SetRectEmpty: 使矩形为空;
IsRectEmpty: 判断矩形是否为空;
所谓矩形为空就是矩形是无区域的, 或者说是 Right <= Left 或 Bottom <= Top 情形下的矩形.
IsRectEmpty: 判断矩形是否为空;
所谓矩形为空就是矩形是无区域的, 或者说是 Right <= Left 或 Bottom <= Top 情形下的矩形.
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.FormCreate(Sender: TObject);
var
R: TRect;
buf: array[Byte] of Char;
begin
R := Rect(10,20,-30,-40);
ShowMessage(BoolToStr(IsRectEmpty(R), True)); {True; 是空矩形}
R := Rect(10,20,30,40);
ShowMessage(BoolToStr(IsRectEmpty(R), True)); {False}
wvsprintf(buf, 'L:%d, T:%d, R:%d, B:%d', @R);
ShowMessage(buf); {L:10, T:20, R:30, B:40}
SetRectEmpty(R);
ShowMessage(BoolToStr(IsRectEmpty(R), True)); {True}
wvsprintf(buf, 'L:%d, T:%d, R:%d, B:%d', @R);
ShowMessage(buf); {L:0, T:0, R:0, B:0}
end;
end.
