Fix RoundedCornersTransformation not scaling the input bitmap. (#1437)

* Fix RoundedCornersTransformation not scaling the input bitmap.

* Revert.

coil-base/src/androidTest/java/coil/request/DisposableTest.kt

@@ -17,6 +17,7 @@ import coil.util.ViewTestActivity
 import coil.util.activity
 import coil.util.requestManager
 import coil.util.runTestMain
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.first
 import org.junit.After
@@ -28,6 +29,7 @@ import kotlin.test.assertNotNull
 import kotlin.test.assertNull
 import kotlin.test.assertTrue
 
+@OptIn(ExperimentalCoroutinesApi::class)
 class DisposableTest {
 
     private lateinit var context: Context

coil-base/src/androidTest/java/coil/transform/RoundedCornerTransformationTest.kt

@@ -2,8 +2,10 @@ package coil.transform
 
 import android.content.Context
 import androidx.test.core.app.ApplicationProvider
+import coil.base.test.R
 import coil.size.Dimension
 import coil.size.Size
+import coil.util.assertIsSimilarTo
 import coil.util.decodeBitmapAsset
 import coil.util.size
 import kotlinx.coroutines.ExperimentalCoroutinesApi
@@ -30,6 +32,7 @@ class RoundedCornerTransformationTest {
         val actual = transformation.transform(input, Size(100, 100))
 
         assertEquals(Size(100, 100), actual.size)
+        actual.assertIsSimilarTo(R.drawable.rounded_corners_1)
     }
 
     @Test
@@ -38,6 +41,7 @@ class RoundedCornerTransformationTest {
         val actual = transformation.transform(input, Size(Dimension.Undefined, 100))
 
         assertEquals(Size(80, 100), actual.size)
+        actual.assertIsSimilarTo(R.drawable.rounded_corners_2)
     }
 
     @Test
@@ -46,6 +50,7 @@ class RoundedCornerTransformationTest {
         val actual = transformation.transform(input, Size(100, Dimension.Undefined))
 
         assertEquals(Size(100, 125), actual.size)
+        actual.assertIsSimilarTo(R.drawable.rounded_corners_3)
     }
 
     @Test
@@ -54,5 +59,27 @@ class RoundedCornerTransformationTest {
         val actual = transformation.transform(input, Size.ORIGINAL)
 
         assertEquals(Size(103, 129), actual.size)
+        actual.assertIsSimilarTo(R.drawable.rounded_corners_4)
+    }
+
+    /** Regression test: https://github.com/coil-kt/coil/issues/1426 */
+    @Test
+    fun imageIsSmallerThanTarget() = runTest {
+        val expectedSize = Size(200, 200)
+        val input = context.decodeBitmapAsset("normal_small.jpg")
+        val actual = transformation.transform(input, expectedSize)
+
+        assertEquals(expectedSize, actual.size)
+        actual.assertIsSimilarTo(R.drawable.rounded_corners_5)
+    }
+
+    @Test
+    fun imageIsLargerThanTarget() = runTest {
+        val expectedSize = Size(200, 200)
+        val input = context.decodeBitmapAsset("normal.jpg")
+        val actual = transformation.transform(input, expectedSize)
+
+        assertEquals(expectedSize, actual.size)
+        actual.assertIsSimilarTo(R.drawable.rounded_corners_6)
     }
 }

coil-base/src/main/java/coil/transform/RoundedCornersTransformation.kt

@@ -60,7 +60,18 @@ class RoundedCornersTransformation(
             drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR)
 
             val matrix = Matrix()
-            matrix.setTranslate((outputWidth - input.width) / 2f, (outputHeight - input.height) / 2f)
+            val multiplier = DecodeUtils.computeSizeMultiplier(
+                srcWidth = input.width,
+                srcHeight = input.height,
+                dstWidth = outputWidth,
+                dstHeight = outputHeight,
+                scale = Scale.FILL
+            ).toFloat()
+            val dx = (outputWidth - multiplier * input.width) / 2
+            val dy = (outputHeight - multiplier * input.height) / 2
+            matrix.setTranslate(dx, dy)
+            matrix.preScale(multiplier, multiplier)
+
             val shader = BitmapShader(input, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP)
             shader.setLocalMatrix(matrix)
             paint.shader = shader
@@ -69,7 +80,7 @@ class RoundedCornersTransformation(
                 topLeft, topLeft,
                 topRight, topRight,
                 bottomRight, bottomRight,
-                bottomLeft, bottomLeft
+                bottomLeft, bottomLeft,
             )
             val rect = RectF(0f, 0f, width.toFloat(), height.toFloat())
             val path = Path().apply { addRoundRect(rect, radii, Path.Direction.CW) }

coil-test/src/main/java/coil/util/Bitmaps.kt

@@ -1,11 +1,14 @@
 package coil.util
 
 import android.graphics.Bitmap
+import androidx.annotation.DrawableRes
 import androidx.annotation.FloatRange
 import androidx.core.graphics.alpha
 import androidx.core.graphics.blue
+import androidx.core.graphics.drawable.toBitmap
 import androidx.core.graphics.green
 import androidx.core.graphics.red
+import androidx.test.platform.app.InstrumentationRegistry
 import coil.size.Size
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.async
@@ -102,3 +105,15 @@ fun Bitmap.assertIsSimilarTo(
         "The images are not visually similar. Expected: $threshold; Actual: $similarity."
     }
 }
+
+/**
+ * Asserts that [this] and [expected] are the same size and that
+ * the cross correlation of their ARGB channels is >= [threshold].
+ */
+fun Bitmap.assertIsSimilarTo(
+    @DrawableRes expected: Int,
+    @FloatRange(from = -1.0, to = 1.0) threshold: Double = 0.99
+) {
+    val context = InstrumentationRegistry.getInstrumentation().targetContext
+    assertIsSimilarTo(context.getDrawable(expected)!!.toBitmap(), threshold)
+}

coil-test/src/main/java/coil/util/JvmTestFunctions.kt

@@ -68,15 +68,15 @@ fun Context.copyAssetToFile(fileName: String): File {
     return file
 }
 
-@OptIn(ExperimentalCoroutinesApi::class)
+@ExperimentalCoroutinesApi
 fun runTestMain(
     context: CoroutineContext = EmptyCoroutineContext,
     block: suspend CoroutineScope.() -> Unit
 ) = runTest(context) {
     withContext(Dispatchers.Main.immediate, block)
 }
 
-@OptIn(ExperimentalCoroutinesApi::class)
+@ExperimentalCoroutinesApi
 fun runTestAsync(
     context: CoroutineContext = EmptyCoroutineContext,
     block: suspend CoroutineScope.() -> Unit