C#中使用byte[]数据,生成Bitmap
2009-04-21 08:25:55 来源:WEB开发网 闂傚倸鍊搁崐鎼佸磹閹间礁纾归柟闂寸绾惧綊鏌熼梻瀵割槮缁炬儳缍婇弻鐔兼⒒鐎靛壊妲紒鎯у⒔閹虫捇鈥旈崘顏佸亾閿濆簼绨绘い鎺嬪灪閵囧嫰骞囬姣挎捇鏌熸笟鍨妞ゎ偅绮撳畷鍗炍旈埀顒勭嵁婵犲嫮纾介柛灞捐壘閳ь剛鎳撻~婵嬪Ω閳轰胶鐤呯紓浣割儐椤戞瑩宕ョ€n喗鐓曟い鎰靛亝缁舵氨绱撻崘鈺傜婵﹤顭峰畷鎺戔枎閹搭厽袦婵犵數濮崑鎾绘⒑椤掆偓缁夌敻骞嗛悙鍝勭婵烇綆鍓欐俊鑲╃磼閹邦収娈滈柡灞糕偓鎰佸悑閹肩补鈧尙鏁栧┑鐐村灦閹稿摜绮旈悽绋课﹂柛鏇ㄥ灠閸愨偓濡炪倖鍔﹀鈧繛宀婁邯濮婅櫣绱掑Ο璇茶敿闂佺ǹ娴烽弫璇差嚕婵犳碍鏅插璺猴工瀹撳棝姊虹紒妯哄缂佷焦鎸冲畷鎴﹀箻鐠囧弶宓嶅銈嗘尰缁嬫垶绂嶉悙顒佸弿婵☆垳鍘ф禍楣冩倵濮樼偓瀚�

/// <summary>
/// 使用byte[]数据,生成256色灰度 BMP 位图
/// </summary>
/// <param name="originalImageData"></param>
/// <param name="originalWidth"></param>
/// <param name="originalHeight"></param>
/// <returns></returns>
public static Bitmap CreateBitmap(byte[] originalImageData, int originalWidth, int originalHeight)
{
//指定8位格式,即256色
Bitmap resultBitmap = new Bitmap(originalWidth, originalHeight, System.Drawing.Imaging.PixelFormat.Format8bppIndexed);
//将该位图存入内存中
MemoryStream curImageStream = new MemoryStream();
resultBitmap.Save(curImageStream, System.Drawing.Imaging.ImageFormat.Bmp);
curImageStream.Flush();
//由于位图数据需要DWORD对齐(4byte倍数),计算需要补位的个数
int curPadNum = ((originalWidth * 8 + 31) / 32 * 4) - originalWidth;
//最终生成的位图数据大小
int bitmapDataSize = ((originalWidth * 8 + 31) / 32 * 4) * originalHeight;
//数据部分相对文件开始偏移,具体可以参考位图文件格式
int dataOffset = ReadData(curImageStream, 10, 4);
//改变调色板,因为默认的调色板是32位彩色的,需要修改为256色的调色板
int paletteStart = 54;
int paletteEnd = dataOffset;
int color = 0;
for (int i = paletteStart; i < paletteEnd; i += 4)
{
byte[] tempColor = new byte[4];
tempColor[0] = (byte)color;
tempColor[1] = (byte)color;
tempColor[2] = (byte)color;
tempColor[3] = (byte)0;
color++;
curImageStream.Position = i;
curImageStream.Write(tempColor, 0, 4);
}
//最终生成的位图数据,以及大小,高度没有变,宽度需要调整
byte[] destImageData = new byte[bitmapDataSize];
int destWidth = originalWidth + curPadNum;
//生成最终的位图数据,注意的是,位图数据 从左到右,从下到上,所以需要颠倒
for (int originalRowIndex = originalHeight - 1; originalRowIndex >= 0; originalRowIndex--)
{
int destRowIndex = originalHeight - originalRowIndex - 1;
for (int dataIndex = 0; dataIndex < originalWidth; dataIndex++)
{
//同时还要注意,新的位图数据的宽度已经变化destWidth,否则会产生错位
destImageData[destRowIndex * destWidth + dataIndex] = originalImageData[originalRowIndex * originalWidth + dataIndex];
}
}
//将流的Position移到数据段
curImageStream.Position = dataOffset;
//将新位图数据写入内存中
curImageStream.Write(destImageData, 0, bitmapDataSize);
curImageStream.Flush();
//将内存中的位图写入Bitmap对象
resultBitmap = new Bitmap(curImageStream);
return resultBitmap;
}
/// <summary>
/// 从内存流中指定位置,读取数据
/// </summary>
/// <param name="curStream"></param>
/// <param name="startPosition"></param>
/// <param name="length"></param>
/// <returns></returns>
public static int ReadData(MemoryStream curStream, int startPosition, int length)
{
int result = -1;
byte[] tempData = new byte[length];
curStream.Position = startPosition;
curStream.Read(tempData, 0, length);
result = BitConverter.ToInt32(tempData, 0);
return result;
}
/// <summary>
/// 向内存流中指定位置,写入数据
/// </summary>
/// <param name="curStream"></param>
/// <param name="startPosition"></param>
/// <param name="length"></param>
/// <param name="value"></param>
public static void WriteData(MemoryStream curStream, int startPosition, int length, int value)
{
curStream.Position = startPosition;
curStream.Write(BitConverter.GetBytes(value), 0, length);
}
更多精彩
赞助商链接