ui/views/controls/label.cc

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This source file includes following definitions.
SetFontList
SetText
SetTextInternal
SetAutoColorReadabilityEnabled
SetEnabledColor
SetDisabledColor
SetBackgroundColor
SetShadowColors
SetShadowOffset
ClearEmbellishing
SetHorizontalAlignment
SetLineHeight
SetMultiLine
SetObscured
SetAllowCharacterBreak
SetElideBehavior
SetTooltipText
SizeToFit
GetInsets
GetBaseline
GetPreferredSize
GetMinimumSize
GetHeightForWidth
GetClassName
GetTooltipHandlerForPoint
HitTestRect
GetTooltipText
GetAccessibleState
PaintText
GetTextSize
OnBoundsChanged
OnPaint
OnNativeThemeChanged
Init
RecalculateColors
GetTextBounds
ComputeDrawStringFlags
GetAvailableRect
CalculateDrawStringParams
UpdateColorsFromTheme
ResetCachedSize
ShouldShowDefaultTooltip
// 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/controls/label.h"

#include <algorithm>
#include <cmath>
#include <limits>
#include <vector>

#include "base/i18n/rtl.h"
#include "base/logging.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "ui/accessibility/ax_view_state.h"
#include "ui/base/resource/resource_bundle.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/color_utils.h"
#include "ui/gfx/insets.h"
#include "ui/gfx/shadow_value.h"
#include "ui/gfx/text_elider.h"
#include "ui/gfx/text_utils.h"
#include "ui/gfx/utf16_indexing.h"
#include "ui/native_theme/native_theme.h"
#include "ui/views/background.h"

namespace {

const int kCachedSizeLimit = 10;
const base::char16 kPasswordReplacementChar = '*';

}  // namespace

namespace views {

// static
const char Label::kViewClassName[] = "Label";
const int Label::kFocusBorderPadding = 1;

Label::Label() {
  Init(base::string16(), gfx::FontList());
}

Label::Label(const base::string16& text) {
  Init(text, gfx::FontList());
}

Label::Label(const base::string16& text, const gfx::FontList& font_list) {
  Init(text, font_list);
}

Label::~Label() {
}

void Label::SetFontList(const gfx::FontList& font_list) {
  font_list_ = font_list;
  ResetCachedSize();
  PreferredSizeChanged();
  SchedulePaint();
}

void Label::SetText(const base::string16& text) {
  if (text != text_)
    SetTextInternal(text);
}

void Label::SetTextInternal(const base::string16& text) {
  text_ = text;

  if (is_obscured_) {
    size_t obscured_text_length =
        static_cast<size_t>(gfx::UTF16IndexToOffset(text_, 0, text_.length()));
    layout_text_.assign(obscured_text_length, kPasswordReplacementChar);
  } else {
    layout_text_ = text_;
  }

  ResetCachedSize();
  PreferredSizeChanged();
  SchedulePaint();
}

void Label::SetAutoColorReadabilityEnabled(bool enabled) {
  auto_color_readability_ = enabled;
  RecalculateColors();
}

void Label::SetEnabledColor(SkColor color) {
  requested_enabled_color_ = color;
  enabled_color_set_ = true;
  RecalculateColors();
}

void Label::SetDisabledColor(SkColor color) {
  requested_disabled_color_ = color;
  disabled_color_set_ = true;
  RecalculateColors();
}

void Label::SetBackgroundColor(SkColor color) {
  background_color_ = color;
  background_color_set_ = true;
  RecalculateColors();
}

void Label::SetShadowColors(SkColor enabled_color, SkColor disabled_color) {
  enabled_shadow_color_ = enabled_color;
  disabled_shadow_color_ = disabled_color;
  has_shadow_ = true;
}

void Label::SetShadowOffset(int x, int y) {
  shadow_offset_.SetPoint(x, y);
}

void Label::ClearEmbellishing() {
  has_shadow_ = false;
}

void Label::SetHorizontalAlignment(gfx::HorizontalAlignment alignment) {
  // If the View's UI layout is right-to-left and directionality_mode_ is
  // USE_UI_DIRECTIONALITY, we need to flip the alignment so that the alignment
  // settings take into account the text directionality.
  if (base::i18n::IsRTL() && (directionality_mode_ == USE_UI_DIRECTIONALITY) &&
      (alignment != gfx::ALIGN_CENTER)) {
    alignment = (alignment == gfx::ALIGN_LEFT) ?
        gfx::ALIGN_RIGHT : gfx::ALIGN_LEFT;
  }
  if (horizontal_alignment_ != alignment) {
    horizontal_alignment_ = alignment;
    SchedulePaint();
  }
}

void Label::SetLineHeight(int height) {
  if (height != line_height_) {
    line_height_ = height;
    ResetCachedSize();
    PreferredSizeChanged();
    SchedulePaint();
  }
}

void Label::SetMultiLine(bool multi_line) {
  DCHECK(!multi_line || (elide_behavior_ != ELIDE_IN_MIDDLE &&
      elide_behavior_ != ELIDE_AT_BEGINNING));
  if (multi_line != is_multi_line_) {
    is_multi_line_ = multi_line;
    ResetCachedSize();
    PreferredSizeChanged();
    SchedulePaint();
  }
}

void Label::SetObscured(bool obscured) {
  if (obscured != is_obscured_) {
    is_obscured_ = obscured;
    SetTextInternal(text_);
  }
}

void Label::SetAllowCharacterBreak(bool allow_character_break) {
  if (allow_character_break != allow_character_break_) {
    allow_character_break_ = allow_character_break;
    ResetCachedSize();
    PreferredSizeChanged();
    SchedulePaint();
  }
}

void Label::SetElideBehavior(ElideBehavior elide_behavior) {
  DCHECK(elide_behavior != ELIDE_IN_MIDDLE || !is_multi_line_);
  if (elide_behavior != elide_behavior_) {
    elide_behavior_ = elide_behavior;
    ResetCachedSize();
    PreferredSizeChanged();
    SchedulePaint();
  }
}

void Label::SetTooltipText(const base::string16& tooltip_text) {
  tooltip_text_ = tooltip_text;
}

void Label::SizeToFit(int max_width) {
  DCHECK(is_multi_line_);

  std::vector<base::string16> lines;
  base::SplitString(layout_text(), '\n', &lines);

  int label_width = 0;
  for (std::vector<base::string16>::const_iterator iter = lines.begin();
       iter != lines.end(); ++iter) {
    label_width = std::max(label_width, gfx::GetStringWidth(*iter, font_list_));
  }

  label_width += GetInsets().width();

  if (max_width > 0)
    label_width = std::min(label_width, max_width);

  SetBounds(x(), y(), label_width, 0);
  SizeToPreferredSize();
}

gfx::Insets Label::GetInsets() const {
  gfx::Insets insets = View::GetInsets();
  if (focusable()) {
    insets += gfx::Insets(kFocusBorderPadding, kFocusBorderPadding,
                          kFocusBorderPadding, kFocusBorderPadding);
  }
  return insets;
}

int Label::GetBaseline() const {
  return GetInsets().top() + font_list_.GetBaseline();
}

gfx::Size Label::GetPreferredSize() {
  // Return a size of (0, 0) if the label is not visible and if the
  // collapse_when_hidden_ flag is set.
  // TODO(munjal): This logic probably belongs to the View class. But for now,
  // put it here since putting it in View class means all inheriting classes
  // need ot respect the collapse_when_hidden_ flag.
  if (!visible() && collapse_when_hidden_)
    return gfx::Size();

  gfx::Size size(GetTextSize());
  gfx::Insets insets = GetInsets();
  size.Enlarge(insets.width(), insets.height());
  return size;
}

gfx::Size Label::GetMinimumSize() {
  gfx::Size text_size(GetTextSize());
  if ((!visible() && collapse_when_hidden_) || text_size.IsEmpty())
    return gfx::Size();

  gfx::Size size(gfx::GetStringWidth(base::string16(gfx::kEllipsisUTF16),
                                     font_list_),
                 font_list_.GetHeight());
  size.SetToMin(text_size);  // The actual text may be shorter than an ellipsis.
  gfx::Insets insets = GetInsets();
  size.Enlarge(insets.width(), insets.height());
  return size;
}

int Label::GetHeightForWidth(int w) {
  if (!is_multi_line_)
    return View::GetHeightForWidth(w);

  w = std::max(0, w - GetInsets().width());

  for (size_t i = 0; i < cached_heights_.size(); ++i) {
    const gfx::Size& s = cached_heights_[i];
    if (s.width() == w)
      return s.height() + GetInsets().height();
  }

  int cache_width = w;

  int h = font_list_.GetHeight();
  const int flags = ComputeDrawStringFlags();
  gfx::Canvas::SizeStringInt(
      layout_text(), font_list_, &w, &h, line_height_, flags);
  cached_heights_[cached_heights_cursor_] = gfx::Size(cache_width, h);
  cached_heights_cursor_ = (cached_heights_cursor_ + 1) % kCachedSizeLimit;
  return h + GetInsets().height();
}

const char* Label::GetClassName() const {
  return kViewClassName;
}

View* Label::GetTooltipHandlerForPoint(const gfx::Point& point) {
  // Bail out if the label does not contain the point.
  // Note that HitTestPoint() cannot be used here as it uses
  // Label::HitTestRect() to determine if the point hits the label; and
  // Label::HitTestRect() always fails. Instead, default HitTestRect()
  // implementation should be used.
  if (!View::HitTestRect(gfx::Rect(point, gfx::Size(1, 1))))
    return NULL;

  if (tooltip_text_.empty() && !ShouldShowDefaultTooltip())
    return NULL;

  return this;
}

bool Label::HitTestRect(const gfx::Rect& rect) const {
  return false;
}

bool Label::GetTooltipText(const gfx::Point& p, base::string16* tooltip) const {
  DCHECK(tooltip);

  // If a tooltip has been explicitly set, use it.
  if (!tooltip_text_.empty()) {
    tooltip->assign(tooltip_text_);
    return true;
  }

  // Show the full text if the text does not fit.
  if (ShouldShowDefaultTooltip()) {
    *tooltip = layout_text();
    return true;
  }

  return false;
}

void Label::GetAccessibleState(ui::AXViewState* state) {
  state->role = ui::AX_ROLE_STATIC_TEXT;
  state->AddStateFlag(ui::AX_STATE_READ_ONLY);
  state->name = layout_text();
}

void Label::PaintText(gfx::Canvas* canvas,
                      const base::string16& text,
                      const gfx::Rect& text_bounds,
                      int flags) {
  gfx::ShadowValues shadows;
  if (has_shadow_)
    shadows.push_back(gfx::ShadowValue(shadow_offset_, 0,
        enabled() ? enabled_shadow_color_ : disabled_shadow_color_));
  canvas->DrawStringRectWithShadows(text, font_list_,
      enabled() ? actual_enabled_color_ : actual_disabled_color_,
      text_bounds, line_height_, flags, shadows);

  if (HasFocus()) {
    gfx::Rect focus_bounds = text_bounds;
    focus_bounds.Inset(-kFocusBorderPadding, -kFocusBorderPadding);
    canvas->DrawFocusRect(focus_bounds);
  }
}

gfx::Size Label::GetTextSize() const {
  if (!text_size_valid_) {
    // For single-line strings, we supply the largest possible width, because
    // while adding NO_ELLIPSIS to the flags works on Windows for forcing
    // SizeStringInt() to calculate the desired width, it doesn't seem to work
    // on Linux.
    int w = is_multi_line_ ?
        GetAvailableRect().width() : std::numeric_limits<int>::max();
    int h = font_list_.GetHeight();
    // For single-line strings, ignore the available width and calculate how
    // wide the text wants to be.
    int flags = ComputeDrawStringFlags();
    if (!is_multi_line_)
      flags |= gfx::Canvas::NO_ELLIPSIS;
    gfx::Canvas::SizeStringInt(
        layout_text(), font_list_, &w, &h, line_height_, flags);
    text_size_.SetSize(w, h);
    text_size_valid_ = true;
  }

  return text_size_;
}

void Label::OnBoundsChanged(const gfx::Rect& previous_bounds) {
  text_size_valid_ &= !is_multi_line_;
}

void Label::OnPaint(gfx::Canvas* canvas) {
  OnPaintBackground(canvas);
  // We skip painting the focus border because it is being handled seperately by
  // some subclasses of Label. We do not want View's focus border painting to
  // interfere with that.
  OnPaintBorder(canvas);

  base::string16 paint_text;
  gfx::Rect text_bounds;
  int flags = 0;
  CalculateDrawStringParams(&paint_text, &text_bounds, &flags);
  PaintText(canvas, paint_text, text_bounds, flags);
}

void Label::OnNativeThemeChanged(const ui::NativeTheme* theme) {
  UpdateColorsFromTheme(theme);
}

void Label::Init(const base::string16& text, const gfx::FontList& font_list) {
  font_list_ = font_list;
  enabled_color_set_ = disabled_color_set_ = background_color_set_ = false;
  auto_color_readability_ = true;
  UpdateColorsFromTheme(ui::NativeTheme::instance());
  horizontal_alignment_ = gfx::ALIGN_CENTER;
  line_height_ = 0;
  is_multi_line_ = false;
  is_obscured_ = false;
  allow_character_break_ = false;
  elide_behavior_ = ELIDE_AT_END;
  collapse_when_hidden_ = false;
  directionality_mode_ = USE_UI_DIRECTIONALITY;
  enabled_shadow_color_ = 0;
  disabled_shadow_color_ = 0;
  shadow_offset_.SetPoint(1, 1);
  has_shadow_ = false;
  cached_heights_.resize(kCachedSizeLimit);
  ResetCachedSize();

  SetText(text);
}

void Label::RecalculateColors() {
  actual_enabled_color_ = auto_color_readability_ ?
      color_utils::GetReadableColor(requested_enabled_color_,
                                    background_color_) :
      requested_enabled_color_;
  actual_disabled_color_ = auto_color_readability_ ?
      color_utils::GetReadableColor(requested_disabled_color_,
                                    background_color_) :
      requested_disabled_color_;
}

gfx::Rect Label::GetTextBounds() const {
  gfx::Rect available_rect(GetAvailableRect());
  gfx::Size text_size(GetTextSize());
  text_size.set_width(std::min(available_rect.width(), text_size.width()));

  gfx::Insets insets = GetInsets();
  gfx::Point text_origin(insets.left(), insets.top());
  switch (horizontal_alignment_) {
    case gfx::ALIGN_LEFT:
      break;
    case gfx::ALIGN_CENTER:
      // We put any extra margin pixel on the left rather than the right.  We
      // used to do this because measurement on Windows used
      // GetTextExtentPoint32(), which could report a value one too large on the
      // right; we now use DrawText(), and who knows if it can also do this.
      text_origin.Offset((available_rect.width() + 1 - text_size.width()) / 2,
                         0);
      break;
    case gfx::ALIGN_RIGHT:
      text_origin.set_x(available_rect.right() - text_size.width());
      break;
    default:
      NOTREACHED();
      break;
  }
  text_origin.Offset(0,
      std::max(0, (available_rect.height() - text_size.height())) / 2);
  return gfx::Rect(text_origin, text_size);
}

int Label::ComputeDrawStringFlags() const {
  int flags = 0;

  // We can't use subpixel rendering if the background is non-opaque.
  if (SkColorGetA(background_color_) != 0xFF)
    flags |= gfx::Canvas::NO_SUBPIXEL_RENDERING;

  if (directionality_mode_ == AUTO_DETECT_DIRECTIONALITY) {
    base::i18n::TextDirection direction =
        base::i18n::GetFirstStrongCharacterDirection(layout_text());
    if (direction == base::i18n::RIGHT_TO_LEFT)
      flags |= gfx::Canvas::FORCE_RTL_DIRECTIONALITY;
    else
      flags |= gfx::Canvas::FORCE_LTR_DIRECTIONALITY;
  }

  switch (horizontal_alignment_) {
    case gfx::ALIGN_LEFT:
      flags |= gfx::Canvas::TEXT_ALIGN_LEFT;
      break;
    case gfx::ALIGN_CENTER:
      flags |= gfx::Canvas::TEXT_ALIGN_CENTER;
      break;
    case gfx::ALIGN_RIGHT:
      flags |= gfx::Canvas::TEXT_ALIGN_RIGHT;
      break;
  }

  if (!is_multi_line_)
    return flags;

  flags |= gfx::Canvas::MULTI_LINE;
#if !defined(OS_WIN)
    // Don't elide multiline labels on Linux.
    // Todo(davemoore): Do we depend on eliding multiline text?
    // Pango insists on limiting the number of lines to one if text is
    // elided. You can get around this if you can pass a maximum height
    // but we don't currently have that data when we call the pango code.
    flags |= gfx::Canvas::NO_ELLIPSIS;
#endif
  if (allow_character_break_)
    flags |= gfx::Canvas::CHARACTER_BREAK;

  return flags;
}

gfx::Rect Label::GetAvailableRect() const {
  gfx::Rect bounds(size());
  bounds.Inset(GetInsets());
  return bounds;
}

void Label::CalculateDrawStringParams(base::string16* paint_text,
                                      gfx::Rect* text_bounds,
                                      int* flags) const {
  DCHECK(paint_text && text_bounds && flags);

  // TODO(msw): Use ElideRectangleText to support eliding multi-line text.  Once
  // this is done, we can set NO_ELLIPSIS unconditionally at the bottom.
  if (is_multi_line_ || (elide_behavior_ == NO_ELIDE)) {
    *paint_text = layout_text();
  } else if (elide_behavior_ == ELIDE_AT_BEGINNING) {
    *paint_text = gfx::ElideText(layout_text(),
                                 font_list_,
                                 GetAvailableRect().width(),
                                 gfx::ELIDE_AT_BEGINNING);
  } else if (elide_behavior_ == ELIDE_IN_MIDDLE) {
    *paint_text = gfx::ElideText(layout_text(),
                                 font_list_,
                                 GetAvailableRect().width(),
                                 gfx::ELIDE_IN_MIDDLE);
  } else if (elide_behavior_ == ELIDE_AT_END) {
    *paint_text = gfx::ElideText(layout_text(),
                                 font_list_,
                                 GetAvailableRect().width(),
                                 gfx::ELIDE_AT_END);
  } else {
    DCHECK_EQ(ELIDE_AS_EMAIL, elide_behavior_);
    *paint_text =
        gfx::ElideEmail(layout_text(), font_list_, GetAvailableRect().width());
  }

  *text_bounds = GetTextBounds();
  *flags = ComputeDrawStringFlags();
  if (!is_multi_line_ || (elide_behavior_ == NO_ELIDE))
     *flags |= gfx::Canvas::NO_ELLIPSIS;
}

void Label::UpdateColorsFromTheme(const ui::NativeTheme* theme) {
  if (!enabled_color_set_) {
    requested_enabled_color_ = theme->GetSystemColor(
        ui::NativeTheme::kColorId_LabelEnabledColor);
  }
  if (!disabled_color_set_) {
    requested_disabled_color_ = theme->GetSystemColor(
        ui::NativeTheme::kColorId_LabelDisabledColor);
  }
  if (!background_color_set_) {
    background_color_ = theme->GetSystemColor(
        ui::NativeTheme::kColorId_LabelBackgroundColor);
  }
  RecalculateColors();
}

void Label::ResetCachedSize() {
  text_size_valid_ = false;
  cached_heights_cursor_ = 0;
  for (int i = 0; i < kCachedSizeLimit; ++i)
    cached_heights_[i] = gfx::Size();
}

bool Label::ShouldShowDefaultTooltip() const {
  return !is_multi_line_ && !is_obscured_ &&
         gfx::GetStringWidth(layout_text(), font_list_) >
             GetAvailableRect().width();
}

}  // namespace views
/* [<][>][^][v][top][bottom][index][help] */
root/ui/views/controls/label.cc

DEFINITIONS
