From e85e470f4bbb0dee67f85338bab6dcdf7ef65101 Mon Sep 17 00:00:00 2001
From: Maxim Shafirov <max@jetbrains.com>
Date: Thu, 2 Sep 2010 14:55:31 +0400
Subject: [PATCH] Defensive bounds checking

---
 .../intellij/openapi/editor/impl/EditorMarkupModelImpl.java  | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/platform/platform-impl/src/com/intellij/openapi/editor/impl/EditorMarkupModelImpl.java b/platform/platform-impl/src/com/intellij/openapi/editor/impl/EditorMarkupModelImpl.java
index ee4b317c9be7..81863eb455ab 100644
--- a/platform/platform-impl/src/com/intellij/openapi/editor/impl/EditorMarkupModelImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/editor/impl/EditorMarkupModelImpl.java
@@ -700,12 +700,13 @@ public class EditorMarkupModelImpl extends MarkupModelImpl implements EditorMark
     if (myEditorScrollbarTop == -1 || myEditorTargetHeight == -1) {
       recalcEditorDimensions();
     }
+    final int safeY = Math.max(0, y - myEditorScrollbarTop);
     VisualPosition visual;
     if (myEditorSourceHeight < myEditorTargetHeight) {
-      visual = myEditor.xyToVisualPosition(new Point(0, y - myEditorScrollbarTop));
+      visual = myEditor.xyToVisualPosition(new Point(0, safeY));
     }
     else {
-      float fraction = Math.max(0, Math.min(1, (y - myEditorScrollbarTop) / (float)myEditorTargetHeight));
+      float fraction = Math.max(0, Math.min(1, safeY / (float)myEditorTargetHeight));
       final int lineCount = myEditorSourceHeight / myEditor.getLineHeight();
       visual = new VisualPosition((int)(fraction * lineCount),0);
     }