From 46fce02e4b9a103bed2401754a27303e98cbe7cd Mon Sep 17 00:00:00 2001
From: Dmitry Batrak <Dmitry.Batrak@jetbrains.com>
Date: Mon, 10 Feb 2014 12:00:52 +0400
Subject: [PATCH] IDEA-120265 Incorrect whitespaces (tab) painting when cursor
 change position

---
 .../openapi/editor/impl/ArrowPainter.java         | 15 ++++++++++++---
 .../intellij/openapi/editor/impl/EditorImpl.java  |  1 +
 .../impl/softwrap/ArrowSoftWrapPainter.java       | 11 +++++++++--
 3 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/platform/platform-impl/src/com/intellij/openapi/editor/impl/ArrowPainter.java b/platform/platform-impl/src/com/intellij/openapi/editor/impl/ArrowPainter.java
index b5b9e6945d61..38b00078596d 100644
--- a/platform/platform-impl/src/com/intellij/openapi/editor/impl/ArrowPainter.java
+++ b/platform/platform-impl/src/com/intellij/openapi/editor/impl/ArrowPainter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2010 JetBrains s.r.o.
+ * 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.
@@ -30,10 +30,19 @@ import java.awt.*;
 public class ArrowPainter {
 
   private final ColorProvider myColorHolder;
+  private final Computable<Integer> myWidthProvider;
   private final Computable<Integer> myHeightProvider;
 
-  public ArrowPainter(@NotNull ColorProvider colorHolder, @NotNull Computable<Integer> heightProvider) {
+  /**
+   * Creates an ArrowPainter with specified parameters.
+   *
+   * @param colorHolder defines arrow color
+   * @param widthProvider defines character width, it is used to calculate an inset for the arrow's tip
+   * @param heightProvider defines character height, it's used to calculate an arrow's width and height
+   */
+  public ArrowPainter(@NotNull ColorProvider colorHolder, @NotNull Computable<Integer> widthProvider, @NotNull Computable<Integer> heightProvider) {
     myColorHolder = colorHolder;
+    myWidthProvider = widthProvider;
     myHeightProvider = heightProvider;
   }
 
@@ -46,7 +55,7 @@ public class ArrowPainter {
    * @param stop    ending <code>'x'</code> position to use during drawing
    */
   public void paint(Graphics g, int y, int start, int stop) {
-    stop -= g.getFontMetrics().charWidth(' ') / 2;
+    stop -= myWidthProvider.compute() / 2;
     Color oldColor = g.getColor();
     g.setColor(myColorHolder.getColor());
     final int height = myHeightProvider.compute();
diff --git a/platform/platform-impl/src/com/intellij/openapi/editor/impl/EditorImpl.java b/platform/platform-impl/src/com/intellij/openapi/editor/impl/EditorImpl.java
index b9c391a0c545..ef49b827c7dc 100644
--- a/platform/platform-impl/src/com/intellij/openapi/editor/impl/EditorImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/editor/impl/EditorImpl.java
@@ -729,6 +729,7 @@ public final class EditorImpl extends UserDataHolderBase implements EditorEx, Hi
   private void initTabPainter() {
     myTabPainter = new ArrowPainter(
       ColorProvider.byColorsScheme(myScheme, EditorColors.WHITESPACES_COLOR),
+      new Computable.PredefinedValueComputable(EditorUtil.getSpaceWidth(Font.PLAIN, this)),
       new Computable<Integer>() {
         @Override
         public Integer compute() {
diff --git a/platform/platform-impl/src/com/intellij/openapi/editor/impl/softwrap/ArrowSoftWrapPainter.java b/platform/platform-impl/src/com/intellij/openapi/editor/impl/softwrap/ArrowSoftWrapPainter.java
index ccd241e977ef..d00eb487a627 100644
--- a/platform/platform-impl/src/com/intellij/openapi/editor/impl/softwrap/ArrowSoftWrapPainter.java
+++ b/platform/platform-impl/src/com/intellij/openapi/editor/impl/softwrap/ArrowSoftWrapPainter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2010 JetBrains s.r.o.
+ * 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.
@@ -43,7 +43,7 @@ public class ArrowSoftWrapPainter implements SoftWrapPainter {
 
   public ArrowSoftWrapPainter(Editor editor) {
     myEditor = editor;
-    myArrowPainter = new ArrowPainter(ColorProvider.byColor(myEditor.getColorsScheme().getDefaultForeground()), myHeightProvider);
+    myArrowPainter = new ArrowPainter(ColorProvider.byColor(myEditor.getColorsScheme().getDefaultForeground()), new WidthProvider(), myHeightProvider);
   }
 
   @Override
@@ -102,4 +102,11 @@ public class ArrowSoftWrapPainter implements SoftWrapPainter {
       return myHeight;
     }
   }
+
+  private class WidthProvider implements Computable<Integer> {
+    @Override
+    public Integer compute() {
+      return EditorUtil.getSpaceWidth(Font.PLAIN, myEditor);
+    }
+  }
 }