Version: 2021.2+
This example demonstrates how to use custom USS variables in a custom control.
This example creates a custom control that reads two colors from USS and uses them to generate a texture.
You can find the completed files that this example creates in this GitHub repository.
This guide is for developers familiar with the Unity Editor, UI(User Interface) Allows a user to interact with your application. Unity currently supports three UI systems. More info
See in Glossary Toolkit, and C# scripting. Before you start, get familiar with the following:
Create a C# script to define the custom control and a USS file to define the custom style.
Create a Unity project with any template.
Create a folder named create-custom-style-custom-control
to store your files.
In the ExampleElementCustomStyle
folder, create a C# script named ExampleElementCustomStyle.cs
and replace its contents with the following:
using UnityEngine;
using UnityEngine.UIElements;
namespace UIToolkitExamples
{
public class ExampleElementCustomStyle : VisualElement
{
// Factory class, required to expose this custom control to UXML
public new class UxmlFactory : UxmlFactory<ExampleElementCustomStyle, UxmlTraits> { }
// Traits class
public new class UxmlTraits : VisualElement.UxmlTraits { }
// Use CustomStyleProperty<T> to fetch custom style properties from USS
static readonly CustomStyleProperty<Color> S_GradientFrom = new CustomStyleProperty<Color>("--gradient-from");
static readonly CustomStyleProperty<Color> S_GradientTo = new CustomStyleProperty<Color>("--gradient-to");
// Image child element and its texture
Texture2D m_Texture2D;
Image m_Image;
public ExampleElementCustomStyle()
{
// Create an Image and a texture for it. Attach Image to self.
m_Texture2D = new Texture2D(100, 100);
m_Image = new Image();
m_Image.image = m_Texture2D;
Add(m_Image);
RegisterCallback<CustomStyleResolvedEvent>(OnStylesResolved);
}
// When custom styles are known for this control, make a gradient from the colors.
void OnStylesResolved(CustomStyleResolvedEvent evt)
{
Color from, to;
if (evt.customStyle.TryGetValue(S_GradientFrom, out from)
&& evt.customStyle.TryGetValue(S_GradientTo, out to))
{
GenerateGradient(from, to);
}
}
public void GenerateGradient(Color from, Color to)
{
for (int i = 0; i < m_Texture2D.width; ++i)
{
Color color = Color.Lerp(from, to, i / (float)m_Texture2D.width);
for (int j = 0; j < m_Texture2D.height; ++j)
{
m_Texture2D.SetPixel(i, j, color);
}
}
m_Texture2D.Apply();
m_Image.MarkDirtyRepaint();
}
}
}
Create a USS file named ExampleElementCustomStyle.uss
and replace its contents with the following:
ExampleElementCustomStyle {
--gradient-from: red;
--gradient-to: yellow;
}
Create a UI Document to use the custom control and apply the custom style to the custom control.
ExampleElementCustomStyle
folder, create a UI Document named ExampleElementCustomStyle.uxml
.ExampleElementCustomStyle.uxml
to open it in the UI Builder.ExampleElementCustomStyle.uss
file as an existing USS. This applies the custom USS variables to the square.When you visit any website, it may store or retrieve information on your browser, mostly in the form of cookies. This information might be about you, your preferences or your device and is mostly used to make the site work as you expect it to. The information does not usually directly identify you, but it can give you a more personalized web experience. Because we respect your right to privacy, you can choose not to allow some types of cookies. Click on the different category headings to find out more and change our default settings. However, blocking some types of cookies may impact your experience of the site and the services we are able to offer.
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