unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ExtCtrls, StdCtrls;
type
TPanel = Class(ExtCtrls.TPanel)
private
FAspectRatio: TPoint;
procedure SetAspectRatio(const Value: TPoint);
public
constructor Create(AOwner: TComponent); override;
procedure SetBounds(ALeft, ATop, AWidth, AHeight: Integer); override;
property AspectRatio: TPoint read FAspectRatio write SetAspectRatio;
end;
TForm1 = class(TForm)
Panel1: TPanel;
Button1: TButton;
Button2: TButton;
Button3: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
{ TPanel }
constructor TPanel.Create(AOwner: TComponent);
begin
inherited;
FAspectRatio.X := 4;
FAspectRatio.Y := 3;
end;
procedure TPanel.SetAspectRatio(const Value: TPoint);
begin
FAspectRatio := Value;
AdjustSize;
end;
procedure TPanel.SetBounds(ALeft, ATop, AWidth, AHeight: Integer);
var
vh: Double;
begin
if FAspectRatio.Y <> 0 then
begin
vh := FAspectRatio.X / FAspectRatio.Y;
if Round(AHeight * vh) <> AWidth then
begin
if AWidth <> Width then
AHeight := Round(AWidth / vh)
else
AWidth := Round(AHeight * vh);
end;
end;
inherited;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
Panel1.Width := 101;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
Panel1.Height := 101;
end;
procedure TForm1.Button3Click(Sender: TObject);
var
p: TPoint;
begin
p.X := 5;
p.Y := 3;
Panel1.AspectRatio := p;
end;
end.
覆盖 Setbounds 将确保保持给定的 AspectRatio。
AspectRatio 的 Setter 中的 AdjustSize 将确保立即应用 AspectRatio 的更改。
按钮事件仅用于演示。