change: Target.getCrossfadeTransition(CrossfadeTransition.Factory) ch…

…ange to convertTransition(Transition.Factory)

sketch-compose-core/src/commonMain/kotlin/com/github/panpf/sketch/AsyncImageState.common.kt

@@ -315,6 +315,7 @@ class AsyncImageState internal constructor(
         }
     }
 
+    // TODO Go out independently for easy testing
     private inner class AsyncImageTarget : GenericComposeTarget() {
 
         override var painter: Painter?

sketch-compose-core/src/commonMain/kotlin/com/github/panpf/sketch/target/ComposeTarget.common.kt

@@ -55,13 +55,16 @@ interface ComposeTarget : Target {
         return ComposeResizeOnDrawHelper
     }
 
-    override fun getCrossfadeTransition(factory: CrossfadeTransition.Factory): Transition.Factory? {
-        return ComposeCrossfadeTransition.Factory(
-            durationMillis = factory.durationMillis,
-            fadeStart = factory.fadeStart,
-            preferExactIntrinsicSize = factory.preferExactIntrinsicSize,
-            alwaysUse = factory.alwaysUse,
-        )
+    override fun convertTransition(factory: Transition.Factory): Transition.Factory? {
+        if (factory is CrossfadeTransition.Factory) {
+            return ComposeCrossfadeTransition.Factory(
+                durationMillis = factory.durationMillis,
+                fadeStart = factory.fadeStart,
+                preferExactIntrinsicSize = factory.preferExactIntrinsicSize,
+                alwaysUse = factory.alwaysUse,
+            )
+        }
+        return null
     }
 
     override fun getComponents(): ComponentRegistry? = ComponentRegistry.Builder().apply {

sketch-core/src/commonMain/kotlin/com/github/panpf/sketch/target/Target.kt

@@ -36,43 +36,90 @@ import com.github.panpf.sketch.transition.Transition
 import kotlinx.coroutines.Job
 
 /**
- * A listener that accepts the result of an image request.
+ * [Target] is mainly used to display [Image].
+ *
+ * [Target] can also provide [RequestManager], [RequestDelegate], [Listener], [ProgressListener],
+ * [LifecycleResolver], [SizeResolver], [ScaleDecider], [ResizeOnDrawHelper], [CrossfadeTransition]
+ * related to [Target] when building the request, [ImageOptions], [ComponentRegistry] and other configurations
+ *
+ * @see com.github.panpf.sketch.compose.core.common.test.target.GenericComposeTargetTest
+ * @see com.github.panpf.sketch.view.core.test.target.GenericViewTargetTest
+ * @see com.github.panpf.sketch.view.core.test.target.RemoteViewsTargetTest
  */
 interface Target {
 
+    /**
+     * The current image displayed by the target.
+     *
+     * @see com.github.panpf.sketch.state.CurrentStateImage
+     */
     val currentImage: Image?
         get() = null
 
 
+    /**
+     * Get the [RequestManager] associated with the target.
+     */
     fun getRequestManager(): RequestManager? = null
 
+    /**
+     * Create a new [RequestDelegate] for the request.
+     */
     fun newRequestDelegate(
         sketch: Sketch,
         initialRequest: ImageRequest,
         job: Job
     ): RequestDelegate? = null
 
 
+    /**
+     * Get the [Listener] associated with the target.
+     */
     fun getListener(): Listener? = null
 
+    /**
+     * Get the [ProgressListener] associated with the target.
+     */
     fun getProgressListener(): ProgressListener? = null
 
+    /**
+     * Get the [LifecycleResolver] associated with the target.
+     */
     fun getLifecycleResolver(): LifecycleResolver? = null
 
 
+    /**
+     * Get the [SizeResolver] associated with the target.
+     */
     fun getSizeResolver(): SizeResolver? = null
 
+    /**
+     * Get the [ScaleDecider] associated with the target.
+     */
     fun getScaleDecider(): ScaleDecider? = null
 
+    /**
+     * Get the [ResizeOnDrawHelper] associated with the target.
+     */
     fun getResizeOnDrawHelper(): ResizeOnDrawHelper? = null
 
-    fun getCrossfadeTransition(factory: CrossfadeTransition.Factory): Transition.Factory? = null
-
+    /**
+     * Get the [ImageOptions] associated with the target.
+     */
     fun getImageOptions(): ImageOptions? = null
 
+    /**
+     * Get the [ComponentRegistry] associated with the target.
+     */
     fun getComponents(): ComponentRegistry? = null
 
 
+    /**
+     * Convert a generic [Transition.Factory] to a [Transition.Factory] appropriate for the current Target
+     */
+    fun convertTransition(factory: Transition.Factory): Transition.Factory? = null
+
+
     /**
      * Called when the request starts.
      */

sketch-core/src/commonMain/kotlin/com/github/panpf/sketch/transition/CrossfadeTransition.kt

@@ -50,11 +50,9 @@ class CrossfadeTransition(transition: Transition) : Transition by transition {
         ): Transition? {
             val fromMemoryCache = result.asOrNull<ImageResult.Success>()?.dataFrom == MEMORY_CACHE
             if (!alwaysUse && fromMemoryCache) return null
-            val targetCrossfadeTransitionFactory =
-                target.getCrossfadeTransition(this)
+            val targetCrossfadeTransitionFactory = target.convertTransition(this) ?: return null
             val targetCrossfadeTransition = targetCrossfadeTransitionFactory
-                ?.create(requestContext, target, result)
-                ?: return null
+                .create(requestContext, target, result) ?: return null
             return CrossfadeTransition(targetCrossfadeTransition)
         }
 

sketch-view-core/src/main/kotlin/com/github/panpf/sketch/target/ViewTarget.kt

@@ -86,13 +86,16 @@ interface ViewTarget<T : View> : Target {
 
     override fun getResizeOnDrawHelper(): ResizeOnDrawHelper? = ViewResizeOnDrawHelper
 
-    override fun getCrossfadeTransition(factory: CrossfadeTransition.Factory): Transition.Factory? {
-        return ViewCrossfadeTransition.Factory(
-            durationMillis = factory.durationMillis,
-            fadeStart = factory.fadeStart,
-            preferExactIntrinsicSize = factory.preferExactIntrinsicSize,
-            alwaysUse = factory.alwaysUse,
-        )
+    override fun convertTransition(factory: Transition.Factory): Transition.Factory? {
+        if (factory is CrossfadeTransition.Factory) {
+            return ViewCrossfadeTransition.Factory(
+                durationMillis = factory.durationMillis,
+                fadeStart = factory.fadeStart,
+                preferExactIntrinsicSize = factory.preferExactIntrinsicSize,
+                alwaysUse = factory.alwaysUse,
+            )
+        }
+        return null
     }
 
     override fun getImageOptions(): ImageOptions? =