让一个控件透明，可以看到背面下的图？

[panjinfu80]

现有一个矢量控件，再放有一个IMAGE 控件，想让矢量控件透明，看到IMAGE的图片，请问怎么才能让前面的控件（矢量控件）透明，或者用别的办法实现两样的办法即可。

[budded]

看看我的Panel如何透明吧~
{******************************************************************************}
{ @UnitName : uTransPanel,pas }
{ @Project : Budded Software Studio }
{ @Copyright : Budded Software Studio }
{ @Author : Budded }
{ @Description : 透明 Panel }
{ @FileVersion : 1.0.0.0 }
{ @CreateDate : 2005-08-24 }
{ @Comment : 单元评论（代码审查结论） }
{ @LastUpdate : Budded, 2005-08-24 }
{ @History : Created By Budded, 2005-08-24 10:20 }
{******************************************************************************}

unit uTransPanel;

interface

uses
Windows, Messages, SysUtils, Graphics, Classes, Controls, ExtCtrls, Buttons;

type
TTransMode = (tmNone, tmSRCCOPY, tmSRCPAINT, tmSRCAND, tmSRCINVERT, tmSRCERASE,
tmNOTSRCCOPY, tmNOTSRCERASE, tmMERGECOPY, tmMERGEPAINT,
tmPATCOPY, tmPATPAINT, tmPATINVERT, tmDSTINVERT, tmBLACKNESS, tmWHITENESS);

TTransPanel = class(TPanel)
private
{ Private declarations }
FTransMode: TTransMode;

procedure CMCtl3DChanged(var Message: TMessage); message CM_CTL3DCHANGED;
procedure WMEraseBkgnd(var Message: TMessage); message WM_ERASEBKGND;
procedure WMWindowPosChanging(var Message: TWMWindowPosChanging); message WM_WINDOWPOSCHANGING;
function GetTransModeEx: Integer;
protected
{ Protected declarations }
Buffer: TBitmap;
procedure CreateParams(var Params: TCreateParams); override;
procedure Paint; override;
procedure Resize; override;
public
{ Public declarations }
constructor Create(AOwner: TComponent); override;
destructor Destroy(); override;
property TransModeEx: Integer read GetTransModeEx;
published
{ Published declarations }
property TransMode: TTransMode read FTransMode write FTransMode default tmSRCCOPY;
end;

procedure Register;

implementation

procedure Register;
begin
RegisterComponents('Budded', [TTransPanel]);
end;

{ TTransPanel }

procedure TTransPanel.CMCtl3DChanged(var Message: TMessage);
begin
inherited;
RecreateWnd;
end;

constructor TTransPanel.Create(AOwner: TComponent);
begin
inherited;
Buffer := TBitmap.Create;
FTransMode := tmSRCCOPY;
end;

procedure TTransPanel.CreateParams(var Params: TCreateParams);
begin
inherited;
Params.ExStyle := Params.ExStyle + WS_EX_TRANSPARENT;
end;

destructor TTransPanel.Destroy;
begin
if Assigned(Buffer) then
Buffer.Free;
inherited;
end;

function TTransPanel.GetTransModeEx: Integer;
begin
Result := 0;
case TransMode of //case
tmNone: Result := 0;
tmSRCCOPY: Result := SRCCOPY;
tmSRCPAINT: Result := SRCPAINT;
tmSRCAND: Result := SRCAND;
tmSRCINVERT: Result := SRCINVERT;
tmSRCERASE: Result := SRCERASE;
tmNOTSRCCOPY: Result := NOTSRCCOPY;
tmNOTSRCERASE: Result := NOTSRCERASE;
tmMERGECOPY: Result := MERGECOPY;
tmMERGEPAINT: Result := MERGEPAINT;
tmPATCOPY: Result := PATCOPY;
tmPATPAINT: Result := PATPAINT;
tmPATINVERT: Result := PATINVERT;
tmDSTINVERT: Result := DSTINVERT;
tmBLACKNESS: Result := BLACKNESS;
tmWHITENESS: Result := WHITENESS;
end; // end case
end;

procedure TTransPanel.Paint;
var
Rect: TRect;
TopColor, BottomColor: TColor;

procedure AdjustColors(Bevel: TPanelBevel);
begin
TopColor := clBtnHighlight;
if Bevel = bvLowered then TopColor := clBtnShadow;
BottomColor := clBtnShadow;
if Bevel = bvLowered then BottomColor := clBtnHighlight;
end;

begin
// inherited;

Rect := ClientRect;//Rect(0, 0, Width, Height);
Buffer.Width := Width;
Buffer.Height := Height;
Buffer.Canvas.Brush.Style := bsSolid;
Buffer.Canvas.Brush.Color := Color;
Buffer.Canvas.FillRect(Rect);
StretchBlt(Buffer.Canvas.Handle, 0, 0, Width, Height,
Canvas.Handle, 0, 0, Width, Height, TransModeEx);

if Ctl3D then DrawEdge(Buffer.Canvas.Handle, Rect, BDR_RAISEDINNER, BF_RECT);

if BevelOuter <> bvNone then
begin
AdjustColors(BevelOuter);
Frame3D(Buffer.Canvas, Rect, TopColor, BottomColor, BevelWidth);
end;
if BevelInner <> bvNone then
begin
AdjustColors(BevelInner);
Frame3D(Buffer.Canvas, Rect, TopColor, BottomColor, BevelWidth);
end;

Buffer.Canvas.Pen.Mode := pmCopy;
Buffer.Canvas.Pen.Style := psSolid;

Canvas.Draw(0, 0, Buffer);
end;

procedure TTransPanel.Resize;
begin
inherited;
end;

procedure TTransPanel.WMEraseBkgnd(var Message: TMessage);
begin
Message.Result := 0;
end;

procedure TTransPanel.WMWindowPosChanging(var Message: TWMWindowPosChanging);
begin
Invalidate;
inherited;
end;

end.

[liangyong007a]

一堆代码啊，随便把原理说说看代码就容易了。现在的程序员越来越懒了……

[飞天揽月]

panel 本身是可以透明的 设置一下

[panjinfu80]

想了很久了
没有什么好的办法

[panjinfu80]

绘制透明位图的代码
procedure DrawTrans(DestCanvas: TCanvas; X,Y: smallint; SrcBitmap:TBitmap; AColor: TColor);
var
ANDBitmap, ORBitmap: TBitmap;
CM: TCopyMode;
Src: TRect;
begin
ANDBitmap:= NIL;
ORBitmap:= NIL;
try
ANDBitmap:= TBitmap.Create;
ORBitmap:= TBitmap.Create;
Src := Bounds(0,0, SrcBitmap.Width, SrcBitmap.Height);
with ORBitmap do
begin
Width:= SrcBitmap.Width;
Height:= SrcBitmap.Height;
Canvas.Brush.Color := clBlack;
Canvas.CopyMode := cmSrcCopy;
Canvas.BrushCopy(Src, SrcBitmap, Src, AColor);
end;
with ANDBitmap do
begin
Width:= SrcBitmap.Width;
Height:= SrcBitmap.Height;
Canvas.Brush.Color := clWhite;
Canvas.CopyMode := cmSrcInvert;
Canvas.BrushCopy(Src, SrcBitmap, Src, AColor);
end;
with DestCanvas do
begin
CM := CopyMode;
CopyMode := cmSrcAnd;
Draw(X,Y, ANDBitmap);
CopyMode := cmSrcPaint;
Draw(X,Y, ORBitmap);
CopyMode := CM;
end;
finally
ANDBitmap.Free;
ORBitmap.Free;
end;
end;