Region::GetRegionScansCount method (gdiplusheaders.h)

Article
02/22/2024

The Region::GetRegionScansCount method gets the number of rectangles that approximate this region. The region is transformed by a specified matrix before the rectangles are calculated.

Syntax

UINT GetRegionScansCount(
  [in] const Matrix *matrix
);

Parameters

[in] matrix

Type: const Matrix*

Pointer to a matrix that is used to transform the region.

Return value

Type: UINT

This method returns an integer that indicates the number of rectangles that approximate this region.

Remarks

The Region::GetRegionScansCount method can be used before the GetRegionScans method to determine the number of rectangles. Then, you can allocate a buffer that is the correct size to store the rectangles that are obtained with the GetRegionScans method.

Examples

The following example creates a region from a path and gets a set of rectangles that approximate the region. The code then draws each of the rectangles.

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

   SolidBrush solidBrush(Color(255, 255, 0, 0));
   Pen pen(Color(255, 0, 0, 0));
   GraphicsPath path;
   Matrix matrix;
   RectF* rects = NULL;
   INT count = 0;  

   // Create a region from a path.
   path.AddEllipse(10, 10, 50, 300);
   Region pathRegion(&path);    
   graphics.FillRegion(&solidBrush, &pathRegion);

   // Get the rectangles.
   graphics.GetTransform(&matrix);
   count = pathRegion.GetRegionScansCount(&matrix);
   rects = (RectF*)malloc(count*sizeof(RectF));
   pathRegion.GetRegionScans(&matrix, rects, &count);
    
   // Draw the rectangles.
   for(INT j = 0; j < count; ++j)
      graphics.DrawRectangle(&pen, rects[j]);

   free(rects);
}

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