RenderText: handle center-aligned text in UpdateCachedBoundsAndOffset()

ui/gfx/render_text_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/render_text.h"
 
 #include <algorithm>
 
 #include "base/format_macros.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 1061 matching lines @@
   EXPECT_EQ(Range(5), render_text->selection());
   render_text->MoveCursor(CHARACTER_BREAK, CURSOR_RIGHT, false);
   EXPECT_EQ(Range(4), render_text->selection());
   render_text->MoveCursor(CHARACTER_BREAK, CURSOR_LEFT, true);
   EXPECT_EQ(Range(4, 5), render_text->selection());
   render_text->MoveCursor(CHARACTER_BREAK, CURSOR_LEFT, true);
   EXPECT_EQ(Range(4, 6), render_text->selection());
   render_text->MoveCursor(CHARACTER_BREAK, CURSOR_RIGHT, false);
   EXPECT_EQ(Range(4), render_text->selection());
 }
+
+TEST_F(RenderTextTest, CenteredDisplayOffset) {
+  scoped_ptr<RenderText> render_text(RenderText::CreateInstance());
+  render_text->SetText(ASCIIToUTF16("abcdefghij"));
+  render_text->SetHorizontalAlignment(ALIGN_CENTER);
+
+  const int kEnlargement = 10;
+  const int content_width = render_text->GetContentWidth();
+  Rect display_rect(0, 0, content_width / 2,
+                    render_text->font_list().GetHeight());
+  render_text->SetDisplayRect(display_rect);
+
+  // Move the cursor to the beginning of the text and, by checking the cursor
+  // bounds, make sure no empty space is to the left of the text.
+  render_text->SetCursorPosition(0);
+  EXPECT_EQ(display_rect.x(), render_text->GetUpdatedCursorBounds().x());
+
+  // Widen the display rect and, by checking the cursor bounds, make sure no
+  // empty space is introduced to the left of the text.
+  display_rect.Inset(0, 0, -kEnlargement, 0);
+  render_text->SetDisplayRect(display_rect);
+  EXPECT_EQ(display_rect.x(), render_text->GetUpdatedCursorBounds().x());
+
+  // Move the cursor to the end of the text and, by checking the cursor bounds,
+  // make sure no empty space is to the right of the text.
+  render_text->SetCursorPosition(render_text->text().length());
+  EXPECT_EQ(display_rect.right(),
+            render_text->GetUpdatedCursorBounds().right());
+
+  // Widen the display rect and, by checking the cursor bounds, make sure no
+  // empty space is introduced to the right of the text.
+  display_rect.Inset(0, 0, -kEnlargement, 0);
+  render_text->SetDisplayRect(display_rect);
+  EXPECT_EQ(display_rect.right(),
+            render_text->GetUpdatedCursorBounds().right());
+}
 #endif  // !defined(OS_MACOSX)
 
 // TODO(xji): Make these work on Windows.
 #if defined(OS_LINUX)
 void MoveLeftRightByWordVerifier(RenderText* render_text,
                                  const wchar_t* str) {
   render_text->SetText(WideToUTF16(str));
 
   // Test moving by word from left ro right.
   render_text->MoveCursor(LINE_BREAK, CURSOR_LEFT, false);
@@ skipping 460 matching lines @@
     // [-kEnlargement, 0].
     { ALIGN_LEFT, -2 * kEnlargement, -kEnlargement },
     { ALIGN_LEFT, -kEnlargement / 2, -kEnlargement / 2 },
     { ALIGN_LEFT, kEnlargement, 0 },
     // When text is right-aligned, display offset can be in range
     // [0, kEnlargement].
     { ALIGN_RIGHT, -kEnlargement, 0 },
     { ALIGN_RIGHT, kEnlargement / 2, kEnlargement / 2 },
     { ALIGN_RIGHT, 2 * kEnlargement, kEnlargement },
     // When text is center-aligned, display offset can be in range
-    // [-kEnlargement / 2, kEnlargement / 2].
-    { ALIGN_CENTER, -kEnlargement, -kEnlargement / 2 },
+    // [-kEnlargement / 2 - 1, (kEnlargement - 1) / 2].
+    { ALIGN_CENTER, -kEnlargement, -kEnlargement / 2 - 1 },
     { ALIGN_CENTER, -kEnlargement / 4, -kEnlargement / 4 },
     { ALIGN_CENTER, kEnlargement / 4, kEnlargement / 4 },
-    { ALIGN_CENTER, kEnlargement, kEnlargement / 2 },
+    { ALIGN_CENTER, kEnlargement, (kEnlargement - 1) / 2 },
   };
 
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(large_content_cases); i++) {
     render_text->SetHorizontalAlignment(large_content_cases[i].alignment);
     render_text->SetDisplayOffset(large_content_cases[i].offset);
     EXPECT_EQ(large_content_cases[i].expected_offset,
               render_text->GetUpdatedDisplayOffset().x());
   }
 }
 
@@ skipping 543 matching lines @@
   for (size_t i = 0; i < arraysize(kTestStrings); ++i) {
     render_text->SetText(WideToUTF16(kTestStrings[i]));
     render_text->EnsureLayout();
 
     for (size_t j = 0; j < render_text->text().length(); ++j)
       EXPECT_FALSE(render_text->GetGlyphBounds(j).is_empty());
   }
 }
 
 }  // namespace gfx