take enclosing scrollview visible rect or self visible rect into acco…

…unt when calculate viewport

Sources/STTextView/STTextView+NSTextViewportLayoutControllerDelegate.swift

@@ -13,35 +13,24 @@ extension STTextView: NSTextViewportLayoutControllerDelegate {
         let minX: CGFloat
         let maxX: CGFloat
 
+        let visibleRect = scrollView?.documentVisibleRect ?? self.visibleRect
+
         if !overdrawRect.isEmpty, overdrawRect.intersects(visibleRect) {
             // Use preparedContentRect for vertical overdraw and ensure visibleRect is included at the minimum,
             // the width is always bounds width for proper line wrapping.
             minX = min(overdrawRect.minX, max(visibleRect.minX, bounds.minX))
             minY = min(overdrawRect.minY, max(visibleRect.minY, bounds.minY))
             maxX = max(overdrawRect.maxX, visibleRect.maxX)
             maxY = max(overdrawRect.maxY, visibleRect.maxY)
-        } else if !visibleRect.isEmpty {
+        } else {
             // We use visible rect directly if preparedContentRect does not intersect.
             // This can happen if overdraw has not caught up with scrolling yet, such as before the first layout.
             minX = visibleRect.minX
             minY = visibleRect.minY
             maxX = visibleRect.maxX
             maxY = visibleRect.maxY
-        } else if let enclosingScrollView {
-            /// if not visible, but in the scroll view,
-            /// layout estimated size that enclosing scroll view display
-            minX = enclosingScrollView.documentVisibleRect.minX
-            minY = enclosingScrollView.documentVisibleRect.minY
-            maxX = enclosingScrollView.documentVisibleRect.maxX
-            maxY = enclosingScrollView.documentVisibleRect.maxY
-        } else {
-            // last reasort, when view is not visible
-            // and this is the fist time layout
-            minX = bounds.minX
-            minY = bounds.minY
-            maxX = bounds.maxX
-            maxY = bounds.maxY
         }
+
         return CGRect(x: minX, y: minY, width: maxX, height: maxY - minY)
     }