Draw nicer arrows when the scrollbar buttons are not square.

ui/native_theme/native_theme_aura_unittest.cc

 // Copyright 2016 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/native_theme/native_theme_aura.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/core/SkPath.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/native_theme/native_theme.h"
 
 namespace ui {
 namespace {
 void VerifyPoint(SkPoint a, SkPoint b) {
   EXPECT_EQ(a.x(), b.x());
   EXPECT_EQ(a.y(), b.y());
 }
 
 void VerifyTriangle(SkPath actualPath, SkPoint p0, SkPoint p1, SkPoint p2) {
   EXPECT_EQ(3, actualPath.countPoints());
   VerifyPoint(p0, actualPath.getPoint(0));
   VerifyPoint(p1, actualPath.getPoint(1));
   VerifyPoint(p2, actualPath.getPoint(2));
 }
 }
 
-TEST(NativeThemeAuraTest, VerticalArrows) {
-  NativeThemeAura* theme = NativeThemeAura::instance();
+class NativeThemeAuraTest : public testing::Test {
+ protected:
+  NativeThemeAuraTest() : theme_(NativeThemeAura::instance()) {}
+
+  SkPath PathForArrow(const gfx::Rect& rect,
+                      NativeTheme::Part direction) const {
+    return theme_->PathForArrow(rect, direction);
+  }
+
+  gfx::Rect BoundingRectForArrow(const gfx::Rect& rect) const {
+    return theme_->BoundingRectForArrow(rect);
+  }
+
+ private:
+  NativeThemeAura* theme_;
+};
+
+TEST_F(NativeThemeAuraTest, VerticalArrows) {
   SkPath path;
 
   // Up arrow, sized for 1x.
-  path = theme->PathForArrow(gfx::Rect(100, 200, 17, 17),
-                             NativeTheme::kScrollbarUpArrow);
+  path =
+      PathForArrow(gfx::Rect(100, 200, 17, 17), NativeTheme::kScrollbarUpArrow);
   VerifyTriangle(path, SkPoint::Make(105, 211), SkPoint::Make(112, 211),
                  SkPoint::Make(108.5, 207));
 
   // 1.25x, should be larger.
-  path = theme->PathForArrow(gfx::Rect(50, 70, 21, 21),
-                             NativeTheme::kScrollbarUpArrow);
+  path =
+      PathForArrow(gfx::Rect(50, 70, 21, 21), NativeTheme::kScrollbarUpArrow);
   VerifyTriangle(path, SkPoint::Make(56, 84), SkPoint::Make(65, 84),
                  SkPoint::Make(60.5, 79));
 
   // Down arrow is just a flipped up arrow.
-  path = theme->PathForArrow(gfx::Rect(20, 80, 17, 17),
-                             NativeTheme::kScrollbarDownArrow);
+  path =
+      PathForArrow(gfx::Rect(20, 80, 17, 17), NativeTheme::kScrollbarDownArrow);
   VerifyTriangle(path, SkPoint::Make(25, 86), SkPoint::Make(32, 86),
                  SkPoint::Make(28.5, 90));
 }
 
-TEST(NativeThemeAuraTest, HorizontalArrows) {
-  NativeThemeAura* theme = NativeThemeAura::instance();
+TEST_F(NativeThemeAuraTest, HorizontalArrows) {
   SkPath path;
 
   // Right arrow, sized for 1x.
-  path = theme->PathForArrow(gfx::Rect(100, 200, 17, 17),
-                             NativeTheme::kScrollbarRightArrow);
+  path = PathForArrow(gfx::Rect(100, 200, 17, 17),
+                      NativeTheme::kScrollbarRightArrow);
   VerifyTriangle(path, SkPoint::Make(107, 205), SkPoint::Make(107, 212),
                  SkPoint::Make(111, 208.5));
 
   // Button size for 1.25x, should be larger.
-  path = theme->PathForArrow(gfx::Rect(50, 70, 21, 21),
-                             NativeTheme::kScrollbarRightArrow);
+  path = PathForArrow(gfx::Rect(50, 70, 21, 21),
+                      NativeTheme::kScrollbarRightArrow);
   VerifyTriangle(path, SkPoint::Make(58, 76), SkPoint::Make(58, 85),
                  SkPoint::Make(63, 80.5));
 
   // Left arrow is just a flipped right arrow.
-  path = theme->PathForArrow(gfx::Rect(20, 80, 17, 17),
-                             NativeTheme::kScrollbarLeftArrow);
+  path =
+      PathForArrow(gfx::Rect(20, 80, 17, 17), NativeTheme::kScrollbarLeftArrow);
   VerifyTriangle(path, SkPoint::Make(30, 85), SkPoint::Make(30, 92),
                  SkPoint::Make(26, 88.5));
 }
 
+TEST_F(NativeThemeAuraTest, ArrowForNonSquareButton) {
+  SkPath path =
+      PathForArrow(gfx::Rect(90, 80, 42, 37), NativeTheme::kScrollbarLeftArrow);
+  VerifyTriangle(path, SkPoint::Make(116, 89), SkPoint::Make(116, 109),
+                 SkPoint::Make(105, 99));
+}
+
+TEST_F(NativeThemeAuraTest, BoundingRectSquare) {
+  gfx::Rect bounding_rect = BoundingRectForArrow(gfx::Rect(42, 61, 21, 21));
+  EXPECT_EQ(48.f, bounding_rect.x());
+  EXPECT_EQ(67.f, bounding_rect.y());
+  EXPECT_EQ(9.f, bounding_rect.width());
+  EXPECT_EQ(bounding_rect.width(), bounding_rect.height());
+}
+
+TEST_F(NativeThemeAuraTest, BoundingRectSlightlyRectangular) {
+  // Stretched horzontally.
+  gfx::Rect bounding_rect = BoundingRectForArrow(gfx::Rect(42, 61, 25, 20));
+  EXPECT_EQ(49.f, bounding_rect.x());
+  EXPECT_EQ(66.f, bounding_rect.y());
+  EXPECT_EQ(11.f, bounding_rect.width());
+  EXPECT_EQ(bounding_rect.width(), bounding_rect.height());
+
+  // Stretched vertically.
+  bounding_rect = BoundingRectForArrow(gfx::Rect(42, 61, 14, 10));
+  EXPECT_EQ(46.f, bounding_rect.x());
+  EXPECT_EQ(63.f, bounding_rect.y());
+  EXPECT_EQ(6.f, bounding_rect.width());
+  EXPECT_EQ(bounding_rect.width(), bounding_rect.height());
+}
+
+TEST_F(NativeThemeAuraTest, BoundingRectVeryRectangular) {
+  // Stretched horzontally.
+  gfx::Rect bounding_rect = BoundingRectForArrow(gfx::Rect(42, 61, 30, 8));
+  EXPECT_EQ(53.f, bounding_rect.x());
+  EXPECT_EQ(61.f, bounding_rect.y());
+  EXPECT_EQ(8.f, bounding_rect.width());
+  EXPECT_EQ(bounding_rect.width(), bounding_rect.height());
+
+  // Stretched vertically.
+  bounding_rect = BoundingRectForArrow(gfx::Rect(42, 61, 6, 44));
+  EXPECT_EQ(42.f, bounding_rect.x());
+  EXPECT_EQ(80.f, bounding_rect.y());
+  EXPECT_EQ(6.f, bounding_rect.width());
+  EXPECT_EQ(bounding_rect.width(), bounding_rect.height());
+}
+
+TEST_F(NativeThemeAuraTest, BoundingRectSnappedToWholePixels) {
+  gfx::Rect bounding_rect = BoundingRectForArrow(gfx::Rect(0, 0, 9, 10));
+  EXPECT_EQ(3.f, bounding_rect.x());
+
+  bounding_rect = BoundingRectForArrow(gfx::Rect(0, 0, 10, 9));
+  EXPECT_EQ(3.f, bounding_rect.y());
+}
+
 }  // namespace ui