unit1.pas

Demo program for Memo and Panels

unit Unit1;

interface

uses
  SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
  Forms, Dialogs, ExtCtrls, StdCtrls, FileCtrl, Buttons;

const
  CornerWidth = 10;

type
  TResize = (rsNone,rsLeft,rsRight,rsTop,rsBottom,
             rsTopLeft,rsTopRight,rsBottomLeft,rsBottomRight);

  TForm1 = class(TForm)
    Panel1: TPanel;
    ScrollBox1: TScrollBox;
    Memo1: TMemo;
    procedure Panel1MouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure Panel1MouseUp(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure Panel1MouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
  private
    { Private declarations }
    ResizeMode : TResize;
    Resizing   : Boolean;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Panel1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  Resizing := True;
end;

procedure TForm1.Panel1MouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  Resizing := False;
end;

procedure TForm1.Panel1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
  if not Resizing then begin
    { Check top left corner }
    if (X < CornerWidth) and (Y < CornerWidth) then begin
      ResizeMode := rsTopLeft;
      Panel1.Cursor := crSizeNWSE;
    end

    { Check top right corner }
    else if (X > Panel1.Width-CornerWidth-1) and (Y < CornerWidth) then begin
      ResizeMode := rsTopRight;
      Panel1.Cursor := crSizeNESW;
    end

    { Check bottom left corner }
    else if (X < CornerWidth) and (Y > Panel1.Height-CornerWidth-1) then begin
      ResizeMode := rsBottomLeft;
      Panel1.Cursor := crSizeNESW;
    end

    { Check bottom right corner }
    else if (X > Panel1.Width-CornerWidth-1) and (Y > Panel1.Height-CornerWidth-1) then begin
      ResizeMode := rsBottomRight;
      Panel1.Cursor := crSizeNWSE;
    end

    { Check left border }
    else if X = 0 then begin
      ResizeMode := rsLeft;
      Panel1.Cursor := crSizeWE;
    end

    { Check right border }
    else if X = Panel1.Width-1 then begin
      ResizeMode := rsRight;
      Panel1.Cursor := crSizeWE;
    end

    { Check top border }
    else if Y = 0 then begin
      ResizeMode := rsTop;
      Panel1.Cursor := crSizeNS;
    end

    { Check bottom border }
    else if Y = Panel1.Height-1 then begin
      ResizeMode := rsBottom;
      Panel1.Cursor := crSizeNS;
    end;
  end;

  if Resizing then
    with Panel1 do
      case ResizeMode of
        rsLeft        : begin
{
                          Width := Width-X;
}
                          Left := Left+X;
                        end;
        rsRight       : Width := X;
        rsTop         : begin
{
                          Height := Height-Y;
}
                          Top := Top+Y;
                        end;
        rsBottom      : Height := Y;
        rsTopLeft     : begin
{
                          Width := Width-X;
}
                          Left := Left+X;
{
                          Height := Height-Y;
}
                          Top := Top+Y;
                        end;
        rsTopRight    : begin
                          Width := X;
                          Height := Height-Y;
                          Top := Top+Y;
                        end;
        rsBottomLeft  : begin
                          Width := Width-X;
                          Left := Left+X;
                          Height := Y;
                        end;
        rsBottomRight : begin
                          Width := X;
                          Height := Y;
                        end;
      end;
end;

end.