各位谈谈制作透明控件。

我们看看下面的这一段代码：
TCustomLabel.h
TTextLayout = (tlTop, tlCenter, tlBottom);
TCustomLabel = class(TGraphicControl)
private
    FFocusControl: TWinControl;
    FAlignment: TAlignment;
    FAutoSize: Boolean;
    FLayout: TTextLayout;
    FWordWrap: Boolean;
    FShowAccelChar: Boolean;
    function GetTransparent: Boolean;
    procedure SetAlignment(Value: TAlignment);
    procedure SetFocusControl(Value: TWinControl);
    procedure SetShowAccelChar(Value: Boolean);
    procedure SetTransparent(Value: Boolean);
    procedure SetLayout(Value: TTextLayout);
    procedure SetWordWrap(Value: Boolean);
    procedure CMTextChanged(var Message: TMessage); message CM_TEXTCHANGED;
    procedure CMFontChanged(var Message: TMessage); message CM_FONTCHANGED;
    procedure CMDialogChar(var Message: TCMDialogChar); message CM_DIALOGCHAR;
protected
    procedure AdjustBounds; dynamic;
    procedure DoDrawText(var Rect: TRect; Flags: Longint); dynamic;
    function GetLabelText: string; virtual;
    procedure Loaded; override;
    procedure Notification(AComponent: TComponent;
      Operation: TOperation); override;
    procedure Paint; override;
    procedure SetAutoSize(Value: Boolean); virtual;
    property Alignment: TAlignment read FAlignment write SetAlignment
      default taLeftJustify;
    property AutoSize: Boolean read FAutoSize write SetAutoSize default True;
    property FocusControl: TWinControl read FFocusControl write SetFocusControl;
    property ShowAccelChar: Boolean read FShowAccelChar write SetShowAccelChar default True;
    property Transparent: Boolean read GetTransparent write SetTransparent default False;
    property Layout: TTextLayout read FLayout write SetLayout default tlTop;
    property WordWrap: Boolean read FWordWrap write SetWordWrap default False;
public
    constructor Create(AOwner: TComponent); override;
    property Canvas;
end;
[TCustomLabel.cpp]
constructor TCustomLabel.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  ControlStyle := ControlStyle + [csOpaque, csReplicatable];
  Width := 65;
  Height := 17;
  FAutoSize := True;
  FShowAccelChar := True;
end;function TCustomLabel.GetLabelText: string;
begin
  Result := Caption;
end;procedure TCustomLabel.DoDrawText(var Rect: TRect; Flags: Longint);
var
  Text: string;
begin
  Text := GetLabelText;
  if (Flags and DT_CALCRECT <> 0) and ((Text = '') or FShowAccelChar and
    (Text[1] = '&') and (Text[2] = #0)) then Text := Text + ' ';
  if not FShowAccelChar then Flags := Flags or DT_NOPREFIX;
  Flags := DrawTextBiDiModeFlags(Flags);
  Canvas.Font := Font;
  if not Enabled then
  begin
    OffsetRect(Rect, 1, 1);
    Canvas.Font.Color := clBtnHighlight;
    DrawText(Canvas.Handle, PChar(Text), Length(Text), Rect, Flags);
    OffsetRect(Rect, -1, -1);
    Canvas.Font.Color := clBtnShadow;
    DrawText(Canvas.Handle, PChar(Text), Length(Text), Rect, Flags);
  end
  else
    DrawText(Canvas.Handle, PChar(Text), Length(Text), Rect, Flags);
end;procedure TCustomLabel.Paint;
const
  Alignments: array[TAlignment] of Word = (DT_LEFT, DT_RIGHT, DT_CENTER);
  WordWraps: array[Boolean] of Word = (0, DT_WORDBREAK);
var
  Rect, CalcRect: TRect;
  DrawStyle: Longint;
begin
  with Canvas do
  begin
    if not Transparent then
    begin
      Brush.Color := Self.Color;
      Brush.Style := bsSolid;
      FillRect(ClientRect);
    end;
    Brush.Style := bsClear;
    Rect := ClientRect;
    { DoDrawText takes care of BiDi alignments }
    DrawStyle := DT_EXPANDTABS or WordWraps[FWordWrap] or Alignments[FAlignment];
    { Calculate vertical layout }
    if FLayout <> tlTop then
    begin
      CalcRect := Rect;
      DoDrawText(CalcRect, DrawStyle or DT_CALCRECT);
      if FLayout = tlBottom then OffsetRect(Rect, 0, Height - CalcRect.Bottom)
      else OffsetRect(Rect, 0, (Height - CalcRect.Bottom) div 2);
    end;
    DoDrawText(Rect, DrawStyle);
  end;
end;procedure TCustomLabel.Loaded;
begin
  inherited Loaded;
  AdjustBounds;
end;procedure TCustomLabel.AdjustBounds;
const
  WordWraps: array[Boolean] of Word = (0, DT_WORDBREAK);
var
  DC: HDC;
  X: Integer;
  Rect: TRect;
  AAlignment: TAlignment;
begin
  if not (csReading in ComponentState) and FAutoSize then
  begin
    Rect := ClientRect;
    DC := GetDC(0);
    Canvas.Handle := DC;
    DoDrawText(Rect, (DT_EXPANDTABS or DT_CALCRECT) or WordWraps[FWordWrap]);
    Canvas.Handle := 0;
    ReleaseDC(0, DC);
    X := Left;
    AAlignment := FAlignment;
    if UseRightToLeftAlignment then ChangeBiDiModeAlignment(AAlignment);
    if AAlignment = taRightJustify then Inc(X, Width - Rect.Right);
    SetBounds(X, Top, Rect.Right, Rect.Bottom);
  end;
end;procedure TCustomLabel.SetAlignment(Value: TAlignment);
begin
  if FAlignment <> Value then
  begin
    FAlignment := Value;
    Invalidate;
  end;
end;procedure TCustomLabel.SetAutoSize(Value: Boolean);
begin
  if FAutoSize <> Value then
  begin
    FAutoSize := Value;
    AdjustBounds;
  end;
end;function TCustomLabel.GetTransparent: Boolean;
begin
  Result := not (csOpaque in ControlStyle);
end;procedure TCustomLabel.SetFocusControl(Value: TWinControl);
begin
  FFocusControl := Value;
  if Value <> nil then Value.FreeNotification(Self);
end;procedure TCustomLabel.SetShowAccelChar(Value: Boolean);
begin
  if FShowAccelChar <> Value then
  begin
    FShowAccelChar := Value;
    Invalidate;
  end;
end;procedure TCustomLabel.SetTransparent(Value: Boolean);
begin
  if Transparent <> Value then
  begin
    if Value then
      ControlStyle := ControlStyle - [csOpaque] else
      ControlStyle := ControlStyle + [csOpaque];
    Invalidate;
  end;
end;procedure TCustomLabel.SetLayout(Value: TTextLayout);
begin
  if FLayout <> Value then
  begin
    FLayout := Value;
    Invalidate;
  end;
end;procedure TCustomLabel.SetWordWrap(Value: Boolean);
begin
  if FWordWrap <> Value then
  begin
    FWordWrap := Value;
    AdjustBounds;
    Invalidate;
  end;
end;procedure TCustomLabel.Notification(AComponent: TComponent;
  Operation: TOperation);
begin
  inherited Notification(AComponent, Operation);
  if (Operation = opRemove) and (AComponent = FFocusControl) then
    FFocusControl := nil;
end;procedure TCustomLabel.CMTextChanged(var Message: TMessage);
begin
  Invalidate;
  AdjustBounds;
end;procedure TCustomLabel.CMFontChanged(var Message: TMessage);
begin
  inherited;
  AdjustBounds;
end;procedure TCustomLabel.CMDialogChar(var Message: TCMDialogChar);
begin
  if (FFocusControl <> nil) and Enabled and ShowAccelChar and
    IsAccel(Message.CharCode, Caption) then
    with FFocusControl do
      if CanFocus then
      begin
        SetFocus;
        Message.Result := 1;
      end;
end;
TGraphicControl中没有Transparent属性，Transparent属性是在TCustomLabel中实现，但是在我的代码我按照这种方法却不行。

http://www.snowdeer.net/BBS/dispbbs.asp?boardID=4&RootID=31370&ID=31370

如果这个compounent属于纯粹VCL的组件，应该没有问题啊，你有机会控制他的一切啊。首先是CreateParam方法，然后消息的截获和处理，在适当的时候处理WM_ERASEBKGND这样的消息，以及重载Paint方法，还有SetParent(),Invalidate()等等最终总是可以达到目的的

To cker:
你可能理解错了我的意思，我现在关键问题是要知道透明效果是如何实现的。

直接的办法我不知道，不过投机取巧的办法我倒是有一个：那就是直接把父控件的画面作为一个Bitmap画到子控件的背景上，这样子控件“看起来就象透明了”。

现在主要问题是要实现透明，我的代码：
#ifndef FocusLabelH
#define FocusLabelH
#include <SysUtils.hpp>
#include <Controls.hpp>
#include <Classes.hpp>
#include <Forms.hpp>
class PACKAGE TFocusLabel : public TCustomControl
{
private:
    TLabel *FLabel;
    bool FTransParent;
    bool FAutoSize;
    AnsiString  FCaption;protected:
   virtual void __fastcall CreateWnd();
   virtual void __fastcall Paint();public:
    void __fastcall SetCaption(AnsiString S);
    void __fastcall SetTransParent(bool TransParent);
    bool _fastcall GetTransParent();
    void __fastcall SetSize();
    void __fastcall SetAutoSize(bool AutoSize);
    __fastcall TFocusLabel(TComponent* Owner);
    virtual __fastcall ~TFocusLabel();
__published:
   __property bool TransParent={read=GetTransParent,write=SetTransParent};
   __property bool AutoSize={read=FAutoSize,write=SetAutoSize};
   __property AnsiString Caption={read=FCaption,write=SetCaption};
   __property Color;
};
#endif
.cpp File
//---------------------------------------------------------------------------#include <vcl.h>
#pragma hdrstop#include "FocusLabel.h"
#pragma package(smart_init)
//---------------------------------------------------------------------------
// ValidCtrCheck is used to assure that the components created do not have
// any pure virtual functions.
//static inline void ValidCtrCheck(TFocusLabel *)
{
    new TFocusLabel(NULL);
}
//---------------------------------------------------------------------------
__fastcall TFocusLabel::TFocusLabel(TComponent* Owner)
    : TCustomControl(Owner)
{

    FLabel=new TLabel(this);
    FLabel->Caption="Label1";
    Caption="Label1";
    Width=40;
    Height=20;
    ControlStyle<<csOpaque<<csReplicatable;}
//GetTransParent
bool __fastcall TFocusLabel::GetTransParent()
{
   if(ControlStyle.Contains(csOpaque))
   {
      return false;
   }
   else
   {
      return true;
   }}
//SetTransParent
void __fastcall TFocusLabel::SetTransParent(bool TransParent)
{
    FTransParent=TransParent; //这些实现透明效果的代码没有起到作用
    FLabel->Transparent=TransParent;
    if(TransParent)
    {
        ControlStyle>>csOpaque;
    }
    else
    {
        ControlStyle<<csOpaque;
    }
    Invalidate();
}
//CreateWnd Method
void __fastcall TFocusLabel::CreateWnd()
{
    TCustomControl::CreateWnd();
}
//Paint Method
void __fastcall TFocusLabel::Paint()
{
    SetSize();
    FLabel->Parent=this;
    FLabel->Left=0;
    FLabel->Top=0;
    FLabel->Transparent=TransParent;
    if(TransParent)       //whether the controls is transparent or not.
    {
       long DrawStyle;
       Canvas->Brush->Color=Color;
       Canvas->Brush->Style=bsClear;
    }
    else
    {
        Canvas->Brush->Color=Color;
        Canvas->Brush->Style=bsSolid;
        Canvas->FillRect(ClientRect);
    }
}
//SetCaption
void __fastcall TFocusLabel::SetCaption(AnsiString S)
{
    FCaption=S;
    FLabel->Caption=S;
}
//SetSize
void __fastcall TFocusLabel::SetSize()
{
    if(FAutoSize)
    {
        Canvas->Font=Font;
        Width=Canvas->TextWidth(Caption)+20;
        Height=Canvas->TextHeight(Caption)+30;
        FLabel->Width=Canvas->TextWidth(Caption)+20;
        FLabel->Height=Canvas->TextHeight(Caption)+30;    }
}
//SetAutoSize
void __fastcall TFocusLabel::SetAutoSize(bool AutoSize)
{
    FAutoSize=AutoSize;
    FLabel->AutoSize=AutoSize;
    if(FAutoSize)
    {
        SetSize();
        Repaint();
    }
}//Deconstructor
__fastcall TFocusLabel::~TFocusLabel()
{
    if(FLabel)
    {
        delete FLabel;
    }
}namespace Focuslabel
{
    void __fastcall PACKAGE Register()
    {
         TComponentClass classes[1] = {__classid(TFocusLabel)};
         RegisterComponents("AKing", classes, 0);
    }
}
如果从TLabel的继承层次来看，首先查看TGraphicControl，它并没有Transparent属性，TrasnParent属性是在TCustomLabel中实现的，但我在代码中按照它的实现方法，并不能成功，有人能解释一下原因吗？

http://www.snowdeer.net/BBS/dispbbs.asp?boardID=4&RootID=31370&ID=31370

1.重载 CreateParams
Procedure TYourWinControl.CreateParams( Var params: TCreateParams );
begin
  inherited CreateParams( params );
  params.ExStyle := params.ExStyle  or WS_EX_TRANSPARENT;
end;2.重载 WMEraseBkGnd
Procedure WMEraseBkGnd( Var msg: TWMEraseBkGnd );message WM_ERASEBKGND;Procedure TYourWinControl.WMEraseBkGnd( Var msg: TWMEraseBkGnd );
begin
  SetBkMode( msg.DC, TRANSPARENT );
  msg.result := 1;
end;

unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics,
  Controls, Forms, Dialogs,StdCtrls, ExtCtrls, Buttons;type
  TForm1 = class(TForm)
    Label1: TLabel;
    Shape1: TShape;
    Shape2: TShape;
    Shape3: TShape;
    Shape4: TShape;
    Image1: TImage;
    SpeedButton1: TSpeedButton;
    procedure FormCreate(Sender: TObject);
    procedure SpeedButton1Click(Sender: TObject);
  private
    { Private declarations }
    //截获背景图像
    function  GetBackgroundBmp:TBitmap;
    //对背景图像进行滤镜处理
procedure TranslucentBmp(Bmp:TBitmap;
AColor:TColor;ATransparent:Longint);
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{＄R ＊.DFM}
//以下截获背景图像
function TForm1.GetBackgroundBmp:TBitmap;
var Scn:TCanvas;
h,w:Integer;
begin
Scn:=TCanvas.Create; //建立整个屏幕的画布
h:=ClientHeight;     //窗口的高
w:=ClientWidth;      //窗口的宽
Result.Height:=h;    //设返回位图的高就是窗口的高
Result.Width:=w;     //设返回位图的宽就是窗口的宽
try
Scn.Handle:=GetDC(0);//取得整个屏幕的DC
//以下一行将窗口的背景部分复制到指定的
//画布中，也就是本函数的返回值
     Result.Canvas.CopyRect(Rect(0,0,w,h),
      Scn,Rect(Left,Top,Left＋w,Top＋h));
     ReleaseDC(0, Scn.handle);
     finally
     Scn.Free;
     end;
end;//以下函数对背景图像进行滤镜处理，
//Bmp是要处理的位图；ATransparent是透明度
procedure TForm1.TranslucentBmp
(Bmp:TBitmap;AColor:TColor;ATransparent:Longint);
var BkColor:COLORREF;
    ForeColor:Longint;
    R,G,B:Int64;
    i,j:Integer;
begin
     ForeColor:=ColorToRGB(AColor);
     with Bmp.Canvas do
     for i:=ClientHeight－1 downto 0 do
        for j:=ClientWidth－1 downto 0 do
        begin
           BkColor:=GetPixel(Handle,j,i); //取得每一像素
           R:=Byte(ForeColor)＋(Byte(BkColor)
           －Byte(ForeColor))＊ATransparent;
           G:=Byte(ForeColor shr 8)＋(Byte
           (BkColor shr 8)－Byte(ForeColor shr 8))
             ＊ATransparent;
           B:=Byte(ForeColor shr 16)＋(Byte
              (BkColor shr 16)
            －Byte(ForeColor shr 16))＊ATransparent;
           SetPixelV(Handle,j,i,RGB(R,G,B));//合成像素
        end;
end;procedure TForm1.FormCreate(Sender: TObject);
var BackgroundBmp:TBitmap;
begin
     try
     BackgroundBmp:=Tbitmap.Create;
       //建立窗口背景图
   BackgroundBmp.PixelFormat:=pf24bit;
      //指定该图是24位真彩色
BackgroundBmp:=GetBackgroundBmp;
//取得窗口背景图
     TranslucentBmp(BackgroundBmp,clBlack,50);
     //对该图像进行滤镜处理
Image1.Picture.Bitmap:=BackgroundBmp;
//将处理过的图像显示出来
     finally
     BackgroundBmp.Free;
     end;
end;procedure TForm1.SpeedButton1Click(Sender: TObject);
begin
     Close;
end;end.
最好能调用MMX进行优化!

调试易

各位谈谈制作透明控件。

解决方案 »