From e357d25feb5e8f6d46737f9a2d2537b101ceb822 Mon Sep 17 00:00:00 2001
From: Sergey Malenkov <sergey.malenkov@jetbrains.com>
Date: Tue, 13 Mar 2018 12:03:31 +0300
Subject: [PATCH] IDEA-185543 calculate preferred viewport size without
 scrollbars

---
 .../intellij/ui/components/JBScrollPane.java  |  4 +--
 .../intellij/ui/components/JBViewport.java    | 26 +++++++++++++++----
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/platform/platform-api/src/com/intellij/ui/components/JBScrollPane.java b/platform/platform-api/src/com/intellij/ui/components/JBScrollPane.java
index bfe0ad0d1b78..9a5b8a74fcad 100644
--- a/platform/platform-api/src/com/intellij/ui/components/JBScrollPane.java
+++ b/platform/platform-api/src/com/intellij/ui/components/JBScrollPane.java
@@ -691,9 +691,7 @@ public class JBScrollPane extends JScrollPane {
           Dimension viewPreferredSize = view.getPreferredSize();
           if (viewPreferredSize == null) viewPreferredSize = new Dimension();
           if (view instanceof JComponent && !view.isPreferredSizeSet()) {
-            Insets insets = JBViewport.getViewInsets((JComponent)view);
-            JBInsets.removeFrom(viewportExtentSize, insets);
-            JBInsets.removeFrom(viewPreferredSize, insets);
+            JBInsets.removeFrom(viewPreferredSize, JBViewport.getViewInsets((JComponent)view));
           }
           result.width += viewportExtentSize.width;
           result.height += viewportExtentSize.height;
diff --git a/platform/platform-api/src/com/intellij/ui/components/JBViewport.java b/platform/platform-api/src/com/intellij/ui/components/JBViewport.java
index 1182ee35dce5..99dd9575ec78 100644
--- a/platform/platform-api/src/com/intellij/ui/components/JBViewport.java
+++ b/platform/platform-api/src/com/intellij/ui/components/JBViewport.java
@@ -317,8 +317,16 @@ public class JBViewport extends JViewport implements ZoomableViewport {
            (view instanceof JList || view instanceof JTree || (!SystemInfo.isMac && ScrollSettings.isGapNeededForAnyComponent()));
   }
 
-  static Insets getViewInsets(JComponent view) {
+  private static Insets getInnerInsets(JComponent view) {
+    Border border = view.getBorder();
+    if (border instanceof ViewBorder) {
+      ViewBorder vb = (ViewBorder)border;
+      border = vb.myBorder;
+    }
+    return border == null ? null : border.getBorderInsets(view);
+  }
 
+  static Insets getViewInsets(JComponent view) {
     Border border = view.getBorder();
     if (border instanceof ViewBorder) {
       ViewBorder vb = (ViewBorder)border;
@@ -515,9 +523,17 @@ public class JBViewport extends JViewport implements ZoomableViewport {
     if (view instanceof JList) return getPreferredScrollableViewportSize((JList)view);
     if (view instanceof JTree) return getPreferredScrollableViewportSize((JTree)view);
     if (view instanceof Scrollable) return ((Scrollable)view).getPreferredScrollableViewportSize();
+    if (view instanceof JComponent) return getPreferredSizeWithoutScrollBars((JComponent)view);
     return view == null ? null : view.getPreferredSize();
   }
 
+  private static Dimension getPreferredSizeWithoutScrollBars(@NotNull JComponent view) {
+    Dimension size = view.getPreferredSize();
+    if (size == null) return new Dimension();
+    JBInsets.removeFrom(size, getViewInsets(view));
+    return size;
+  }
+
   private static Class<?> getPreferredScrollableViewportSizeDeclaringClass(@NotNull Scrollable scrollable) {
     try {
       return scrollable.getClass().getMethod("getPreferredScrollableViewportSize").getDeclaringClass();
@@ -531,7 +547,7 @@ public class JBViewport extends JViewport implements ZoomableViewport {
     if (JList.class != getPreferredScrollableViewportSizeDeclaringClass(list)) {
       return list.getPreferredScrollableViewportSize(); // may be null
     }
-    Dimension size = list.getPreferredSize();
+    Dimension size = getPreferredSizeWithoutScrollBars(list);
     if (size == null) return new Dimension();
     if (JList.VERTICAL != list.getLayoutOrientation()) return size;
 
@@ -550,7 +566,7 @@ public class JBViewport extends JViewport implements ZoomableViewport {
     if (visibleRows <= 0) visibleRows = Registry.intValue("ide.preferred.scrollable.viewport.visible.rows");
 
     boolean addExtraSpace = 0 < visibleRows && visibleRows < modelRows && Registry.is("ide.preferred.scrollable.viewport.extra.space");
-    Insets insets = list.getInsets();
+    Insets insets = getInnerInsets(list);
     size.height = insets != null ? insets.top + insets.bottom : 0;
     if (0 < fixedWidth && 0 < fixedHeight) {
       size.width = insets != null ? insets.left + insets.right + fixedWidth : fixedWidth;
@@ -576,7 +592,7 @@ public class JBViewport extends JViewport implements ZoomableViewport {
     if (JTree.class != getPreferredScrollableViewportSizeDeclaringClass(tree)) {
       return tree.getPreferredScrollableViewportSize(); // may be null
     }
-    Dimension size = tree.getPreferredSize();
+    Dimension size = getPreferredSizeWithoutScrollBars(tree);
     if (size == null) return new Dimension();
 
     int fixedHeight = tree.getRowHeight();
@@ -590,7 +606,7 @@ public class JBViewport extends JViewport implements ZoomableViewport {
     if (visibleRows <= 0) visibleRows = Registry.intValue("ide.preferred.scrollable.viewport.visible.rows");
 
     boolean addExtraSpace = Registry.is("ide.preferred.scrollable.viewport.extra.space");
-    Insets insets = tree.getInsets();
+    Insets insets = getInnerInsets(tree);
     size.height = insets != null ? insets.top + insets.bottom : 0;
     if (0 < fixedHeight) {
       size.height += fixedHeight * visibleRows;