一、Byte[] 转 System.Drawing.Bitmap
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;
}
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;
}