trasparent panel with solid border - delphi

Question

Below is a transparent panel vcl
it works.
but I hope to draw solid border(other parts are still transparent)
Is there any hint?
Your comment welcome
unit aframek;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
ExtCtrls;
type
TAframekStyle = (
gsBlackness, gsDstInvert, gsMergeCopy, gsMergePaint, gsNotSrcCopy,
gsNotSrcErase, gsPatCopy, gsPatInvert, gsPatPaint, gsSrcAnd,
gsSrcCopy, gsSrcErase, gsSrcInvert, gsSrcPaint, gsWhiteness);
TAframek = class(TCustomControl)
private
FColor: TColor;
FStyle: TAframekStyle;
FOnPaint: TNotifyEvent;
procedure SetColor(Value: TColor);
procedure SetStyle(Value: TAframekStyle);
procedure CMCtl3DChanged(var Message: TMessage); message CM_CTL3DCHANGED;
procedure WMEraseBkgnd(var Message: TMessage); message WM_ERASEBKGND;
procedure WMWindowPosChanging(var Message: TWMWindowPosChanging); message WM_WINDOWPOSCHANGING;
protected
Buffer: TBitmap;
procedure CreateParams(var Params: TCreateParams); override;
procedure Paint; override;
procedure Resize; override;
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
property Canvas;
published
property Align;
property Anchors;
property AutoSize;
property BiDiMode;
property BorderWidth;
property Color: TColor read FColor write SetColor;
property Ctl3D;
property Enabled;
property Style: TAframekStyle read FStyle write SetStyle default gsSrcAnd;
property Visible;
property OnClick;
property OnDblClick;
property OnEnter;
property OnExit;
property OnMouseDown;
property OnMouseMove;
property OnMouseUp;
property OnResize;
property OnPaint: TNotifyEvent read FOnPaint write FOnPaint;
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('aka', [TAframek]);
end;
function AframekStyleToInt(gs: TAframekStyle): LongInt;
begin
case gs of
gsBlackness : Result := cmBlackness;
gsDstInvert : Result := cmDstInvert;
gsMergeCopy : Result := cmMergeCopy;
gsMergePaint : Result := cmMergePaint;
gsNotSrcCopy : Result := cmNotSrcCopy;
gsNotSrcErase: Result := cmNotSrcErase;
gsPatCopy : Result := cmPatCopy;
gsPatInvert : Result := cmPatInvert;
gsPatPaint : Result := cmPatPaint;
gsSrcAnd : Result := cmSrcAnd;
gsSrcCopy : Result := cmSrcCopy;
gsSrcErase : Result := cmSrcErase;
gsSrcInvert : Result := cmSrcInvert;
gsSrcPaint : Result := cmSrcPaint;
gsWhiteness : Result := cmWhiteness;
else Assert(True, 'Error parameter in function AframeStyleToInt');
end;
end;
constructor TAframek.Create(AOwner: TComponent);
var
FMarkBrush: LOGBRUSH;
FMarkPen: HPEN;
FPenStyle: array[0..1] of Integer;
FStartAngle: Single;
begin
inherited Create(AOwner);
Buffer := TBitmap.Create;
ControlStyle := [csAcceptsControls, csCaptureMouse, csClickEvents,
csDoubleClicks, csReplicatable];
Width := 100;
Height := 100;
FStyle := gsSrcAnd;
ParentCtl3d := False;
Ctl3D := False;
ParentColor := False;
FColor := clWhite;
end;
destructor TAframek.Destroy;
begin
Buffer.Free;
inherited Destroy;
end;
procedure TAframek.Paint;
var
R: TRect;
rop: LongInt;
begin
R := Rect(0, 0, Width, Height);
Buffer.Width := Width;
Buffer.Height := Height;
Buffer.Canvas.Brush.Style := bsSolid;
Buffer.Canvas.Brush.Color := FColor;
Buffer.Canvas.FillRect(Rect(0, 0, Width, Height));
rop := AframekStyleToInt(FStyle);
StretchBlt(Buffer.Canvas.Handle, 0, 0, Width, Height,
Canvas.Handle, 0, 0, Width, Height, rop);
if Ctl3D then DrawEdge(Buffer.Canvas.Handle, R, BDR_RAISEDINNER, BF_RECT);
Buffer.Canvas.Pen.Mode := pmCopy;
Buffer.Canvas.Pen.Style := psSolid;
Canvas.Draw(0, 0, Buffer);
if Assigned(FOnPaint) then FOnPaint(Self);
end;
procedure TAframek.SetColor(Value: TColor);
begin
if Value <> FColor then
begin
FColor := Value;
RecreateWnd;
end;
end;
procedure TAframek.CreateParams(var Params: TCreateParams);
begin
inherited CreateParams(Params);
Params.ExStyle := Params.ExStyle + WS_EX_TRANSPARENT;
end;
procedure TAframek.WMWindowPosChanging(var Message: TWMWindowPosChanging);
begin
Invalidate;
inherited;
end;
procedure TAframek.WMEraseBkgnd(var Message: TMessage);
begin
Message.Result := 0;
end;
procedure TAframek.Resize;
begin
Invalidate;
inherited;
end;
procedure TAframek.CMCtl3DChanged(var Message: TMessage);
begin
inherited;
RecreateWnd;
end;
procedure TAframek.SetStyle(Value: TAframekStyle);
begin
if Value <> FStyle then
begin
FStyle := Value;
RecreateWnd;
end;
end;
end.

Answer 1

Looks like you did not draw the border excepting the case Ctrl3D property is True. But it gets False in constructor :)
If you want to draw the border in your own way, try to call TCanvas.Rectangle or TCanvas.FrameRect in Paint method after TCanvas.FillRect.