{ How to add a new design control type to the demo (example: add a TEdit):

  -  In the Initialization section register the new class. Add the line
       "RegisterClass(TEdit);"
  -  Add the palette icon of the new class to the ImageList of the demo. You
     can find the palette icons of the LCL components in the folder
     "images/components" of your Lazarus installation. Select the one without
     size appending, e.g. "tedit.png" (not "tedit_150.png") - this demo does
     not support the LCL multi-size image list.
  -  Add a new button to the toolbar. Set its ImageIndex to the index of the
     correspondig icon in the image list. Each tool button has a Tag property.
     Set the Tag of the new button to the next value - look at the other buttons
     to see their Tag values.
  -  Assign the handler "PaletteButtonClick" to the new button.
  -  Go to "TMainForm.PaletteButtonClick" and add the name of the new class to
     the array "oClasses". Don't forget to increment the upper array index.
     Note that the array index is equal to the Tag of the corresponding
     button.
}

unit main;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, ComCtrls,
  Menus, StdCtrls, ExtCtrls, JvDesignSurface, JvDesignUtils;

type

  { TMainForm }

  TMainForm = class(TForm)
    Active1: TMenuItem;
    ButtonButton: TToolButton;
    csDesigning1: TMenuItem;
    DelphiSelector1: TMenuItem;
    File1: TMenuItem;
    Grid1: TMenuItem;
    ImageButton: TToolButton;
    ImageList1: TImageList;
    JvDesignPanel: TJvDesignPanel;
    LabelButton: TToolButton;
    MainMenu1: TMainMenu;
    N1: TMenuItem;
    N2: TMenuItem;
    N3: TMenuItem;
    N4: TMenuItem;
    New1: TMenuItem;
    Open1: TMenuItem;
    OpenDialog: TOpenDialog;
    PanelButton: TToolButton;
    Rules1: TMenuItem;
    Save1: TMenuItem;
    SaveDialog: TSaveDialog;
    SelectButton: TToolButton;
    ToolBar1: TToolBar;
    VSSelector1: TMenuItem;
    WindowProcHook1: TMenuItem;
    procedure Active1Click(Sender: TObject);
    procedure csDesigning1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure Grid1Click(Sender: TObject);
    procedure New1Click(Sender: TObject);
    procedure Open1Click(Sender: TObject);
    procedure Rules1Click(Sender: TObject);
    procedure Save1Click(Sender: TObject);
    procedure JvDesignPanelGetAddClass(Sender: TObject; var ioClass: String);
    procedure JvDesignPanelPaint(Sender: TObject);
    procedure PaletteButtonClick(Sender: TObject);

  private
    { private declarations }
  public
    { public declarations }
    DesignClass: string;
    StickyClass: Boolean;

  end; 

var
  MainForm: TMainForm;

implementation

uses
  JvDesignImp;
{$R *.lfm}

{ TMainForm }

procedure TMainForm.New1Click(Sender: TObject);
begin
  JvDesignPanel.Clear;
end;

procedure TMainForm.Grid1Click(Sender: TObject);
begin
  //
end;

procedure TMainForm.csDesigning1Click(Sender: TObject);
begin
  JvDesignPanel.Active := false;
  if WindowProcHook1.Checked then
    JvDesignPanel.Surface.MessengerClass := TJvDesignWinControlHookMessenger
  else
    JvDesignPanel.Surface.MessengerClass := TJvDesignDesignerMessenger;
  JvDesignPanel.Active := true;
  JvDesignPanel.Invalidate;
end;

procedure TMainForm.FormCreate(Sender: TObject);
begin
//  OpenDialog.InitialDir := ExtractFilePath(Application.ExeName);
  OpenDialog.InitialDir := '../../../examples/JvDesigner/';
  SaveDialog.InitialDir := OpenDialog.InitialDir;
  JvDesignPanel.Surface.Active := true;
end;

procedure TMainForm.Active1Click(Sender: TObject);
begin
  JvDesignPanel.Active := Active1.Checked;
  JvDesignPanel.Invalidate;
end;

procedure TMainForm.Open1Click(Sender: TObject);
begin
  if OpenDialog.Execute then
    JvDesignPanel.LoadFromFile(OpenDialog.Filename);
end;

procedure TMainForm.Rules1Click(Sender: TObject);
begin
  if Rules1.Checked then
  begin
    JvDesignPanel.Color := clWhite;
    JvDesignPanel.DrawRules := true;
    JvDesignPanel.OnPaint := nil;
  end else
  begin
    JvDesignPanel.Color := clBtnFace;
    JvDesignPanel.DrawRules := false;
    JvDesignPanel.OnPaint := @JvDesignPanelPaint;
  end;
  JvDesignPanel.Invalidate;
end;

procedure TMainForm.Save1Click(Sender: TObject);
begin
  if SaveDialog.Execute then
    JvDesignPanel.SaveToFile(SaveDialog.Filename);
end;

procedure TMainForm.JvDesignPanelGetAddClass(Sender: TObject;
  var ioClass: String);
begin
  ioClass := DesignClass;
  if not StickyClass then
  begin
    DesignClass := '';
    SelectButton.Down  := true;
  end;
end;

procedure TMainForm.JvDesignPanelPaint(Sender: TObject);
begin
  with JvDesignPanel do
    DesignPaintGrid(Canvas, ClientRect, Color);
end;

procedure TMainForm.PaletteButtonClick(Sender: TObject);
const
  cClasses: array[0..4] of string = ( '', 'TButton', 'TLabel', 'TPanel',
    'TImage');
begin
// StickyClass := (GetKeyState(VK_SHIFT) < 0);
   StickyClass := False;
   DesignClass := cClasses[TControl(Sender).Tag];
end;

initialization
  RegisterClass(TButton);
  RegisterClass(TLabel);
  RegisterClass(TPanel);
  RegisterClass(TImage);
end.