From: "adub" <adub@cybertrails.com>
Newsgroups: borland.public.delphi.graphics
References: <3e233fbf@newsgroups.borland.com>
Subject: Re: Polygon pixel testing
Date: Mon, 13 Jan 2003 17:23:24 -0700
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function PtInPolygon( const pt : TPoint;  points : array of TPoint;  NumPts
: integer): boolean;
var
   Region : HRGN;
begin
   Result:=false;
   Region := CreatePolygonRgn(Points, NumPts, Alternate);
   if PtInRegion( region, pt.x, pt.y ) then result:=true;
   DeleteObject( region );
end;

"Jon Lennart Berg" <64pixels@tiscali.no> wrote in message
news:3e233fbf@newsgroups.borland.com...
> Hi!
>
> Is there any quick way to test if a coordinate is within the range of a
> polygon shape?
>
> for example, let's say i have a polygon with 8 or more points that
describe
> a shape, how is it possible for me to check if a pixel is inside the
bounds
> of that shape?
>
> I seem to remember there was an API method that did this, but is it
> compatible with the DrawPolygon method of the Delphi canvas?
>
> Or do i have to render a mask?
> Surely there must be a more clever way of doing this...
>
> Jon Lennart Berg