plaintextex.cs

gif图像处理 包括对多帧gif动画的缩放

#region Copyright & License
/*----------------------------------------------------------------
// Copyright (C) 2008 jillzhang 版权所有。 
//  
// 文件名：PlainTextEx.cs   使用请保留版权信息  
// 文件功能描述： 更多信息请访问 http://jillzhang.cnblogs.com
// 
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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;
using System.IO;

namespace Jillzhang.GifUtility
{
    #region 结构PlainTextEx
    /// <summary>
    /// 形文本扩展(Plain Text Extension)这一部分是可选的（需要89a版本），
    /// 用来绘制一个简单的文本图象，这一部分由用来绘制的纯文本数据（7-bit ASCII字符）
    /// 和控制绘制的参数等组成。绘制文本借助于一个文本框（Text Grid）来定义边界，在文
    /// 本框中划分多个单元格，每个字符占用一个单元，绘制时按从左到右、从上到下的顺序
    /// 依次进行，直到最后一个字符或者占满整个文本框（之后的字符将被忽略，因此定义文
    /// 本框的大小时应该注意到是否可以容纳整个文本），绘制文本的颜色使用全局颜色列表，
    /// 没有则可以使用一个已经保存的前一个颜色列表。另外，图形文本扩展块也属于图形块
    /// (Graphic Rendering Block)，可以在它前面定义图形控制扩展对它的表现形式进一步修改。
    /// </summary>
    internal struct PlainTextEx
    {

        #region 结构字段       

        /// <summary>
        /// Block Size - 块大小，固定值12
        /// </summary>
        internal static readonly byte BlockSize = 0X0C;

        /// <summary>
        /// Text Glid Left Posotion - 像素值，文本框离逻辑屏幕的左边界距
        /// </summary>
        internal short XOffSet;

        /// <summary>
        /// Text Glid Top Posotion - 像素值，文本框离逻辑屏幕的上边界距离
        /// </summary>
        internal short YOffSet;

        /// <summary>
        /// 文本框高度 Text Glid Width -像素值
        /// </summary>
        internal short Width;

        /// <summary>
        /// 文本框高度 Text Glid Height - 像素值
        /// </summary>
        internal short Height;

        /// <summary>
        /// 字符单元格宽度 Character Cell Width - 像素值，单个单元格宽度
        /// </summary>
        internal byte CharacterCellWidth;

        /// <summary>
        /// 字符单元格高度 Character Cell Height- 像素值，单个单元格高度
        /// </summary>
        internal byte CharacterCellHeight;

        /// <summary>
        /// 文本前景色索引 Text Foreground Color Index - 前景色在全局颜色列表中的索引
        /// </summary>
        internal byte ForegroundColorIndex;

        /// <summary>
        /// 文本背景色索引 Text Blackground Color Index - 背景色在全局颜色列表中的索引
        /// </summary>
        internal byte BgColorIndex;

          /// <summary>
        /// 文本数据块集合Plain Text Data - 一个或多个数据块(Data Sub-Blocks)组成，保存要在显示的字符串。
        /// </summary>
        internal List<string> TextDatas;
  
       #endregion    

        #region 方法函数
        internal byte[] GetBuffer()
        {
            List<byte> list = new List<byte>();
            list.Add(GifExtensions.ExtensionIntroducer);
            list.Add(GifExtensions.PlainTextLabel);
            list.Add(BlockSize);
            list.AddRange(BitConverter.GetBytes(XOffSet));
            list.AddRange(BitConverter.GetBytes(YOffSet));
            list.AddRange(BitConverter.GetBytes(Width));
            list.AddRange(BitConverter.GetBytes(Height));
            list.Add(CharacterCellWidth);
            list.Add(CharacterCellHeight);
            list.Add(ForegroundColorIndex);
            list.Add(BgColorIndex);
            if (TextDatas != null)
            {
                foreach (string text in TextDatas)
                {
                    list.Add((byte)text.Length);
                    foreach (char c in text)
                    {
                        list.Add((byte)c);
                    }
                }
            }
            list.Add(GifExtensions.Terminator);
            return list.ToArray();
        }
        #endregion
    }
    #endregion
}