如何：使用图像绘制区域

此示例演示如何使用 ImageBrush 类绘制具有图像的区域。 ImageBrush 显示单个图像，该图像由其 ImageSource 属性指定。

示例：

以下示例使用 ImageBrush 来绘制按钮的 Background。

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

namespace Microsoft.Samples.Graphics.UsingImageBrush
{

    public class PaintingWithImagesExample : Page
    {

        public PaintingWithImagesExample()
        {
            Background = Brushes.White;
            StackPanel mainPanel = new StackPanel();
            mainPanel.Margin = new Thickness(20.0);

            // Create a button.
            Button berriesButton = new Button();
            berriesButton.Foreground = Brushes.White;
            berriesButton.FontWeight = FontWeights.Bold;
            FontSizeConverter sizeConverter = new FontSizeConverter();
            berriesButton.FontSize = (Double)sizeConverter.ConvertFromString("16pt");
            berriesButton.FontFamily = new FontFamily("Verdana");
            berriesButton.Content = "Berries";
            berriesButton.Padding = new Thickness(20.0);
            berriesButton.HorizontalAlignment = HorizontalAlignment.Left;

            // Create an ImageBrush.
            ImageBrush berriesBrush = new ImageBrush();
            berriesBrush.ImageSource =
                new BitmapImage(
                    new Uri(@"sampleImages\berries.jpg", UriKind.Relative)
                );

            // Use the brush to paint the button's background.
            berriesButton.Background = berriesBrush;

            mainPanel.Children.Add(berriesButton);
            this.Content = mainPanel;
        }
    }
}

默认情况下，ImageBrush 会拉伸其图像，以完全填充您正在绘制的区域。 在前面的示例中，图像拉伸以填充按钮，可能扭曲图像。 可以通过将TileBrush的Stretch属性设置为Uniform或UniformToFill，来控制此行为，从而使画笔保留图像的纵横比。

如果在 ImageBrush 上设置 Viewport 和 TileMode 属性，就可以创建一个重复模式。 以下示例使用从图像创建的模式绘制按钮。

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

namespace Microsoft.Samples.Graphics.UsingImageBrush
{

    public class TiledImageBrushExample : Page
    {

        public TiledImageBrushExample()
        {
            Background = Brushes.White;
            StackPanel mainPanel = new StackPanel();
            mainPanel.Margin = new Thickness(20.0);

            // Create a button.
            Button berriesButton = new Button();
            berriesButton.Foreground = Brushes.White;
            berriesButton.FontWeight = FontWeights.Bold;
            FontSizeConverter sizeConverter = new FontSizeConverter();
            berriesButton.FontSize = (Double)sizeConverter.ConvertFromString("16pt");
            berriesButton.FontFamily = new FontFamily("Verdana");
            berriesButton.Content = "Berries";
            berriesButton.Padding = new Thickness(20.0);
            berriesButton.HorizontalAlignment = HorizontalAlignment.Left;

            // Create an ImageBrush.
            ImageBrush berriesBrush = new ImageBrush();
            berriesBrush.ImageSource =
                new BitmapImage(
                    new Uri(@"sampleImages\berries.jpg", UriKind.Relative)
                );

            // Set the ImageBrush's Viewport and TileMode
            // so that it produces a pattern from
            // the image.
            berriesBrush.Viewport = new Rect(0,0,0.5,0.5);
            berriesBrush.TileMode = TileMode.FlipXY;

            // Use the brush to paint the button's background.
            berriesButton.Background = berriesBrush;

            mainPanel.Children.Add(berriesButton);
            this.Content = mainPanel;
        }
    }
}

Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Media.Imaging
Imports System.Windows.Media

Namespace Microsoft.Samples.Graphics.UsingImageBrush

    Public Class TiledImageBrushExample
        Inherits Page

        Public Sub New()
            Background = Brushes.White
            Dim mainPanel As New StackPanel()
            mainPanel.Margin = New Thickness(20.0)

            ' Create a button.
            Dim berriesButton As New Button()
            With berriesButton
                .Foreground = Brushes.White
                .FontWeight = FontWeights.Bold
                Dim sizeConverter As New FontSizeConverter()
                .FontSize = CType(sizeConverter.ConvertFromString("16pt"), Double)
                .FontFamily = New FontFamily("Verdana")
                .Content = "Berries"
                .Padding = New Thickness(20.0)
                .HorizontalAlignment = HorizontalAlignment.Left
            End With

            ' Create an ImageBrush.
            Dim berriesBrush As New ImageBrush()
            berriesBrush.ImageSource = New BitmapImage(New Uri("sampleImages\berries.jpg", UriKind.Relative))

            ' Set the ImageBrush's Viewport and TileMode
            ' so that it produces a pattern from
            ' the image.
            berriesBrush.Viewport = New Rect(0, 0, 0.5, 0.5)
            berriesBrush.TileMode = TileMode.FlipXY

            ' Use the brush to paint the button's background.
            berriesButton.Background = berriesBrush

            mainPanel.Children.Add(berriesButton)
            Me.Content = mainPanel
        End Sub
    End Class
End Namespace

有关该 ImageBrush 类的详细信息，请参阅 “使用图像、绘图和视觉对象进行绘制”。

此代码示例是为 ImageBrush 类提供的较大示例的一部分。 有关完整示例，请参阅 ImageBrush 示例。

另请参阅

• 使用图像、绘图和视觉对象进行绘制