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RadialGradientBrush Class

Paints an area with a radial gradient. A focal point defines the beginning of the gradient, and a circle defines the end point of the gradient.

Namespace:  System.Windows.Media
Assembly:  PresentationCore (in PresentationCore.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation

public sealed class RadialGradientBrush : GradientBrush
<RadialGradientBrush>
  GradientStops
</RadialGradientBrush>

The RadialGradientBrush type exposes the following members.

  NameDescription
Public methodRadialGradientBrush() Initializes a new instance of the RadialGradientBrush class.
Public methodRadialGradientBrush(GradientStopCollection) Initializes a new instance of the RadialGradientBrush class that has the specified gradient stops.
Public methodRadialGradientBrush(Color, Color) Initializes a new instance of the RadialGradientBrush class with the specified start and stop colors.
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  NameDescription
Public propertyCanFreezeGets a value that indicates whether the object can be made unmodifiable. (Inherited from Freezable.)
Public propertyCenter Gets or sets the center of the outermost circle of the radial gradient.
Public propertyColorInterpolationModeGets or sets a ColorInterpolationMode enumeration that specifies how the gradient's colors are interpolated. (Inherited from GradientBrush.)
Public propertyDependencyObjectTypeGets the DependencyObjectType that wraps the CLR type of this instance.  (Inherited from DependencyObject.)
Public propertyDispatcherGets the Dispatcher this DispatcherObject is associated with. (Inherited from DispatcherObject.)
Public propertyGradientOrigin Gets or sets the location of the two-dimensional focal point that defines the beginning of the gradient.
Public propertyGradientStopsGets or sets the brush's gradient stops. (Inherited from GradientBrush.)
Public propertyHasAnimatedPropertiesGets a value that indicates whether one or more AnimationClock objects is associated with any of this object's dependency properties. (Inherited from Animatable.)
Public propertyIsFrozenGets a value that indicates whether the object is currently modifiable. (Inherited from Freezable.)
Public propertyIsSealedGets a value that indicates whether this instance is currently sealed (read-only). (Inherited from DependencyObject.)
Public propertyMappingMode Gets or sets a BrushMappingMode enumeration that specifies whether the gradient brush's positioning coordinates are absolute or relative to the output area. (Inherited from GradientBrush.)
Public propertyOpacity Gets or sets the degree of opacity of a Brush. (Inherited from Brush.)
Public propertyRadiusX Gets or sets the horizontal radius of the outermost circle of the radial gradient.
Public propertyRadiusY Gets or sets the vertical radius of the outermost circle of a radial gradient.
Public propertyRelativeTransformGets or sets the transformation that is applied to the brush using relative coordinates. (Inherited from Brush.)
Public propertySpreadMethod Gets or sets the type of spread method that specifies how to draw a gradient that starts or ends inside the bounds of the object to be painted. (Inherited from GradientBrush.)
Public propertyTransform Gets or sets the transformation that is applied to the brush. This transformation is applied after the brush's output has been mapped and positioned. (Inherited from Brush.)
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  NameDescription
Public methodApplyAnimationClock(DependencyProperty, AnimationClock)Applies an AnimationClock to the specified DependencyProperty. If the property is already animated, the SnapshotAndReplace handoff behavior is used. (Inherited from Animatable.)
Public methodApplyAnimationClock(DependencyProperty, AnimationClock, HandoffBehavior)Applies an AnimationClock to the specified DependencyProperty. If the property is already animated, the specified HandoffBehavior is used. (Inherited from Animatable.)
Public methodBeginAnimation(DependencyProperty, AnimationTimeline)Applies an animation to the specified DependencyProperty. The animation is started when the next frame is rendered. If the specified property is already animated, the SnapshotAndReplace handoff behavior is used. (Inherited from Animatable.)
Public methodBeginAnimation(DependencyProperty, AnimationTimeline, HandoffBehavior)Applies an animation to the specified DependencyProperty. The animation is started when the next frame is rendered. If the specified property is already animated, the specified HandoffBehavior is used. (Inherited from Animatable.)
Public methodCheckAccessDetermines whether the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject.)
Public methodClearValue(DependencyProperty)Clears the local value of a property. The property to be cleared is specified by a DependencyProperty identifier. (Inherited from DependencyObject.)
Public methodClearValue(DependencyPropertyKey)Clears the local value of a read-only property. The property to be cleared is specified by a DependencyPropertyKey. (Inherited from DependencyObject.)
Public methodCloneCreates a modifiable clone of this RadialGradientBrush, making deep copies of this object's values. When copying dependency properties, this method copies resource references and data bindings (but they might no longer resolve) but not animations or their current values.
Public methodCloneCurrentValueCreates a modifiable clone of this RadialGradientBrush object, making deep copies of this object's current values. Resource references, data bindings, and animations are not copied, but their current values are.
Public methodCoerceValueCoerces the value of the specified dependency property. This is accomplished by invoking any CoerceValueCallback function specified in property metadata for the dependency property as it exists on the calling DependencyObject. (Inherited from DependencyObject.)
Public methodEqualsDetermines whether a provided DependencyObject is equivalent to the current DependencyObject. (Inherited from DependencyObject.)
Public methodFreeze()Makes the current object unmodifiable and sets its IsFrozen property to true. (Inherited from Freezable.)
Public methodGetAnimationBaseValueReturns the non-animated value of the specified DependencyProperty. (Inherited from Animatable.)
Public methodGetAsFrozenCreates a frozen copy of the Freezable, using base (non-animated) property values. Because the copy is frozen, any frozen sub-objects are copied by reference. (Inherited from Freezable.)
Public methodGetCurrentValueAsFrozenCreates a frozen copy of the Freezable using current property values. Because the copy is frozen, any frozen sub-objects are copied by reference. (Inherited from Freezable.)
Public methodGetHashCodeGets a hash code for this DependencyObject. (Inherited from DependencyObject.)
Public methodGetLocalValueEnumeratorCreates a specialized enumerator for determining which dependency properties have locally set values on this DependencyObject. (Inherited from DependencyObject.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodGetValueReturns the current effective value of a dependency property on this instance of a DependencyObject. (Inherited from DependencyObject.)
Public methodInvalidatePropertyRe-evaluates the effective value for the specified dependency property (Inherited from DependencyObject.)
Public methodReadLocalValueReturns the local value of a dependency property, if it exists. (Inherited from DependencyObject.)
Public methodSetCurrentValueSets the value of a dependency property without changing its value source. (Inherited from DependencyObject.)
Public methodSetValue(DependencyProperty, Object)Sets the local value of a dependency property, specified by its dependency property identifier. (Inherited from DependencyObject.)
Public methodSetValue(DependencyPropertyKey, Object)Sets the local value of a read-only dependency property, specified by the DependencyPropertyKey identifier of the dependency property. (Inherited from DependencyObject.)
Protected methodShouldSerializePropertyReturns a value that indicates whether serialization processes should serialize the value for the provided dependency property. (Inherited from DependencyObject.)
Public methodToString() Return string representation of this Brush. (Inherited from Brush.)
Public methodToString(IFormatProvider) Creates a string representation of this object based on the specified culture-specific formatting information. (Inherited from Brush.)
Public methodVerifyAccessEnforces that the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject.)
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  NameDescription
Public eventChangedOccurs when the Freezable or an object it contains is modified. (Inherited from Freezable.)
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  NameDescription
Public fieldStatic memberCenterProperty Identifies the Center dependency property.
Public fieldStatic memberGradientOriginPropertyIdentifies the GradientOrigin dependency property.
Public fieldStatic memberRadiusXProperty Identifies the RadiusX dependency property.
Public fieldStatic memberRadiusYProperty Identifies the RadiusY dependency property.
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  NameDescription
Explicit interface implemetationPrivate methodIFormattable.ToStringFormats the value of the current instance using the specified format. (Inherited from Brush.)
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The RadialGradientBrush is similar in programming model to the LinearGradientBrush. However, the linear gradient has a start and an end point to define the gradient vector, while the radial gradient has a circle, along with a focal point, to define the gradient behavior. The circle defines the end point of the gradient. In other words, a gradient stop at 1.0 defines the color at the circle's circumference. The focal point defines the center of the gradient. A gradient stop at 0.0 defines the color at the focal point.

The following image shows a rectangle filled with a radial gradient. The radial gradient that goes from white to gray. The outside circle represents the gradient circle while the red dot denotes the focal point. This gradient has its SpreadMethod set to Pad.

Radial gradient with a highlighted focal point

A radial gradient with highlighted components
NoteNote

RadialGradientBrush objects are rendered using hardware acceleration on Tier 2 systems. For more information about hardware tiers, see Graphics Rendering Tiers.

Freezable Features

Because it inherits from the Freezable class, the RadialGradientBrush class provides several special features: RadialGradientBrush objects can be declared as resources, shared among multiple objects, made read-only to improve performance, cloned, and made thread safe. For more information about the different features provided by Freezable objects, see Freezable Objects Overview.

This example shows how to use the RadialGradientBrush class to paint an area with a radial gradient.

The following example uses a RadialGradientBrush to paint a rectangle with a radial gradient that transitions from yellow to red to blue to lime green.


using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace BrushesIntroduction
{
    public class RadialGradientBrushSnippet : Page
    {
        public RadialGradientBrushSnippet()
        {
            Title = "RadialGradientBrush Example";
            Background = Brushes.White;
            Margin = new Thickness(20);

            // 
            // Create a RadialGradientBrush with four gradient stops. 
            //
            RadialGradientBrush radialGradient = new RadialGradientBrush();

            // Set the GradientOrigin to the center of the area being painted.
            radialGradient.GradientOrigin = new Point(0.5, 0.5);

            // Set the gradient center to the center of the area being painted.
            radialGradient.Center = new Point(0.5, 0.5);

            // Set the radius of the gradient circle so that it extends to 
            // the edges of the area being painted.
            radialGradient.RadiusX = 0.5; 
            radialGradient.RadiusY = 0.5;

            // Create four gradient stops.
            radialGradient.GradientStops.Add(new GradientStop(Colors.Yellow, 0.0));
            radialGradient.GradientStops.Add(new GradientStop(Colors.Red, 0.25));
            radialGradient.GradientStops.Add(new GradientStop(Colors.Blue, 0.75));
            radialGradient.GradientStops.Add(new GradientStop(Colors.LimeGreen, 1.0));

            // Freeze the brush (make it unmodifiable) for performance benefits.
            radialGradient.Freeze();

            // Create a rectangle and paint it with the  
            // RadialGradientBrush.
            Rectangle aRectangle = new Rectangle();
            aRectangle.Width = 200;
            aRectangle.Height = 100;
            aRectangle.Fill = radialGradient;

            StackPanel mainPanel = new StackPanel();
            mainPanel.Children.Add(aRectangle);
            Content = mainPanel;

        }

    }
}
<Page 
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="RadialGradientBrush Example"
  Background="White" Margin="20">
  <StackPanel>

    <!-- This rectangle is painted with a radial gradient. -->
    <Rectangle Width="200" Height="100">
      <Rectangle.Fill>
        <RadialGradientBrush 
          GradientOrigin="0.5,0.5" 
          Center="0.5,0.5" RadiusX="0.5" RadiusY="0.5">
          <RadialGradientBrush.GradientStops>
            <GradientStop Color="Yellow" Offset="0" />
            <GradientStop Color="Red" Offset="0.25" />
            <GradientStop Color="Blue" Offset="0.75" />
            <GradientStop Color="LimeGreen" Offset="1" />
          </RadialGradientBrush.GradientStops>
        </RadialGradientBrush>
      </Rectangle.Fill>
    </Rectangle>
  </StackPanel>
</Page>

The following illustration shows the gradient from the preceding example. The gradient's stops have been highlighted.

Gradient stops in a radial gradient
NoteNote

The examples in this topic use the default coordinate system for setting control points. The default coordinate system is relative to a bounding box: 0 indicates 0 percent of the bounding box, and 1 indicates 100 percent of the bounding box. You can change this coordinate system by setting the MappingMode property to the value Absolute. An absolute coordinate system is not relative to a bounding box. Values are interpreted directly in local space.

For additional RadialGradientBrush examples, see the Brushes Sample. For more information about gradients and other types of brushes, see Painting with Solid Colors and Gradients Overview.

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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