Version: 2021.2
USS サポートプロパティ

USS プロパティータイプ


USS を使用する場合、UI コード内のビルトインの VisualElement プロパティーの値や カスタムプロパティーの値を指定できます。

In addition of reading their values from USS files, you can assign built-in property values in C#, using the C# properties of VisualElement. Values assigned in C# override values from a Unity style sheet (USS).

You can extend USS with custom properties. Custom USS Properties require the -- prefix.




UI Toolkit supports pixels (px) and percentages (%) as units of measurement for length. Pixel values are absolute, while percentages are usually relative to the element’s parent.


  • width:200px; は、幅が 200 ピクセルであることを表します。
  • width:50%; は、幅が親要素の半分であることを表しています。

It’s important to specify the unit of measurement. If you do not specify a unit of measurement, UI Toolkit assumes that the property value is expressed in pixels.

注意: 0 は、測定単位を必要としない特別な値です。


数値は、浮動小数点数または整数リテラルで表されます。例えば、flex:1.0 です。


一部のビルトインプロパティーでは、特定のキーワードがサポートされています。キーワードは、数字ではなく説明的な名前を提供します。例えば、position:absolute です。すべてのプロパティーは、プロパティーをデフォルト値にリセットする initial グローバルキーワードをサポートします。キーワードのリストについては、サポートされているプロパティー を参照してください。

UI Toolkit supports the following literal color values and functions:

  • 16 進数値: #FFFF00 (rgba はチャンネルごとに 1 バイト)、#0F0 (rgb)
  • RGB 関数: rgb(255, 255, 0)
  • RGBA 関数: rgba(255, 255, 0, 1.0)
  • カラーキーワード: bluetransparent


You can reference project assets such as fonts and textures from your USS files. For example, you might reference a texture to use as the background image for an element.

To reference an asset, you can use either the url() function or the resource() function. Referenced Assets are resolved when the style sheet is imported.

For example, the style declaration below uses the resource() function to reference a texture asset named img.png in the Images directory, and specify it as the background image.

`background-image: resource("Images/img.png");

Unity recommends using url() function in most cases. However, the resource() function supports automatically loading different versions of image assets for different screen densities.

Referencing assets with the url function

When you reference an asset with the url() function, the path you specify can be relative or absolute:

  • Relative paths must be relative to the folder that contains the USS file that references the asset.
  • Absolute paths are relative to the project.

The path must include the file extension.

For example, let’s say your project has a USS folder that contains all of your style sheets, and a Resources folder that contains all of your image assets.

  └─ Editor
      └─ Resources
      └─ USS

To reference an image named thumb.png, you can use one of the following paths:

Relative path Absolute path
url("../Resources/thumb.png") url("/Assets/Editor/Resources/thumb.png")



Referencing assets with the resource function

The resource() function can reference assets in Unity’s resource folders (Resources and Editor Default Resources). You reference an asset by name.

  • If the file is in the Editor Default Resources Resources folder, you must include the file extension.
  • If the file is in the Resources folder, you must not include the file extension.

Path to file Reference syntax
Assets/Resources/Images/my-image.png resource("Images/my-image")
Assets/Editor Default Resources/Images/my-image.png resource("Images/default-image.png")

Referencing image assets for High DPI/Retina screens

If you need to support screens with different screen densities (DPI), the resource() function allows you to load the correct versions of texture assets automatically.

You have to:

  • Make sure that the high DPI versions of your textures have a @2x suffix in their file names. For example the high DPI version of myimage.png should be myimage@2x.png
  • Place the regular and high DPI versions of the texture assets in the same project folder.

When Unity loads the asset, it automatically chooses the correct version for the current screen DPI.

For example, if you use resource("myimage") in USS, Unity loads either Resources/myimage.png or Resources/myimage@2x.png.


引用符を使用して文字列の値を指定します。例えば --my-property: "foo"

USS サポートプロパティ