Use Vector API to create a radial progress indicator

Example overview

Prerequisites

• UI Builder
• UXML
• USS
• Generate 2D visual content

• MeshGenerationContext

Create the radial progress control and its custom mesh

RadialProgress

1. Create a Unity project with any template.
2. Create a folder named

   radial-progress

   to store your files.
3. In the

   radial-progress

   folder, create a C# script named

   RadialProgress.cs

   with the following content:

using Unity.Collections;using UnityEngine;using UnityEngine.UIElements;namespace Painter2DExample{    // An element that displays progress inside a partially filled circle    [UxmlElement]    public partial class RadialProgress : VisualElement    {        // These are USS class names for the control overall and the label.        public static readonly string ussClassName = "radial-progress";        public static readonly string ussLabelClassName = "radial-progress__label";        // These objects allow C# code to access custom USS properties.        static CustomStyleProperty<Color> s_TrackColor = new CustomStyleProperty<Color>("--track-color");        static CustomStyleProperty<Color> s_ProgressColor = new CustomStyleProperty<Color>("--progress-color");        Color m_TrackColor = Color.gray;        Color m_ProgressColor = Color.red;        // This is the label that displays the percentage.        Label m_Label;        // This is the number that the Label displays as a percentage.        float m_Progress;        // A value between 0 and 100        [UxmlAttribute]        public float progress        {            // The progress property is exposed in C#.            get => m_Progress;            set            {                // Whenever the progress property changes, MarkDirtyRepaint() is named. This causes a call to the                // generateVisualContents callback.                m_Progress = value;                m_Label.text = Mathf.Clamp(Mathf.Round(value), 0, 100) + "%";                MarkDirtyRepaint();            }        }        // This default constructor is RadialProgress's only constructor.        public RadialProgress()        {            // Create a Label, add a USS class name, and add it to this visual tree.            m_Label = new Label();            m_Label.AddToClassList(ussLabelClassName);            Add(m_Label);            // Add the USS class name for the overall control.            AddToClassList(ussClassName);            // Register a callback after custom style resolution.            RegisterCallback<CustomStyleResolvedEvent>(evt => CustomStylesResolved(evt));            // Register a callback to generate the visual content of the control.            generateVisualContent += GenerateVisualContent;            progress = 0.0f;        }        static void CustomStylesResolved(CustomStyleResolvedEvent evt)        {            RadialProgress element = (RadialProgress)evt.currentTarget;            element.UpdateCustomStyles();        }        // After the custom colors are resolved, this method uses them to color the meshes and (if necessary) repaint        // the control.        void UpdateCustomStyles()        {            bool repaint = false;            if (customStyle.TryGetValue(s_ProgressColor, out m_ProgressColor))                repaint = true;            if (customStyle.TryGetValue(s_TrackColor, out m_TrackColor))                repaint = true;            if (repaint)                MarkDirtyRepaint();        }        void GenerateVisualContent(MeshGenerationContext context)        {            float width = contentRect.width;            float height = contentRect.height;            var painter = context.painter2D;            painter.lineWidth = 10.0f;            painter.lineCap = LineCap.Butt;            // Draw the track            painter.strokeColor = m_TrackColor;            painter.BeginPath();            painter.Arc(new Vector2(width * 0.5f, height * 0.5f), width * 0.5f, 0.0f, 360.0f);            painter.Stroke();            // Draw the progress            painter.strokeColor = m_ProgressColor;            painter.BeginPath();            painter.Arc(new Vector2(width * 0.5f, height * 0.5f), width * 0.5f, -90.0f, 360.0f * (progress / 100.0f) - 90.0f);            painter.Stroke();        }    }}

Style the custom control

RadialProgress.uss

.radial-progress {    min-width: 26px;    min-height: 20px;    --track-color: rgb(130, 130, 130);    --progress-color: rgb(46, 132, 24);    --percentage-color: white;    margin-left: 5px;    margin-right: 5px;    margin-top: 5px;    margin-bottom: 5px;    flex-direction: row;    justify-content: center;    width: 100px;     height: 100px;}.radial-progress__label {    -unity-text-align: middle-left;    color: var(--percentage-color);}

Test the custom control in UI Builder

Progress

1. Create a UXML file named

   RadialProgressExample.uxml

   .
2. Double-click

   RadialProgressExample.uxml

   to open it in the UI Builder.
3. In the Library window, select Project > Custom Controls.
4. Drag RadialProgress to the Hierarchy window.
5. In the StyleSheets section of the UI Builder, add

   RadialProgress.uss

   as the existing USS.
6. In the Hierarchy window, select RadialProgress.
7. In the Inspector window, enter

   radial-progress

   in the Name box.
8. In the Inspector window, enter different values in the Progress box. The percentage in the
   Viewport

   ?

   changes, and the green progress ring resizes.

Create a script to update the progress with dynamic values

Progress

radial-progress

RadialProgressComponent2D.cs

using Painter2DExample;using UnityEngine;using UnityEngine.UIElements;[RequireComponent(typeof(PanelRenderer))]public class RadialProgressComponent2D : MonoBehaviour{    RadialProgress m_RadialProgress;    void OnEnable()    {        GetComponent<PanelRenderer>().RegisterUIReloadCallback(OnUIReload);    }    void OnDisable()    {        GetComponent<PanelRenderer>().UnregisterUIReloadCallback(OnUIReload);    }    private void OnUIReload(PanelRenderer panelRenderer, VisualElement rootElement, int version)    {        // Find the RadialProgress element defined in UXML        m_RadialProgress = rootElement.Q<RadialProgress>("radial-progress");    }    void Update()    {        if (m_RadialProgress != null)        {            m_RadialProgress.progress = ((Mathf.Sin(Time.time) + 1.0f) / 2.0f) * 60.0f + 10.0f;        }    }}

Test the progress indicator in runtime

1. In Unity, select
   GameObject

   ?

   > UI Toolkit > Panel Renderer.
2. In the Source Asset field of the Panel Renderer component, select

   RadialProgressExample.uxml

   .
3. Add RadialProgressComponent2D.cs as a component of the Panel Renderer GameObject.
4. Enter Play mode. The progress indicator appears in the scene, and the progress ring and value change dynamically.

Additional resources

• Create custom controls
• Use Mesh API to create a radial progress indicator