DrawingContext.PushOpacity 方法

定义

命名空间:

System.Windows.Media

程序集:

PresentationCore.dll

将指定的不透明度设置推送到绘图上下文上。

重载

PushOpacity(Double)	将指定的不透明度设置推送到绘图上下文上。
PushOpacity(Double, AnimationClock)	将指定的不透明度设置推送到绘图上下文上，并应用指定的动画时钟。

PushOpacity(Double)

将指定的不透明度设置推送到绘图上下文上。

public:
 abstract void PushOpacity(double opacity);

public abstract void PushOpacity (double opacity);

abstract member PushOpacity : double -> unit

Public MustOverride Sub PushOpacity (opacity As Double)

参数

opacity

Double

要应用于后续的绘图命令的不透明度因子。 此因子会在以前 PushOpacity(Double) 操作的基础上累积。

示例

以下示例演示PushOpacity了和PushEffectPop命令。

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Navigation;
using System.Windows.Media.Effects;

namespace SDKSample
{

    public class PushEffectExample : Page
    {

        public PushEffectExample()
        {
            Pen shapeOutlinePen = new Pen(Brushes.Black, 2);
            shapeOutlinePen.Freeze();

            // Create a DrawingGroup
            DrawingGroup dGroup = new DrawingGroup();

            // Obtain a DrawingContext from 
            // the DrawingGroup.
            using (DrawingContext dc = dGroup.Open())
            {
                // Draw a rectangle at full opacity.
                dc.DrawRectangle(Brushes.Blue, shapeOutlinePen, new Rect(0, 0, 25, 25));

                // Push an opacity change of 0.5. 
                // The opacity of each subsequent drawing will
                // will be multiplied by 0.5.
                dc.PushOpacity(0.5);

                // This rectangle is drawn at 50% opacity.
                dc.DrawRectangle(Brushes.Blue, shapeOutlinePen, new Rect(25, 25, 25, 25));

                // Blurs subsquent drawings. 
                dc.PushEffect(new BlurBitmapEffect(), null);

                // This rectangle is blurred and drawn at 50% opacity (0.5 x 0.5). 
                dc.DrawRectangle(Brushes.Blue, shapeOutlinePen, new Rect(50, 50, 25, 25));

                // This rectangle is also blurred and drawn at 50% opacity.
                dc.DrawRectangle(Brushes.Blue, shapeOutlinePen, new Rect(75, 75, 25, 25));

                // Stop applying the blur to subsquent drawings.
                dc.Pop();

                // This rectangle is drawn at 50% opacity with no blur effect.
                dc.DrawRectangle(Brushes.Blue, shapeOutlinePen, new Rect(100, 100, 25, 25));
            }

            // Display the drawing using an image control.
            Image theImage = new Image();
            DrawingImage dImageSource = new DrawingImage(dGroup);
            theImage.Source = dImageSource;

            this.Content = theImage;
        }
    }
}

Imports System.Windows.Media.Animation
Imports System.Windows.Media.Effects

Namespace SDKSample


    Public Class PushEffectExample
        Inherits Page

        Public Sub New()
            Dim shapeOutlinePen As New Pen(Brushes.Black, 2)
            shapeOutlinePen.Freeze()

            ' Create a DrawingGroup
            Dim dGroup As New DrawingGroup()

            ' Obtain a DrawingContext from 
            ' the DrawingGroup.
            Using dc As DrawingContext = dGroup.Open()
                ' Draw a rectangle at full opacity.
                dc.DrawRectangle(Brushes.Blue, shapeOutlinePen, New Rect(0, 0, 25, 25))

                ' Push an opacity change of 0.5. 
                ' The opacity of each subsequent drawing will
                ' will be multiplied by 0.5.
                dc.PushOpacity(0.5)

                ' This rectangle is drawn at 50% opacity.
                dc.DrawRectangle(Brushes.Blue, shapeOutlinePen, New Rect(25, 25, 25, 25))

                ' Blurs subsquent drawings. 
                dc.PushEffect(New BlurBitmapEffect(), Nothing)

                ' This rectangle is blurred and drawn at 50% opacity (0.5 x 0.5). 
                dc.DrawRectangle(Brushes.Blue, shapeOutlinePen, New Rect(50, 50, 25, 25))

                ' This rectangle is also blurred and drawn at 50% opacity.
                dc.DrawRectangle(Brushes.Blue, shapeOutlinePen, New Rect(75, 75, 25, 25))

                ' Stop applying the blur to subsquent drawings.
                dc.Pop()

                ' This rectangle is drawn at 50% opacity with no blur effect.
                dc.DrawRectangle(Brushes.Blue, shapeOutlinePen, New Rect(100, 100, 25, 25))
            End Using

            ' Display the drawing using an image control.
            Dim theImage As New Image()
            Dim dImageSource As New DrawingImage(dGroup)
            theImage.Source = dImageSource

            Me.Content = theImage

        End Sub




    End Class

End Namespace

注解

不透明度将混合到所有后续绘图命令中，直到命令将其删除 Pop 。

PushOpacity(Double, AnimationClock)

将指定的不透明度设置推送到绘图上下文上，并应用指定的动画时钟。

public:
 abstract void PushOpacity(double opacity, System::Windows::Media::Animation::AnimationClock ^ opacityAnimations);

public abstract void PushOpacity (double opacity, System.Windows.Media.Animation.AnimationClock opacityAnimations);

abstract member PushOpacity : double * System.Windows.Media.Animation.AnimationClock -> unit

Public MustOverride Sub PushOpacity (opacity As Double, opacityAnimations As AnimationClock)

参数

opacity

Double

要应用于后续的绘图命令的不透明度因子。 此因子会在以前 PushOpacity(Double) 操作的基础上累积。

opacityAnimations

AnimationClock

用于对不透明度值进行动画处理的时钟；如果没有动画，则为 null。 此时钟必须基于能够对 AnimationTimeline 值进行动画处理的 Double 来创建。

注解

不透明度将混合到所有后续绘图命令中，直到命令将其删除 Pop 。