How to fill the brush area of ​​a linear gradient from the source area?

Question

Im using the LinearGradient brush to fill the area, and I created a linearGradient brush using the start and end points, Color.

  Rectangle linearGradientregion= new Rectangl(20,-50,30,30);
  LinearGradientBrush linearGradientBrush = new LinearGradientBrush(new PointF(20, -20), new PointF(50, -50), Color.Green, Color.Red);


  Rectangle pathRegion= new Rectangl(-50,-25,50,50);
  GraphicsPath path = new GraphicsPath();
  path.AddRectangle(pathRegion);
  graphics.FillPath(linearGradientBrush, path);

And the size of the area is larger than the boundGradientBrush area.

Now I want to know how to fill an area using the boundGradientBrush area only using linearGradientBrush and the remaining area from the area filled with a different color.

Below image is expected output.

   http://i.stack.imgur.com/B4CHB.png

But I get this result

  http://i.stack.imgur.com/Pxwiw.png

In the first image, a circle filled with green goes beyond the scope of a linear gradient brush.

A gradient brush appears again in the second image to fill this area.

.

,

Answer 1

:

• , , , ClippingPath (Graphics.SetClip(path)) Graphics.

• , Graphics , , Rectangle, , ClippingPath Graphics . .

• : LinearGradientBrush , .

, ( ), ( ):

, :

private void panel1_Paint(object sender, PaintEventArgs e)
{
    e.Graphics.Clear(Color.White);
    e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
    Rectangle linearGradientregion = new Rectangle(10, 10, 150, 150);
    Rectangle pathRegion = new Rectangle(15, 15, 140, 140);
    GraphicsPath path = new GraphicsPath();
    path.AddEllipse(pathRegion);
    LinearGradientBrush linearGradientBrush = 
       new LinearGradientBrush(linearGradientregion, Color.Red, Color.Yellow, 45);

    ColorBlend cblend = new ColorBlend(4);
    cblend.Colors = new Color[4]  { Color.Red, Color.Yellow, Color.Green, Color.Green };
    cblend.Positions = new float[4] { 0f, 0.65f, 0.65f, 1f };

    linearGradientBrush.InterpolationColors = cblend;

    e.Graphics.FillPath(linearGradientBrush, path);
}

, . , .

, Colors Brush!

, . :

private void panel3_Paint(object sender, PaintEventArgs e)
{
    e.Graphics.Clear(Color.White);
    e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
    Rectangle linearGradientregion = new Rectangle(10, 10, 95, 95);
    Rectangle pathRegion = new Rectangle(15, 15, 140, 140);
    int centerX = pathRegion.X + pathRegion.Width / 2;
    int centerY = pathRegion.Y + pathRegion.Height / 2;

    GraphicsPath path = new GraphicsPath();
    path.AddEllipse(pathRegion);
    LinearGradientBrush linearGradientBrush = 
        new LinearGradientBrush(linearGradientregion, Color.Red, Color.Yellow, 45);
    e.Graphics.FillPath(linearGradientBrush, path);
    e.Graphics.SetClip(path);

    e.Graphics.TranslateTransform(centerX, centerY);
    e.Graphics.RotateTransform(45f);
    e.Graphics.FillRectangle(Brushes.Green, 25, -90, 240, 240);
    e.Graphics.ResetTransform();
}

, .

Answer 2

, . , linearGradientregion:

graphics.FillRectangle(linearGradientBrush, linearGradientregion);

, GraphicsPath ( ). , , , . :

using(var externalPath = new GraphicsPath(FillMode.Alternate))
{
    externalPath.AddRectangle(pathRegion);
    externalPath.AddRectangle(linearGradientregion);

    graphics.FillPath(Brushes.Black, externalPath);
}