Declare Function GetRgnBox Lib "gdi32.dll" (ByVal hRgn As Long, lpRect As RECT) As Long
Platforms: Win 32s, Win 95/98, Win NT
GetRgnBox determines the bounding rectangle of a given region. The bounding rectangle is the smallest possible rectangle which fully encompases the region. The bounding rectangle is placed in the structure passed as lpRect. The function returns 0 if an error occured, or exactly one of the following flags specifying the shape of the input region:
Example:
' Fill a triangular region on Form1 in dark gray and fill its bounding ' rectangle (behind it) in light gray. Dim triangle(0 To 2) As POINT_TYPE ' vertices of triangular region Dim hRgn As Long ' handle to the triangular region Dim hLightBrush As Long, hDarkBrush As Long ' handles to the two brushes Dim bounding As RECT ' receives bounding rectangle of region Dim retval As Long ' generic return value ' Create the triangular region. triangle(0).x = 150: triangle(0).y = 100 ' point #1: (150,100) triangle(1).x = 200: triangle(1).y = 150 ' point #2: (200,150) triangle(2).x = 175: triangle(2).y = 200 ' point #3: (175,200) hRgn = CreatePolygonRgn(triangle(0), 3, ALTERNATE) ' create the region ' Get handles to the light and dark gray solid stock brushes to use. hLightBrush = GetStockObject(LTGRAY_BRUSH) hDarkBrush = GetStockObject(DKGRAY_BRUSH) ' Calculate the triangular region's bounding rectangle. retval = GetRgbBox(hRgn, bounding) ' now bounding is the bounding rectangle ' Fill the bounding rectangle in ligh gray, the region in dark gray. retval = FillRect(Form1.hDC, bounding, hLightBrush) retval = FillRgn(Form1.hDC, hRgn, hDarkBrush) ' Delete the region to free up resources. retval = DeleteObject(hRgn)
Category: Regions
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