/*
The GetFormImage allows you to easily obtain a bitmap of a
form. The following method can be added to a custom
TWinControl descendant to save itself as a bitmap.  Check the
produced BMP file to confirm.  Click the button and them
double click on the newly created foo.bmp file to view.
*/

#include <memory>       //for STL auto_ptr class

class TMyControl : public TColorListBox
{
__published:    // IDE-managed Components
    void __fastcall SaveAsBmp(TFileName fileName);
private:    // User declarations
public:     // User declarations
    __fastcall TMyControl(TComponent* Owner);
};

TForm1 *Form1;
TMyControl *MyControl1;

__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{
}

__fastcall TMyControl::TMyControl(TComponent* Owner)
    : TColorListBox(Owner)
{
}

typedef struct {
  TLogPalette lpal;
  TPaletteEntry dummy[256];
} LogPal;

void __fastcall TMyControl::SaveAsBmp(TFileName fileName)
{
  std::auto_ptr<TCanvas> tempCanvas(new TCanvas);
  HWND notUsed;
  tempCanvas->Handle = GetDeviceContext(notUsed);
  std::auto_ptr<TImage> image2save(new TImage(Form1)); // The owner will clean this up.
  image2save->Height = Height;
  image2save->Width = Width;
  TRect destRect = Rect(0,0,Width,Height);
  TRect sourceRect = destRect;
  image2save->Canvas->CopyRect(destRect, tempCanvas.get(), sourceRect);
  LogPal SysPal;
  SysPal.lpal.palVersion = 0x300;
  SysPal.lpal.palNumEntries = 256;
  GetSystemPaletteEntries(tempCanvas->Handle,0,256,SysPal.lpal.palPalEntry);
  image2save->Picture->Bitmap->Palette =
    CreatePalette(dynamic_cast<const tagLOGPALETTE *>(&SysPal.lpal));
  image2save->Picture->SaveToFile(fileName);
}

void __fastcall TForm1::Button1Click(TObject *Sender)
{
  static_cast<TMyControl*>(MyControl1)->SaveAsBmp("../foo.bmp");
}

void __fastcall TForm1::FormCreate(TObject *Sender)
{
  TMyControl* control = new TMyControl(Form1); // The owner will clean this up.
  
  MyControl1 = control;
  control->Parent = this;
  control->Visible = true;
}

{
The GetFormImage allows you to easily obtain a bitmap of a
form. The following method can be added to a custom
TWinControl descendant to save itself as a bitmap.  Check the
produced BMP file to confirm.  Click the button and then
double click on the newly created foo.bmp file to view.
}
type
  TMyControl = class(TColorListBox)
    procedure SaveAsBmp(fileName: TFileName);
  end;
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  MyControl1: TMyControl;
implementation

{$R *.dfm}

type
  LogPal = record
  lpal : TLogPalette;
  dummy:Array[0..255] of TPaletteEntry;
  end;  

procedure TMyControl.SaveAsBmp(fileName: TFileName);
var
  Source: TComponent;
  SysPal : LogPal;
  tempCanvas: TCanvas;
  sourceRect, destRect: TRect;
  image2save: TImage;
  notUsed: HWND;
begin
  tempCanvas := TCanvas.Create;
  try
    tempCanvas.Handle := GetDeviceContext(notUsed);
    image2save:=TImage.create(self);
    try
      with image2save do
      begin
        Height := Self.Height;
        Width :=  Self.Width;
        destRect := Rect(0,0,Width,Height);
        sourceRect := destRect;
        Canvas.CopyRect(destRect,tempCanvas,sourceRect);
        SysPal.lPal.palVersion:=$300;
        SysPal.lPal.palNumEntries:=256;
        GetSystemPaletteEntries(
          tempCanvas.Handle,0,256,SysPal.lpal.palPalEntry);
        Picture.Bitmap.Palette:= CreatePalette(Syspal.lpal);
      end;
      image2save.Picture.SaveToFile(fileName);
    finally
     image2save.Free;
    end;
  finally
    tempCanvas.Free;
  end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
  MyControl1.SaveAsBmp('foo.bmp');
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  MyControl1:= TMyControl.Create(Form1);
  MyControl1.Parent:= Form1;
  MyControl1.visible := true;
end;