图片反转

if (_srcBitmap != null) //_srcBitmap = (Bitmap)Image.FromFile(_curFileName)
{
_dstBitmap = (Bitmap)_srcBitmap.Clone();
BitmapData bmpData = _srcBitmap.LockBits(new Rectangle(0, 0, _srcBitmap.Width, _srcBitmap.Height),ImageLockMode.ReadWrite, _srcBitmap.PixelFormat);
BitmapData dstData = _dstBitmap.LockBits(new Rectangle(0, 0, _dstBitmap.Width, _dstBitmap.Height),ImageLockMode.ReadWrite, _dstBitmap.PixelFormat);
unsafe
{
byte* p = (byte*)bmpData.Scan0;
for (int y = 0; y < bmpData.Height; y++)
{
for (int x = 0; x < bmpData.Width; x++)
{
byte* dstp = (byte*)dstData.Scan0 + y * dstData.Stride + x * 3;
dstp[0] = p[bmpData.Width * 3 - (x + 1) * 3];
dstp[1] = p[bmpData.Width * 3 - (x + 1) * 3 + 1];
dstp[2] = p[bmpData.Width * 3 - (x + 1) * 3 + 2];
}
p += bmpData.Stride;    //Stride 为扫描宽度 Stride > bmpData.Width * 3 ,Width 表示每行的像素个数，每个像素占3个byte位
}
_srcBitmap.UnlockBits(bmpData);
_dstBitmap.UnlockBits(dstData);
}
_srcBitmap = (Bitmap)_dstBitmap.Clone();
Invalidate();
}

private void Form1_Paint(object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
if (_srcBitmap != null)
{
g.DrawImage(_srcBitmap, 10, 30, _srcBitmap.Width, _srcBitmap.Height);
}
}

private Bitmap gcTrans(Bitmap bmp, bool method, byte seg)
{
if (bmp != null)
{
if (System.Drawing.Imaging.PixelFormat.Format24bppRgb == bmp.PixelFormat)
{
Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
System.Drawing.Imaging.BitmapData bmpData = bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, bmp.PixelFormat);
IntPtr ptr = bmpData.Scan0;
int bytes = bmp.Width * bmp.Height * 3;
byte[] grayValues = new byte[bytes];
System.Runtime.InteropServices.Marshal.Copy(ptr, grayValues, 0, bytes);
bmp.UnlockBits(bmpData);
byte[] rgbValues = new byte[bytes];
//清零
Array.Clear(rgbValues, 0, bytes);
byte tempB;
if (method == false)
{
//强度分层法
for (int i = 0; i < bytes; i += 3)
{
byte ser = (byte)(256 / seg);
tempB = (byte)(grayValues[i] / ser);
//分配任意一种颜色
rgbValues[i + 1] = (byte)(tempB * ser);
rgbValues[i] = (byte)((seg - 1 - tempB) * ser);
rgbValues[i + 2] = 0;
}
}
else
{
//灰度级-彩色变换法
for (int i = 0; i < bytes; i += 3)
{
if (grayValues[i] < 64)
{
rgbValues[i + 2] = 0;
rgbValues[i + 1] = (byte)(4 * grayValues[i]);
rgbValues[i] = 255;
}
else if (grayValues[i] < 128)
{
rgbValues[i + 2] = 0;
rgbValues[i + 1] = 255;
rgbValues[i] = (byte)(-4 * grayValues[i] + 2 * 255);
}
else if (grayValues[i] < 192)
{
rgbValues[i + 2] = (byte)(4 * grayValues[i] - 2 * 255);
rgbValues[i + 1] = 255;
rgbValues[i] = 0;
}
else
{
rgbValues[i + 2] = 255;
rgbValues[i + 1] = (byte)(-4 * grayValues[i] + 4 * 255);
rgbValues[i] = 0;
}
}
}
bmp = new Bitmap(bmp.Width, bmp.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
bmpData = bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, bmp.PixelFormat);
ptr = bmpData.Scan0;
System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, bytes);
bmp.UnlockBits(bmpData);
return bmp;
}
else
{
return null;
}
}
else
{
return null;
}
}