带图片背景的Panel控件源代码：TImagePanel

带图片背景的Panel控件源代码：TImagePanel

 unit   ImagePanel;

  interface 

 uses  
  Windows, ExtCtrls, Graphics, Classes, Controls;  //  SysUtils

  type  
  TImagePanel  =  class  (TCustomPanel)
    private 
     {   Private declarations   }  
    FPicture : TPicture;
    FTransparent : Boolean;
    FAutoSize : Boolean;

      procedure   PictureChanged(Sender: TObject);
      procedure  SetPicture( const   Value: TPicture);
      procedure  SetAutoSize( const  Value: Boolean);  reintroduce  ;
      procedure  SetTransparent( const   Value: Boolean);
      procedure  SetFont( const   Value: TFont);
      procedure  SetCaption( const   Value: TCaption);
      procedure  SetAlignment( const   Value: TAlignment);
    protected 
     {   Protected declarations   } 
     procedure  Paint();  override  ;
    public 
     {   Public declarations   } 
     constructor  Create(AOwner: TComponent);  override  ;
      destructor  Destroy();  override  ;
    published 
     property  Picture: TPicture  read  FPicture  write   SetPicture;
      property  Transparent: Boolean  read  FTransparent  write  SetTransparent  default   false;
      property  AutoSize: Boolean  read  FAutoSize  write   SetAutoSize;

      property  Font  write   SetFont;
      property  Caption  write   SetCaption;
      property  Alignment  write   SetAlignment;
      {   Published declarations   } 
   end  ;

  procedure   Register;

  implementation 

 procedure   Register;
  begin  
  RegisterComponents(  '  Sunisoft  '  , [TImagePanel]);
  end  ;

  {   TImagePanel   } 

 constructor   TImagePanel.Create(AOwner: TComponent);
  begin 
   inherited   Create(AOwner);

  FPicture: = TPicture.Create();
  FPicture.OnChange : =  PictureChanged;

  Repaint();
  end  ;

  destructor   TImagePanel.Destroy;
  begin  
  FPicture.Free();
  FPicture: = nil  ;

    inherited  ;
  end  ;

  procedure   TImagePanel.Paint;
  const  
  Alignments:   array [TAlignment]  of  Longint =  (DT_LEFT, DT_RIGHT, DT_CENTER);
  var  
  Flags: longint;
  Rect: TRect;
  FontHeight: Integer;
  begin  
  Canvas.Brush.Style : =  bsClear;
  Canvas.Font : =  Font;

    if  Assigned(FPicture.Graphic)  then 
   begin 
     if  FAutoSize  then 
     begin  
      Width : =  FPicture.Width;
      Height : =  FPicture.Height;
      end  ;

      if  FPicture.Graphic.Transparent<> FTransparent  then  
      FPicture.graphic.Transparent : =  FTransparent;

    Canvas.stretchDraw(ClientRect, FPicture.Graphic);
    end 
   else 
   begin  
    Canvas.Brush.Color : =  Color;
    Canvas.FillRect(ClientRect);
    end  ;

    if  Caption<> ''   then 
   begin  
    Rect : =  GetClientRect;
    FontHeight : = Canvas.TextHeight( '  W  '  );

    Rect.Top : = ((Rect.Bottom + Rect.Top) - FontHeight)  div   2  ;
    Rect.Bottom : = Rect.Top +  FontHeight;
    Flags : = DT_EXPANDTABS  or  DT_VCENTER  or   Alignments[Alignment];
    Flags : =  DrawTextBiDiModeFlags(Flags);
    DrawText(Canvas.Handle, PChar(Caption),  - 1  , Rect, Flags);
    end  ;
  end  ;

  procedure   TImagePanel.PictureChanged(Sender: TObject);
  begin  
  Repaint();
  end  ;

  procedure  TImagePanel.SetAlignment( const   Value: TAlignment);
  begin 
   inherited  Alignment :=  Value;
  Repaint();
  end  ;

  procedure  TImagePanel.SetAutoSize( const   Value: Boolean);
  begin  
  FAutoSize : =  Value;
  Repaint();
  end  ;

  procedure  TImagePanel.SetCaption( const   Value: TCaption);
  begin 
   inherited  Caption :=  Value;
  Repaint();
  end  ;

  procedure  TImagePanel.SetFont( const   Value: TFont);
  begin 
   inherited  Font :=  Value;
  Repaint();
  end  ;

  procedure  TImagePanel.SetPicture( const   Value: TPicture);
  begin  
  FPicture.Assign(Value);
  Repaint();
  end  ;

  procedure  TImagePanel.SetTransparent( const   Value: Boolean);
  begin  
  FTransparent : =  Value;
  Repaint();
  end  ;

  end .

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