void __fastcall TForm1::Button4Click(TObject *Sender)
{
 if (Image1->Picture->Bitmap->Empty==true)
 ShowMessage("請載入圖檔!!");
 Graphics::TBitmap *Bmp = new Graphics::TBitmap();
 Byte *ptr;
 int r,g,b;
 int gray;
 int i,j;
 int threshold;
 threshold=ScrollBar1->Position;
 Edit1->Text=ScrollBar1->Position;
 Bmp->Assign(Image1->Picture->Bitmap);
 for(j=0;jHeight;j  )
 {
  ptr = (Byte *)Bmp->ScanLine[j];
  for(i=0;iWidth;i  )
  {
   b=ptr[i*3];
   g=ptr[i*3 1];
   r=ptr[i*3 2];
   gray=0.299*r  0.587*g 0.114*b;
   
   if(gray>threshold)
    gray=255;
   else
    gray=0;       ptr[i*3]=(Byte)gray;
   ptr[i*3 1]=(Byte)gray;
   ptr[i*3 2]=(Byte)gray;
  }
 }
Image2->Picture->Assign(Bmp);
}

引言: 大部分處理圖形都是以24bit為基準吧?