判断某一个点TPOINT是否在一个区域内TRECT用PtInRect函数，函数具体用法如下：

Indicates whether a specified point lies inside a specified rectangle.

Unit

Types

Category:

geometric routines

Delphi syntax:

function PtInRect(const Rect: TRect; const P: TPoint): Boolean;

C++ syntax:

extern PACKAGE bool __fastcall PtInRect(const TRect Rect, const TPoint P);

Description

PtInRect returns true if the point, P, lies inside the rectangle, Rect, and false if P is not in Rect.

PtInRect does not consider a point inside a rectangle if the rectangle has a negative width or height. A point is considered inside a rectangle if it lies on the left or top edge, but not if it lies on the right or bottom edge.