//下面四种赋值方法相同
procedure TForm1.Button1Click(Sender: TObject);
begin
  Rectangle1.Fill.Color := $FFFF0000;
  Rectangle1.Fill.Color := claRed;
  Rectangle1.Fill.Color := TAlphaColors.Red;
  Rectangle1.Fill.Color := TAlphaColorRec.Red;
end;

//通过函数构建 TAlphaColor
procedure TForm1.Button2Click(Sender: TObject);
begin
  Rectangle1.Fill.Color := MakeColor(0, 0, 255);
  //另有 AppendColor()、SubtractColor() 等颜色加减或转换函数
end;

//通过 TAlphaColorRec 结构调整颜色获取或设置颜色分量
procedure TForm1.Button3Click(Sender: TObject);
var
  C: TAlphaColor;
  A,R,G,B: Byte;
begin
  C := MakeColor($82, $00, $4B, $FF);
  Rectangle1.Fill.Color := C;

  A := TAlphaColorRec(C).A;
  R := TAlphaColorRec(C).R;
  G := TAlphaColorRec(C).G;
  B := TAlphaColorRec(C).B;
  ShowMessageFmt('%x %x %x %x', [A, R, G, B]);

  TAlphaColorRec(C).A := 127; //调下透明度
  Rectangle1.Fill.Color := C;
  A := TAlphaColorRec(C).A;
  ShowMessageFmt('%x %x %x %x', [A, R, G, B]);
end;

//在 TColorComboBox 的 OnChange 中修改颜色
procedure TForm1.ColorComboBox1Change(Sender: TObject);
begin
  Rectangle1.Fill.Color := ColorComboBox1.Color;
end;

//在 TColorPanel 的 OnChange 中修改颜色
procedure TForm1.ColorPanel1Change(Sender: TObject);
begin
  Rectangle1.Fill.Color := ColorPanel1.Color;
end;

//在 TColorPicker 的 OnChange 中修改颜色
procedure TForm1.ColorPicker1Click(Sender: TObject);
begin
  Rectangle1.Fill.Color := ColorPicker1.Color;
end;

//在 TComboColorBox 的 OnChange 中修改颜色
procedure TForm1.ComboColorBox1Change(Sender: TObject);
begin
  Rectangle1.Fill.Color := ComboColorBox1.Color;
end;

//通过 TColorQuad 调整 HSL(色调、饱和度、亮度)
procedure TForm1.ColorQuad1Change(Sender: TObject);
var
  C: TAlphaColor;
begin
  C := Rectangle1.Fill.Color;
  Rectangle1.Fill.Color := ChangeHSL(C, ColorQuad1.Hue, ColorQuad1.Sat, ColorQuad1.Lum);
  Caption := Format('%f, %f, %f', [ColorQuad1.Hue, ColorQuad1.Sat, ColorQuad1.Lum]);
end;