Fix blurry material edge seam

androidApp/src/androidTest/kotlin/com/moriafly/salt/sample/ui/MaterialEdgeRenderingTest.kt

@@ -0,0 +1,146 @@
+/*
+ * Salt UI
+ * Copyright (C) 2026 Moriafly
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.moriafly.salt.sample.ui
+
+import android.graphics.Bitmap
+import android.graphics.Color
+import android.os.Handler
+import android.os.Looper
+import android.view.PixelCopy
+import androidx.activity.compose.setContent
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color as ComposeColor
+import androidx.test.core.app.ActivityScenario
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.platform.app.InstrumentationRegistry
+import com.moriafly.salt.ui.SaltConfigs
+import com.moriafly.salt.ui.SaltMaterial
+import com.moriafly.salt.ui.SaltTheme
+import com.moriafly.salt.ui.UnstableSaltUiApi
+import com.moriafly.salt.ui.material.MaterialSource
+import com.moriafly.salt.ui.material.MaterialType
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
+import java.util.concurrent.atomic.AtomicReference
+import kotlin.math.abs
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class MaterialEdgeRenderingTest {
+    @OptIn(UnstableSaltUiApi::class)
+    @Test
+    fun blurryGlassCoversTheRightmostPixelColumn() {
+        val activityReference = AtomicReference<MainActivity>()
+
+        ActivityScenario.launch(MainActivity::class.java).use { scenario ->
+            scenario.onActivity { activity ->
+                activityReference.set(activity)
+                activity.setContent {
+                    SaltTheme(
+                        configs = SaltConfigs.default(isDarkTheme = true),
+                        material = SaltMaterial.default(MaterialType.BlurryGlass)
+                    ) {
+                        MaterialSource(
+                            modifier = Modifier.fillMaxSize(),
+                            materialSelf = true
+                        ) {
+                            Box(
+                                modifier = Modifier
+                                    .fillMaxSize()
+                                    .background(ComposeColor.Red)
+                            )
+                        }
+                    }
+                }
+            }
+
+            val instrumentation = InstrumentationRegistry.getInstrumentation()
+            instrumentation.waitForIdleSync()
+            Thread.sleep(500)
+
+            val bitmap = captureWindow(activityReference.get())
+            val center = sampleColumn(bitmap, bitmap.width / 2)
+            val rightEdge = sampleColumn(bitmap, bitmap.width - 1)
+
+            assertTrue(
+                "Expected the blurry-glass overlay to darken the red source, but was $center",
+                center.red < 220
+            )
+            assertTrue(
+                "Expected the right edge $rightEdge to match the covered center $center",
+                colorDistance(center, rightEdge) <= 24
+            )
+        }
+    }
+
+    private fun captureWindow(activity: MainActivity): Bitmap {
+        val view = activity.window.decorView
+        val bitmap = Bitmap.createBitmap(view.width, view.height, Bitmap.Config.ARGB_8888)
+        val result = AtomicReference<Int>()
+        val latch = CountDownLatch(1)
+
+        PixelCopy.request(
+            activity.window,
+            bitmap,
+            {
+                result.set(it)
+                latch.countDown()
+            },
+            Handler(Looper.getMainLooper())
+        )
+
+        assertTrue("PixelCopy timed out", latch.await(5, TimeUnit.SECONDS))
+        assertEquals(PixelCopy.SUCCESS, result.get())
+        return bitmap
+    }
+
+    private fun sampleColumn(bitmap: Bitmap, x: Int): Rgb {
+        val centerY = bitmap.height / 2
+        val radius = 24
+        var red = 0
+        var green = 0
+        var blue = 0
+
+        for (y in centerY - radius until centerY + radius) {
+            val color = bitmap.getPixel(x, y)
+            red += Color.red(color)
+            green += Color.green(color)
+            blue += Color.blue(color)
+        }
+
+        val count = radius * 2
+        return Rgb(red / count, green / count, blue / count)
+    }
+
+    private fun colorDistance(first: Rgb, second: Rgb): Int =
+        abs(first.red - second.red) +
+            abs(first.green - second.green) +
+            abs(first.blue - second.blue)
+
+    private data class Rgb(
+        val red: Int,
+        val green: Int,
+        val blue: Int
+    )
+}

ui2/src/commonMain/kotlin/com/moriafly/salt/ui/material/Material.kt

@@ -157,13 +157,11 @@ internal fun Modifier.basicMaterial(
             blurEffect {
                 style = blurStyle
             }
-            inputScale = HazeInputScale.Fixed(InputScale)
+            inputScale = HazeInputScale.None
         }
     } else {
         background(fallback)
     }
 }
 
 internal val LocalHazeState = compositionLocalOf<HazeState?> { null }
-
-private const val InputScale = 0.67f