| -api-id | -api-type |
|---|---|
T:Windows.UI.Xaml.Media.ImageBrush |
winrt class |
Paints an area with an image. The image source is typically obtained from file formats such as Joint Photographic Experts Group (JPEG).
<ImageBrush .../>An ImageBrush is a type of brush that defines its content as an image which can be optionally stretched and aligned. Uses for an ImageBrush include decorative effects for text, or image backgrounds for controls or layout containers.
It's useful to use an ImageBrush instead of an Image control in two main scenarios:
- You want to paint a non-rectangular area such as an ellipse or border with an image
- You want to use a single ImageBrush to paint multiple areas or UIElements with the same image, which is more efficient than using multiple Image controls
If you define an ImageBrush using code, use the default constructor, then set ImageBrush.ImageSource. This requires a BitmapImage (not a Uniform Resource Identifier (URI)) in code. If your source is a stream, use the SetSourceAsync method to initialize the value. If your source is a Uniform Resource Identifier (URI), which includes content in your app that uses the ms-appx or ms-resource schemes, use the BitmapImage constructor that takes a Uniform Resource Identifier (URI). You might also consider handling the ImageOpened event if there are any timing issues with retrieving or decoding the image source, where you might need alternate content to display until the image source is available. See XAML images sample for example code.
Note
You can use automatic handling for accessing unqualified resources with current scale and culture qualifiers, or you can use ResourceManager and ResourceMap with qualifiers for culture and scale to obtain the resources directly. For more info see Resource management system.
The Stretch property is important for how the image is applied when used as a brush. Some images look good when stretched as applied to a particular Brush property with the Fill behavior whereas other images do not stretch or scale well and might require a value of None or Uniform for Stretch. Experiment with different values for Stretch to see which behavior looks best when applied to the UI.
You should create your image sources at several recommended sizes, to ensure that your app looks great when Windows 8 scales it. When specifying an ImageSource for an ImageBrush, you can use a naming convention that will automatically reference the correct resource for the current scaling. For specifics of the naming convention and more info, see Quickstart: Using file or image resources.
For more info on how to design for scaling, see UX guidelines for layout and scaling.
Windows 8
Windows 8 had an issue with ImageSource resolution from a XAML attribute URI value, if the ImageBrush is part of a XAML style or template that's applied to a control. The control usage would sometimes use a component-specific base URI rather than the appropriate base URI for the style or template, which usually comes from the app. The issue is fixed starting with Windows 8.1; the base URI is correctly determined for app resources or component resources depending on the scope that needs the base URI. Apps that were compiled for Windows 8 might have used workarounds for this behavior, by putting their image source files in the "wrong" place, where the XAML URI would resolve and the app would show the images. If you are migrating XAML from Windows 8 to Windows 8.1 you should test any ImageBrush usages in a style or template from your XAML and verify that the image resolution in your app is working with Windows 8.1. If you have a problem, you should move your image source files within the package so that they're in the correct resource scope for the new behavior.
Apps that were compiled for Windows 8 but running on Windows 8.1 continue to use the Windows 8 behavior.
This XAML example shows how to set the Foreground property of a TextBlock to an ImageBrush, whose image is used as the fill for the TextBlock-rendered text.
[!code-xamlimaging_ovw_painting_with_an_image]
TileBrush, Image, Image and ImageBrush, XAML vector-based drawing sample (see Scenario 2)