PathGradientBrush::GetBlendCount method (gdipluspath.h)

Article
08/03/2021

The PathGradientBrush::GetBlendCount method gets the number of blend factors currently set for this path gradient brush.

Syntax

INT GetBlendCount();

Return value

Type: INT

This method returns the number of blend factors currently set for this path gradient brush.

Remarks

Before you call the PathGradientBrush::GetBlend method of a PathGradientBrush object, you must allocate two buffers: one to receive an array of blend factors and one to receive an array of blend positions. To determine the size of the required buffers, call the PathGradientBrush::GetBlendCount method of the PathGradientBrush object. The size (in bytes) of each buffer should be the return value of PathGradientBrush::GetBlendCount multiplied by sizeof( REAL).

Examples

The following example demonstrates several methods of the PathGradientBrush class, including PathGradientBrush::SetBlend, PathGradientBrush::GetBlendCount, and PathGradientBrush::GetBlend. The code creates a PathGradientBrush object and calls the PathGradientBrush::SetBlend method to establish a set of blend factors and blend positions for the brush. Then the code calls the PathGradientBrush::GetBlendCount method to retrieve the number of blend factors. After the number of blend factors is retrieved, the code allocates two buffers: one to receive the array of blend factors and one to receive the array of blend positions. Then the code calls the PathGradientBrush::GetBlend method to retrieve the blend factors and the blend positions.

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

   // Create a path that consists of a single ellipse.
   GraphicsPath path;
   path.AddEllipse(0, 0, 200, 100);

   // Use the path to construct a brush.
   PathGradientBrush pthGrBrush(&path);

   // Set the color at the center of the path to blue.
   pthGrBrush.SetCenterColor(Color(255, 0, 0, 255));

   // Set the color along the entire boundary of the path to aqua.
   Color colors[] = {Color(255, 0, 255, 255)};
   INT count = 1;
   pthGrBrush.SetSurroundColors(colors, &count);

   // Set blend factors and positions for the path gradient brush.
   REAL fac[] = {
      0.0f, 
      0.4f,     // 40 percent of the way from aqua to blue
      0.8f,     // 80 percent of the way from aqua to blue
      1.0f};

   REAL pos[] = {
      0.0f, 
      0.3f,   // 30 percent of the way from the boundary to the center
      0.7f,   // 70 percent of the way from the boundary to the center
      1.0f};

   pthGrBrush.SetBlend(fac, pos, 4);

   // Fill the ellipse with the path gradient brush.
   graphics.FillEllipse(&pthGrBrush, 0, 0, 200, 100);

   // Obtain information about the path gradient brush.
   INT blendCount = pthGrBrush.GetBlendCount();
   REAL* factors = new REAL[blendCount];
   REAL* positions = new REAL[blendCount];

   pthGrBrush.GetBlend(factors, positions, blendCount);

   for(INT j = 0; j < blendCount; ++j)
   {
      // Inspect or use the value in factors[j].
      // Inspect or use the value in positions[j].    
   }

   delete [] factors;
   delete [] positions; 
}

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	gdipluspath.h (include Gdiplus.h)
Library	Gdiplus.lib
DLL	Gdiplus.dll