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How to: Create a Composite Drawing

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This example shows how to use a DrawingGroup to create complex drawings by combining multiple Drawing objects into a single composite drawing.

Example

The following example uses a DrawingGroup to create a composite drawing from the GeometryDrawing and ImageDrawing objects. The following illustration shows the output that this example produces.

Illustration of a composite drawing showing a square filled with kiwi slices overlapping a black rimmed, green circle on the upper left with a black rimmed, green circle overlapping on the bottom right.
A composite drawing that is created by using DrawingGroup

Note the gray border, which shows the bounds of the drawing.

//
// Create three drawings.
//
GeometryDrawing ellipseDrawing =
    new GeometryDrawing(
        new SolidColorBrush(Color.FromArgb(102, 181, 243, 20)),
        new Pen(Brushes.Black, 4),
        new EllipseGeometry(new Point(50,50), 50, 50)
    );

ImageDrawing kiwiPictureDrawing =
    new ImageDrawing(
        new BitmapImage(new Uri(@"sampleImages\kiwi.png", UriKind.Relative)),
        new Rect(50,50,100,100));

GeometryDrawing ellipseDrawing2 =
    new GeometryDrawing(
        new SolidColorBrush(Color.FromArgb(102,181,243,20)),
        new Pen(Brushes.Black, 4),
        new EllipseGeometry(new Point(150, 150), 50, 50)
    );

// Create a DrawingGroup to contain the drawings.
DrawingGroup aDrawingGroup = new DrawingGroup();
aDrawingGroup.Children.Add(ellipseDrawing);
aDrawingGroup.Children.Add(kiwiPictureDrawing);
aDrawingGroup.Children.Add(ellipseDrawing2);


<DrawingGroup>

  <GeometryDrawing Brush="#66B5F314">
    <GeometryDrawing.Geometry>
      <EllipseGeometry Center="50,50" RadiusX="50"  RadiusY="50"/>
    </GeometryDrawing.Geometry>
    <GeometryDrawing.Pen>
      <Pen Brush="Black" Thickness="4" />
    </GeometryDrawing.Pen>
  </GeometryDrawing>
  <ImageDrawing ImageSource="sampleImages\kiwi.png" Rect="50,50,100,100"/>
  <GeometryDrawing Brush="#66B5F314">
    <GeometryDrawing.Geometry>
      <EllipseGeometry Center="150,150" RadiusX="50"  RadiusY="50"/>
    </GeometryDrawing.Geometry>
    <GeometryDrawing.Pen>
      <Pen Brush="Black" Thickness="4" />
    </GeometryDrawing.Pen>
  </GeometryDrawing>
</DrawingGroup>

You can use a DrawingGroup to apply a Transform, Opacity setting, OpacityMask, BitmapEffect, ClipGeometry, or GuidelineSet to the drawings it contains. Because a DrawingGroup is also a Drawing, it can contain other DrawingGroup objects.

The following example is similar to the preceding example, except that it uses additional DrawingGroup objects to apply bitmap effects and an opacity mask to some of its drawings. The following illustration shows the output that this example produces.

Illustration of a composite drawing showing a square filled with kiwi slices overlapping a black rimmed, green circle on the upper left with a black rimmed, green circle overlapping on the bottom right. Bitmap effects and an opacity mask have been applied distorting the original drawing.
Composite drawing that has multiple DrawingGroup objects

Note the gray border, which shows the bounds of the drawing.


// Create a DrawingGroup.
DrawingGroup mainGroup = new DrawingGroup();

//
// Create a GeometryDrawing
//
GeometryDrawing ellipseDrawing =
    new GeometryDrawing(
        new SolidColorBrush(Color.FromArgb(102, 181, 243, 20)),
        new Pen(Brushes.Black, 4),
        new EllipseGeometry(new Point(50, 50), 50, 50)
    );

//
// Use a DrawingGroup to apply a blur
// bitmap effect to the drawing.
//
DrawingGroup blurGroup = new DrawingGroup();
blurGroup.Children.Add(ellipseDrawing);
BlurBitmapEffect blurEffect = new BlurBitmapEffect();
blurEffect.Radius = 5;
blurGroup.BitmapEffect = blurEffect;

// Add the DrawingGroup to the main DrawingGroup.
mainGroup.Children.Add(blurGroup);

//
// Create an ImageDrawing.
//
ImageDrawing kiwiPictureDrawing =
    new ImageDrawing(
        new BitmapImage(new Uri(@"sampleImages\kiwi.png", UriKind.Relative)),
        new Rect(50, 50, 100, 100));

//
// Use a DrawingGroup to apply an opacity mask
// and a bevel.
//
DrawingGroup maskedAndBeveledGroup = new DrawingGroup();
maskedAndBeveledGroup.Children.Add(kiwiPictureDrawing);

// Create an opacity mask.
RadialGradientBrush rgBrush =new RadialGradientBrush();
rgBrush.GradientStops.Add(new GradientStop(Color.FromArgb(0,0,0,0), 0.55));
rgBrush.GradientStops.Add(new GradientStop(Color.FromArgb(255,0,0,0), 0.65));
rgBrush.GradientStops.Add(new GradientStop(Color.FromArgb(0,0,0,0), 0.75));
rgBrush.GradientStops.Add(new GradientStop(Color.FromArgb(255,0,0,0), 0.80));
rgBrush.GradientStops.Add(new GradientStop(Color.FromArgb(0,0,0,0), 0.90));
rgBrush.GradientStops.Add(new GradientStop(Color.FromArgb(255,0,0,0), 1.0));
maskedAndBeveledGroup.OpacityMask = rgBrush;

// Apply a bevel.
maskedAndBeveledGroup.BitmapEffect = new BevelBitmapEffect();

// Add the DrawingGroup to the main group.
mainGroup.Children.Add(maskedAndBeveledGroup);

//
// Create another GeometryDrawing.
//
GeometryDrawing ellipseDrawing2 =
  new GeometryDrawing(
      new SolidColorBrush(Color.FromArgb(102, 181, 243, 20)),
      new Pen(Brushes.Black, 4),
      new EllipseGeometry(new Point(150, 150), 50, 50)
  );

// Add the DrawingGroup to the main group.
mainGroup.Children.Add(ellipseDrawing2);


<DrawingGroup>

  <DrawingGroup>
    <GeometryDrawing Brush="#66B5F314">
      <GeometryDrawing.Geometry>
        <EllipseGeometry Center="50,50" RadiusX="50"  RadiusY="50"/>
      </GeometryDrawing.Geometry>
      <GeometryDrawing.Pen>
        <Pen Brush="Black" Thickness="4" />
      </GeometryDrawing.Pen>
    </GeometryDrawing>
    <DrawingGroup.BitmapEffect>
      <BlurBitmapEffect Radius="5" />
    </DrawingGroup.BitmapEffect>
  </DrawingGroup>

  <DrawingGroup>
    <ImageDrawing ImageSource="sampleImages\kiwi.png" Rect="50,50,100,100"/>
    <DrawingGroup.BitmapEffect>
      <BevelBitmapEffect  />
    </DrawingGroup.BitmapEffect>
    <DrawingGroup.OpacityMask>
      <RadialGradientBrush>
        <GradientStop Offset="0.55" Color="#00000000" />
        <GradientStop Offset="0.65" Color="#FF000000" />
        <GradientStop Offset="0.75" Color="#00000000" />
        <GradientStop Offset="0.80" Color="#FF000000" />
        <GradientStop Offset="0.90" Color="#00000000" />
        <GradientStop Offset="1.0" Color="#FF000000" />
      </RadialGradientBrush>
    </DrawingGroup.OpacityMask>
  </DrawingGroup>

  <GeometryDrawing Brush="#66B5F314">
    <GeometryDrawing.Geometry>
      <EllipseGeometry Center="150,150" RadiusX="50"  RadiusY="50"/>
    </GeometryDrawing.Geometry>
    <GeometryDrawing.Pen>
      <Pen Brush="Black" Thickness="4" />
    </GeometryDrawing.Pen>
  </GeometryDrawing>

</DrawingGroup>

For more information about Drawing objects, see Drawing Objects Overview.

See also