Comment : dessiner une image à l'aide d'ImageDrawing

Mise à jour : novembre 2007

Cet exemple indique comment utiliser un ImageDrawing pour dessiner une image. Un ImageDrawing vous permet d'afficher une ImageSource avec un DrawingBrush, un DrawingImage ou un Visual. Pour dessiner une image, créez un ImageDrawing et définissez ses propriétés ImageDrawing.ImageSource et ImageDrawing.Rect. La propriété ImageDrawing.ImageSource spécifie l'image à dessiner, tandis que la propriété ImageDrawing.Rect spécifie la position et la taille de chaque image.

Exemple

L'exemple suivant crée un dessin composite à l'aide de quatre objets ImageDrawing. Cet exemple génère l'image suivante :

Quatre objets ImageDrawing

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

namespace SDKSample
{
    public class ImageDrawingExample : Page
    {
        public ImageDrawingExample()
        {
            // Create a DrawingGroup to combine the ImageDrawing objects.
            DrawingGroup imageDrawings = new DrawingGroup();

            // Create a 100 by 100 image with an upper-left point of (75,75). 
            ImageDrawing bigKiwi = new ImageDrawing();
            bigKiwi.Rect = new Rect(75, 75, 100, 100);
            bigKiwi.ImageSource = new BitmapImage(
                new Uri(@"sampleImages\kiwi.png", UriKind.Relative));

            imageDrawings.Children.Add(bigKiwi);

            // Create a 25 by 25 image with an upper-left point of (0,150). 
            ImageDrawing smallKiwi1 = new ImageDrawing();
            smallKiwi1.Rect = new Rect(0, 150, 25, 25);
            smallKiwi1.ImageSource = new BitmapImage(new Uri(@"sampleImages\kiwi.png", UriKind.Relative));
            imageDrawings.Children.Add(smallKiwi1);

            // Create a 25 by 25 image with an upper-left point of (150,0). 
            ImageDrawing smallKiwi2 = new ImageDrawing();
            smallKiwi2.Rect = new Rect(150, 0, 25, 25);
            smallKiwi2.ImageSource = new BitmapImage(new Uri(@"sampleImages\kiwi.png", UriKind.Relative));
            imageDrawings.Children.Add(smallKiwi2);

            // Create a 75 by 75 image with an upper-left point of (0,0). 
            ImageDrawing wholeKiwi = new ImageDrawing();
            wholeKiwi.Rect = new Rect(0, 0, 75, 75);
            wholeKiwi.ImageSource = new BitmapImage(new Uri(@"sampleImages\wholekiwi.png", UriKind.Relative));
            imageDrawings.Children.Add(wholeKiwi);

            //
            // Use a DrawingImage and an Image control to
            // display the drawings.
            //
            DrawingImage drawingImageSource = new DrawingImage(imageDrawings);

            // Freeze the DrawingImage for performance benefits.
            drawingImageSource.Freeze();

            Image imageControl = new Image();
            imageControl.Stretch = Stretch.None;
            imageControl.Source = drawingImageSource;

            // Create a border to contain the Image control.
            Border imageBorder = new Border();
            imageBorder.BorderBrush = Brushes.Gray;
            imageBorder.BorderThickness = new Thickness(1);
            imageBorder.HorizontalAlignment = HorizontalAlignment.Left;
            imageBorder.VerticalAlignment = VerticalAlignment.Top;
            imageBorder.Margin = new Thickness(20);
            imageBorder.Child = imageControl;

            this.Background = Brushes.White;
            this.Margin = new Thickness(20);
            this.Content = imageBorder;
        }

    }
}

<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation" 
  xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml" 
  xmlns:PresentationOptions="https://schemas.microsoft.com/winfx/2006/xaml/presentation/options" 
  xmlns:mc="https://schemas.openxmlformats.org/markup-compatibility/2006"
  mc:Ignorable="PresentationOptions"
  Background="White" Margin="20">
  <Border BorderBrush="Gray" BorderThickness="1" 
    HorizontalAlignment="Left" VerticalAlignment="Top"
    Margin="20">
    <Image Stretch="None">
      <Image.Source>
        <DrawingImage PresentationOptions:Freeze="True">
          <DrawingImage.Drawing>
            <DrawingGroup>

              <!-- The Rect property specifies that the image only fill a 100 by 100
                   rectangular area. -->
              <ImageDrawing Rect="75,75,100,100" ImageSource="sampleImages\kiwi.png"/>

              <!-- This image is set to fill a 25 by 25 rectangular area. -->
              <ImageDrawing Rect="0,150,25,25" ImageSource="sampleImages\kiwi.png"/>

              <!-- This image is set to fill a 25 by 25 rectangular area. -->
              <ImageDrawing Rect="150,0,25,25" ImageSource="sampleImages\kiwi.png"/>

              <!-- This image is set to fill a 75 by 75 rectangular area. -->
              <ImageDrawing Rect="0,0,75,75" ImageSource="sampleImages\wholekiwi.png"/>

            </DrawingGroup>
          </DrawingImage.Drawing>
        </DrawingImage>
      </Image.Source>
    </Image>
  </Border>
</Page>

Pour obtenir un exemple de méthode simple pour afficher une image sans utiliser ImageDrawing, consultez Comment : utiliser l'élément Image.

Voir aussi

Concepts

Vue d'ensemble des objets Drawing

Vue d'ensemble des objets Freezable

Référence

Freeze

PresentationOptions:Freeze, attribut

Image