IDEA-56098 diff: add ability to disable autoscroll

platform/platform-impl/src/com/intellij/openapi/diff/actions/ToggleAutoScrollAction.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2000-2014 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.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.openapi.diff.actions;
+
+import com.intellij.icons.AllIcons;
+import com.intellij.openapi.actionSystem.AnActionEvent;
+import com.intellij.openapi.diff.ex.DiffPanelEx;
+import com.intellij.openapi.diff.impl.DiffPanelImpl;
+import com.intellij.openapi.project.DumbAware;
+import com.intellij.ui.ToggleActionButton;
+
+import javax.swing.*;
+
+public class ToggleAutoScrollAction extends ToggleActionButton implements DumbAware {
+  public ToggleAutoScrollAction() {
+    super("Auto Scroll", AllIcons.General.AutoscrollToSource);
+  }
+
+  @Override
+  public boolean isSelected(AnActionEvent e) {
+    DiffPanelEx diffPanel = DiffPanelImpl.fromDataContext(e.getDataContext());
+    if (diffPanel != null) {
+      return diffPanel.isAutoScrollEnabled();
+    }
+    else {
+      return true;
+    }
+  }
+
+  @Override
+  public void setSelected(AnActionEvent e, boolean state) {
+    final DiffPanelImpl diffPanel = DiffPanelImpl.fromDataContext(e.getDataContext());
+    if (diffPanel != null) {
+      diffPanel.setAutoScrollEnabled(state);
+    }
+  }
+}

platform/platform-impl/src/com/intellij/openapi/diff/ex/DiffPanelEx.java

@@ -41,4 +41,8 @@ public interface DiffPanelEx extends DiffPanel, Disposable {
   void setComparisonPolicy(ComparisonPolicy comparisonPolicy);
 
   ComparisonPolicy getComparisonPolicy();
+
+  void setAutoScrollEnabled(boolean enabled);
+
+  boolean isAutoScrollEnabled();
 }

platform/platform-impl/src/com/intellij/openapi/diff/impl/DiffPanelImpl.java

@@ -26,6 +26,7 @@ import com.intellij.openapi.components.ServiceManager;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.diff.*;
 import com.intellij.openapi.diff.actions.MergeActionGroup;
+import com.intellij.openapi.diff.actions.ToggleAutoScrollAction;
 import com.intellij.openapi.diff.ex.DiffPanelEx;
 import com.intellij.openapi.diff.ex.DiffPanelOptions;
 import com.intellij.openapi.diff.impl.external.DiffManagerImpl;
@@ -111,6 +112,8 @@ public class DiffPanelImpl implements DiffPanelEx, ContentChangeListener, TwoSid
         ActionManager actionManager = ActionManager.getInstance();
         toolbar.addAction(actionManager.getAction("DiffPanel.Toolbar"));
         toolbar.addSeparator();
+        toolbar.addAction(new ToggleAutoScrollAction());
+        toolbar.addSeparator();
         toolbar.addAction(actionManager.getAction("ContextHelp"));
         toolbar.addAction(getEditSourceAction());
         toolbar.addSeparator();
@@ -468,6 +471,14 @@ public class DiffPanelImpl implements DiffPanelEx, ContentChangeListener, TwoSid
     }
   }
 
+  public void setAutoScrollEnabled(boolean enabled) {
+    myScrollSupport.setEnabled(enabled);
+  }
+
+  public boolean isAutoScrollEnabled() {
+    return myScrollSupport.isEnabled();
+  }
+
   public void setComparisonPolicy(ComparisonPolicy comparisonPolicy) {
     setComparisonPolicy(comparisonPolicy, true);
   }

platform/platform-impl/src/com/intellij/openapi/diff/impl/util/SyncScrollSupport.java

@@ -36,6 +36,7 @@ public class SyncScrollSupport implements Disposable {
   private static final Logger LOG = Logger.getInstance("#com.intellij.openapi.diff.impl.util.SyncScrollSupport");
   private boolean myDuringVerticalScroll = false;
   private final ArrayList<ScrollListener> myScrollers = new ArrayList<ScrollListener>();
+  private boolean myEnabled = true;
 
   public void install(EditingSides[] sideContainers) {
     Disposer.dispose(this);
@@ -58,6 +59,14 @@ public class SyncScrollSupport implements Disposable {
     myScrollers.clear();
   }
 
+  public void setEnabled(boolean enabled) {
+    myEnabled = enabled;
+  }
+
+  public boolean isEnabled() {
+    return myEnabled;
+  }
+
   private void install2(Editor[] editors, EditingSides[] sideContainers) {
     addSlavesScroller(editors[0], new Pair<FragmentSide, EditingSides>(FragmentSide.SIDE1, sideContainers[0]));
     addSlavesScroller(editors[1], new Pair<FragmentSide, EditingSides>(FragmentSide.SIDE2, sideContainers[0]));
@@ -100,7 +109,7 @@ public class SyncScrollSupport implements Disposable {
     }
 
     public void visibleAreaChanged(VisibleAreaEvent e) {
-      if (myDuringVerticalScroll) return;
+      if (!myEnabled || myDuringVerticalScroll) return;
       Rectangle newRectangle = e.getNewRectangle();
       Rectangle oldRectangle = e.getOldRectangle();
       if (newRectangle == null || oldRectangle == null) return;