Add DrawCommandSpan Usable with PreparedLayoutTextView

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/text/PreparedLayoutTextView.kt

@@ -27,6 +27,7 @@ import com.facebook.proguard.annotations.DoNotStrip
 import com.facebook.react.uimanager.BackgroundStyleApplicator
 import com.facebook.react.uimanager.ReactCompoundView
 import com.facebook.react.uimanager.style.Overflow
+import com.facebook.react.views.text.internal.span.DrawCommandSpan
 import com.facebook.react.views.text.internal.span.ReactFragmentIndexSpan
 import kotlin.collections.ArrayList
 import kotlin.math.roundToInt
@@ -119,11 +120,37 @@ internal class PreparedLayoutTextView(context: Context) : ViewGroup(context), Re
             selectionColor ?: DefaultStyleValuesUtil.getDefaultTextColorHighlight(context)
       }
 
+      val spanned = text as? Spanned
+      val drawCommandSpans =
+          spanned?.getSpans(0, spanned.length, DrawCommandSpan::class.java) ?: emptyArray()
+
+      if (spanned != null) {
+        for (span in drawCommandSpans) {
+          span.onPreDraw(
+              spanned.getSpanStart(span),
+              spanned.getSpanEnd(span),
+              canvas,
+              layout,
+          )
+        }
+      }
+
       if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
         Api34Utils.draw(layout, canvas, selection?.path, selectionPaint)
       } else {
         layout.draw(canvas, selection?.path, selectionPaint, 0)
       }
+
+      if (spanned != null) {
+        for (span in drawCommandSpans) {
+          span.onDraw(
+              spanned.getSpanStart(span),
+              spanned.getSpanEnd(span),
+              canvas,
+              layout,
+          )
+        }
+      }
     }
   }
 

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/text/internal/span/DrawCommandSpan.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react.views.text.internal.span
+
+import android.graphics.Canvas
+import android.text.Layout
+import android.text.style.UpdateAppearance
+
+/**
+ * May be overriden to implement charater styles which are applied by [PreparedLayoutTextView]
+ * during the drawing of text, against the underlying Android canvas
+ */
+public abstract class DrawCommandSpan : UpdateAppearance, ReactSpan {
+  /**
+   * Called before the text is drawn. This happens after the Paragraph component has drawn its
+   * background, but may be called before text spans with their own background color are drawn.
+   */
+  public open fun onPreDraw(start: Int, end: Int, canvas: Canvas, layout: Layout): Unit = Unit
+
+  /** Called after the text is drawn, including some effects like text shadows */
+  public open fun onDraw(start: Int, end: Int, canvas: Canvas, layout: Layout): Unit = Unit
+}