fix(image): Coil 2 대응 BlurTransformation 구현을 추가한다

app/src/main/java/kr/co/vividnext/sodalive/common/image/BlurTransformation.kt

@@ -0,0 +1,79 @@
+package kr.co.vividnext.sodalive.common.image
+
+import android.content.Context
+import android.graphics.Bitmap
+import android.graphics.Bitmap.Config.ARGB_8888
+import android.graphics.Paint
+import android.renderscript.Allocation
+import android.renderscript.Element
+import android.renderscript.RenderScript
+import android.renderscript.ScriptIntrinsicBlur
+import androidx.annotation.RequiresApi
+import androidx.core.graphics.applyCanvas
+import coil.size.Size
+import coil.transform.Transformation
+
+/**
+ * Coil 2.x 환경에서 기존 blur 호출부를 유지하기 위한 Android blur transformation이다.
+ */
+@RequiresApi(18)
+class BlurTransformation @JvmOverloads constructor(
+    private val context: Context,
+    private val radius: Float = DEFAULT_RADIUS,
+    private val sampling: Float = DEFAULT_SAMPLING
+) : Transformation {
+
+    init {
+        require(radius in 0.0f..25.0f) { "radius must be in [0, 25]." }
+        require(sampling > 0f) { "sampling must be > 0." }
+    }
+
+    override val cacheKey: String = "${BlurTransformation::class.java.name}-$radius-$sampling"
+
+    @Suppress("DEPRECATION")
+    override suspend fun transform(input: Bitmap, size: Size): Bitmap {
+        val paint = Paint(Paint.ANTI_ALIAS_FLAG or Paint.FILTER_BITMAP_FLAG)
+        val scaledWidth = (input.width / sampling).toInt().coerceAtLeast(1)
+        val scaledHeight = (input.height / sampling).toInt().coerceAtLeast(1)
+        val output = Bitmap.createBitmap(scaledWidth, scaledHeight, input.config ?: ARGB_8888)
+
+        output.applyCanvas {
+            scale(1f / sampling, 1f / sampling)
+            drawBitmap(input, 0f, 0f, paint)
+        }
+
+        var renderScript: RenderScript? = null
+        var inputAllocation: Allocation? = null
+        var outputAllocation: Allocation? = null
+        var blurScript: ScriptIntrinsicBlur? = null
+
+        try {
+            renderScript = RenderScript.create(context)
+            inputAllocation = Allocation.createFromBitmap(
+                renderScript,
+                output,
+                Allocation.MipmapControl.MIPMAP_NONE,
+                Allocation.USAGE_SCRIPT
+            )
+            outputAllocation = Allocation.createTyped(renderScript, inputAllocation.type)
+            blurScript = ScriptIntrinsicBlur.create(renderScript, Element.U8_4(renderScript))
+
+            blurScript.setRadius(radius)
+            blurScript.setInput(inputAllocation)
+            blurScript.forEach(outputAllocation)
+            outputAllocation.copyTo(output)
+        } finally {
+            blurScript?.destroy()
+            inputAllocation?.destroy()
+            outputAllocation?.destroy()
+            renderScript?.destroy()
+        }
+
+        return output
+    }
+
+    private companion object {
+        private const val DEFAULT_RADIUS = 10f
+        private const val DEFAULT_SAMPLING = 1f
+    }
+}

app/src/test/java/kr/co/vividnext/sodalive/common/image/BlurTransformationTest.kt

@@ -0,0 +1,35 @@
+package kr.co.vividnext.sodalive.common.image
+
+import android.content.Context
+import io.mockk.mockk
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertThrows
+import org.junit.Test
+
+class BlurTransformationTest {
+
+    @Test
+    fun `cacheKey includes radius and sampling`() {
+        val transformation = BlurTransformation(
+            context = mockk<Context>(relaxed = true),
+            radius = 25f,
+            sampling = 2.5f
+        )
+
+        assertEquals(
+            "kr.co.vividnext.sodalive.common.image.BlurTransformation-25.0-2.5",
+            transformation.cacheKey
+        )
+    }
+
+    @Test
+    fun `constructor rejects radius above max`() {
+        assertThrows(IllegalArgumentException::class.java) {
+            BlurTransformation(
+                context = mockk<Context>(relaxed = true),
+                radius = 26f,
+                sampling = 2.5f
+            )
+        }
+    }
+}