Actually fix animated images

Author: jobobby04

app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/ReaderPageImageView.kt

@@ -343,8 +343,9 @@ open class ReaderPageImageView @JvmOverloads constructor(
             .diskCachePolicy(CachePolicy.DISABLED)
             .target(
                 onSuccess = { result ->
-                    setImageDrawable(result.asDrawable(context.resources))
-                    (result as? Animatable)?.start()
+                    val drawable = result.asDrawable(context.resources)
+                    setImageDrawable(drawable)
+                    (drawable as? Animatable)?.start()
                     isVisible = true
                     this@ReaderPageImageView.onImageLoaded()
                 },

core/common/src/main/kotlin/tachiyomi/core/common/util/system/ImageUtil.kt

@@ -91,6 +91,9 @@ object ImageUtil {
                 // Coil supports animated WebP on Android 9.0+
                 // https://coil-kt.github.io/coil/getting_started/#supported-image-formats
                 Format.Webp -> type.isAnimated && Build.VERSION.SDK_INT >= Build.VERSION_CODES.P
+                // Coil supports animated Heif on Android 11+
+                // https://coil-kt.github.io/coil/getting_started/#supported-image-formats
+                Format.Heif -> type.isAnimated && Build.VERSION.SDK_INT >= Build.VERSION_CODES.R
                 else -> false
             }
         } catch (e: Exception) {