feat: 优化代码

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

@@ -176,6 +176,7 @@ object ChapterProvider {
                     x = x1
                 }
             }
+            textLine.lineBottom = textLine.lineBottom + titlePaint.fontMetrics.descent
         }
         durY += paragraphSpacing
         return durY
@@ -286,6 +287,7 @@ object ChapterProvider {
                     x = x1
                 }
             }
+            textLine.lineBottom = textLine.lineBottom + contentPaint.fontMetrics.descent
         }
         durY += paragraphSpacing
         return durY

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

@@ -104,9 +104,9 @@ class ContentTextView(context: Context, attrs: AttributeSet?) : View(context, at
                 if (it.selected) {
                     canvas.drawRect(
                         it.leftBottomPosition.x,
-                        it.rightTopPosition.y,
+                        textLine.lineTop,
                         it.rightTopPosition.x,
-                        it.leftBottomPosition.y,
+                        textLine.lineBottom,
                         selectedPaint
                     )
                 }