优化

app/src/main/java/io/legado/app/ui/book/read/page/provider/ChapterProvider.kt

@@ -1022,21 +1022,32 @@ object ChapterProvider {
 
         if (paddingLeft >= visibleRight || paddingTop >= visibleBottom) {
             AppLog.put("边距设置过大，请重新设置", toast = true)
-            visibleRect.set(
+            setFallbackLayout()
-                0f,
+        }
-                0f,
+
-                viewWidth.toFloat(),
-                viewHeight.toFloat()
-            )
-        } else {
         visibleRect.set(
             paddingLeft.toFloat(),
             paddingTop.toFloat(),
             visibleRight.toFloat(),
             visibleBottom.toFloat()
         )
+
     }
 
+    private fun setFallbackLayout() {
+        paddingLeft = 20.dpToPx()
+        paddingTop = 5.dpToPx()
+        paddingRight = 20.dpToPx()
+        paddingBottom = 5.dpToPx()
+        visibleWidth = if (doublePage) {
+            viewWidth / 2 - paddingLeft - paddingRight
+        } else {
+            viewWidth - paddingLeft - paddingRight
+        }
+        //留1dp画最后一行下划线
+        visibleHeight = viewHeight - paddingTop - paddingBottom
+        visibleRight = viewWidth - paddingRight
+        visibleBottom = paddingTop + visibleHeight
     }
 
 }