using scanline to rotate bitmap in borland c++ builder

scanline属性,适合初学者进行学习研究，不错的源码-scanline property, suitable for beginners to learn research, a good source

procedure GrayScale(const Image:TImage) var BytesPerScan: Integer iWidth, iHeight: Integer pScanLine: pByteArray R,G,B: Byte begin try BytesPerScan := Abs(Integer(Image.Picture.Bitmap.ScanLine[1])- In