Wes xx mediapipe integration

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Unity/Annotation/LabelAnnotation.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;
+using UnityEngine.UI;
+
+namespace Mediapipe.Unity
+{
+#pragma warning disable IDE0065
+  using Color = UnityEngine.Color;
+#pragma warning restore IDE0065
+
+  public class LabelAnnotation : HierarchicalAnnotation
+  {
+    [SerializeField] private Text _labelText;
+    [SerializeField] private Transform _backgroundTransform;
+
+    public void Draw(string text, Vector3 position, Color color, float maxWidth, float maxHeight)
+    {
+      if (ActivateFor(text))
+      {
+        // move to the front to show background plane.
+        _labelText.transform.localPosition = new Vector3(position.x, position.y, -1);
+        _labelText.transform.localRotation = Quaternion.Euler(0, 0, -(int)rotationAngle);
+        _labelText.text = text;
+        _labelText.color = DecideTextColor(color);
+        _labelText.fontSize = GetFontSize(text, maxWidth, Mathf.Min(maxHeight, 48.0f));
+
+        var width = Mathf.Min(_labelText.preferredWidth + 24, maxWidth); // add margin
+        var height = _labelText.preferredHeight;
+        var rectTransform = _labelText.GetComponent<RectTransform>();
+        rectTransform.sizeDelta = new Vector2(width, height);
+
+        _backgroundTransform.localScale = new Vector3(width / 10, 1, height / 10);
+        _backgroundTransform.gameObject.GetComponent<Renderer>().material.color = color;
+      }
+    }
+
+    private int GetFontSize(string text, float maxWidth, float maxHeight)
+    {
+      var ch = Mathf.Min(maxWidth / text.Length, maxHeight);
+      return (int)Mathf.Clamp(ch, 24.0f, 72.0f);
+    }
+
+    private Color DecideTextColor(Color backgroundColor)
+    {
+      var lw = CalcContrastRatio(Color.white, backgroundColor);
+      var lb = CalcContrastRatio(backgroundColor, Color.black);
+      return lw < lb ? Color.black : Color.white;
+    }
+
+    private float CalcRelativeLuminance(Color color)
+    {
+      var r = color.r <= 0.03928f ? color.r / 12.92f : Mathf.Pow((color.r + 0.055f) / 1.055f, 2.4f);
+      var g = color.g <= 0.03928f ? color.g / 12.92f : Mathf.Pow((color.g + 0.055f) / 1.055f, 2.4f);
+      var b = color.b <= 0.03928f ? color.b / 12.92f : Mathf.Pow((color.b + 0.055f) / 1.055f, 2.4f);
+      return (0.2126f * r) + (0.7152f * g) + (0.0722f * b);
+    }
+
+    private float CalcContrastRatio(Color lighter, Color darker)
+    {
+      var l1 = CalcRelativeLuminance(lighter);
+      var l2 = CalcRelativeLuminance(darker);
+      return (l1 + 0.05f) / (l2 + 0.05f);
+    }
+  }
+}