variable indent options for trees (IDEA-126373)

platform/util/resources/misc/registry.properties

@@ -503,6 +503,9 @@ vcs.add.remove.silent=true
 ide.ui.scale.override=false
 ide.ui.scale=1.0
 
+ide.ui.tree.indent=-1
+ide.ui.tree.indent.description=Allows to increase or decrease indents in trees. Use -1 to use default indent
+
 ide.new.notification.enabled=true
 ide.new.notification.visible.count=2
 

platform/util/src/com/intellij/util/ui/tree/WideSelectionTreeUI.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2015 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,8 @@ package com.intellij.util.ui.tree;
 import com.intellij.openapi.util.Condition;
 import com.intellij.openapi.util.Conditions;
 import com.intellij.openapi.util.SystemInfo;
+import com.intellij.openapi.util.registry.Registry;
+import com.intellij.util.ui.JBUI;
 import com.intellij.util.ui.MouseEventAdapter;
 import com.intellij.util.ui.UIUtil;
 import org.jetbrains.annotations.NonNls;
@@ -73,19 +75,15 @@ public class WideSelectionTreeUI extends BasicTreeUI {
 
   @Override
   public int getRightChildIndent() {
-    return isSkinny() ? 8 : super.getRightChildIndent();
+    return isCustomIndent() ? getCustomIndent() : super.getRightChildIndent();
   }
 
-  public boolean isSkinny() {
-    return mySkinny;
+  public boolean isCustomIndent() {
+    return getCustomIndent() > 0;
   }
 
-  /**
-   * Setting to <code>true</code> make tree to reduce row offset
-   * @param skinny <code>true</code> to reduce row offset
-   */
-  public void setSkinny(boolean skinny) {
-    mySkinny = skinny;
+  protected int getCustomIndent() {
+    return JBUI.scale(Registry.intValue("ide.ui.tree.indent"));
   }
 
   @Override
@@ -237,7 +235,7 @@ public class WideSelectionTreeUI extends BasicTreeUI {
 
   @Override
   protected int getRowX(int row, int depth) {
-    if (isSkinny()) {
+    if (isCustomIndent()) {
       int off = tree.isRootVisible() ? 8 : 0;
       return 8 * depth + 8 + off;
     } else {