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 "base/macros.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;
using base::WideToUTF16;

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() : Label() {
    SetBorder(CreateSolidBorder(1, SK_ColorGRAY));
  }
  ~ExamplePreferredSizeLabel() override {}

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

  static const char* kElideBehaviors[];

 private:
  DISALLOW_COPY_AND_ASSIGN(ExamplePreferredSizeLabel);
};

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

}  // namespace

LabelExample::LabelExample()
    : ExampleBase("Label"),
      textfield_(NULL),
      alignment_(NULL),
      elide_behavior_(NULL),
      multiline_(NULL),
      shadows_(NULL),
      custom_label_(NULL) {
}

LabelExample::~LabelExample() {
  // Remove the views first as some reference combobox models.
  container()->RemoveAllChildViews(true);
}

void LabelExample::CreateExampleView(View* container) {
  // A very simple label example, followed by additional helpful examples.
  container->SetLayoutManager(
      std::make_unique<BoxLayout>(BoxLayout::kVertical, gfx::Insets(), 10));
  Label* label = new Label(ASCIIToUTF16("Hello world!"));
  container->AddChildView(label);

  const wchar_t hello_world_hebrew[] =
      L"\x5e9\x5dc\x5d5\x5dd \x5d4\x5e2\x5d5\x5dc\x5dd!";
  label = new Label(WideToUTF16(hello_world_hebrew));
  label->SetHorizontalAlignment(gfx::ALIGN_RIGHT);
  container->AddChildView(label);

  label = new Label(WideToUTF16(L"A UTF16 surrogate pair: \x5d0\x5b0"));
  label->SetHorizontalAlignment(gfx::ALIGN_RIGHT);
  container->AddChildView(label);

  label = new Label(ASCIIToUTF16("A left-aligned blue label."));
  label->SetHorizontalAlignment(gfx::ALIGN_LEFT);
  label->SetEnabledColor(SK_ColorBLUE);
  container->AddChildView(label);

  label = new Label(WideToUTF16(L"Password!"));
  label->SetObscured(true);
  container->AddChildView(label);

  label = new Label(ASCIIToUTF16("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(label);

  label = new ExamplePreferredSizeLabel();
  label->SetText(ASCIIToUTF16("A long label will elide toward its logical end "
      "if the text's width exceeds the label's available width."));
  container->AddChildView(label);

  label = new ExamplePreferredSizeLabel();
  label->SetText(ASCIIToUTF16("A multi-line label will wrap onto subsequent "
    "lines if the text's width exceeds the label's available width, which is "
    "helpful for extemely long text used to demonstrate line wrapping."));
  label->SetMultiLine(true);
  container->AddChildView(label);

  label = new Label(ASCIIToUTF16("Label with thick border"));
  label->SetBorder(CreateSolidBorder(20, SK_ColorRED));
  container->AddChildView(label);

  label = new Label(
      ASCIIToUTF16("A multiline label...\n\n...which supports text selection"));
  label->SetSelectable(true);
  label->SetMultiLine(true);
  container->AddChildView(label);

  AddCustomLabel(container);
}

void LabelExample::ButtonPressed(Button* button, const ui::Event& event) {
  if (button == multiline_) {
    custom_label_->SetMultiLine(multiline_->checked());
  } else if (button == shadows_) {
    gfx::ShadowValues shadows;
    if (shadows_->checked()) {
      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);
  } else if (button == selectable_) {
    custom_label_->SetSelectable(selectable_->checked());
  }
  custom_label_->parent()->parent()->Layout();
  custom_label_->SchedulePaint();
}

void LabelExample::OnPerformAction(Combobox* combobox) {
  if (combobox == alignment_) {
    custom_label_->SetHorizontalAlignment(
        static_cast<gfx::HorizontalAlignment>(combobox->selected_index()));
  } else if (combobox == elide_behavior_) {
    custom_label_->SetElideBehavior(
        static_cast<gfx::ElideBehavior>(combobox->selected_index()));
  }
}

void LabelExample::ContentsChanged(Textfield* sender,
                                   const base::string16& new_contents) {
  custom_label_->SetText(new_contents);
  custom_label_->parent()->parent()->Layout();
}

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

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

  layout->StartRow(0, 0);
  layout->AddView(new Label(ASCIIToUTF16("Content: ")));
  textfield_ = new Textfield();
  textfield_->SetText(ASCIIToUTF16("Use the provided controls to configure the "
      "content and presentation of this custom label."));
  textfield_->SetSelectionRange(gfx::Range());
  textfield_->set_controller(this);
  layout->AddView(textfield_);

  alignment_ = AddCombobox(layout, "Alignment: ", kAlignments,
                           arraysize(kAlignments));
  elide_behavior_ = AddCombobox(
      layout, "Elide Behavior: ", ExamplePreferredSizeLabel::kElideBehaviors,
      arraysize(ExamplePreferredSizeLabel::kElideBehaviors));

  column_set = layout->AddColumnSet(1);
  column_set->AddColumn(GridLayout::LEADING, GridLayout::LEADING,
                        0, GridLayout::USE_PREF, 0, 0);
  column_set->AddColumn(GridLayout::LEADING, GridLayout::LEADING,
                        0, GridLayout::USE_PREF, 0, 0);
  column_set->AddColumn(GridLayout::LEADING, GridLayout::LEADING, 0,
                        GridLayout::USE_PREF, 0, 0);
  layout->StartRow(0, 1);
  multiline_ = new Checkbox(base::ASCIIToUTF16("Multiline"), this);
  layout->AddView(multiline_);
  shadows_ = new Checkbox(base::ASCIIToUTF16("Shadows"), this);
  layout->AddView(shadows_);
  selectable_ = new Checkbox(base::ASCIIToUTF16("Selectable"), this);
  layout->AddView(selectable_);
  layout->AddPaddingRow(0, 8);

  column_set = layout->AddColumnSet(2);
  column_set->AddColumn(GridLayout::FILL, GridLayout::FILL,
                        1, GridLayout::USE_PREF, 0, 0);
  layout->StartRow(0, 2);
  custom_label_ = new ExamplePreferredSizeLabel();
  custom_label_->SetHorizontalAlignment(gfx::ALIGN_LEFT);
  custom_label_->SetElideBehavior(gfx::NO_ELIDE);
  custom_label_->SetText(textfield_->text());
  layout->AddView(custom_label_);

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

  container->AddChildView(control_container);
}

Combobox* LabelExample::AddCombobox(GridLayout* layout,
                                    const char* name,
                                    const char** strings,
                                    int count) {
  layout->StartRow(0, 0);
  layout->AddView(new Label(base::ASCIIToUTF16(name)));
  ExampleComboboxModel* model = new ExampleComboboxModel(strings, count);
  example_combobox_models_.push_back(base::WrapUnique(model));
  Combobox* combobox = new Combobox(model);
  combobox->SetSelectedIndex(0);
  combobox->set_listener(this);
  layout->AddView(combobox);
  return combobox;
}

}  // namespace examples
}  // namespace views