unit1.pas

Delphi编程实效百例的随书程序 这是其中的界面操作部分

unit Unit1;

interface

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

type
  TMainForm = class(TForm)
    FramePanel: TPanel;
    BackImage: TImage;
    ForeImage: TImage;
    procedure FormCreate(Sender: TObject);
    procedure ForeImageMouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
  private
    { Private declarations }
  public
  procedure ImageCopy(CenterX, CenterY, Side: Integer);
    { Public declarations }
  end;

var
  MainForm: TMainForm;
implementation
const
sSide=30;
dSide=45;
var
msHide: Boolean;
OldX, OldY, NewX, NewY: Integer;
Dest, Source : TRect;
{$R *.DFM}

procedure TMainForm.FormCreate(Sender: TObject);
begin
  msHide:=True;
  Canvas.CopyMode:=cmSrcCopy
end;
procedure TMainForm.ImageCopy(CenterX, CenterY, Side: Integer);
begin
with Source do
begin
Left:=CenterX-Side;
Top:=CenterY-Side;
Right:=CenterX+Side;
Bottom:=CenterY+Side;
end;
with Dest do
  begin
    Left:=CenterX-dSide;
    Top:=CenterY-dSide;
    Right:=CenterX+dSide;
    Bottom:=CenterY+dSide;
  end;
ForeImage.Canvas.CopyRect(Dest, BackImage.Canvas, Source);
end;

procedure TMainForm.ForeImageMouseMove(Sender: TObject; Shift: TShiftState;
  X, Y: Integer);
begin
NewX:=X;
NewY:=Y;
if msHide then
  begin
    OldX:=NewX;
    OldY:=NewY;
    msHide:=False;
    ShowCursor(False);
  end
else
  begin
    ImageCopy(OldX, OldY, dSide);
  end;
ImageCopy(NewX, NewY, sSide);
OldX:=NewX;
OldY:=NewY;
end;

end.