问题是:我在桌面上绘制一些矩形,而鼠标移动(矩形大小增加)我没有滞后,人工制品等,一切都很好:

但是当我将矩形调整到低于它的尺寸时,我有了人工制品:

红色矩形是真正的矩形,其他都是bug.
完美的解决方案是重绘画布,但在鼠标移动时我不能一直这样做.
移动后鼠标绝对停止时有解决办法吗?
更新
代码:
unit Unit2;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ExtCtrls;
type
TForm2 = class(TForm)
Timer1: TTimer;
procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);
procedure FormCreate(Sender: TObject);
procedure FormMouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
procedure FormDestroy(Sender: TObject);
private
{ Private declarations }
isDown: Boolean;
downX, downY: Integer;
public
{ Public declarations }
Bild: TBitMap;
end;
implementation …Run Code Online (Sandbox Code Playgroud)