Improve touch target detection and UI layout in the A11y Scanner

scanner-rules/src/main/java/com/composea11yscanner/rules/TouchTargetRule.kt

@@ -19,7 +19,12 @@ class TouchTargetRule(
 
         val w = node.touchTargetSize.width
         val h = node.touchTargetSize.height
-        if (w >= minTouchTargetDp && h >= minTouchTargetDp) return null
+        // Pixel bounds converted back to dp can land infinitesimally below an exact dp value
+        // (for example, a 48 dp target may be reported as 47.999996 dp).
+        if (
+            w + MeasurementToleranceDp >= minTouchTargetDp &&
+            h + MeasurementToleranceDp >= minTouchTargetDp
+        ) return null
 
         return issue(
             node = node,
@@ -29,4 +34,8 @@ class TouchTargetRule(
                 "composable reaches at least ${minTouchTargetDp}dp in both dimensions.",
         )
     }
+
+    private companion object {
+        const val MeasurementToleranceDp = 0.01f
+    }
 }

scanner-rules/src/test/java/com/composea11yscanner/rules/TouchTargetRuleTest.kt

@@ -24,6 +24,18 @@ class TouchTargetRuleTest {
         assertNull(rule.evaluate(createNode(isTouchTarget = true, touchTargetSize = DpSize(48f, 48f))))
     }
 
+    @Test
+    fun `floating point noise just below minimum size passes`() {
+        assertNull(
+            rule.evaluate(
+                createNode(
+                    isTouchTarget = true,
+                    touchTargetSize = DpSize(47.999996f, 47.999996f),
+                )
+            )
+        )
+    }
+
     @Test
     fun `touch target larger than minimum passes`() {
         assertNull(rule.evaluate(createNode(isTouchTarget = true, touchTargetSize = DpSize(56f, 64f))))
@@ -49,6 +61,18 @@ class TouchTargetRuleTest {
         assertNotNull(rule.evaluate(createNode(isTouchTarget = true, touchTargetSize = DpSize(44f, 48f))))
     }
 
+    @Test
+    fun `meaningfully undersized target is not hidden by measurement tolerance`() {
+        assertNotNull(
+            rule.evaluate(
+                createNode(
+                    isTouchTarget = true,
+                    touchTargetSize = DpSize(47.98f, 48f),
+                )
+            )
+        )
+    }
+
     @Test
     fun `height below minimum fails`() {
         assertNotNull(rule.evaluate(createNode(isTouchTarget = true, touchTargetSize = DpSize(48f, 44f))))

scanner-ui/src/androidTest/java/com/composea11yscanner/ui/A11yNodeExtractorTest.kt

@@ -2,11 +2,14 @@ package com.composea11yscanner.ui
 
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.size
 import androidx.compose.material3.Text
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.test.junit4.createComposeRule
 import androidx.compose.ui.test.onRoot
 import androidx.compose.ui.unit.Density
+import androidx.compose.ui.unit.dp
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertTrue
 import org.junit.Rule
@@ -49,4 +52,26 @@ class A11yNodeExtractorTest {
         assertEquals("Clickable", clickableNode.composableName)
         assertTrue(clickableNode.contentDescription.isNullOrBlank())
     }
+
+    @Test
+    fun compactClickable_usesExpandedTouchBounds() {
+        lateinit var density: Density
+        composeRule.setContent {
+            density = LocalDensity.current
+            Box(
+                modifier = Modifier
+                    .size(width = 40.dp, height = 48.dp)
+                    .clickable { },
+            )
+        }
+
+        composeRule.waitForIdle()
+
+        val nodes = A11yNodeExtractor(density)
+            .extract(composeRule.onRoot(useUnmergedTree = true).fetchSemanticsNode())
+        val clickableNode = nodes.single { it.isTouchTarget }
+
+        assertTrue(clickableNode.touchTargetSize.width >= 48f)
+        assertTrue(clickableNode.touchTargetSize.height >= 48f)
+    }
 }

scanner-ui/src/main/java/com/composea11yscanner/ui/A11yNodeExtractor.kt

@@ -68,7 +68,10 @@ class A11yNodeExtractor(private val density: Density) {
             null
         }
         val visualBounds = boundsInRoot
-        val touchTargetBounds = layoutBoundsInRoot()
+        // Compose expands pointer input for small clickables to the platform minimum touch
+        // target without changing their visual/layout bounds. Measure the region that actually
+        // accepts input so compact controls such as a short FilterChip are not false positives.
+        val touchTargetBounds = touchBoundsInRoot
         val bounds = visualBounds.toCoreRect()
 
         return A11yNode(
@@ -146,16 +149,6 @@ class A11yNodeExtractor(private val density: Density) {
         }
     }
 
-    private fun SemanticsNode.layoutBoundsInRoot(): androidx.compose.ui.geometry.Rect {
-        val position = positionInRoot
-        return androidx.compose.ui.geometry.Rect(
-            left = position.x,
-            top = position.y,
-            right = position.x + layoutInfo.width,
-            bottom = position.y + layoutInfo.height,
-        )
-    }
-
     private fun androidx.compose.ui.geometry.Rect.toCoreRect(): Rect = Rect(
         left = left.roundToInt(),
         top = top.roundToInt(),

scanner-ui/src/main/java/com/composea11yscanner/ui/ScanSummaryBar.kt

@@ -18,9 +18,12 @@ import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.WindowInsets
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.statusBars
+import androidx.compose.foundation.layout.windowInsetsPadding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.RoundedCornerShape
@@ -101,6 +104,8 @@ fun ScanSummaryBar(
     Box(
         modifier = modifier
             .fillMaxWidth()
+            // topOffset clears the host toolbar; the inset additionally clears the system bar.
+            .windowInsetsPadding(WindowInsets.statusBars)
             .padding(top = topOffset, start = 16.dp, end = 16.dp),
         contentAlignment = Alignment.TopCenter,
     ) {