ash/controls/scroll_view_gradient_helper_unittest.cc

   1 // Copyright 2021 The Chromium Authors
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include <memory>
   6
   7 #include "ash/controls/gradient_layer_delegate.h"
   8 #include "ash/controls/scroll_view_gradient_helper.h"
   9 #include "ui/compositor/layer.h"
  10 #include "ui/compositor/layer_type.h"
  11 #include "ui/gfx/geometry/rect.h"
  12 #include "ui/views/controls/scroll_view.h"
  13 #include "ui/views/test/views_test_base.h"
  14 #include "ui/views/test/views_test_utils.h"
  15 #include "ui/views/widget/unique_widget_ptr.h"
  16 #include "ui/views/widget/widget.h"
  17 #include "ui/views/widget/widget_utils.h"
  18
  19 namespace ash {
  20 namespace {
  21
  22 constexpr int kWidgetHeight = 100;
  23 constexpr int kWidgetWidth = 100;
  24 constexpr int kGradientSize = 16;
  25
  26 // Uses ViewsTestBase because we may want to move this helper into //ui/views
  27 // in the future.
  28 class ScrollViewGradientHelperTest : public views::ViewsTestBase {
  29  public:
  30   ScrollViewGradientHelperTest() = default;
  31   ~ScrollViewGradientHelperTest() override = default;
  32
  33   // testing::Test:
  34   void SetUp() override {
  35     ViewsTestBase::SetUp();
  36
  37     // Create a small widget.
  38     widget_ = std::make_unique<views::Widget>();
  39     views::Widget::InitParams params =
  40         CreateParams(views::Widget::InitParams::TYPE_POPUP);
  41     params.bounds = gfx::Rect(10, 10, kWidgetWidth, kWidgetHeight);
  42     widget_->Init(std::move(params));
  43     widget_->Show();
  44
  45     // Add a scroll view and gradient helper.
  46     auto* contents = widget_->SetContentsView(std::make_unique<views::View>());
  47     scroll_view_ =
  48         contents->AddChildView(std::make_unique<views::ScrollView>());
  49     scroll_view_->SetBounds(0, 0, kWidgetWidth, kWidgetHeight);
  50     scroll_view_->SetPaintToLayer(ui::LAYER_NOT_DRAWN);
  51     gradient_helper_ =
  52         std::make_unique<ScrollViewGradientHelper>(scroll_view_, kGradientSize);
  53   }
  54
  55   void TearDown() override {
  56     gradient_helper_.reset();
  57     widget_.reset();
  58     ViewsTestBase::TearDown();
  59   }
  60
  61   void AddScrollViewContentsWithHeight(int height) {
  62     auto contents = std::make_unique<views::View>();
  63     contents->SetSize({kWidgetWidth, height});
  64     scroll_view_->SetContents(std::move(contents));
  65     views::test::RunScheduledLayout(scroll_view_);
  66   }
  67
  68   bool HasGradientAtTop() {
  69     const auto& gradient_mask = gradient_helper_->gradient_mask_for_test();
  70     EXPECT_FALSE(gradient_mask.IsEmpty());
  71     return cc::MathUtil::IsWithinEpsilon(gradient_mask.steps()[0].fraction,
  72                                          0.f);
  73   }
  74
  75   bool HasGradientAtBottom() {
  76     const auto& gradient_mask = gradient_helper_->gradient_mask_for_test();
  77     EXPECT_FALSE(gradient_mask.IsEmpty());
  78     return cc::MathUtil::IsWithinEpsilon(
  79         gradient_mask.steps()[gradient_mask.step_count() - 1].fraction, 1.f);
  80   }
  81
  82   bool HasGradientMask(const ui::Layer* layer) {
  83     return !layer->gradient_mask().IsEmpty();
  84   }
  85
  86   views::UniqueWidgetPtr widget_;
  87   views::ScrollView* scroll_view_ = nullptr;
  88   std::unique_ptr<ScrollViewGradientHelper> gradient_helper_;
  89 };
  90
  91 TEST_F(ScrollViewGradientHelperTest, NoGradientForViewThatDoesNotScroll) {
  92   // Create a short contents view, so the scroll view won't scroll.
  93   AddScrollViewContentsWithHeight(10);
  94   gradient_helper_->UpdateGradientMask();
  95
  96   EXPECT_FALSE(HasGradientMask(scroll_view_->layer()));
  97   EXPECT_TRUE(gradient_helper_->gradient_mask_for_test().IsEmpty());
  98 }
  99
 100 TEST_F(ScrollViewGradientHelperTest, HasGradientForViewThatScrolls) {
 101   // Create a tall contents view.
 102   AddScrollViewContentsWithHeight(500);
 103   gradient_helper_->UpdateGradientMask();
 104
 105   // Gradient is shown.
 106   EXPECT_TRUE(HasGradientMask(scroll_view_->layer()));
 107   EXPECT_FALSE(gradient_helper_->gradient_mask_for_test().IsEmpty());
 108
 109   // Shrink the contents view.
 110   scroll_view_->contents()->SetSize({kWidgetWidth, 10});
 111   views::test::RunScheduledLayout(scroll_view_);
 112   gradient_helper_->UpdateGradientMask();
 113
 114   // Gradient is removed.
 115   EXPECT_FALSE(HasGradientMask(scroll_view_->layer()));
 116   EXPECT_TRUE(gradient_helper_->gradient_mask_for_test().IsEmpty());
 117 }
 118
 119 TEST_F(ScrollViewGradientHelperTest, ShowsGradientsBasedOnScrollPosition) {
 120   // Create a tall contents view.
 121   AddScrollViewContentsWithHeight(500);
 122   ASSERT_TRUE(scroll_view_->vertical_scroll_bar());
 123   gradient_helper_->UpdateGradientMask();
 124
 125   // Because the scroll position is at the top, only the bottom gradient shows.
 126   EXPECT_FALSE(HasGradientAtTop());
 127   EXPECT_TRUE(HasGradientAtBottom());
 128
 129   // Scroll down. Now both top and bottom should have gradients.
 130   scroll_view_->vertical_scroll_bar()->ScrollByAmount(
 131       views::ScrollBar::ScrollAmount::kNextLine);
 132   EXPECT_TRUE(HasGradientAtTop());
 133   EXPECT_TRUE(HasGradientAtBottom());
 134
 135   // Scroll to end. Now only the top should have a gradient.
 136   scroll_view_->vertical_scroll_bar()->ScrollByAmount(
 137       views::ScrollBar::ScrollAmount::kEnd);
 138   EXPECT_TRUE(HasGradientAtTop());
 139   EXPECT_FALSE(HasGradientAtBottom());
 140 }
 141
 142 TEST_F(ScrollViewGradientHelperTest, DeletingHelperRemovesMaskLayer) {
 143   // Create a tall contents view.
 144   AddScrollViewContentsWithHeight(500);
 145   gradient_helper_->UpdateGradientMask();
 146
 147   // Precondition: Mask exists.
 148   ASSERT_TRUE(HasGradientMask(scroll_view_->layer()));
 149
 150   gradient_helper_.reset();
 151   ASSERT_FALSE(HasGradientMask(scroll_view_->layer()));
 152 }
 153
 154 }  // namespace
 155 }  // namespace ash