fix(android): measure text visual bounds safely

Author: TorinAsakura

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

@@ -40,6 +40,7 @@ import com.facebook.react.uimanager.PixelUtil
 import com.facebook.react.uimanager.PixelUtil.dpToPx
 import com.facebook.react.uimanager.PixelUtil.pxToDp
 import com.facebook.react.uimanager.ReactAccessibilityDelegate
+import com.facebook.react.util.AndroidVersion.VERSION_CODE_VANILLA_ICE_CREAM
 import com.facebook.react.views.text.internal.span.CustomLetterSpacingSpan
 import com.facebook.react.views.text.internal.span.CustomLineHeightSpan
 import com.facebook.react.views.text.internal.span.CustomStyleSpan
@@ -764,13 +765,32 @@ internal object TextLayoutManager {
       )
     }
 
-    val desiredWidth = ceil(Layout.getDesiredWidth(text, paint)).toInt()
-
     val layoutWidth =
         when (widthYogaMeasureMode) {
           YogaMeasureMode.EXACTLY -> ceil(width).toInt()
-          YogaMeasureMode.AT_MOST -> min(desiredWidth, floor(width).toInt())
-          else -> desiredWidth
+          YogaMeasureMode.AT_MOST ->
+              min(
+                  getDesiredWidth(
+                      text,
+                      includeFontPadding,
+                      textBreakStrategy,
+                      hyphenationFrequency,
+                      alignment,
+                      justificationMode,
+                      paint,
+                  ),
+                  floor(width).toInt(),
+              )
+          else ->
+              getDesiredWidth(
+                  text,
+                  includeFontPadding,
+                  textBreakStrategy,
+                  hyphenationFrequency,
+                  alignment,
+                  justificationMode,
+                  paint,
+              )
         }
     return buildLayout(
         text,
@@ -786,6 +806,47 @@ internal object TextLayoutManager {
     )
   }
 
+  private fun getDesiredWidth(
+      text: Spannable,
+      includeFontPadding: Boolean,
+      textBreakStrategy: Int,
+      hyphenationFrequency: Int,
+      alignment: Layout.Alignment,
+      justificationMode: Int,
+      paint: TextPaint,
+  ): Int {
+    val advanceWidth = ceil(Layout.getDesiredWidth(text, paint)).toInt()
+
+    if (
+        Build.VERSION.SDK_INT < VERSION_CODE_VANILLA_ICE_CREAM ||
+            setUseBoundsForWidthMethod == null
+    ) {
+      return advanceWidth
+    }
+
+    val visualBoundsLayout =
+        buildLayout(
+            text,
+            Int.MAX_VALUE / 2,
+            includeFontPadding,
+            textBreakStrategy,
+            hyphenationFrequency,
+            alignment,
+            justificationMode,
+            null,
+            ReactConstants.UNSET,
+            paint,
+            useBoundsForWidth = true,
+        )
+
+    var visualBoundsWidth = 0f
+    for (i in 0 until visualBoundsLayout.lineCount) {
+      visualBoundsWidth = max(visualBoundsWidth, visualBoundsLayout.getLineMax(i))
+    }
+
+    return max(advanceWidth, ceil(visualBoundsWidth).toInt())
+  }
+
   private fun buildLayout(
       text: Spannable,
       layoutWidth: Int,
@@ -797,6 +858,7 @@ internal object TextLayoutManager {
       ellipsizeMode: TextUtils.TruncateAt?,
       maxNumberOfLines: Int,
       paint: TextPaint,
+      useBoundsForWidth: Boolean = false,
   ): Layout {
     val builder =
         StaticLayout.Builder.obtain(text, 0, text.length, paint, layoutWidth)
@@ -818,6 +880,10 @@ internal object TextLayoutManager {
       builder.setUseLineSpacingFromFallbacks(true)
     }
 
+    if (useBoundsForWidth) {
+      setUseBoundsForWidthMethod?.invoke(builder, true)
+    }
+
     return builder.build()
   }
 

packages/react-native/ReactAndroid/src/test/java/com/facebook/react/views/text/TextLayoutManagerAbsoluteLayoutWithFractionalPixelTest.kt

@@ -15,9 +15,11 @@ import android.text.TextPaint
 import android.text.TextUtils
 import com.facebook.yoga.YogaMeasureMode
 import kotlin.math.ceil
+import kotlin.math.floor
 import org.assertj.core.api.Assertions.assertThat
 import org.junit.Test
 import org.junit.runner.RunWith
+import org.robolectric.annotation.Config
 import org.robolectric.RobolectricTestRunner
 
 /**
@@ -77,6 +79,42 @@ class TextLayoutManagerAbsoluteLayoutWithFractionalPixelTest {
         .isGreaterThanOrEqualTo(renderedLineWidth)
   }
 
+  @Test
+  @Config(sdk = [35])
+  fun `Android 15 EXACTLY mode keeps the width provided by Yoga`() {
+    val text = SpannableString("First line\nSecond line")
+    val paint = TextPaint(TextPaint.ANTI_ALIAS_FLAG).apply { textSize = 16f }
+    val exactWidth = 48.5f
+
+    val layout = invokeCreateLayout(text, exactWidth, paint)
+
+    assertThat(layout.width).isEqualTo(ceil(exactWidth).toInt())
+  }
+
+  @Test
+  @Config(sdk = [35])
+  fun `Android 15 AT_MOST mode does not exceed the width provided by Yoga`() {
+    val text = SpannableString("Prison Break")
+    val paint = TextPaint(TextPaint.ANTI_ALIAS_FLAG).apply { textSize = 16f }
+    val maxWidth = 8.5f
+
+    val layout = invokeCreateLayout(text, maxWidth, paint, YogaMeasureMode.AT_MOST)
+
+    assertThat(layout.width).isLessThanOrEqualTo(floor(maxWidth).toInt())
+  }
+
+  @Test
+  @Config(sdk = [35])
+  fun `Android 15 UNDEFINED mode does not shrink below advance width`() {
+    val text = SpannableString("Prison Break")
+    val paint = TextPaint(TextPaint.ANTI_ALIAS_FLAG).apply { textSize = 16f }
+    val advanceWidth = ceil(Layout.getDesiredWidth(text, paint)).toInt()
+
+    val layout = invokeCreateLayout(text, 0f, paint, YogaMeasureMode.UNDEFINED)
+
+    assertThat(layout.width).isGreaterThanOrEqualTo(advanceWidth)
+  }
+
   /**
    * Invokes the private TextLayoutManager.createLayout via reflection. We can't call it directly
    * because it's `private` (friend_paths only opens up `internal`). Default values mirror what
@@ -90,6 +128,7 @@ class TextLayoutManagerAbsoluteLayoutWithFractionalPixelTest {
       text: SpannableString,
       width: Float,
       paint: TextPaint,
+      widthYogaMeasureMode: YogaMeasureMode = YogaMeasureMode.EXACTLY,
   ): Layout {
     val boring: BoringLayout.Metrics? = BoringLayout.isBoring(text, paint)
     val method =
@@ -117,7 +156,7 @@ class TextLayoutManagerAbsoluteLayoutWithFractionalPixelTest {
         text,
         boring,
         width,
-        YogaMeasureMode.EXACTLY,
+        widthYogaMeasureMode,
         /* includeFontPadding = */ false,
         /* textBreakStrategy = */ Layout.BREAK_STRATEGY_HIGH_QUALITY,
         /* hyphenationFrequency = */ Layout.HYPHENATION_FREQUENCY_NONE,