unit ControlHandler;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, ExtCtrls, ComCtrls, Contnrs;

type
  TControlPoint = (pcTopLeft, pcTopRight, pcBottomLeft, pcBottomRight, pcOther);

  TControlHandler = class(TCustomControl)
  private
    Rgn: HRGN;
    R, R1: TRect;
    Pos: TPoint;
    Pt: TControlPoint;
    bDrag: Boolean;
  protected
    FControl: TControl;
    FObjectList: TObjectList;
    FExternalBorder: Boolean;
    procedure SetRegion;
    function GetControlPoint(const Point: TPoint): TControlPoint;
    procedure Paint; override;
    procedure MouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
    procedure MouseUp(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
    procedure MouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    procedure SetControl(Control: TControl);
    procedure SetObjectList(ObjectList: TObjectList);
    procedure SetExternalBorder(Value: Boolean);
  published
    property Control: TControl read FControl write SetControl;
    property ObjectList: TObjectList read FObjectList write SetObjectList;
    property ExternalBorder: Boolean read FExternalBorder write SetExternalBorder;
  end;

implementation

const
  LARGEUR = 5;


// Méthodes de TControlHandler

constructor TControlHandler.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Parent := AOwner as TWinControl;

  Rgn := 0;
  bDrag := False;
  FExternalBorder := true;
  FObjectList := nil;
  
  OnMouseDown := MouseDown;
  OnMouseMove := MouseMove;
  OnMouseUp := MouseUp;
end;

destructor TControlHandler.Destroy;
begin
  if Rgn <> 0 then
    DeleteObject(Rgn);
  inherited Destroy;
end;

function TControlHandler.GetControlPoint(const Point: TPoint): TControlPoint;
begin
  Result := pcOther;
  if PtInRect(Rect(0, 0, LARGEUR, LARGEUR), Point) then
    Result := pcTopLeft
  else if PtInRect(Rect(Width-LARGEUR, 0, Width, LARGEUR), Point) then
    Result := pcTopRight
  else if PtInRect(Rect(0, Height-LARGEUR, LARGEUR, Height), Point) then
    Result := pcBottomLeft
  else if PtInRect(Rect(Width-LARGEUR, Height-LARGEUR, Width, Height), Point) then
    Result := pcBottomRight;
end;

procedure TControlHandler.MouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
  Pos.x := X;
  Pos.y := Y;
  bDrag := True;

  R := Rect(FControl.Left, FControl.Top, FControl.Left + FControl.Width, FControl.Top + FControl.Height);
  R1 := Rect(FControl.Left, FControl.Top, FControl.Left + FControl.Width, FControl.Top + FControl.Height);

  Pt := GetControlPoint(Pos);

  Visible := False;
end;

procedure TControlHandler.MouseUp(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
  Screen.Cursor := crDefault;
  bDrag := False;

  Control.Left := R.Left;
  Control.Top := R.Top;
  Control.Width := R.Right - R.Left;
  Control.Height := R.Bottom - R.Top;

  SetRegion;

  Visible := True;
end;

procedure TControlHandler.MouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);
var
  i, dtop, dleft: integer;
begin
  case GetControlPoint(Point(X, Y)) of
    pcTopLeft :
        Cursor := crSizeNWSE;
    pcTopRight :
        Cursor := crSizeNESW;
    pcBottomLeft :
        Cursor := crSizeNESW;
    pcBottomRight :
        Cursor := crSizeNWSE;
    pcOther :
        Cursor := crDrag;
  end;

  if not bDrag then Exit;

  case Pt of
    pcTopLeft : begin
        R.Left := R1.Left + X - Pos.x;
        R.Top := R1.Top + Y - Pos.y;
      end;
    pcTopRight : begin
        R.Right := R1.Right + X - Pos.x;
        R.Top := R1.Top + Y - Pos.y;
      end;
    pcBottomLeft : begin
        R.Left := R1.Left + X - Pos.x;
        R.Bottom := R1.Bottom + Y - Pos.y;
      end;
    pcBottomRight : begin
        R.Right := R1.Right + X - Pos.x;
        R.Bottom := R1.Bottom + Y - Pos.y;
      end;
    pcOther : begin
        R.Left := R1.Left + X - Pos.x;
        R.Top := R1.Top + Y - Pos.y;
        R.Right := R1.Right + X - Pos.x;
        R.Bottom := R1.Bottom + Y - Pos.y;
      end;
  end;

// répéter lz paragraphe suivant pour tous les objets de DesignerCHlist si cette liste est référence dans l'objet 
  with FControl do
  begin
    dleft := R.Left - Left;
    dtop := R.Top - Top;
    Left := R.Left;
    Top := R.Top;
    Width := R.Right - R.Left;
    Height := R.Bottom - R.Top;
  end;
  BringToFront;

  if not assigned(FObjectList) then exit;
  if FObjectList.Count>0 then begin
    for i:=0 to FObjectList.Count-1 do begin
      with TControlHandler(FObjectList.Items[i]).Control do begin
        if integer(TControlHandler(FObjectList.Items[i]).Control)<>integer((sender as TControlHandler).Control) then begin
          Left := Left+ dleft;
          Top := Top + dtop;
{          Width := R.Right - R.Left;
          Height := R.Bottom - R.Top;    }
          TControlHandler(FObjectList.Items[i]).SetRegion;
        end;
      end;
    end;
  end;

end;

procedure TControlHandler.SetRegion;
var
  Rgn1, Rgn2: HRGN;
begin
  if Rgn <> 0 then DeleteObject(Rgn);
  Visible := False;

  if FExternalBorder then begin
    Left := Control.Left - LARGEUR;
    Top := Control.Top - LARGEUR;
    Width := Control.Width + 2*LARGEUR;
    Height := Control.Height + 2*LARGEUR;
    Rgn := CreateRectRgn(0, 0, Width, Height);
    Rgn1 := CreateRectRgn(0, 0, Width, Height);
    Rgn2 := CreateRectRgn(LARGEUR, LARGEUR, Control.Width + LARGEUR, Control.Height + LARGEUR);
  end else begin
    Left := Control.Left;
    Top := Control.Top;
    Width := Control.Width;
    Height := Control.Height;
    Rgn := CreateRectRgn(0, 0, Width, Height);
    Rgn1 := CreateRectRgn(0, 0, Width, Height);
    Rgn2 := CreateRectRgn(LARGEUR, LARGEUR, Control.Width - LARGEUR, Control.Height - LARGEUR);
  end;

  CombineRgn(Rgn, Rgn1, Rgn2, RGN_DIFF);
  DeleteObject(Rgn1);
  DeleteObject(Rgn2);
  SetWindowRgn(Handle, Rgn, True);
  BringToFront;

  Visible := True;
end;

procedure TControlHandler.SetControl(Control: TControl);
begin
  FControl := Control;
  SetRegion;
end;

procedure TControlHandler.SetObjectList(ObjectList: TObjectList);
begin
  FObjectList := ObjectList;
end;

procedure TControlHandler.SetExternalBorder(Value: Boolean);
begin
  FExternalBorder := Value;
end;

procedure TControlHandler.Paint;
begin
  with Canvas do
  begin
    Brush.Color := clBlack;
    Brush.Style := bsBDiagonal;
    Rectangle(0, 0, Width, Height);

    // Dessiner les poignets
    Brush.Style := bsSolid;
    FillRect(Rect(0, 0, LARGEUR, LARGEUR));
    FillRect(Rect(Width-LARGEUR, 0, Width, LARGEUR));
    FillRect(Rect(0, Height-LARGEUR, LARGEUR, Height));
    FillRect(Rect(Width-LARGEUR, Height-LARGEUR, Width, Height));
  end;
end;

end.