Region::IsVisible(constPoint&,constGraphics*) method (gdiplusheaders.h)

Article
02/22/2024

The Region::IsVisible method determines whether a point is inside this region.

Syntax

BOOL IsVisible(
  [in, ref] const Point &  point,
  [in]      const Graphics *g
);

Parameters

[in, ref] point

Type: const Point

Reference to a point to test.

[in] g

Type: const Graphics*

Optional. Pointer to a Graphics object that contains the world and page transformations required to calculate the device coordinates of this region and the point. The default value is NULL.

Return value

Type: BOOL

If the point is inside this region, this method returns TRUE; otherwise, it returns FALSE.

Remarks

Note A region contains its border.

Examples

The following example creates a region from a path and then tests to determine whether a point is in the region.

VOID Example_IsVisiblePoint(HDC hdc)
{
   Graphics graphics(hdc);

   Point points[] = {
      Point(110, 20),
      Point(120, 30),
      Point(100, 60),
      Point(120, 70),
      Point(150, 60),
      Point(140, 10)};

   GraphicsPath path;
   SolidBrush solidBrush(Color(255, 255, 0, 0));

   path.AddClosedCurve(points, 6);

   // Create a region from a path.
   Region pathRegion(&path);
   graphics.FillRegion(&solidBrush, &pathRegion);

   // Check to see whether a point is in the region.
   Point testPoint(125, 30);

   if(pathRegion.IsVisible(testPoint, &graphics))
   {
      // The test point is in the region.
   }

   // Fill a small circle centered at the test point.
   SolidBrush brush(Color(255, 0, 0, 0));
   graphics.FillEllipse(&brush, testPoint.X - 4, testPoint.Y - 4, 8, 8);
}

Requirements

Requirement	Value
Minimum supported client	Windows XP, Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	gdiplusheaders.h (include Gdiplus.h)
Library	Gdiplus.lib
DLL	Gdiplus.dll