feat: 优化代码

app/src/main/java/io/legado/app/ui/book/read/page/delegate/CoverPageDelegate.kt

@@ -34,11 +34,12 @@ class CoverPageDelegate(pageView: PageView) : HorizontalPageDelegate(pageView) {
         if (!isRunning) return
         if (mDirection == Direction.PREV) {
             prevPage.translationX = offsetX - viewWidth
+            addShadow(distanceX.toInt(), canvas)
         } else if (mDirection == Direction.NEXT) {
             curPage.translationX = offsetX
-        }
             addShadow(distanceX.toInt(), canvas)
         }
+    }
 
     private fun addShadow(left: Int, canvas: Canvas) {
         if (left < 0) {