Add AmbientImageLoader for Coil

coil/README.md

@@ -93,6 +93,24 @@ CoilImage(
 
 Accompanist Coil supports GIFs through Coil's own GIF support. Follow the [setup instructions](https://coil-kt.github.io/coil/gifs/) and it should just work.
 
+## Custom ImageLoader
+
+If you wish to provide a default [`ImageLoader`](https://coil-kt.github.io/coil/image_loaders/) to use across all of your `CoilImage`
+calls, we provide the `AmbientImageLoader` ambient. You can see it like so:
+
+``` kotlin
+val imageLoader = ImageLoader.Builder(context)
+    // customize the ImageLoader as needed
+    .build()
+
+Providers(AmbientImageLoader provides imageLoader) {
+    // This will automatically use the value of AmbientImageLoader
+    CoilImage(
+        data = ...
+    )
+}
+```
+
 ## Download
 
 ```groovy

coil/api/coil.api

@@ -8,5 +8,11 @@ public final class dev/chrisbanes/accompanist/coil/CoilImage {
 	public static fun ErrorResult$annotations ()V
 	public static fun RequestResult$annotations ()V
 	public static fun SuccessResult$annotations ()V
+	public static final fun getAmbientImageLoader ()Landroidx/compose/runtime/ProvidableAmbient;
+}
+
+public final class dev/chrisbanes/accompanist/coil/CoilImageConstants {
+	public static final field INSTANCE Ldev/chrisbanes/accompanist/coil/CoilImageConstants;
+	public final fun defaultImageLoader (Landroidx/compose/runtime/Composer;I)Lcoil/ImageLoader;
 }
 

coil/src/androidTest/java/dev/chrisbanes/accompanist/coil/CoilTest.kt

@@ -19,6 +19,7 @@ package dev.chrisbanes.accompanist.coil
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.Text
 import androidx.compose.foundation.layout.preferredSize
+import androidx.compose.runtime.Providers
 import androidx.compose.runtime.collectAsState
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
@@ -67,6 +68,7 @@ import org.junit.runner.RunWith
 import org.junit.runners.JUnit4
 import java.util.concurrent.CountDownLatch
 import java.util.concurrent.TimeUnit
+import java.util.concurrent.atomic.AtomicInteger
 
 @LargeTest
 @RunWith(JUnit4::class)
@@ -194,11 +196,10 @@ class CoilTest {
 
         // Build a custom ImageLoader with a fake EventListener
         val eventListener = object : EventListener {
-            var startCalled = 0
-                private set
+            val startCalled = AtomicInteger()
 
             override fun fetchStart(request: ImageRequest, fetcher: Fetcher<*>, options: Options) {
-                startCalled++
+                startCalled.incrementAndGet()
             }
         }
         val imageLoader = ImageLoader.Builder(context)
@@ -218,7 +219,42 @@ class CoilTest {
         latch.await(5, TimeUnit.SECONDS)
 
         // Verify that our eventListener was invoked
-        assertThat(eventListener.startCalled).isAtLeast(1)
+        assertThat(eventListener.startCalled.get()).isAtLeast(1)
+    }
+
+    @OptIn(ExperimentalCoilApi::class)
+    @Test
+    fun basicLoad_customImageLoader_ambient() {
+        val context = InstrumentationRegistry.getInstrumentation().targetContext
+        val latch = CountDownLatch(1)
+
+        // Build a custom ImageLoader with a fake EventListener
+        val eventListener = object : EventListener {
+            val startCalled = AtomicInteger()
+
+            override fun fetchStart(request: ImageRequest, fetcher: Fetcher<*>, options: Options) {
+                startCalled.incrementAndGet()
+            }
+        }
+        val imageLoader = ImageLoader.Builder(context)
+            .eventListener(eventListener)
+            .build()
+
+        composeTestRule.setContent {
+            Providers(AmbientImageLoader provides imageLoader) {
+                CoilImage(
+                    data = server.url("/image"),
+                    modifier = Modifier.preferredSize(128.dp, 128.dp),
+                    onRequestCompleted = { latch.countDown() }
+                )
+            }
+        }
+
+        // Wait for the onRequestCompleted to release the latch
+        latch.await(5, TimeUnit.SECONDS)
+
+        // Verify that our eventListener was invoked
+        assertThat(eventListener.startCalled.get()).isAtLeast(1)
     }
 
     @OptIn(ExperimentalCoroutinesApi::class)

coil/src/main/java/dev/chrisbanes/accompanist/coil/Coil.kt

@@ -22,6 +22,7 @@ package dev.chrisbanes.accompanist.coil
 import androidx.compose.foundation.Image
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.staticAmbientOf
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.ColorFilter
@@ -43,6 +44,21 @@ import dev.chrisbanes.accompanist.imageloading.ImageLoadState
 import dev.chrisbanes.accompanist.imageloading.MaterialLoadingImage
 import dev.chrisbanes.accompanist.imageloading.toPainter
 
+/**
+ * Ambient containing the preferred [ImageLoader] to use in [CoilImage].
+ */
+val AmbientImageLoader = staticAmbientOf<ImageLoader?> { null }
+
+object CoilImageConstants {
+    /**
+     * Returns the default [ImageLoader] value for the `imageLoader` parameter in [CoilImage].
+     */
+    @Composable
+    fun defaultImageLoader(): ImageLoader {
+        return AmbientImageLoader.current ?: ContextAmbient.current.imageLoader
+    }
+}
+
 /**
  * Creates a composable that will attempt to load the given [data] using [Coil], and provides
  * complete content of how the current state is displayed:
@@ -63,8 +79,8 @@ import dev.chrisbanes.accompanist.imageloading.toPainter
  * @param data The data to load. See [ImageRequest.Builder.data] for the types allowed.
  * @param modifier [Modifier] used to adjust the layout algorithm or draw decoration content.
  * @param requestBuilder Optional builder for the [ImageRequest].
- * @param imageLoader The [ImageLoader] to use when requesting the image. Defaults to [Coil]'s
- * default image loader.
+ * @param imageLoader The [ImageLoader] to use when requesting the image. Defaults to
+ * [CoilImageConstants.defaultImageLoader].
  * @param shouldRefetchOnSizeChange Lambda which will be invoked when the size changes, allowing
  * optional re-fetching of the image. Return true to re-fetch the image.
  * @param onRequestCompleted Listener which will be called when the loading request has finished.
@@ -75,7 +91,7 @@ fun CoilImage(
     data: Any,
     modifier: Modifier = Modifier,
     requestBuilder: (ImageRequest.Builder.(size: IntSize) -> ImageRequest.Builder)? = null,
-    imageLoader: ImageLoader = ContextAmbient.current.imageLoader,
+    imageLoader: ImageLoader = CoilImageConstants.defaultImageLoader(),
     shouldRefetchOnSizeChange: (currentResult: ImageLoadState, size: IntSize) -> Boolean = DefaultRefetchOnSizeChangeLambda,
     onRequestCompleted: (ImageLoadState) -> Unit = EmptyRequestCompleteLambda,
     content: @Composable (imageLoadState: ImageLoadState) -> Unit
@@ -112,8 +128,8 @@ fun CoilImage(
  * set, one will be set on the request using the layout constraints.
  * @param modifier [Modifier] used to adjust the layout algorithm or draw decoration content.
  * @param requestBuilder Optional builder for the [ImageRequest].
- * @param imageLoader The [ImageLoader] to use when requesting the image. Defaults to [Coil]'s
- * default image loader.
+ * @param imageLoader The [ImageLoader] to use when requesting the image. Defaults to
+ * [CoilImageConstants.defaultImageLoader].
  * @param shouldRefetchOnSizeChange Lambda which will be invoked when the size changes, allowing
  * optional re-fetching of the image. Return true to re-fetch the image.
  * @param onRequestCompleted Listener which will be called when the loading request has finished.
@@ -124,7 +140,7 @@ fun CoilImage(
     request: ImageRequest,
     modifier: Modifier = Modifier,
     requestBuilder: (ImageRequest.Builder.(size: IntSize) -> ImageRequest.Builder)? = null,
-    imageLoader: ImageLoader = ContextAmbient.current.imageLoader,
+    imageLoader: ImageLoader = CoilImageConstants.defaultImageLoader(),
     shouldRefetchOnSizeChange: (currentResult: ImageLoadState, size: IntSize) -> Boolean = DefaultRefetchOnSizeChangeLambda,
     onRequestCompleted: (ImageLoadState) -> Unit = EmptyRequestCompleteLambda,
     content: @Composable (imageLoadState: ImageLoadState) -> Unit
@@ -196,8 +212,8 @@ fun CoilImage(
  * @param fadeIn Whether to run a fade-in animation when images are successfully loaded.
  * Default: `false`.
  * @param requestBuilder Optional builder for the [ImageRequest].
- * @param imageLoader The [ImageLoader] to use when requesting the image. Defaults to [Coil]'s
- * default image loader.
+ * @param imageLoader The [ImageLoader] to use when requesting the image. Defaults to
+ * [CoilImageConstants.defaultImageLoader].
  * @param shouldRefetchOnSizeChange Lambda which will be invoked when the size changes, allowing
  * optional re-fetching of the image. Return true to re-fetch the image.
  * @param onRequestCompleted Listener which will be called when the loading request has finished.
@@ -211,7 +227,7 @@ fun CoilImage(
     colorFilter: ColorFilter? = null,
     fadeIn: Boolean = false,
     requestBuilder: (ImageRequest.Builder.(size: IntSize) -> ImageRequest.Builder)? = null,
-    imageLoader: ImageLoader = ContextAmbient.current.imageLoader,
+    imageLoader: ImageLoader = CoilImageConstants.defaultImageLoader(),
     shouldRefetchOnSizeChange: (currentResult: ImageLoadState, size: IntSize) -> Boolean = DefaultRefetchOnSizeChangeLambda,
     onRequestCompleted: (ImageLoadState) -> Unit = EmptyRequestCompleteLambda,
     error: @Composable ((ImageLoadState.Error) -> Unit)? = null,
@@ -269,8 +285,8 @@ fun CoilImage(
  * @param loading Content to be displayed when the request is in progress.
  * @param fadeIn Whether to run a fade-in animation when images are successfully loaded. Default: `false`.
  * @param requestBuilder Optional builder for the [ImageRequest].
- * @param imageLoader The [ImageLoader] to use when requesting the image. Defaults to [Coil]'s
- * default image loader.
+ * @param imageLoader The [ImageLoader] to use when requesting the image. Defaults to
+ * [CoilImageConstants.defaultImageLoader].
  * @param shouldRefetchOnSizeChange Lambda which will be invoked when the size changes, allowing
  * optional re-fetching of the image. Return true to re-fetch the image.
  * @param onRequestCompleted Listener which will be called when the loading request has finished.
@@ -284,7 +300,7 @@ fun CoilImage(
     colorFilter: ColorFilter? = null,
     fadeIn: Boolean = false,
     requestBuilder: (ImageRequest.Builder.(size: IntSize) -> ImageRequest.Builder)? = null,
-    imageLoader: ImageLoader = ContextAmbient.current.imageLoader,
+    imageLoader: ImageLoader = CoilImageConstants.defaultImageLoader(),
     shouldRefetchOnSizeChange: (currentResult: ImageLoadState, size: IntSize) -> Boolean = DefaultRefetchOnSizeChangeLambda,
     onRequestCompleted: (ImageLoadState) -> Unit = EmptyRequestCompleteLambda,
     error: @Composable ((ImageLoadState.Error) -> Unit)? = null,