Wes xx mediapipe integration

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Unity/Annotation/AnnotationController.cs

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+// Copyright (c) 2021 homuler
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+using UnityEngine;
+
+namespace Mediapipe.Unity
+{
+  /// <summary>
+  ///   This class draws annotations on the screen which is the parent of the attached <see cref="GameObject" />.<br />
+  ///   That is, it's used like this.<br />
+  ///       1. Select a GameObject where you'd like to draw annotations.<br />
+  ///       2. Create an empty child GameObject (let's say AnnotationLayer) directly under it.<br />
+  ///       3. Attach <see cref="AnnotationController{T}" /> to AnnotationLayer.<br />
+  ///       4. Create an empty child GameObject (let's say RootAnnotation) directly under AnnotationLayer.<br />
+  ///       5. Attach <see cref="HierarchicalAnnotation" /> to RootAnnotation.<br />
+  /// </summary>
+  /// <remarks>
+  ///   Note that this class can be accessed from a thread other than main thread.
+  ///   Extended classes must be implemented to work in such a situation, since Unity APIs won't work in other threads.
+  /// </remarks>
+  public abstract class AnnotationController<T> : MonoBehaviour where T : HierarchicalAnnotation
+  {
+    [SerializeField] protected T annotation;
+    protected bool isStale = false;
+
+    public bool isMirrored
+    {
+      get => annotation.isMirrored;
+      set
+      {
+        if (annotation.isMirrored != value)
+        {
+          annotation.isMirrored = value;
+        }
+      }
+    }
+
+    public RotationAngle rotationAngle
+    {
+      get => annotation.rotationAngle;
+      set
+      {
+        if (annotation.rotationAngle != value)
+        {
+          annotation.rotationAngle = value;
+        }
+      }
+    }
+
+    protected virtual void Start()
+    {
+      if (!TryGetComponent<RectTransform>(out var _))
+      {
+        Logger.LogVerbose(GetType().Name, $"Adding RectTransform to {gameObject.name}");
+        var rectTransform = gameObject.AddComponent<RectTransform>();
+        // stretch width and height by default
+        rectTransform.pivot = new Vector2(0.5f, 0.5f);
+        rectTransform.anchorMin = Vector2.zero;
+        rectTransform.anchorMax = Vector2.one;
+        rectTransform.anchoredPosition3D = Vector3.zero;
+        rectTransform.sizeDelta = Vector2.zero;
+      }
+    }
+
+    protected virtual void LateUpdate()
+    {
+      if (isStale)
+      {
+        SyncNow();
+      }
+    }
+
+    protected virtual void OnDestroy()
+    {
+      if (annotation != null)
+      {
+        Destroy(annotation);
+        annotation = null;
+      }
+      isStale = false;
+    }
+
+    /// <summary>
+    ///   Draw annotations in current thread.
+    ///   This method must set <see cref="isStale" /> to false.
+    /// </summary>
+    /// <remarks>
+    ///   This method can only be called from main thread.
+    /// </remarks>
+    protected abstract void SyncNow();
+
+    protected void UpdateCurrentTarget<TValue>(TValue newTarget, ref TValue currentTarget)
+    {
+      if (IsTargetChanged(newTarget, currentTarget))
+      {
+        currentTarget = newTarget;
+        isStale = true;
+      }
+    }
+
+    protected bool IsTargetChanged<TValue>(TValue newTarget, TValue currentTarget)
+    {
+      // It's assumed that target has not changed iff previous target and new target are both null.
+      return currentTarget != null || newTarget != null;
+    }
+  }
+}