Add PicassoAmbient for Picasso (#128)

* Add PicassoAmbient for Picasso

* Update API

picasso/README.md

@@ -89,6 +89,25 @@ PicassoImage(
 }
 ```
 
+## Custom Picasso
+
+If you wish to provide a default `Picasso` to use across all of your `PicassoImage`
+calls, we provide the `AmbientPicasso` ambient. You can see it like so:
+
+``` kotlin
+val picasso = Picasso.Builder(...)
+    // Customize as required
+    .build()
+
+Providers(AmbientPicasso provides picasso) {
+    // This will automatically use the value of AmbientPicasso
+    PicasoImage(
+        data = ...
+    )
+}
+```
+
+
 ## Download
 
 ```groovy

picasso/api/picasso.api

@@ -1,5 +1,6 @@
 public final class dev/chrisbanes/accompanist/picasso/PicassoImage {
 	public static final fun PicassoImage (Ljava/lang/Object;Landroidx/compose/ui/Modifier;Landroidx/compose/ui/Alignment;Landroidx/compose/ui/layout/ContentScale;Landroidx/compose/ui/graphics/ColorFilter;ZLcom/squareup/picasso/Picasso;Lkotlin/jvm/functions/Function2;Lkotlin/jvm/functions/Function2;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function3;Lkotlin/jvm/functions/Function2;Landroidx/compose/runtime/Composer;II)V
 	public static final fun PicassoImage (Ljava/lang/Object;Landroidx/compose/ui/Modifier;Lcom/squareup/picasso/Picasso;Lkotlin/jvm/functions/Function2;Lkotlin/jvm/functions/Function2;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function3;Landroidx/compose/runtime/Composer;II)V
+	public static final fun getAmbientPicasso ()Landroidx/compose/runtime/ProvidableAmbient;
 }
 

picasso/src/androidTest/java/dev/chrisbanes/accompanist/picasso/PicassoTest.kt

@@ -19,12 +19,14 @@ package dev.chrisbanes.accompanist.picasso
 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
 import androidx.compose.ui.graphics.painter.ColorPainter
 import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.unit.dp
+import androidx.core.net.toUri
 import androidx.test.filters.LargeTest
 import androidx.test.filters.SdkSuppress
 import androidx.test.platform.app.InstrumentationRegistry
@@ -223,6 +225,73 @@ class PicassoTest {
             .assertIsDisplayed()
     }
 
+    @SdkSuppress(minSdkVersion = 26) // captureToBitmap
+    @Test
+    fun customPicasso_param() {
+        val latch = CountDownLatch(1)
+
+        val picasso = Picasso.Builder(InstrumentationRegistry.getInstrumentation().targetContext)
+            .requestTransformer { request ->
+                // Transform any request so that it points to a valid red image uri instead
+                request.buildUpon()
+                    .setUri(server.url("/red").toString().toUri())
+                    .build()
+            }
+            .build()
+
+        composeTestRule.setContent {
+            PicassoImage(
+                data = server.url("/noimage"),
+                picasso = picasso,
+                modifier = Modifier.preferredSize(128.dp, 128.dp).testTag(TestTags.Image),
+                onRequestCompleted = { latch.countDown() }
+            )
+        }
+
+        // Wait for the onRequestCompleted to release the latch
+        latch.await(5, TimeUnit.SECONDS)
+
+        // Assert that the layout is displayed and that we're showing the red image
+        composeTestRule.onNodeWithTag(TestTags.Image)
+            .assertIsDisplayed()
+            .captureToBitmap()
+            .assertPixels { Color.Red }
+    }
+
+    @SdkSuppress(minSdkVersion = 26) // captureToBitmap
+    @Test
+    fun customPicasso_ambient() {
+        val latch = CountDownLatch(1)
+
+        val picasso = Picasso.Builder(InstrumentationRegistry.getInstrumentation().targetContext)
+            .requestTransformer { request ->
+                // Transform any request so that it points to a valid red image uri instead
+                request.buildUpon()
+                    .setUri(server.url("/red").toString().toUri())
+                    .build()
+            }
+            .build()
+
+        composeTestRule.setContent {
+            Providers(AmbientPicasso provides picasso) {
+                PicassoImage(
+                    data = server.url("/noimage"),
+                    modifier = Modifier.preferredSize(128.dp, 128.dp).testTag(TestTags.Image),
+                    onRequestCompleted = { latch.countDown() }
+                )
+            }
+        }
+
+        // Wait for the onRequestCompleted to release the latch
+        latch.await(5, TimeUnit.SECONDS)
+
+        // Assert that the layout is displayed and that we're showing the red image
+        composeTestRule.onNodeWithTag(TestTags.Image)
+            .assertIsDisplayed()
+            .captureToBitmap()
+            .assertPixels { Color.Red }
+    }
+
     @Test
     fun errorStillHasSize() {
         val latch = CountDownLatch(1)

picasso/src/main/java/dev/chrisbanes/accompanist/picasso/Picasso.kt

@@ -24,6 +24,7 @@ import android.graphics.drawable.Drawable
 import android.net.Uri
 import androidx.compose.foundation.Image
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.staticAmbientOf
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.ColorFilter
@@ -47,6 +48,11 @@ import kotlinx.coroutines.suspendCancellableCoroutine
 import okhttp3.HttpUrl
 import java.io.File
 
+/**
+ * Ambient containing the preferred [Picasso] to use in [PicassoImage]. Defaults to [Picasso.get].
+ */
+val AmbientPicasso = staticAmbientOf { Picasso.get() }
+
 /**
  * Creates a composable that will attempt to load the given [data] using [Picasso], and provides
  * complete content of how the current state is displayed:
@@ -66,6 +72,8 @@ import java.io.File
  *
  * @param data The data to load. See [RequestCreator.data] for the types allowed.
  * @param modifier [Modifier] used to adjust the layout algorithm or draw decoration content.
+ * @param picasso The [Picasso] instance to use for requests. Defaults to the current value of
+ * [AmbientPicasso].
  * @param requestBuilder Optional builder for the [RequestCreator].
  * @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.
@@ -76,7 +84,7 @@ import java.io.File
 fun PicassoImage(
     data: Any,
     modifier: Modifier = Modifier,
-    picasso: Picasso = Picasso.get(),
+    picasso: Picasso = AmbientPicasso.current,
     requestBuilder: (RequestCreator.(size: IntSize) -> RequestCreator)? = null,
     shouldRefetchOnSizeChange: (currentResult: ImageLoadState, size: IntSize) -> Boolean = DefaultRefetchOnSizeChangeLambda,
     onRequestCompleted: (ImageLoadState) -> Unit = EmptyRequestCompleteLambda,
@@ -191,6 +199,8 @@ fun PicassoImage(
  * @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 picasso The [Picasso] instance to use for requests. Defaults to the current value
+ * of [AmbientPicasso].
  * @param requestBuilder Optional builder for the [RequestCreator].
  * @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.
@@ -204,7 +214,7 @@ fun PicassoImage(
     contentScale: ContentScale = ContentScale.Fit,
     colorFilter: ColorFilter? = null,
     fadeIn: Boolean = false,
-    picasso: Picasso = Picasso.get(),
+    picasso: Picasso = AmbientPicasso.current,
     requestBuilder: (RequestCreator.(size: IntSize) -> RequestCreator)? = null,
     shouldRefetchOnSizeChange: (currentResult: ImageLoadState, size: IntSize) -> Boolean = DefaultRefetchOnSizeChangeLambda,
     onRequestCompleted: (ImageLoadState) -> Unit = EmptyRequestCompleteLambda,