DrawingContext DrawingContext DrawingContext DrawingContext Class

定義

public ref class DrawingContext abstract : System::Windows::Threading::DispatcherObject, IDisposable

public abstract class DrawingContext : System.Windows.Threading.DispatcherObject, IDisposable

type DrawingContext = class
    inherit DispatcherObject
    interface IDisposable

Public MustInherit Class DrawingContext
Inherits DispatcherObject
Implements IDisposable

継承

ObjectObjectObjectObject

DispatcherObjectDispatcherObjectDispatcherObjectDispatcherObject

DrawingContextDrawingContextDrawingContextDrawingContext

実装

IDisposableIDisposableIDisposableIDisposable

例

次の例では、取得、DrawingContextから、DrawingVisual四角形を描画するためにこれを使用しています。The following example retrieves a DrawingContext from a DrawingVisual and uses it to draw a rectangle.

// Create a DrawingVisual that contains a rectangle.
private DrawingVisual CreateDrawingVisualRectangle()
{
    DrawingVisual drawingVisual = new DrawingVisual();

    // Retrieve the DrawingContext in order to create new drawing content.
    DrawingContext drawingContext = drawingVisual.RenderOpen();

    // Create a rectangle and draw it in the DrawingContext.
    Rect rect = new Rect(new System.Windows.Point(160, 100), new System.Windows.Size(320, 80));
    drawingContext.DrawRectangle(System.Windows.Media.Brushes.LightBlue, (System.Windows.Media.Pen)null, rect);

    // Persist the drawing content.
    drawingContext.Close();

    return drawingVisual;
}

' Create a DrawingVisual that contains a rectangle.
Private Function CreateDrawingVisualRectangle() As DrawingVisual
	Dim drawingVisual As New DrawingVisual()

	' Retrieve the DrawingContext in order to create new drawing content.
	Dim drawingContext As DrawingContext = drawingVisual.RenderOpen()

	' Create a rectangle and draw it in the DrawingContext.
	Dim rect As New Rect(New Point(160, 100), New Size(320, 80))
	drawingContext.DrawRectangle(Brushes.LightBlue, CType(Nothing, Pen), rect)

	' Persist the drawing content.
	drawingContext.Close()

	Return drawingVisual
End Function

次の例を示します、 PushOpacity、 PushEffect、およびPopコマンド。The next example demonstrates the PushOpacity, PushEffect, and Pop commands. DrawingContextから取得したが、DrawingGroupを使用して表示し、Imageコントロール。The DrawingContext is obtained from a DrawingGroup and displayed using an Image control.

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

注釈

使用して、DrawingContextを設定する、VisualまたはDrawingにビジュアル コンテンツ。Use a DrawingContext to populate a Visual or a Drawing with visual content.

DrawingContextの描画メソッドのような描画メソッドが表示されます、System.Drawing.Graphics型、その動作非常が異なります:DrawingContextは保持モード グラフィックス システムで使用中に、System.Drawing.Graphics型は、イミディ エイト モードで使用グラフィックス システム。Although the DrawingContext draw methods appear similar to the draw methods of the System.Drawing.Graphics type, they function very differently: DrawingContext is used with a retained mode graphics system, while the System.Drawing.Graphics type is used with an immediate mode graphics system. 使用すると、DrawingContextオブジェクトの描画コマンド、レンダリング命令のセットを実際に格納する (厳密なストレージ メカニズムを提供するオブジェクトの種類によって異なります、 DrawingContext)、グラフィックスによって後で使用されるシステムはリアルタイムの画面に描画されません。When you use a DrawingContext object's draw commands, you are actually storing a set of rendering instructions (although the exact storage mechanism depends on the type of object that supplies the DrawingContext) that will later be used by the graphics system; you are not drawing to the screen in real-time. Windows Presentation Foundation (WPF) のグラフィックス システムのしくみの詳細については、次を参照してください。 WPF グラフィックス レンダリングの概要します。For more information about how the Windows Presentation Foundation (WPF) graphics system works, see WPF Graphics Rendering Overview.

決して直接インスタンス化する、 DrawingContext; など、特定のメソッドから描画コンテキストを取得することができます、ただし、DrawingGroup.OpenとDrawingVisual.RenderOpenします。You never directly instantiate a DrawingContext; you can, however, acquire a drawing context from certain methods, such as DrawingGroup.Open and DrawingVisual.RenderOpen.

メソッド

明示的なインターフェイスの実装

プロパティ

適用対象

こちらもご覧ください

• DrawingGroup
• Drawing Drawing Drawing Drawing