请问一下在一张图中如何判断颜色是白色的部分的范围,赶着要,谢谢了啊

function CompareColor(mColorA, mColorB: TColor): Integer;
begin
mColorA := ColorToRGB(mColorA);
mColorB := ColorToRGB(mColorB);
Result := Abs(GetRValue(mColorA) - GetRValue(mColorB)) +
Abs(GetGValue(mColorA) - GetGValue(mColorB)) +
Abs(GetBValue(mColorA) - GetBValue(mColorB));
Result := Result div 3;
end; { CompareColor }

procedure TForm1.TrackBar1Change(Sender: TObject);
var
I: Integer;
begin
Color := RGB(TrackBar1.Position, TrackBar2.Position, TrackBar3.Position);
if CompareColor(clWhite, Color) <= 10 then
Caption := '白色相近'
else Caption := '';
end;
//Demo
if CompareColor()

UP.