FONCTION REGIONINREGION

Option Explicit

Private Declare Function CombineRgn Lib "gdi32" (ByVal hDestRgn As Long, ByVal hSrcRgn1 As Long, ByVal hSrcRgn2 As Long, ByVal nCombineMode As Long) As Long
Private Declare Function CreateRectRgn Lib "gdi32" (ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Private Declare Function DeleteObject Lib "gdi32" Alias "DeleteObject" (ByVal hObject As Long) As Long
Private Const RGN_AND = 1
Private Const NULLREGION = 1

Private Sub Form_Load()
Dim RGN1 As Long, RGN2 As Long

'# Cas d'intersection entre les deux regions
RGN1 = CreateRectRgn(0, 0, 100, 100)
RGN2 = CreateRectRgn(50, 50, 150, 150)

MsgBox "Cas 1 : Intersection entre les 2 régions - " & RgnInRgn(RGN1, RGN2)

'# Cas de non intersection entre les deux regions
RGN1 = CreateRectRgn(0, 0, 100, 100)
RGN2 = CreateRectRgn(150, 150, 250, 250)

MsgBox "Cas 2 : Non-intersection entre les 2 régions - " & Not RgnInRgn(RGN1, RGN2)

End
End Sub

Public Function RgnInRgn(ByVal RGN1 As Long, ByVal RGN2 As Long) As Boolean
'# RGNOUT doit pointer sur une region valide !!
Dim RGNOUT As Long: RGNOUT = CreateRectRgn(0, 0, 0, 0)

'# CombineRGN renvoie NULLREGION si la region est vide
'# Dans le cas présent, on tente d'effectuer une intersection des deux regions. (RGN_AND)
RgnInRgn = NULLREGION <> CombineRgn(RGNOUT, RGN1, RGN2, RGN_AND)
Call DeleteObject ( RGNOUT )
End Function