/// <summary>
/// 慢于 bitmap.Save(XX,ImageFormat.Bmp)，只是为了解释BMP文件数据格式
/// </summary>
/// <param name="bitmap"></param>
public BmpFile(Bitmap bitmap)
{
head = new BmpHead();
head.Init(bitmap);
data = new byte[head.FileSize];
Array.Copy(head.StructToBytes(), 0, data, 0, (int)head.BitmapDataOffset);
var sourceArea = new Rectangle(0, 0, bitmap.Width, bitmap.Height);
var bitmapData = bitmap.LockBits(sourceArea, ImageLockMode.ReadOnly, PixelFormat.Format32bppPArgb);
byte[] tmp = new byte[bitmap.Width * bitmap.Height * 4];
Marshal.Copy(bitmapData.Scan0, tmp, 0, tmp.Length);
bitmap.UnlockBits(bitmapData);
//BMP文件的数据从左下角开始，每行向上。System.Drawing.Bitmap数据是从左上角开始，每行向下
int idx = (int)head.BitmapDataOffset;
for (int i = 0; i < bitmap.Height; i++)
{
int offset = bitmap.Height - 1 - i;
offset *= bitmap.Width * 4;
for (int j = 0; j < bitmap.Width; j++)
{
Array.Copy(tmp, offset + j * 4, Data, idx, 3);
idx += 3;
}
idx += bitmap.Width % 4;
}
}
/// <summary>
/// 从图像数据创建Bmp图片
/// </summary>
/// <param name="width">宽度</param>
/// <param name="height">高度</param>
/// <param name="bmpData">数据，从左上角开始，为每个点的B、G、R循环</param>
public BmpFile(int width, int height, byte[] bmpData)
{
head = new BmpHead();
head.Init(width, height);
data = new byte[head.FileSize];
Array.Copy(head.StructToBytes(), 0, data, 0, (int)head.BitmapDataOffset);
if (bmpData.Length != width * height * 3)
{
return;
}
//BMP文件的数据从左下角开始，每行向上。System.Drawing.Bitmap数据是从左上角开始，每行向下
int idx = (int)head.BitmapDataOffset;
for (int i = 0; i < height; i++)
{
int offset = height - 1 - i;
offset *= width * 3;
Array.Copy(bmpData, offset, data, idx, width * 3);
idx += width * 3;
}
}