GDI+: GdipPathIterGetCount

[José Roca]

The following example creates a GraphicsPath object and then adds a rectangle and an ellipse to the path. The code passes the address of that GraphicsPath object to the GdipCreatePathIter function to create an iterator that is associated with the path. The code calls the GdipPathIterGetCount function to determine the number of data points in the path. The call to GdipPathIterEnumerate retrieves two arrays from the path: one that holds the path's data points and one that holds the path's point types. After the data points have been retrieved, the code calls the GdipFillEllipse function to draw each of the data points.

C++

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

   // Create a path that has a rectangle and an ellipse.
   GraphicsPath path;
   path.AddRectangle(Rect(20, 20, 60, 30));
   path.AddEllipse(Rect(20, 70, 100, 50));

   // Create an iterator, and associate it with the path.
   GraphicsPathIterator iterator(&path);

   // Get the number of data points in the path.
   INT count = iterator.GetCount();

   // Get the data points.
   PointF* points = new PointF[count];
   BYTE* types = new BYTE[count];
   iterator.Enumerate(points, types, count);

   // Draw the data points.
   SolidBrush brush(Color(255, 255, 0, 0));
   for(INT j = 0; j < count; ++j)
      graphics.FillEllipse(
         &brush,
         points[j].X - 3.0f,
         points[j].Y - 3.0f,
         6.0f,
         6.0f);

   delete points;
   delete types;
}


PowerBASIC

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SUB GDIP_PathIterGetCount (BYVAL hdc AS DWORD)

   LOCAL hStatus AS LONG
   LOCAL pGraphics AS DWORD
   LOCAL pPath AS DWORD
   LOCAL pBrush AS DWORD
   LOCAL pIterator AS DWORD
   LOCAL c AS LONG
   LOCAL count AS LONG
   LOCAL i AS LONG
   DIM   pts(3) AS POINTF
   DIM   pPoints(0) AS POINTF
   DIM   pTypes(0) AS BYTE

   hStatus = GdipCreateFromHDC(hdc, pGraphics)

   ' // Create a path that has a rectangle and an ellipse.
   hStatus = GdipCreatePath(%FillModeAlternate, pPath)
   hStatus = GdipAddPathRectangle(pPath, 20, 20, 60, 30)
   hStatus = GdipAddPathEllipse(pPath, 20, 70, 100, 50)

   ' // Create a GraphicsPathIterator object, and associate it with the path.
   hStatus = GdipCreatePathIter(pIterator, pPath)

   ' // Get the number of data points in the path.
   hStatus = GdipPathIterGetCount(pIterator, c)

   ' // Get the data points.
   IF c THEN
      REDIM pPoints (c - 1)
      REDIM pTypes(c - 1)
      hStatus = GdipPathIterEnumerate(pIterator, count, pPoints(0), pTypes(0), c)
      IF count THEN
         ' // Draw the data points.
         hStatus = GdipCreateSolidFill(GDIP_ARGB(255, 255, 0, 0), pBrush)
         FOR i = 0 TO count - 1
            hStatus = GdipFillEllipse(pGraphics, pBrush, pPoints(i).x - 3, pPoints(i).y - 3, 6, 6)
         NEXT
      END IF
   END IF

   ' // Cleanup
   IF pIterator THEN GdipDeletePathIter(pIterator)
   IF pBrush THEN GdipDeleteBrush(pBrush)
   IF pPath THEN GdipDeletePath(pPath)
   IF pGraphics THEN GdipDeleteGraphics(pGraphics)

END SUB