DrawingContext.PushOpacity 方法

定義

命名空間:

System.Windows.Media

組件:

PresentationCore.dll

將指定的透明度設定推入至繪圖內容。

多載

PushOpacity(Double)	將指定的透明度設定推入至繪圖內容。
PushOpacity(Double, AnimationClock)	將指定的不透明度設定推入至繪製內容，然後套用指定的動畫時鐘。

PushOpacity(Double)

將指定的透明度設定推入至繪圖內容。

public:
 abstract void PushOpacity(double opacity);

public abstract void PushOpacity (double opacity);

abstract member PushOpacity : double -> unit

Public MustOverride Sub PushOpacity (opacity As Double)

參數

opacity

Double

要套用至後續繪製命令的不透明度因數。 這個因數是從先前的 PushOpacity(Double) 作業累加而來。

範例

下列範例示範 PushOpacity 、 PushEffect 和 Pop 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

備註

不透明度會混合到所有後續的繪圖命令中，直到命令移除 Pop 為止。

PushOpacity(Double, AnimationClock)

將指定的不透明度設定推入至繪製內容，然後套用指定的動畫時鐘。

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)

參數

opacity

Double

要套用至後續繪製命令的不透明度因數。 這個因數是從先前的 PushOpacity(Double) 作業累加而來。

opacityAnimations

AnimationClock

用來建立不透明度值動畫的時鐘，不使用動畫則為 null。 這個時鐘必須從可以將 AnimationTimeline 值顯示為動畫的 Double 建立。

備註

不透明度會混合到所有後續的繪圖命令中，直到命令移除 Pop 為止。