
_Graphics.DelayTime = p_DelayTime;
_Graphics.TransparentColorFlag = true;
_Graphics.TransparentColorIndex = 16;
ColorTable _Table = new ColorTable();
Image _AddImage = Image.FromStream(_MemOry); //获取压缩后的图形
for (int i = 0; i != _AddImage.Palette.Entries.Length; i++) //获取图形颜色表
{
_Table.ColorTableList.Add(_AddImage.Palette.Entries[i]);
}
if (m_GlobalColorTable == null) m_GlobalColorTable = _Table; //不管怎么样都要全局色彩表
if (p_UserColorTable == false)
{
_Graphics.ColorTable = _Table; //根据需要设置全局颜色表
_Graphics.UserColorTable = !p_UserColorTable;
}
_Graphics.Disposal = p_Disposal;
return _Graphics;
}
/// <summary>
/// 添加一个图形图形可以大于虚拟屏幕就是显示不出来而已........
/// </summary>
/// <param name="Image">图形</param>
/// <param name="p_DelayTime">显示时间</param>
/// <param name="p_UserColorTable">是否使用全局色彩表 true使用 false 不使用</param>
public void AddImage(Image p_Image, ushort p_DelayTime, bool p_UserColorTable, DisposalMethod p_Disposal)
{
GraphicControlExtension _Info = GetGraphicsControl(p_Image, p_DelayTime, p_UserColorTable, p_Disposal);
if (_Info != null) m_GraphicControlExtension.Add(_Info);
}
/// <summary>
/// 删除一个图形
/// </summary>
/// <param name="p_Index"></param>
public void RemoveImage(int p_Index)
{
if (p_Index > m_GraphicControlExtension.Count - 1) return;
m_GraphicControlExtension.RemoveAt(p_Index);
}
/// <summary>
/// 插入一个图形
/// </summary>
/// <param name="Image">图形</param>
/// <param name="p_DelayTime">显示时间</param>
/// <param name="p_UserColorTable">是否使用全局色彩表 true使用 false 不使用</param>
public void InsertImage(Image p_Image, ushort p_DelayTime, bool p_UserColorTable, int p_Index, DisposalMethod p_Disposal)
{
if (p_Index > m_GraphicControlExtension.Count - 1) return;
GraphicControlExtension _Info = GetGraphicsControl(p_Image, p_DelayTime, p_UserColorTable, p_Disposal);
if (_Info != null) m_GraphicControlExtension.Insert(p_Index, _Info);
}
#endregion
/// <summary>
/// 设置一个图形播放的时间
/// </summary>
/// <param name="p_Index">索引</param>
/// <param name="p_DelayTime">播放时间</param>
public void SetImageTime(int p_Index, ushort p_DelayTime)
{
if (p_Index > m_GraphicControlExtension.Count - 1) return;
m_GraphicControlExtension[p_Index].DelayTime = p_DelayTime;
}
/// <summary>
/// 设置一个图形开始位置
/// </summary>
/// <param name="p_Index">索引</param>
/// <param name="p_X">X坐标</param>
/// <param name="p_Y">Y坐标</param>
public void SetImageLocatch(int p_Index, Point p_Point)
{
if (p_Index > m_GraphicControlExtension.Count - 1) return;
m_GraphicControlExtension[p_Index].Point = p_Point;
}
/// <summary>
/// 设置处理模式
/// </summary>
/// <param name="p_Index">索引</param>
/// <param name="p_DisposalMethod">处理模式</param>
public void SetImageDisposalMethod(int p_Index, DisposalMethod p_DisposalMethod)
{
if (p_Index > m_GraphicControlExtension.Count - 1) return;
m_GraphicControlExtension[p_Index].Disposal = p_DisposalMethod;
}
/// <summary>
/// 保存文件
/// </summary>
/// <param name="p_FileName"></param>
public void SaveFile(string p_FileName)
{
if (m_GraphicControlExtension.Count == 0) return ;
FileStream _File = new FileStream(p_FileName, FileMode.Create);
_File.Position = 0;
byte[] _Temp = m_Header.GetByte();
_File.Write(_Temp, 0, _Temp.Length);
_Temp = m_LogicalScreen.GetByte();
_File.Write(_Temp, 0, _Temp.Length);
_Temp = m_GlobalColorTable.GetByte();
_File.Write(_Temp, 0, _Temp.Length);
_Temp = m_ApplicationExtension.GetByte();
_File.Write(_Temp, 0, _Temp.Length);
for (int i = 0; i != m_GraphicControlExtension.Count; i++) //保存图形
{
_Temp = m_GraphicControlExtension[i].GetByte();
_File.Write(_Temp, 0, _Temp.Length);
}
for (int i = 0; i != m_ExtensionIntroducer.Count; i++) //保存描述
{
_Temp = m_ExtensionIntroducer[i].GetByte();
_File.Write(_Temp, 0, _Temp.Length);
}
_File.WriteByte(0x3B);
_File.Close();
}
#region 获取图形
/// <summary>
/// 内部方法保存一个图形
/// </summary>
/// <param name="m_Stream">数据流</param>
/// <param name="p_Index">图形索引</param>
/// <returns>图形</returns>
private Stream GetImage(Stream m_Stream, int p_Index)
{
if (p_Index < 0 || p_Index > ImageCount) return null;
m_Stream.Position = 0;
byte[] _Temp = m_Header.GetByte();
m_Stream.Write(_Temp, 0, _Temp.Length);
_Temp = m_LogicalScreen.GetByte();
m_Stream.Write(_Temp, 0, _Temp.Length);
_Temp = m_GlobalColorTable.GetByte();
m_Stream.Write(_Temp, 0, _Temp.Length);
_Temp = m_ApplicationExtension.GetByte();
m_Stream.Write(_Temp, 0, _Temp.Length);
_Temp = m_GraphicControlExtension[p_Index].GetByte();
m_Stream.Write(_Temp, 0, _Temp.Length);
for (int i = 0; i != m_ExtensionIntroducer.Count; i++) //保存描述
{
_Temp = m_ExtensionIntroducer[i].GetByte();
m_Stream.Write(_Temp, 0, _Temp.Length);
}
m_Stream.WriteByte(0x3B);
return m_Stream;
}
/// <summary>
/// 根据索引获取图形
/// </summary>
/// <param name="p_Index">索引</param>
/// <returns>图形</returns>
public Image GetImage(int p_Index)
{
MemoryStream _Memory = new MemoryStream();
return Image.FromStream(GetImage(_Memory, p_Index));
}
/// <summary>
/// 根据索引获取图形
/// </summary>
/// <param name="p_Index">索引</param>
/// <returns>图形</returns>
public void GetImage(int p_Index, string p_FileName)
{
FileStream _File = new FileStream(p_FileName, FileMode.Create);
GetImage(_File, p_Index);
_File.Close();
}
#endregion
/// <summary>
/// 处理模式
/// </summary>
public enum DisposalMethod
{
/// <summary>
/// 不使用处置方法一般的GIF都是这个
/// </summary>
NoDisposalMethod = 0,
/// <summary>
/// 不处置图形，把图形从当前位置移去
/// </summary>
NoDisposalImage = 1,
/// <summary>
/// 回复到背景色
/// </summary>
RestoreBackgroundColor = 2,
/// <summary>
/// 回复到先前状态
/// </summary>
RestoreFrontState = 3,
/// <summary>
/// 为定义4-7
/// </summary>
Null
}
#region 类定义
/// <summary>
/// GIF文件头
/// </summary>
private class Header
{
/// <summary>
///文件头必须是GIF
/// </summary>
private byte[] _Signature = new byte[] { 0x47, 0x49, 0x46 };
/// <summary>
/// 版本信息
/// </summary>
private byte[] _Version = new byte[] { 0x38, 0x39, 0x61 };
public Header(byte[] p_Byte, ref int p_Index, ref bool p_Open)
{
p_Open = false;
if (p_Byte[0] != _Signature[0] || p_Byte[1] != _Signature[1] || p_Byte[2] != _Signature[2])
{
return;
}
_Version[0] = p_Byte[3];
_Version[1] = p_Byte[4];
_Version[2] = p_Byte[5];
p_Index += 6;
p_Open = true;
}
public Header()
{
}
/// <summary>
/// 返回版本号
/// </summary>
public string Version
{
get
{ return Encoding.ASCII.GetString(_Version); }
set
{
if (value == "87a") _Version[1] = 0x37;
}
}
public byte[] GetByte()
{
byte[] _Temp = new byte[6];
_Temp[0] = _Signature[0];
_Temp[1] = _Signature[1];
_Temp[2] = _Signature[2];
_Temp[3] = _Version[0];
_Temp[4] = _Version[1];
_Temp[5] = _Version[2];
return _Temp;
}
}
/// <summary>
/// 逻辑屏幕标识符
/// </summary>
private class LogicalScreen
{
/// <summary>
/// 图形宽
/// </summary>
private byte[] _Width = new byte[2];
/// <summary>
/// 图形高
/// </summary>
private byte[] _Height = new byte[2];
/// <summary>
/// 第8位 - 全局颜色列表标志(Global Color Table Flag)，当置位时表示有全局颜色列表，pixel值有意义.
/// 第5位第6位第7位颜色深度(Color ResoluTion)，cr+1确定图象的颜色深度.
/// 第4位分类标记如果置位表示全局颜色列表分类排列.
/// 第1位第2位第3位全局颜色列表大小，pixel+1确定颜色列表的索引数（2的pixel+1次方）.
/// </summary>
private byte[] _BitArray = new byte[1];
/// <summary>
/// 背景色索引
/// </summary>
private byte _Blackground = 0;
/// <summary>
/// 像素宽高比
/// </summary>
private byte _PixelAspectRadio = 0;
public LogicalScreen(byte[] p_Byte, ref int p_Index, ref bool p_Open)
{
p_Open = false;
_Width[0] = p_Byte[p_Index];
_Width[1] = p_Byte[p_Index + 1];
_Height[0] = p_Byte[p_Index + 2];
_Height[1] = p_Byte[p_Index + 3];
_BitArray[0] = p_Byte[p_Index + 4];
_Blackground = p_Byte[p_Index + 5];
_PixelAspectRadio = p_Byte[p_Index + 6];
p_Index += 7;
p_Open = true;
}
public LogicalScreen(ushort p_Width, ushort p_Height)
{
Width = p_Width;
Height = p_Height;
_Blackground = 0;
_PixelAspectRadio = 0;
_BitArray[0] = 135;
}
/// <summary>
/// 高
/// </summary>
public ushort Width { get { return BitConverter.ToUInt16(_Width, 0); } set { _Width = BitConverter.GetBytes(value); } }
/// <summary>
/// 宽
/// </summary>
public ushort Height { get { return BitConverter.ToUInt16(_Height, 0); } set { _Height = BitConverter.GetBytes(value); } }
/// <summary>
/// 背景索引
/// </summary>
public byte Blackground { get { return _Blackground; } set { _Blackground = value; } }
/// <summary>
/// 像素宽高比
/// </summary>
public byte PixelAspectRadio { get { return _PixelAspectRadio; } set { _PixelAspectRadio = value; } }
/// <summary>
/// 全局颜色列表标志
/// </summary>
public bool GlobalPal
{
get
{
BitArray _BitList = new BitArray(_BitArray);
return _BitList[7];
}
set
{
BitArray _BitList = new BitArray(_BitArray);