ui/views/examples/label_example.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/views/examples/label_example.h"

#include <memory>
#include <utility>

#include "base/cxx17_backports.h"
#include "base/memory/ptr_util.h"
#include "base/strings/utf_string_conversions.h"
#include "ui/gfx/geometry/insets.h"
#include "ui/gfx/geometry/vector2d.h"
#include "ui/views/background.h"
#include "ui/views/border.h"
#include "ui/views/controls/button/checkbox.h"
#include "ui/views/controls/combobox/combobox.h"
#include "ui/views/controls/label.h"
#include "ui/views/controls/textfield/textfield.h"
#include "ui/views/examples/example_combobox_model.h"
#include "ui/views/layout/box_layout.h"
#include "ui/views/layout/grid_layout.h"
#include "ui/views/view.h"

using base::ASCIIToUTF16;

namespace views {
namespace examples {

namespace {

const char* kAlignments[] = {"Left", "Center", "Right", "Head"};

// A Label with a clamped preferred width to demonstrate eliding or wrapping.
class ExamplePreferredSizeLabel : public Label {
 public:
  ExamplePreferredSizeLabel() { SetBorder(CreateSolidBorder(1, SK_ColorGRAY)); }

  ExamplePreferredSizeLabel(const ExamplePreferredSizeLabel&) = delete;
  ExamplePreferredSizeLabel& operator=(const ExamplePreferredSizeLabel&) =
      delete;

  ~ExamplePreferredSizeLabel() override = default;

  // Label:
  gfx::Size CalculatePreferredSize() const override {
    return gfx::Size(50, Label::CalculatePreferredSize().height());
  }

  static const char* kElideBehaviors[];
};

// static
const char* ExamplePreferredSizeLabel::kElideBehaviors[] = {
    "No Elide",   "Truncate",    "Elide Head", "Elide Middle",
    "Elide Tail", "Elide Email", "Fade Tail"};

}  // namespace

LabelExample::LabelExample() : ExampleBase("Label") {}

LabelExample::~LabelExample() = default;

void LabelExample::CreateExampleView(View* container) {
  // A very simple label example, followed by additional helpful examples.
  container->SetLayoutManager(std::make_unique<BoxLayout>(
      BoxLayout::Orientation::kVertical, gfx::Insets(), 10));
  container->AddChildView(std::make_unique<Label>(u"Hello world!"));

  const char16_t hello_world_hebrew[] =
      u"\x5e9\x5dc\x5d5\x5dd \x5d4\x5e2\x5d5\x5dc\x5dd!";
  auto label = std::make_unique<Label>(hello_world_hebrew);
  label->SetHorizontalAlignment(gfx::ALIGN_RIGHT);
  container->AddChildView(std::move(label));

  label = std::make_unique<Label>(u"A UTF16 surrogate pair: \x5d0\x5b0");
  label->SetHorizontalAlignment(gfx::ALIGN_RIGHT);
  container->AddChildView(std::move(label));

  label = std::make_unique<Label>(u"A left-aligned blue label.");
  label->SetHorizontalAlignment(gfx::ALIGN_LEFT);
  label->SetEnabledColor(SK_ColorBLUE);
  container->AddChildView(std::move(label));

  label = std::make_unique<Label>(u"Password!");
  label->SetObscured(true);
  container->AddChildView(std::move(label));

  label = std::make_unique<Label>(u"A Courier-18 label with shadows.");
  label->SetFontList(gfx::FontList("Courier, 18px"));
  gfx::ShadowValues shadows(1,
                            gfx::ShadowValue(gfx::Vector2d(), 1, SK_ColorRED));
  constexpr gfx::ShadowValue shadow(gfx::Vector2d(2, 2), 0, SK_ColorGRAY);
  shadows.push_back(shadow);
  label->SetShadows(shadows);
  container->AddChildView(std::move(label));

  label = std::make_unique<ExamplePreferredSizeLabel>();
  label->SetText(
      u"A long label will elide toward its logical end if the text's width "
      u"exceeds the label's available width.");
  container->AddChildView(std::move(label));

  label = std::make_unique<ExamplePreferredSizeLabel>();
  label->SetText(
      u"A multi-line label will wrap onto subsequent lines if the text's width "
      u"exceeds the label's available width, which is helpful for extemely "
      u"long text used to demonstrate line wrapping.");
  label->SetMultiLine(true);
  container->AddChildView(std::move(label));

  label = std::make_unique<Label>(u"Label with thick border");
  label->SetBorder(CreateSolidBorder(20, SK_ColorRED));
  container->AddChildView(std::move(label));

  label = std::make_unique<Label>(
      u"A multiline label...\n\n...which supports text selection");
  label->SetSelectable(true);
  label->SetMultiLine(true);
  container->AddChildView(std::move(label));

  AddCustomLabel(container);
}

void LabelExample::MultilineCheckboxPressed() {
  custom_label_->SetMultiLine(multiline_->GetChecked());
}

void LabelExample::ShadowsCheckboxPressed() {
  gfx::ShadowValues shadows;
  if (shadows_->GetChecked()) {
    shadows.push_back(gfx::ShadowValue(gfx::Vector2d(), 1, SK_ColorRED));
    shadows.push_back(gfx::ShadowValue(gfx::Vector2d(2, 2), 0, SK_ColorGRAY));
  }
  custom_label_->SetShadows(shadows);
}

void LabelExample::SelectableCheckboxPressed() {
  custom_label_->SetSelectable(selectable_->GetChecked());
}

void LabelExample::ContentsChanged(Textfield* sender,
                                   const std::u16string& new_contents) {
  custom_label_->SetText(new_contents);
  custom_label_->parent()->parent()->InvalidateLayout();
}

void LabelExample::AddCustomLabel(View* container) {
  std::unique_ptr<View> control_container = std::make_unique<View>();
  control_container->SetBorder(CreateSolidBorder(2, SK_ColorGRAY));
  control_container->SetBackground(CreateSolidBackground(SK_ColorLTGRAY));
  GridLayout* layout = control_container->SetLayoutManager(
      std::make_unique<views::GridLayout>());

  ColumnSet* column_set = layout->AddColumnSet(0);
  column_set->AddColumn(GridLayout::LEADING, GridLayout::FILL, 0.0f,
                        GridLayout::ColumnSize::kUsePreferred, 0, 0);
  column_set->AddColumn(GridLayout::FILL, GridLayout::FILL, 1.0f,
                        GridLayout::ColumnSize::kUsePreferred, 0, 0);

  layout->StartRow(0, 0);
  layout->AddView(std::make_unique<Label>(u"Content: "));
  auto textfield = std::make_unique<Textfield>();
  textfield->SetText(
      u"Use the provided controls to configure the content and presentation of "
      u"this custom label.");
  textfield->SetEditableSelectionRange(gfx::Range());
  textfield->set_controller(this);
  textfield_ = layout->AddView(std::move(textfield));

  alignment_ =
      AddCombobox(layout, "Alignment: ", kAlignments, base::size(kAlignments),
                  &LabelExample::AlignmentChanged);
  elide_behavior_ = AddCombobox(
      layout, "Elide Behavior: ", ExamplePreferredSizeLabel::kElideBehaviors,
      base::size(ExamplePreferredSizeLabel::kElideBehaviors),
      &LabelExample::ElidingChanged);

  column_set = layout->AddColumnSet(1);
  column_set->AddColumn(GridLayout::LEADING, GridLayout::LEADING, 0,
                        GridLayout::ColumnSize::kUsePreferred, 0, 0);
  column_set->AddColumn(GridLayout::LEADING, GridLayout::LEADING, 0,
                        GridLayout::ColumnSize::kUsePreferred, 0, 0);
  column_set->AddColumn(GridLayout::LEADING, GridLayout::LEADING, 0,
                        GridLayout::ColumnSize::kUsePreferred, 0, 0);
  layout->StartRow(0, 1);
  multiline_ = layout->AddView(std::make_unique<Checkbox>(
      u"Multiline", base::BindRepeating(&LabelExample::MultilineCheckboxPressed,
                                        base::Unretained(this))));
  shadows_ = layout->AddView(std::make_unique<Checkbox>(
      u"Shadows", base::BindRepeating(&LabelExample::ShadowsCheckboxPressed,
                                      base::Unretained(this))));
  selectable_ = layout->AddView(std::make_unique<Checkbox>(
      u"Selectable",
      base::BindRepeating(&LabelExample::SelectableCheckboxPressed,
                          base::Unretained(this))));
  layout->AddPaddingRow(0, 8);

  column_set = layout->AddColumnSet(2);
  column_set->AddColumn(GridLayout::FILL, GridLayout::FILL, 1,
                        GridLayout::ColumnSize::kUsePreferred, 0, 0);
  layout->StartRow(0, 2);
  auto custom_label = std::make_unique<ExamplePreferredSizeLabel>();
  custom_label->SetHorizontalAlignment(gfx::ALIGN_LEFT);
  custom_label->SetElideBehavior(gfx::NO_ELIDE);
  custom_label->SetText(textfield_->GetText());
  custom_label_ = layout->AddView(std::move(custom_label));

  // Disable the text selection checkbox if |custom_label_| does not support
  // text selection.
  selectable_->SetEnabled(custom_label_->IsSelectionSupported());

  container->AddChildView(std::move(control_container));
}

Combobox* LabelExample::AddCombobox(GridLayout* layout,
                                    const char* name,
                                    const char** strings,
                                    int count,
                                    void (LabelExample::*function)()) {
  layout->StartRow(0, 0);
  layout->AddView(std::make_unique<Label>(base::ASCIIToUTF16(name)));
  auto combobox = std::make_unique<Combobox>(
      std::make_unique<ExampleComboboxModel>(strings, count));
  combobox->SetSelectedIndex(0);
  combobox->SetCallback(base::BindRepeating(function, base::Unretained(this)));
  return layout->AddView(std::move(combobox));
}

void LabelExample::AlignmentChanged() {
  custom_label_->SetHorizontalAlignment(
      static_cast<gfx::HorizontalAlignment>(alignment_->GetSelectedIndex()));
}

void LabelExample::ElidingChanged() {
  custom_label_->SetElideBehavior(
      static_cast<gfx::ElideBehavior>(elide_behavior_->GetSelectedIndex()));
}

}  // namespace examples
}  // namespace views