关于Delphi XE的快速问题。
我正在尝试制作一个具有透明背景的自定义圆形组件,以便在添加到窗体上时,该组件可以与其他组件重叠。我已经尝试了Brush.Style:=bsTransparent;
或ellipse()
以及更多...但仍然找不到使边缘区域透明的方法。
无论如何,我可以在不使用其他库或 API 的情况下使组件的边缘区域透明吗?
好吧,这里有一个快速的答案,应该让你开始。
type
TEllipticPanel = class(Vcl.ExtCtrls.TPanel)
procedure CreateWnd; override;
procedure Paint; override;
procedure Resize; override;
procedure RecreateHRGN;
end;
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
private
{ Private declarations }
panl: TEllipticPanel;
public
{ Public declarations }
end;
implementation
procedure TForm1.FormCreate(Sender: TObject);
begin
panl := TEllipticPanel.Create(self);
panl.Left := 10;
panl.Top := 10;
panl.Width := 100;
panl.Height := 50;
panl.ParentBackground := False;
panl.ParentColor := False;
panl.Color := clYellow;
panl.Parent := self;
end;
{ TEllipticPanel }
procedure TEllipticPanel.RecreateHRGN;
var
hr: hRgn;
begin
inherited;
hr := CreateEllipticRgn(0,0,Width,Height);
SetWindowRgn(Handle, hr, True);
end;
procedure TEllipticPanel.CreateWnd;
begin
inherited;
RecreateHRGN;
end;
procedure TEllipticPanel.Paint;
begin
inherited;
Canvas.Brush.Style := bsClear;
Canvas.Pen.Style := TPenStyle(psSolid);
Canvas.Pen.Width := 1;
Canvas.Pen.Color := clGray;
Canvas.Ellipse(1,1,Width-2,Height-2);
end;
procedure TEllipticPanel.Resize;
begin
inherited;
RecreateHRGN;
end;
关键是Windows CreateEllipticRgn和GDI SetWindowRgn函数。
有关窗口区域的详细信息,请参阅区域。