Google Git
Sign in
cobalt / cobalt / 25902c6cb1ab9cfd8ae2ee6b0fb52953f73deda5 / . / ui / gfx / render_text.cc
blob: 17d8659f9c6fd10f65420fa6781a533a35887ec0 [file] [log] [blame]
// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/gfx/render_text.h"
#include <limits.h>
#include <algorithm>
#include <climits>
#include "base/check_op.h"
#include "base/command_line.h"
#include "base/i18n/break_iterator.h"
#include "base/i18n/char_iterator.h"
#include "base/notreached.h"
#include "base/numerics/safe_conversions.h"
#include "base/ranges/algorithm.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/trace_event/trace_event.h"
#include "build/build_config.h"
#include "cc/paint/paint_canvas.h"
#include "cc/paint/paint_shader.h"
#include "third_party/icu/source/common/unicode/rbbi.h"
#include "third_party/icu/source/common/unicode/uchar.h"
#include "third_party/icu/source/common/unicode/utf16.h"
#include "third_party/skia/include/core/SkDrawLooper.h"
#include "third_party/skia/include/core/SkFontStyle.h"
#include "third_party/skia/include/core/SkTextBlob.h"
#include "third_party/skia/include/core/SkTypeface.h"
#include "third_party/skia/include/effects/SkGradientShader.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/geometry/insets.h"
#include "ui/gfx/geometry/size_conversions.h"
#include "ui/gfx/geometry/skia_conversions.h"
#include "ui/gfx/platform_font.h"
#include "ui/gfx/render_text_harfbuzz.h"
#include "ui/gfx/scoped_canvas.h"
#include "ui/gfx/skia_paint_util.h"
#include "ui/gfx/text_elider.h"
#include "ui/gfx/text_utils.h"
#include "ui/gfx/utf16_indexing.h"
namespace gfx {
namespace {
// Replacement codepoint for elided text.
constexpr char16_t kEllipsisCodepoint = 0x2026;
// Fraction of the text size to raise the center of a strike-through line above
// the baseline.
const SkScalar kStrikeThroughOffset = (SK_Scalar1 * 65 / 252);
// Fraction of the text size to lower an underline below the baseline.
const SkScalar kUnderlineOffset = (SK_Scalar1 / 9);
// Float comparison needs epsilon to consider rounding errors in float
// arithmetic. Epsilon should be dependent on the context and here, we are
// dealing with glyph widths, use a fairly large number.
const float kFloatComparisonEpsilon = 0.001f;
float Clamp(float f) {
return f < kFloatComparisonEpsilon ? 0 : f;
}
// Given |font| and |display_width|, returns the width of the fade gradient.
int CalculateFadeGradientWidth(const FontList& font_list, int display_width) {
// Fade in/out about 3 characters of the beginning/end of the string.
// Use a 1/3 of the display width if the display width is very short.
const int narrow_width = font_list.GetExpectedTextWidth(3);
const int gradient_width =
std::min(narrow_width, base::ClampRound(display_width / 3.f));
DCHECK_GE(gradient_width, 0);
return gradient_width;
}
// Appends to |positions| and |colors| values corresponding to the fade over
// |fade_rect| from color |c0| to color |c1|.
void AddFadeEffect(const Rect& text_rect,
const Rect& fade_rect,
SkColor c0,
SkColor c1,
std::vector<SkScalar>* positions,
std::vector<SkColor>* colors) {
const SkScalar left = static_cast<SkScalar>(fade_rect.x() - text_rect.x());
const SkScalar width = static_cast<SkScalar>(fade_rect.width());
const SkScalar p0 = left / text_rect.width();
const SkScalar p1 = (left + width) / text_rect.width();
// Prepend 0.0 to |positions|, as required by Skia.
if (positions->empty() && p0 != 0.0) {
positions->push_back(0.0);
colors->push_back(c0);
}
positions->push_back(p0);
colors->push_back(c0);
positions->push_back(p1);
colors->push_back(c1);
}
// Creates a SkShader to fade the text, with |left_part| specifying the left
// fade effect, if any, and |right_part| specifying the right fade effect.
sk_sp<cc::PaintShader> CreateFadeShader(const FontList& font_list,
const Rect& text_rect,
const Rect& left_part,
const Rect& right_part,
SkColor color) {
// The shader should only specify transparency of the fade itself, not the
// original transparency, which will be applied by the actual renderer.
DCHECK_EQ(SkColorGetA(color), static_cast<uint8_t>(0xff));
// In general, fade down to 0 alpha. But when the available width is less
// than four characters, linearly ramp up the fade target alpha to as high as
// 20% at zero width. This allows the user to see the last faded characters a
// little better when there are only a few characters shown.
const float width_fraction =
text_rect.width() / static_cast<float>(font_list.GetExpectedTextWidth(4));
const SkAlpha kAlphaAtZeroWidth = 51;
const SkAlpha alpha =
(width_fraction < 1)
? base::ClampRound<SkAlpha>((1 - width_fraction) * kAlphaAtZeroWidth)
: 0;
const SkColor fade_color = SkColorSetA(color, alpha);
std::vector<SkScalar> positions;
std::vector<SkColor> colors;
if (!left_part.IsEmpty())
AddFadeEffect(text_rect, left_part, fade_color, color,
&positions, &colors);
if (!right_part.IsEmpty())
AddFadeEffect(text_rect, right_part, color, fade_color,
&positions, &colors);
DCHECK(!positions.empty());
// Terminate |positions| with 1.0, as required by Skia.
if (positions.back() != 1.0) {
positions.push_back(1.0);
colors.push_back(colors.back());
}
const SkPoint points[2] = { PointToSkPoint(text_rect.origin()),
PointToSkPoint(text_rect.top_right()) };
// TODO(crbug/1308932): Remove this helper vector colors4f and make all
// SkColor4f.
std::vector<SkColor4f> colors4f;
colors4f.reserve(colors.size());
for (auto& c : colors)
colors4f.push_back(SkColor4f::FromColor(c));
return cc::PaintShader::MakeLinearGradient(
&points[0], &colors4f[0], &positions[0],
static_cast<int>(colors4f.size()), SkTileMode::kClamp);
}
// Converts a FontRenderParams::Hinting value to the corresponding
// SkFontHinting value.
SkFontHinting FontRenderParamsHintingToSkFontHinting(
FontRenderParams::Hinting params_hinting) {
switch (params_hinting) {
case FontRenderParams::HINTING_NONE:
return SkFontHinting::kNone;
case FontRenderParams::HINTING_SLIGHT:
return SkFontHinting::kSlight;
case FontRenderParams::HINTING_MEDIUM:
return SkFontHinting::kNormal;
case FontRenderParams::HINTING_FULL:
return SkFontHinting::kFull;
}
return SkFontHinting::kNone;
}
// Make sure ranges don't break text graphemes. If a range in |break_list|
// does break a grapheme in |render_text|, the range will be slightly
// extended to encompass the grapheme.
template <typename T>
void RestoreBreakList(RenderText* render_text, BreakList<T>* break_list) {
break_list->SetMax(render_text->text().length());
Range range;
while (range.end() < break_list->max()) {
const auto& current_break = break_list->GetBreak(range.end());
range = break_list->GetRange(current_break);
if (range.end() < break_list->max() &&
!render_text->IsValidCursorIndex(range.end())) {
range.set_end(
render_text->IndexOfAdjacentGrapheme(range.end(), CURSOR_FORWARD));
break_list->ApplyValue(current_break->second, range);
}
}
}
// Move the iterator |iter| forward until |position| is included in the range.
template <typename T>
typename BreakList<T>::const_iterator IncrementBreakListIteratorToPosition(
const BreakList<T>& break_list,
typename BreakList<T>::const_iterator iter,
size_t position) {
DCHECK_LT(position, break_list.max());
for (;;) {
CHECK(iter != break_list.breaks().end());
const Range range = break_list.GetRange(iter);
if (position >= range.start() && position < range.end())
return iter;
++iter;
}
}
// Replaces the unicode control characters, control characters and PUA (Private
// Use Areas) codepoints.
UChar32 ReplaceControlCharacter(UChar32 codepoint) {
// 'REPLACEMENT CHARACTER' used to replace an unknown,
// unrecognized or unrepresentable character.
constexpr char16_t kReplacementCodepoint = 0xFFFD;
// Control Pictures block (see:
// https://unicode.org/charts/PDF/U2400.pdf).
constexpr char16_t kSymbolsCodepoint = 0x2400;
if (codepoint >= 0 && codepoint <= 0x1F) {
switch (codepoint) {
case 0x09:
// Replace character tabulation ('\t') with its visual arrow symbol.
return 0x21E5;
case 0x0A:
// Replace line feed ('\n') with space character.
return 0x20;
default:
// Replace codepoints with their visual symbols, which are
// at the same offset from kSymbolsCodepoint.
return kSymbolsCodepoint + codepoint;
}
}
if (codepoint == 0x7F) {
// Replace the 'del' codepoint by its symbol (u2421).
return kSymbolsCodepoint + 0x21;
}
if (!U_IS_UNICODE_CHAR(codepoint)) {
// Unicode codepoint that can't be assigned a character.
// This handles:
// - single surrogate codepoints,
// - last two codepoints on each plane,
// - invalid characters (e.g. u+fdd0..u+fdef)
// - codepoints above u+10ffff
return kReplacementCodepoint;
}
if (codepoint > 0x7F) {
// Private use codepoints are working with a pair of font
// and codepoint, but they are not used in Chrome.
#if BUILDFLAG(IS_MAC)
// Support Apple defined PUA on Mac.
// see: http://www.unicode.org/Public/MAPPINGS/VENDORS/APPLE/CORPCHAR.TXT
if (codepoint == 0xF8FF)
return codepoint;
#endif
#if BUILDFLAG(IS_WIN)
// Support Microsoft defined PUA on Windows.
// see:
// https://docs.microsoft.com/en-us/windows/uwp/design/style/segoe-ui-symbol-font
switch (codepoint) {
case 0xF093: // ButtonA
case 0xF094: // ButtonB
case 0xF095: // ButtonY
case 0xF096: // ButtonX
case 0xF108: // LeftStick
case 0xF109: // RightStick
case 0xF10A: // TriggerLeft
case 0xF10B: // TriggerRight
case 0xF10C: // BumperLeft
case 0xF10D: // BumperRight
case 0xF10E: // Dpad
case 0xEECA: // ButtonView2
case 0xEDE3: // ButtonMenu
return codepoint;
default:
break;
}
#endif
const int8_t codepoint_category = u_charType(codepoint);
if (codepoint_category == U_PRIVATE_USE_CHAR ||
codepoint_category == U_CONTROL_CHAR) {
return kReplacementCodepoint;
}
}
return codepoint;
}
// Returns the line segment index for the |line|, |text_x| pair. |text_x| is
// relative to text in the given line. Returns -1 if |text_x| is to the left
// of text in the line and |line|.segments.size() if it's to the right.
// |offset_relative_segment| will contain the offset of |text_x| relative to
// the start of the segment it is contained in.
int GetLineSegmentContainingXCoord(const internal::Line& line,
float line_x,
float* offset_relative_segment) {
DCHECK(offset_relative_segment);
*offset_relative_segment = 0;
if (line_x < 0)
return -1;
for (size_t i = 0; i < line.segments.size(); i++) {
const internal::LineSegment& segment = line.segments[i];
// segment.x_range is not used because it is in text space.
if (line_x < segment.width()) {
*offset_relative_segment = line_x;
return i;
}
line_x -= segment.width();
}
return line.segments.size();
}
} // namespace
namespace internal {
SkiaTextRenderer::SkiaTextRenderer(Canvas* canvas)
: canvas_(canvas), canvas_skia_(canvas->sk_canvas()) {
DCHECK(canvas_skia_);
flags_.setStyle(cc::PaintFlags::kFill_Style);
font_.setEdging(SkFont::Edging::kSubpixelAntiAlias);
font_.setSubpixel(true);
font_.setHinting(SkFontHinting::kNormal);
}
SkiaTextRenderer::~SkiaTextRenderer() {
}
void SkiaTextRenderer::SetDrawLooper(sk_sp<SkDrawLooper> draw_looper) {
flags_.setLooper(std::move(draw_looper));
}
void SkiaTextRenderer::SetFontRenderParams(const FontRenderParams& params,
bool subpixel_rendering_suppressed) {
ApplyRenderParams(params, subpixel_rendering_suppressed, &font_);
}
void SkiaTextRenderer::SetTypeface(sk_sp<SkTypeface> typeface) {
font_.setTypeface(std::move(typeface));
}
void SkiaTextRenderer::SetTextSize(SkScalar size) {
font_.setSize(size);
}
void SkiaTextRenderer::SetForegroundColor(SkColor foreground) {
flags_.setColor(foreground);
}
void SkiaTextRenderer::SetShader(sk_sp<cc::PaintShader> shader) {
flags_.setShader(std::move(shader));
}
void SkiaTextRenderer::DrawPosText(const SkPoint* pos,
const uint16_t* glyphs,
size_t glyph_count) {
SkTextBlobBuilder builder;
const auto& run_buffer = builder.allocRunPos(font_, glyph_count);
static_assert(sizeof(*glyphs) == sizeof(*run_buffer.glyphs), "");
memcpy(run_buffer.glyphs, glyphs, glyph_count * sizeof(*glyphs));
static_assert(sizeof(*pos) == 2 * sizeof(*run_buffer.pos), "");
memcpy(run_buffer.pos, pos, glyph_count * sizeof(*pos));
canvas_skia_->drawTextBlob(builder.make(), 0, 0, flags_);
}
void SkiaTextRenderer::DrawUnderline(int x,
int y,
int width,
SkScalar thickness_factor) {
SkScalar x_scalar = SkIntToScalar(x);
const SkScalar text_size = font_.getSize();
SkRect r = SkRect::MakeLTRB(
x_scalar, y + text_size * kUnderlineOffset, x_scalar + width,
y + (text_size *
(kUnderlineOffset +
(thickness_factor * RenderText::kLineThicknessFactor))));
canvas_skia_->drawRect(r, flags_);
}
void SkiaTextRenderer::DrawStrike(int x,
int y,
int width,
SkScalar thickness_factor) {
const SkScalar text_size = font_.getSize();
const SkScalar height = text_size * thickness_factor;
const SkScalar top = y - text_size * kStrikeThroughOffset - height / 2;
SkScalar x_scalar = SkIntToScalar(x);
const SkRect r =
SkRect::MakeLTRB(x_scalar, top, x_scalar + width, top + height);
canvas_skia_->drawRect(r, flags_);
}
StyleIterator::StyleIterator(const BreakList<SkColor>* colors,
const BreakList<BaselineStyle>* baselines,
const BreakList<int>* font_size_overrides,
const BreakList<Font::Weight>* weights,
const StyleArray* styles)
: colors_(colors),
baselines_(baselines),
font_size_overrides_(font_size_overrides),
weights_(weights),
styles_(styles) {
color_ = colors_->breaks().begin();
baseline_ = baselines_->breaks().begin();
font_size_override_ = font_size_overrides_->breaks().begin();
weight_ = weights_->breaks().begin();
for (size_t i = 0; i < styles_->size(); ++i)
style_[i] = (*styles_)[i].breaks().begin();
}
StyleIterator::StyleIterator(const StyleIterator& style) = default;
StyleIterator::~StyleIterator() = default;
StyleIterator& StyleIterator::operator=(const StyleIterator& style) = default;
Range StyleIterator::GetRange() const {
return GetTextBreakingRange().Intersect(colors_->GetRange(color_));
}
Range StyleIterator::GetTextBreakingRange() const {
Range range = baselines_->GetRange(baseline_);
range = range.Intersect(font_size_overrides_->GetRange(font_size_override_));
range = range.Intersect(weights_->GetRange(weight_));
for (size_t i = 0; i < styles_->size(); ++i)
range = range.Intersect((*styles_)[i].GetRange(style_[i]));
return range;
}
void StyleIterator::IncrementToPosition(size_t position) {
color_ = IncrementBreakListIteratorToPosition(*colors_, color_, position);
baseline_ =
IncrementBreakListIteratorToPosition(*baselines_, baseline_, position);
font_size_override_ = IncrementBreakListIteratorToPosition(
*font_size_overrides_, font_size_override_, position);
weight_ = IncrementBreakListIteratorToPosition(*weights_, weight_, position);
for (size_t i = 0; i < styles_->size(); ++i) {
style_[i] = IncrementBreakListIteratorToPosition((*styles_)[i], style_[i],
position);
}
}
LineSegment::LineSegment() : run(0) {}
LineSegment::~LineSegment() {}
Line::Line() : preceding_heights(0), baseline(0) {}
Line::Line(const Line& other) = default;
Line::~Line() {}
ShapedText::ShapedText(std::vector<Line> lines) : lines_(std::move(lines)) {}
ShapedText::~ShapedText() = default;
void ApplyRenderParams(const FontRenderParams& params,
bool subpixel_rendering_suppressed,
SkFont* font) {
if (!params.antialiasing) {
font->setEdging(SkFont::Edging::kAlias);
} else if (subpixel_rendering_suppressed ||
params.subpixel_rendering ==
FontRenderParams::SUBPIXEL_RENDERING_NONE) {
font->setEdging(SkFont::Edging::kAntiAlias);
} else {
font->setEdging(SkFont::Edging::kSubpixelAntiAlias);
}
font->setSubpixel(params.subpixel_positioning);
font->setForceAutoHinting(params.autohinter);
font->setHinting(FontRenderParamsHintingToSkFontHinting(params.hinting));
}
} // namespace internal
// static
constexpr char16_t RenderText::kPasswordReplacementChar;
constexpr bool RenderText::kDragToEndIfOutsideVerticalBounds;
constexpr int RenderText::kInvalidBaseline;
constexpr SkScalar RenderText::kLineThicknessFactor;
RenderText::~RenderText() = default;
// static
std::unique_ptr<RenderText> RenderText::CreateRenderText() {
return std::make_unique<RenderTextHarfBuzz>();
}
std::unique_ptr<RenderText> RenderText::CreateInstanceOfSameStyle(
const std::u16string& text) const {
std::unique_ptr<RenderText> render_text = CreateRenderText();
// |SetText()| must be called before styles are set.
render_text->SetText(text);
render_text->SetFontList(font_list_);
render_text->SetDirectionalityMode(directionality_mode_);
render_text->SetCursorEnabled(cursor_enabled_);
render_text->set_truncate_length(truncate_length_);
render_text->styles_ = styles_;
render_text->baselines_ = baselines_;
render_text->font_size_overrides_ = font_size_overrides_;
render_text->colors_ = colors_;
render_text->weights_ = weights_;
render_text->glyph_width_for_test_ = glyph_width_for_test_;
return render_text;
}
void RenderText::SetText(const std::u16string& text) {
DCHECK(!composition_range_.IsValid());
if (text_ == text)
return;
text_ = text;
UpdateStyleLengths();
// Clear style ranges as they might break new text graphemes and apply
// the first style to the whole text instead.
colors_.SetValue(colors_.breaks().front().second);
baselines_.SetValue(baselines_.breaks().front().second);
font_size_overrides_.SetValue(font_size_overrides_.breaks().front().second);
weights_.SetValue(weights_.breaks().front().second);
for (auto& style : styles_)
style.SetValue(style.breaks().front().second);
cached_bounds_and_offset_valid_ = false;
// Reset selection model. SetText should always followed by SetSelectionModel
// or SetCursorPosition in upper layer.
SetSelectionModel(SelectionModel());
// Invalidate the cached text direction if it depends on the text contents.
if (directionality_mode_ == DIRECTIONALITY_FROM_TEXT)
text_direction_ = base::i18n::UNKNOWN_DIRECTION;
obscured_reveal_index_ = absl::nullopt;
OnTextAttributeChanged();
}
void RenderText::AppendText(const std::u16string& text) {
text_ += text;
UpdateStyleLengths();
cached_bounds_and_offset_valid_ = false;
obscured_reveal_index_ = absl::nullopt;
// Invalidate the cached text direction if it depends on the text contents.
if (directionality_mode_ == DIRECTIONALITY_FROM_TEXT)
text_direction_ = base::i18n::UNKNOWN_DIRECTION;
OnTextAttributeChanged();
}
void RenderText::SetHorizontalAlignment(HorizontalAlignment alignment) {
if (horizontal_alignment_ != alignment) {
horizontal_alignment_ = alignment;
display_offset_ = Vector2d();
cached_bounds_and_offset_valid_ = false;
}
}
void RenderText::SetVerticalAlignment(VerticalAlignment alignment) {
if (vertical_alignment_ != alignment) {
vertical_alignment_ = alignment;
display_offset_ = Vector2d();
cached_bounds_and_offset_valid_ = false;
}
}
void RenderText::SetFontList(const FontList& font_list) {
font_list_ = font_list;
const int font_style = font_list.GetFontStyle();
weights_.SetValue(font_list.GetFontWeight());
styles_[TEXT_STYLE_ITALIC].SetValue((font_style & Font::ITALIC) != 0);
styles_[TEXT_STYLE_UNDERLINE].SetValue((font_style & Font::UNDERLINE) != 0);
styles_[TEXT_STYLE_HEAVY_UNDERLINE].SetValue(false);
baseline_ = kInvalidBaseline;
cached_bounds_and_offset_valid_ = false;
OnLayoutTextAttributeChanged(false);
}
void RenderText::SetCursorEnabled(bool cursor_enabled) {
if (cursor_enabled_ != cursor_enabled) {
cursor_enabled_ = cursor_enabled;
cached_bounds_and_offset_valid_ = false;
}
}
void RenderText::SetObscured(bool obscured) {
if (obscured != obscured_) {
obscured_ = obscured;
obscured_reveal_index_ = absl::nullopt;
cached_bounds_and_offset_valid_ = false;
OnTextAttributeChanged();
}
}
void RenderText::SetObscuredRevealIndex(absl::optional<size_t> index) {
if (obscured_reveal_index_ != index) {
obscured_reveal_index_ = index;
cached_bounds_and_offset_valid_ = false;
OnTextAttributeChanged();
}
}
void RenderText::SetObscuredGlyphSpacing(int spacing) {
if (obscured_glyph_spacing_ != spacing) {
obscured_glyph_spacing_ = spacing;
OnLayoutTextAttributeChanged(true);
}
}
void RenderText::SetMultiline(bool multiline) {
if (multiline != multiline_) {
multiline_ = multiline;
cached_bounds_and_offset_valid_ = false;
OnTextAttributeChanged();
}
}
void RenderText::SetMaxLines(size_t max_lines) {
if (max_lines_ != max_lines) {
max_lines_ = max_lines;
OnDisplayTextAttributeChanged();
}
}
size_t RenderText::GetNumLines() {
return GetShapedText()->lines().size();
}
size_t RenderText::GetTextIndexOfLine(size_t line) {
const std::vector<internal::Line>& lines = GetShapedText()->lines();
if (line >= lines.size())
return text_.size();
return DisplayIndexToTextIndex(lines[line].display_text_index);
}
void RenderText::SetWordWrapBehavior(WordWrapBehavior behavior) {
// TODO(1150235): ELIDE_LONG_WORDS is not supported.
DCHECK_NE(behavior, ELIDE_LONG_WORDS);
if (word_wrap_behavior_ != behavior) {
word_wrap_behavior_ = behavior;
if (multiline_) {
cached_bounds_and_offset_valid_ = false;
OnTextAttributeChanged();
}
}
}
void RenderText::SetMinLineHeight(int line_height) {
if (min_line_height_ != line_height) {
min_line_height_ = line_height;
cached_bounds_and_offset_valid_ = false;
OnDisplayTextAttributeChanged();
}
}
void RenderText::SetElideBehavior(ElideBehavior elide_behavior) {
if (elide_behavior_ != elide_behavior) {
elide_behavior_ = elide_behavior;
OnDisplayTextAttributeChanged();
}
}
void RenderText::SetWhitespaceElision(absl::optional<bool> whitespace_elision) {
if (whitespace_elision_ != whitespace_elision) {
whitespace_elision_ = whitespace_elision;
OnDisplayTextAttributeChanged();
}
}
void RenderText::SetDisplayRect(const Rect& r) {
if (r != display_rect_) {
display_rect_ = r;
baseline_ = kInvalidBaseline;
cached_bounds_and_offset_valid_ = false;
OnDisplayTextAttributeChanged();
}
}
const std::vector<Range> RenderText::GetAllSelections() const {
return selection_model_.GetAllSelections();
}
void RenderText::SetCursorPosition(size_t position) {
size_t cursor = std::min(position, text().length());
if (IsValidCursorIndex(cursor)) {
SetSelectionModel(SelectionModel(
cursor, (cursor == 0) ? CURSOR_FORWARD : CURSOR_BACKWARD));
}
}
void RenderText::MoveCursor(BreakType break_type,
VisualCursorDirection direction,
SelectionBehavior selection_behavior) {
SelectionModel cursor(cursor_position(), selection_model_.caret_affinity());
// Ensure |cursor| is at the "end" of the current selection, since this
// determines which side should grow or shrink. If the prior change to the
// selection wasn't from cursor movement, the selection may be undirected. Or,
// the selection may be collapsing. In these cases, pick the "end" using
// |direction| (e.g. the arrow key) rather than the current selection range.
if ((!has_directed_selection_ || selection_behavior == SELECTION_NONE) &&
!selection().is_empty()) {
SelectionModel selection_start = GetSelectionModelForSelectionStart();
Point start = GetCursorBounds(selection_start, true).origin();
Point end = GetCursorBounds(cursor, true).origin();
// Use the selection start if it is left (when |direction| is CURSOR_LEFT)
// or right (when |direction| is CURSOR_RIGHT) of the selection end.
// Consider only the y-coordinates if the selection start and end are on
// different lines.
const bool cursor_is_leading =
(start.y() > end.y()) ||
((start.y() == end.y()) && (start.x() > end.x()));
const bool cursor_should_be_trailing =
(direction == CURSOR_RIGHT) || (direction == CURSOR_DOWN);
if (cursor_is_leading == cursor_should_be_trailing) {
// In this case, a direction has been chosen that doesn't match
// |selection_model|, so the range must be reversed to place the cursor at
// the other end. Note the affinity won't matter: only the affinity of
// |start| (which points "in" to the selection) determines the movement.
Range range = selection_model_.selection();
selection_model_ = SelectionModel(Range(range.end(), range.start()),
selection_model_.caret_affinity());
cursor = selection_start;
}
}
// Cancelling a selection moves to the edge of the selection.
if (break_type != FIELD_BREAK && break_type != LINE_BREAK &&
!selection().is_empty() && selection_behavior == SELECTION_NONE) {
// Use the nearest word boundary in the proper |direction| for word breaks.
if (break_type == WORD_BREAK)
cursor = GetAdjacentSelectionModel(cursor, break_type, direction);
// Use an adjacent selection model if the cursor is not at a valid position.
if (!IsValidCursorIndex(cursor.caret_pos()))
cursor = GetAdjacentSelectionModel(cursor, CHARACTER_BREAK, direction);
} else {
cursor = GetAdjacentSelectionModel(cursor, break_type, direction);
}
// |cursor| corresponds to the tentative end point of the new selection. The
// selection direction is reversed iff the current selection is non-empty and
// the old selection end point and |cursor| are at the opposite ends of the
// old selection start point.
uint32_t min_end = std::min(selection().end(), cursor.selection().end());
uint32_t max_end = std::max(selection().end(), cursor.selection().end());
uint32_t current_start = selection().start();
bool selection_reversed = !selection().is_empty() &&
min_end <= current_start &&
current_start <= max_end;
// Take |selection_behavior| into account.
switch (selection_behavior) {
case SELECTION_RETAIN:
cursor.set_selection_start(current_start);
break;
case SELECTION_EXTEND:
cursor.set_selection_start(selection_reversed ? selection().end()
: current_start);
break;
case SELECTION_CARET:
if (selection_reversed) {
cursor =
SelectionModel(current_start, selection_model_.caret_affinity());
} else {
cursor.set_selection_start(current_start);
}
break;
case SELECTION_NONE:
// Do nothing.
break;
}
SetSelection(cursor);
has_directed_selection_ = true;
// |cached_cursor_x| keeps the initial x-coordinates where CURSOR_UP or
// CURSOR_DOWN starts. This enables the cursor to keep the same x-coordinates
// even when the cursor passes through empty or short lines. The cached
// x-coordinates should be reset when the cursor moves in a horizontal
// direction.
if (direction != CURSOR_UP && direction != CURSOR_DOWN)
reset_cached_cursor_x();
}
bool RenderText::SetSelection(const SelectionModel& model) {
// Enforce valid selection model components.
size_t text_length = text().length();
std::vector<Range> ranges = model.GetAllSelections();
for (auto& range : ranges) {
range = {std::min(range.start(), text_length),
std::min(range.end(), text_length)};
// The current model only supports caret positions at valid cursor indices.
if (!IsValidCursorIndex(range.start()) || !IsValidCursorIndex(range.end()))
return false;
}
SelectionModel sel = SelectionModel(ranges, model.caret_affinity());
bool changed = sel != selection_model_;
SetSelectionModel(sel);
return changed;
}
bool RenderText::MoveCursorToPoint(const Point& point,
bool select,
const Point& drag_origin) {
reset_cached_cursor_x();
SelectionModel model = FindCursorPosition(point, drag_origin);
if (select)
model.set_selection_start(selection().start());
return SetSelection(model);
}
bool RenderText::SelectRange(const Range& range, bool primary) {
size_t text_length = text().length();
Range sel(std::min(range.start(), text_length),
std::min(range.end(), text_length));
// Allow selection bounds at valid indices amid multi-character graphemes.
if (!IsValidLogicalIndex(sel.start()) || !IsValidLogicalIndex(sel.end()))
return false;
if (primary) {
LogicalCursorDirection affinity = (sel.is_reversed() || sel.is_empty())
? CURSOR_FORWARD
: CURSOR_BACKWARD;
SetSelectionModel(SelectionModel(sel, affinity));
} else {
AddSecondarySelection(sel);
}
return true;
}
bool RenderText::IsPointInSelection(const Point& point) {
if (selection().is_empty())
return false;
SelectionModel cursor = FindCursorPosition(point);
return RangeContainsCaret(
selection(), cursor.caret_pos(), cursor.caret_affinity());
}
void RenderText::ClearSelection() {
SetSelectionModel(
SelectionModel(cursor_position(), selection_model_.caret_affinity()));
}
void RenderText::SelectAll(bool reversed) {
const size_t length = text().length();
const Range all = reversed ? Range(length, 0) : Range(0, length);
const bool success = SelectRange(all);
DCHECK(success);
}
void RenderText::SelectWord() {
SelectRange(ExpandRangeToWordBoundary(selection()));
}
void RenderText::SetCompositionRange(const Range& composition_range) {
CHECK(!composition_range.IsValid() ||
Range(0, text_.length()).Contains(composition_range));
composition_range_.set_end(composition_range.end());
composition_range_.set_start(composition_range.start());
OnLayoutTextAttributeChanged(false);
}
void RenderText::SetColor(SkColor value) {
if (colors_.SetValue(value))
OnLayoutTextAttributeChanged(false);
}
void RenderText::ApplyColor(SkColor value, const Range& range) {
if (colors_.ApplyValue(value, range))
OnLayoutTextAttributeChanged(false);
}
void RenderText::SetBaselineStyle(BaselineStyle value) {
if (baselines_.SetValue(value))
OnLayoutTextAttributeChanged(false);
}
void RenderText::ApplyBaselineStyle(BaselineStyle value, const Range& range) {
if (baselines_.ApplyValue(value, range))
OnLayoutTextAttributeChanged(false);
}
void RenderText::ApplyFontSizeOverride(int font_size_override,
const Range& range) {
if (font_size_overrides_.ApplyValue(font_size_override, range))
OnLayoutTextAttributeChanged(false);
}
void RenderText::SetStyle(TextStyle style, bool value) {
if (styles_[style].SetValue(value)) {
cached_bounds_and_offset_valid_ = false;
// TODO(oshima|msw): Not all style change requires layout changes.
// Consider optimizing based on the type of change.
OnLayoutTextAttributeChanged(false);
}
}
void RenderText::ApplyStyle(TextStyle style, bool value, const Range& range) {
if (styles_[style].ApplyValue(value, range)) {
cached_bounds_and_offset_valid_ = false;
// TODO(oshima|msw): Not all style change requires layout changes.
// Consider optimizing based on the type of change.
OnLayoutTextAttributeChanged(false);
}
}
void RenderText::SetWeight(Font::Weight weight) {
if (weights_.SetValue(weight)) {
cached_bounds_and_offset_valid_ = false;
OnLayoutTextAttributeChanged(false);
}
}
void RenderText::ApplyWeight(Font::Weight weight, const Range& range) {
if (weights_.ApplyValue(weight, range)) {
cached_bounds_and_offset_valid_ = false;
OnLayoutTextAttributeChanged(false);
}
}
bool RenderText::GetStyle(TextStyle style) const {
return (styles_[style].breaks().size() == 1) &&
styles_[style].breaks().front().second;
}
void RenderText::SetDirectionalityMode(DirectionalityMode mode) {
if (mode != directionality_mode_) {
directionality_mode_ = mode;
text_direction_ = base::i18n::UNKNOWN_DIRECTION;
cached_bounds_and_offset_valid_ = false;
OnLayoutTextAttributeChanged(false);
}
}
base::i18n::TextDirection RenderText::GetTextDirection() const {
if (text_direction_ == base::i18n::UNKNOWN_DIRECTION)
text_direction_ = GetTextDirectionForGivenText(text_);
return text_direction_;
}
base::i18n::TextDirection RenderText::GetDisplayTextDirection() {
EnsureLayout();
if (display_text_direction_ == base::i18n::UNKNOWN_DIRECTION)
display_text_direction_ = GetTextDirectionForGivenText(GetDisplayText());
return display_text_direction_;
}
VisualCursorDirection RenderText::GetVisualDirectionOfLogicalEnd() {
return GetDisplayTextDirection() == base::i18n::LEFT_TO_RIGHT ? CURSOR_RIGHT
: CURSOR_LEFT;
}
VisualCursorDirection RenderText::GetVisualDirectionOfLogicalBeginning() {
return GetDisplayTextDirection() == base::i18n::RIGHT_TO_LEFT ? CURSOR_RIGHT
: CURSOR_LEFT;
}
Size RenderText::GetStringSize() {
const SizeF size_f = GetStringSizeF();
return Size(base::ClampCeil(size_f.width()),
base::ClampCeil(size_f.height()));
}
float RenderText::TotalLineWidth() {
float total_width = 0;
const internal::ShapedText* shaped_text = GetShapedText();
for (const auto& line : shaped_text->lines())
total_width += line.size.width();
return total_width;
}
float RenderText::GetContentWidthF() {
const float string_size = GetStringSizeF().width();
// The cursor is drawn one pixel beyond the int-enclosed text bounds.
return cursor_enabled_ ? std::ceil(string_size) + 1 : string_size;
}
int RenderText::GetContentWidth() {
return base::ClampCeil(GetContentWidthF());
}
int RenderText::GetBaseline() {
if (baseline_ == kInvalidBaseline) {
const int centering_height =
(vertical_alignment_ == ALIGN_MIDDLE)
? display_rect().height()
: std::max(font_list().GetHeight(), min_line_height());
baseline_ = DetermineBaselineCenteringText(centering_height, font_list());
if (vertical_alignment_ == ALIGN_BOTTOM)
baseline_ += display_rect().height() - centering_height;
}
DCHECK_NE(kInvalidBaseline, baseline_);
return baseline_;
}
void RenderText::Draw(Canvas* canvas, bool select_all) {
EnsureLayout();
if (clip_to_display_rect()) {
Rect clip_rect(display_rect());
clip_rect.Inset(ShadowValue::GetMargin(shadows_));
canvas->Save();
canvas->ClipRect(clip_rect);
}
if (!text().empty()) {
std::vector<Range> draw_selections;
if (select_all)
draw_selections = {Range(0, text().length())};
else if (focused())
draw_selections = GetAllSelections();
DrawSelections(canvas, draw_selections);
internal::SkiaTextRenderer renderer(canvas);
DrawVisualText(&renderer, draw_selections);
}
if (clip_to_display_rect())
canvas->Restore();
}
SelectionModel RenderText::FindCursorPosition(const Point& view_point,
const Point& drag_origin) {
const internal::ShapedText* shaped_text = GetShapedText();
DCHECK(!shaped_text->lines().empty());
int line_index = GetLineContainingYCoord((view_point - GetLineOffset(0)).y());
// Handle kDragToEndIfOutsideVerticalBounds above or below the text in a
// single-line by extending towards the mouse cursor.
if (RenderText::kDragToEndIfOutsideVerticalBounds && !multiline() &&
(line_index < 0 ||
line_index >= static_cast<int>(shaped_text->lines().size()))) {
SelectionModel selection_start = GetSelectionModelForSelectionStart();
int edge = drag_origin.x() == 0 ? GetCursorBounds(selection_start, true).x()
: drag_origin.x();
bool left = view_point.x() < edge;
return EdgeSelectionModel(left ? CURSOR_LEFT : CURSOR_RIGHT);
}
// Otherwise, clamp |line_index| to a valid value or drag to logical ends.
if (line_index < 0) {
if (RenderText::kDragToEndIfOutsideVerticalBounds)
return EdgeSelectionModel(GetVisualDirectionOfLogicalBeginning());
line_index = 0;
}
if (line_index >= static_cast<int>(shaped_text->lines().size())) {
if (RenderText::kDragToEndIfOutsideVerticalBounds)
return EdgeSelectionModel(GetVisualDirectionOfLogicalEnd());
line_index = shaped_text->lines().size() - 1;
}
const internal::Line& line = shaped_text->lines()[line_index];
// Newline segment should be ignored in finding segment index with x
// coordinate because it's not drawn.
Vector2d newline_offset;
if (line.segments.size() >= 1 && IsNewlineSegment(line.segments.front()))
newline_offset.set_x(line.segments.front().width());
float point_offset_relative_segment = 0;
const int segment_index = GetLineSegmentContainingXCoord(
line, (view_point - GetLineOffset(line_index) + newline_offset).x(),
&point_offset_relative_segment);
if (segment_index < 0)
return LineSelectionModel(line_index, CURSOR_LEFT);
if (segment_index >= static_cast<int>(line.segments.size()))
return LineSelectionModel(line_index, CURSOR_RIGHT);
const internal::LineSegment& segment = line.segments[segment_index];
const internal::TextRunHarfBuzz& run = *GetRunList()->runs()[segment.run];
const size_t segment_min_glyph_index =
run.CharRangeToGlyphRange(segment.char_range).GetMin();
const float segment_offset_relative_run =
segment_min_glyph_index != 0
? SkScalarToFloat(run.shape.positions[segment_min_glyph_index].x())
: 0;
const float point_offset_relative_run =
point_offset_relative_segment + segment_offset_relative_run;
// TODO(crbug.com/676287): Use offset within the glyph to return the correct
// grapheme position within a multi-grapheme glyph.
for (size_t i = 0; i < run.shape.glyph_count; ++i) {
const float end = i + 1 == run.shape.glyph_count
? run.shape.width
: SkScalarToFloat(run.shape.positions[i + 1].x());
const float middle =
(end + SkScalarToFloat(run.shape.positions[i].x())) / 2;
const size_t index = DisplayIndexToTextIndex(run.shape.glyph_to_char[i]);
if (point_offset_relative_run < middle) {
return run.font_params.is_rtl ? SelectionModel(IndexOfAdjacentGrapheme(
index, CURSOR_FORWARD),
CURSOR_BACKWARD)
: SelectionModel(index, CURSOR_FORWARD);
}
if (point_offset_relative_run < end) {
return run.font_params.is_rtl ? SelectionModel(index, CURSOR_FORWARD)
: SelectionModel(IndexOfAdjacentGrapheme(
index, CURSOR_FORWARD),
CURSOR_BACKWARD);
}
}
return LineSelectionModel(line_index, CURSOR_RIGHT);
}
bool RenderText::IsValidLogicalIndex(size_t index) const {
// Check that the index is at a valid code point (not mid-surrogate-pair) and
// that it's not truncated from the display text (its glyph may be shown).
//
// Indices within truncated text are disallowed so users can easily interact
// with the underlying truncated text using the ellipsis as a proxy. This lets
// users select all text, select the truncated text, and transition from the
// last rendered glyph to the end of the text without getting invisible cursor
// positions nor needing unbounded arrow key presses to traverse the ellipsis.
return index == 0 || index == text().length() ||
(index < text().length() &&
(truncate_length_ == 0 || index < truncate_length_) &&
IsValidCodePointIndex(text(), index));
}
bool RenderText::IsValidCursorIndex(size_t index) const {
return index == 0 || index == text().length() ||
(IsValidLogicalIndex(index) && IsGraphemeBoundary(index));
}
Rect RenderText::GetCursorBounds(const SelectionModel& caret,
bool insert_mode) {
EnsureLayout();
size_t caret_pos = caret.caret_pos();
DCHECK(IsValidLogicalIndex(caret_pos));
// In overtype mode, ignore the affinity and always indicate that we will
// overtype the next character.
LogicalCursorDirection caret_affinity =
insert_mode ? caret.caret_affinity() : CURSOR_FORWARD;
float x = 0;
int width = 1;
// Check whether the caret is attached to a boundary. Always return a 1-dip
// width caret at the boundary. Avoid calling IndexOfAdjacentGrapheme(), since
// it is slow and can impact browser startup here.
// In insert mode, index 0 is always a boundary. The end, however, is not at a
// boundary when the string ends in RTL text and there is LTR text around it.
const bool at_boundary =
(insert_mode && caret_pos == 0) ||
caret_pos == (caret_affinity == CURSOR_BACKWARD ? 0 : text().length());
if (at_boundary) {
const bool rtl = GetDisplayTextDirection() == base::i18n::RIGHT_TO_LEFT;
if (rtl == (caret_pos == 0))
x = TotalLineWidth();
} else {
// Find the next grapheme continuing in the current direction. This
// determines the substring range that should be highlighted.
size_t caret_end = IndexOfAdjacentGrapheme(caret_pos, caret_affinity);
if (caret_end < caret_pos)
std::swap(caret_end, caret_pos);
const RangeF xspan = GetCursorSpan(Range(caret_pos, caret_end));
if (insert_mode) {
x = (caret_affinity == CURSOR_BACKWARD) ? xspan.end() : xspan.start();
} else { // overtype mode
x = xspan.GetMin();
// Ceil the start and end of the |xspan| because the cursor x-coordinates
// are always ceiled.
width = base::ClampCeil(Clamp(xspan.GetMax())) -
base::ClampCeil(Clamp(xspan.GetMin()));
}
}
Size line_size = gfx::ToCeiledSize(GetLineSizeF(caret));
size_t line = GetLineContainingCaret(caret);
return Rect(ToViewPoint(PointF(x, 0), line), Size(width, line_size.height()));
}
const Rect& RenderText::GetUpdatedCursorBounds() {
UpdateCachedBoundsAndOffset();
return cursor_bounds_;
}
internal::GraphemeIterator RenderText::GetGraphemeIteratorAtTextIndex(
size_t index) const {
EnsureLayoutTextUpdated();
return GetGraphemeIteratorAtIndex(
text_, &internal::TextToDisplayIndex::text_index, index);
}
internal::GraphemeIterator RenderText::GetGraphemeIteratorAtDisplayTextIndex(
size_t index) const {
EnsureLayoutTextUpdated();
return GetGraphemeIteratorAtIndex(
layout_text_, &internal::TextToDisplayIndex::display_index, index);
}
size_t RenderText::GetTextIndex(internal::GraphemeIterator iter) const {
DCHECK(layout_text_up_to_date_);
return iter == text_to_display_indices_.end() ? text_.length()
: iter->text_index;
}
size_t RenderText::GetDisplayTextIndex(internal::GraphemeIterator iter) const {
DCHECK(layout_text_up_to_date_);
return iter == text_to_display_indices_.end() ? layout_text_.length()
: iter->display_index;
}
bool RenderText::IsGraphemeBoundary(size_t index) const {
return index >= text_.length() ||
GetTextIndex(GetGraphemeIteratorAtTextIndex(index)) == index;
}
size_t RenderText::IndexOfAdjacentGrapheme(
size_t index,
LogicalCursorDirection direction) const {
// The input is clamped if it is out of that range.
if (text_.empty())
return 0;
if (index > text_.length())
return text_.length();
EnsureLayoutTextUpdated();
internal::GraphemeIterator iter = index == text_.length()
? text_to_display_indices_.end()
: GetGraphemeIteratorAtTextIndex(index);
if (direction == CURSOR_FORWARD) {
if (iter != text_to_display_indices_.end())
++iter;
} else {
DCHECK_EQ(direction, CURSOR_BACKWARD);
// If the index was not at the beginning of the grapheme, it will have been
// moved back to the grapheme start.
if (iter != text_to_display_indices_.begin() && GetTextIndex(iter) == index)
--iter;
}
return GetTextIndex(iter);
}
SelectionModel RenderText::GetSelectionModelForSelectionStart() const {
const Range& sel = selection();
if (sel.is_empty())
return selection_model_;
return SelectionModel(sel.start(),
sel.is_reversed() ? CURSOR_BACKWARD : CURSOR_FORWARD);
}
const Vector2d& RenderText::GetUpdatedDisplayOffset() {
UpdateCachedBoundsAndOffset();
return display_offset_;
}
void RenderText::SetDisplayOffset(int horizontal_offset) {
SetDisplayOffset({horizontal_offset, display_offset_.y()});
}
void RenderText::SetDisplayOffset(Vector2d offset) {
// Use ClampedNumeric for extra content, as it can otherwise overflow during
// later operations if GetContentWidth() returns INT_MAX and
// display_rect_.width() is 0.
const base::ClampedNumeric<int> extra_content =
base::ClampedNumeric<int>(GetContentWidth()) - display_rect_.width();
const int cursor_width = cursor_enabled_ ? 1 : 0;
int min_offset = 0;
int max_offset = 0;
if (extra_content > 0) {
switch (GetCurrentHorizontalAlignment()) {
case ALIGN_LEFT:
min_offset = -extra_content;
break;
case ALIGN_RIGHT:
max_offset = extra_content;
break;
case ALIGN_CENTER:
// The extra space reserved for cursor at the end of the text is ignored
// when centering text. So, to calculate the valid range for offset, we
// exclude that extra space, calculate the range, and add it back to the
// range (if cursor is enabled).
min_offset = -(extra_content - cursor_width + 1) / 2 - cursor_width;
max_offset = (extra_content - cursor_width) / 2;
break;
default:
break;
}
}
const int horizontal_offset = std::clamp(offset.x(), min_offset, max_offset);
// y-offset is set only when the vertical alignment is ALIGN_TOP.
// TODO(jongkown.lee): Support other vertical alignments.
DCHECK(vertical_alignment_ == ALIGN_TOP || offset.y() == 0);
const int vertical_offset = std::clamp(
offset.y(),
std::min(display_rect_.height() - GetStringSize().height(), 0), 0);
cached_bounds_and_offset_valid_ = true;
display_offset_ = {horizontal_offset, vertical_offset};
cursor_bounds_ = GetCursorBounds(selection_model_, true);
}
Vector2d RenderText::GetLineOffset(size_t line_number) {
const internal::ShapedText* shaped_text = GetShapedText();
Vector2d offset = display_rect().OffsetFromOrigin();
if (!multiline()) {
offset.Add(GetUpdatedDisplayOffset());
} else {
DCHECK_LT(line_number, shaped_text->lines().size());
offset.Add(GetUpdatedDisplayOffset());
offset.Add(
Vector2d(0, shaped_text->lines()[line_number].preceding_heights));
}
offset.Add(GetAlignmentOffset(line_number));
return offset;
}
bool RenderText::GetWordLookupDataAtPoint(const Point& point,
DecoratedText* decorated_word,
Point* baseline_point) {
if (obscured())
return false;
EnsureLayout();
const SelectionModel model_at_point = FindCursorPosition(point);
const size_t word_index =
GetNearestWordStartBoundary(model_at_point.caret_pos());
if (word_index >= text().length())
return false;
const Range word_range = ExpandRangeToWordBoundary(Range(word_index));
DCHECK(!word_range.is_reversed());
DCHECK(!word_range.is_empty());
return GetLookupDataForRange(word_range, decorated_word, baseline_point);
}
bool RenderText::GetLookupDataForRange(const Range& range,
DecoratedText* decorated_text,
Point* baseline_point) {
const internal::ShapedText* shaped_text = GetShapedText();
const std::vector<Rect> word_bounds = GetSubstringBounds(range);
if (word_bounds.empty() || !GetDecoratedTextForRange(range, decorated_text)) {
return false;
}
// Retrieve the baseline origin of the left-most glyph.
const auto left_rect = std::min_element(
word_bounds.begin(), word_bounds.end(),
[](const Rect& lhs, const Rect& rhs) { return lhs.x() < rhs.x(); });
const int line_index = GetLineContainingYCoord(left_rect->CenterPoint().y() -
GetLineOffset(0).y());
if (line_index < 0 ||
line_index >= static_cast<int>(shaped_text->lines().size()))
return false;
*baseline_point = left_rect->origin() +
Vector2d(0, shaped_text->lines()[line_index].baseline);
return true;
}
std::u16string RenderText::GetTextFromRange(const Range& range) const {
if (range.IsValid() && range.GetMin() < text().length())
return text().substr(range.GetMin(), range.length());
return std::u16string();
}
Range RenderText::ExpandRangeToGraphemeBoundary(const Range& range) const {
const auto snap_to_grapheme = [this](auto index, auto direction) {
return IsValidCursorIndex(index)
? index
: IndexOfAdjacentGrapheme(index, direction);
};
const size_t min_index = snap_to_grapheme(range.GetMin(), CURSOR_BACKWARD);
const size_t max_index = snap_to_grapheme(range.GetMax(), CURSOR_FORWARD);
return range.is_reversed() ? Range(max_index, min_index)
: Range(min_index, max_index);
}
Range RenderText::ExpandRangeToWordBoundary(const Range& range) const {
const size_t length = text().length();
DCHECK_LE(range.GetMax(), length);
if (obscured()) {
return range.is_reversed() ? Range(length, 0) : Range(0, length);
}
base::i18n::BreakIterator iter(text(), base::i18n::BreakIterator::BREAK_WORD);
const bool success = iter.Init();
DCHECK(success);
if (!success) {
return range;
}
size_t range_min = range.GetMin();
if (range_min == length && range_min != 0) {
--range_min;
}
for (; range_min != 0; --range_min) {
if (iter.IsStartOfWord(range_min) || iter.IsEndOfWord(range_min)) {
break;
}
}
size_t range_max = range.GetMax();
if (range_min == range_max && range_max != length) {
++range_max;
}
for (; range_max < length; ++range_max) {
if (iter.IsEndOfWord(range_max) || iter.IsStartOfWord(range_max)) {
break;
}
}
return range.is_reversed() ? Range(range_max, range_min)
: Range(range_min, range_max);
}
bool RenderText::IsNewlineSegment(const internal::LineSegment& segment) const {
return IsNewlineSegment(text_, segment);
}
bool RenderText::IsNewlineSegment(const std::u16string& text,
const internal::LineSegment& segment) const {
const size_t offset = segment.char_range.start();
const size_t length = segment.char_range.length();
DCHECK_LT(offset + length - 1, text.length());
return (length == 1 && (text[offset] == '\r' || text[offset] == '\n')) ||
(length == 2 && text[offset] == '\r' && text[offset + 1] == '\n');
}
Range RenderText::GetLineRange(const std::u16string& text,
const internal::Line& line) const {
// This will find the logical start and end indices of the given line.
size_t max_index = 0;
size_t min_index = text.length();
for (const auto& segment : line.segments) {
min_index = std::min<size_t>(min_index, segment.char_range.GetMin());
max_index = std::max<size_t>(max_index, segment.char_range.GetMax());
}
// Do not include the newline character, as that could be considered leading
// into the next line. Note that the newline character is always the last
// character of the line regardless of the text direction, so decrease the
// |max_index|.
if (!line.segments.empty() &&
(IsNewlineSegment(text, line.segments.back()) ||
IsNewlineSegment(text, line.segments.front()))) {
--max_index;
}
return Range(min_index, max_index);
}
RenderText::RenderText() = default;
internal::StyleIterator RenderText::GetTextStyleIterator() const {
return internal::StyleIterator(&colors_, &baselines_, &font_size_overrides_,
&weights_, &styles_);
}
internal::StyleIterator RenderText::GetLayoutTextStyleIterator() const {
EnsureLayoutTextUpdated();
return internal::StyleIterator(&layout_colors_, &layout_baselines_,
&layout_font_size_overrides_, &layout_weights_,
&layout_styles_);
}
bool RenderText::IsHomogeneous() const {
if (colors().breaks().size() > 1 || baselines().breaks().size() > 1 ||
font_size_overrides().breaks().size() > 1 ||
weights().breaks().size() > 1) {
return false;
}
return base::ranges::none_of(
styles(), [](const auto& style) { return style.breaks().size() > 1; });
}
internal::ShapedText* RenderText::GetShapedText() {
EnsureLayout();
DCHECK(shaped_text_);
return shaped_text_.get();
}
int RenderText::GetDisplayTextBaseline() {
DCHECK(!GetShapedText()->lines().empty());
return GetShapedText()->lines()[0].baseline;
}
SelectionModel RenderText::GetAdjacentSelectionModel(
const SelectionModel& current,
BreakType break_type,
VisualCursorDirection direction) {
EnsureLayout();
if (direction == CURSOR_UP || direction == CURSOR_DOWN)
return AdjacentLineSelectionModel(current, direction);
if (break_type == FIELD_BREAK || text().empty())
return EdgeSelectionModel(direction);
if (break_type == LINE_BREAK)
return LineSelectionModel(GetLineContainingCaret(current), direction);
if (break_type == CHARACTER_BREAK)
return AdjacentCharSelectionModel(current, direction);
DCHECK(break_type == WORD_BREAK);
return AdjacentWordSelectionModel(current, direction);
}
SelectionModel RenderText::EdgeSelectionModel(
VisualCursorDirection direction) {
if (direction == GetVisualDirectionOfLogicalEnd())
return SelectionModel(text().length(), CURSOR_FORWARD);
return SelectionModel(0, CURSOR_BACKWARD);
}
SelectionModel RenderText::LineSelectionModel(size_t line_index,
VisualCursorDirection direction) {
DCHECK(direction == CURSOR_LEFT || direction == CURSOR_RIGHT);
DCHECK_LT(line_index, GetShapedText()->lines().size());
const internal::Line& line = GetShapedText()->lines()[line_index];
if (line.segments.empty()) {
// Only the last line can be empty.
DCHECK_EQ(GetShapedText()->lines().size() - 1, line_index);
return EdgeSelectionModel(GetVisualDirectionOfLogicalEnd());
}
if (line_index ==
(direction == GetVisualDirectionOfLogicalEnd() ? GetNumLines() - 1 : 0)) {
return EdgeSelectionModel(direction);
}
DCHECK_GT(GetNumLines(), 1U);
Range line_range = GetLineRange(text(), line);
// Cursor affinity should be the opposite of visual direction to preserve the
// line number of the cursor in multiline text.
return direction == GetVisualDirectionOfLogicalEnd()
? SelectionModel(DisplayIndexToTextIndex(line_range.end()),
CURSOR_BACKWARD)
: SelectionModel(DisplayIndexToTextIndex(line_range.start()),
CURSOR_FORWARD);
}
void RenderText::SetSelectionModel(const SelectionModel& model) {
DCHECK_LE(model.selection().GetMax(), text().length());
selection_model_ = model;
cached_bounds_and_offset_valid_ = false;
has_directed_selection_ = kSelectionIsAlwaysDirected;
}
void RenderText::AddSecondarySelection(const Range selection) {
DCHECK_LE(selection.GetMax(), text().length());
selection_model_.AddSecondarySelection(selection);
}
size_t RenderText::TextIndexToDisplayIndex(size_t index) const {
return GetDisplayTextIndex(GetGraphemeIteratorAtTextIndex(index));
}
size_t RenderText::DisplayIndexToTextIndex(size_t index) const {
return GetTextIndex(GetGraphemeIteratorAtDisplayTextIndex(index));
}
void RenderText::OnLayoutTextAttributeChanged(bool text_changed) {
layout_text_up_to_date_ = false;
}
void RenderText::EnsureLayoutTextUpdated() const {
if (layout_text_up_to_date_)
return;
layout_text_.clear();
text_to_display_indices_.clear();
display_text_direction_ = base::i18n::UNKNOWN_DIRECTION;
// Reset the previous layout text attributes. Allocate enough space for
// layout text attributes (upper limit to 2x characters per codepoint). The
// actual size will be updated at the end of the function.
UpdateLayoutStyleLengths(2 * text_.length());
// Create an grapheme iterator to ensure layout BreakLists don't break
// graphemes.
base::i18n::BreakIterator grapheme_iter(
text_, base::i18n::BreakIterator::BREAK_CHARACTER);
bool success = grapheme_iter.Init();
DCHECK(success);
// Ensures the reveal index is at a codepoint boundary (e.g. not in a middle
// of a surrogate pairs).
size_t reveal_index = text_.size();
if (obscured_reveal_index_.has_value()) {
reveal_index = obscured_reveal_index_.value();
// Move |reveal_index| to the beginning of the surrogate pair, if needed.
if (reveal_index < text_.size())
U16_SET_CP_START(text_.data(), 0, reveal_index);
}
// Iterates through graphemes from |text_| and rewrite its codepoints to
// |layout_text_|.
base::i18n::UTF16CharIterator text_iter(text_);
internal::StyleIterator styles = GetTextStyleIterator();
bool text_truncated = false;
while (!text_iter.end() && !text_truncated) {
std::vector<uint32_t> grapheme_codepoints;
const size_t text_grapheme_start_position = text_iter.array_pos();
const size_t layout_grapheme_start_position = layout_text_.size();
// Retrieve codepoints of the current grapheme.
do {
grapheme_codepoints.push_back(text_iter.get());
text_iter.Advance();
} while (!grapheme_iter.IsGraphemeBoundary(text_iter.array_pos()) &&
!text_iter.end());
const size_t text_grapheme_end_position = text_iter.array_pos();
// Keep track of the mapping between |text_| and |layout_text_| indices.
internal::TextToDisplayIndex mapping = {text_grapheme_start_position,
layout_grapheme_start_position};
text_to_display_indices_.push_back(mapping);
// Flag telling if the current grapheme is a newline control sequence.
const bool is_newline_grapheme =
(grapheme_codepoints.size() == 1 &&
(grapheme_codepoints[0] == '\r' || grapheme_codepoints[0] == '\n')) ||
(grapheme_codepoints.size() == 2 && grapheme_codepoints[0] == '\r' &&
grapheme_codepoints[1] == '\n');
// Obscure the layout text by replacing the grapheme by a bullet.
if (obscured_ &&
(reveal_index < text_grapheme_start_position ||
reveal_index >= text_grapheme_end_position) &&
(!is_newline_grapheme || !multiline_)) {
grapheme_codepoints.clear();
grapheme_codepoints.push_back(RenderText::kPasswordReplacementChar);
}
// Rewrite each codepoint of the grapheme.
for (uint32_t codepoint : grapheme_codepoints) {
// Handle unicode control characters ISO 6429 (block C0). Range from 0 to
// 0x1F and 0x7F. The newline character should be kept as-is when
// rendertext is multiline.
if (!multiline_ || !is_newline_grapheme)
codepoint = ReplaceControlCharacter(codepoint);
// Truncate the remaining codepoints if appending the codepoint to
// |layout_text_| is making the text larger than |truncate_length_|.
size_t codepoint_length = U16_LENGTH(codepoint);
text_truncated =
(truncate_length_ != 0 &&
((layout_text_.size() + codepoint_length > truncate_length_) ||
(!text_iter.end() &&
(layout_text_.size() + codepoint_length == truncate_length_))));
if (text_truncated) {
codepoint = kEllipsisCodepoint;
codepoint_length = U16_LENGTH(codepoint);
// On truncate, remove the whole current grapheme.
layout_text_.resize(layout_grapheme_start_position);
}
// Append the codepoint to the layout text.
const size_t current_layout_text_position = layout_text_.size();
if (codepoint_length == 1) {
layout_text_ += codepoint;
} else {
layout_text_ += U16_LEAD(codepoint);
layout_text_ += U16_TRAIL(codepoint);
}
// Apply the style at current grapheme position to the layout text.
styles.IncrementToPosition(text_grapheme_start_position);
Range range(current_layout_text_position, layout_text_.size());
layout_colors_.ApplyValue(styles.color(), range);
layout_baselines_.ApplyValue(styles.baseline(), range);
layout_font_size_overrides_.ApplyValue(styles.font_size_override(),
range);
layout_weights_.ApplyValue(styles.weight(), range);
for (size_t i = 0; i < layout_styles_.size(); ++i) {
layout_styles_[i].ApplyValue(styles.style(static_cast<TextStyle>(i)),
range);
}
// Apply an underline to the composition range in |underlines|.
const Range grapheme_start_range(text_grapheme_start_position,
text_grapheme_start_position + 1);
if (composition_range_.Contains(grapheme_start_range))
layout_styles_[TEXT_STYLE_HEAVY_UNDERLINE].ApplyValue(true, range);
// Stop appending characters if the text is truncated.
if (text_truncated)
break;
}
}
// Resize the layout text attributes to the actual layout text length.
UpdateLayoutStyleLengths(layout_text_.length());
// Ensures that the text got truncated correctly, when needed.
DCHECK(truncate_length_ == 0 || layout_text_.size() <= truncate_length_);
// Wait to reset |layout_text_up_to_date_| until the end, to ensure this
// function's implementation doesn't indirectly rely on it being up to date
// anywhere.
layout_text_up_to_date_ = true;
}
const std::u16string& RenderText::GetLayoutText() const {
EnsureLayoutTextUpdated();
return layout_text_;
}
void RenderText::UpdateDisplayText(float text_width) {
EnsureLayoutTextUpdated();
// TODO(krb): Consider other elision modes for multiline.
if ((multiline_ && (!max_lines_ || elide_behavior() != ELIDE_TAIL)) ||
elide_behavior() == NO_ELIDE || elide_behavior() == FADE_TAIL ||
(text_width > 0 && text_width < display_rect_.width()) ||
layout_text_.empty()) {
text_elided_ = false;
display_text_.clear();
return;
}
if (!multiline_) {
// This doesn't trim styles so ellipsis may get rendered as a different
// style than the preceding text. See crbug.com/327850.
display_text_.assign(Elide(layout_text_, text_width,
static_cast<float>(display_rect_.width()),
elide_behavior_));
} else {
text_elided_ = false;
display_text_.clear();
std::unique_ptr<RenderText> render_text(
CreateInstanceOfSameStyle(layout_text_));
render_text->SetMultiline(true);
render_text->SetWordWrapBehavior(word_wrap_behavior_);
render_text->SetDisplayRect(display_rect_);
// Have it arrange words on |lines_|.
render_text->EnsureLayout();
if (render_text->GetShapedText()->lines().size() > max_lines_) {
// Find the start and end index of the line to be elided.
Range line_range = GetLineRange(
layout_text_, render_text->GetShapedText()->lines()[max_lines_ - 1]);
// Add an ellipsis character in case the last line is short enough to fit
// on a single line. Otherwise that character will be elided anyway.
std::u16string text_to_elide =
layout_text_.substr(line_range.start(), line_range.length()) +
std::u16string(kEllipsisUTF16);
display_text_.assign(layout_text_.substr(0, line_range.start()) +
Elide(text_to_elide, 0,
static_cast<float>(display_rect_.width()),
ELIDE_TAIL));
} else {
// Initial state above is fine.
return;
}
}
text_elided_ = display_text_ != layout_text_;
if (!text_elided_)
display_text_.clear();
}
Point RenderText::ToViewPoint(const PointF& point, size_t line) {
if (GetNumLines() == 1) {
return Point(base::ClampCeil(Clamp(point.x())),
base::ClampRound(point.y())) +
GetLineOffset(0);
}
const internal::ShapedText* shaped_text = GetShapedText();
float x = point.x();
if (GetDisplayTextDirection() == base::i18n::RIGHT_TO_LEFT) {
// |xspan| returned from |GetCursorSpan| in |GetCursorBounds| starts to grow
// from the last character in RTL. On the other hand, the last character is
// positioned in the last line in RTL. So, traverse from the last line.
for (size_t l = GetNumLines() - 1; l > line; --l) {
x -= shaped_text->lines()[l].size.width();
}
} else {
// TODO(crbug.com/1163587): This doesn't account for line breaks caused by
// wrapping, in which case the cursor may end up right after the trailing
// space on the top line instead of before the first character of the second
// line depending on which direction the cursor is moving. Both positions
// are "correct" but most text editors only allow one or the other for
// consistency.
for (size_t l = 0; l < line; ++l) {
x -= shaped_text->lines()[l].size.width();
}
}
return Point(base::ClampCeil(Clamp(x)), base::ClampRound(point.y())) +
GetLineOffset(line);
}
HorizontalAlignment RenderText::GetCurrentHorizontalAlignment() {
if (horizontal_alignment_ != ALIGN_TO_HEAD)
return horizontal_alignment_;
return GetDisplayTextDirection() == base::i18n::RIGHT_TO_LEFT ?
ALIGN_RIGHT : ALIGN_LEFT;
}
Vector2d RenderText::GetAlignmentOffset(size_t line_number) {
DCHECK(!multiline_ || (line_number < GetShapedText()->lines().size()));
Vector2d offset;
HorizontalAlignment horizontal_alignment = GetCurrentHorizontalAlignment();
if (horizontal_alignment != ALIGN_LEFT) {
const int width =
multiline_ ? base::ClampCeil(
GetShapedText()->lines()[line_number].size.width() +
(cursor_enabled_ ? 1.0f : 0.0f))
: GetContentWidth();
offset.set_x(display_rect().width() - width);
// Put any extra margin pixel on the left to match legacy behavior.
if (horizontal_alignment == ALIGN_CENTER)
offset.set_x((offset.x() + 1) / 2);
}
switch (vertical_alignment_) {
case ALIGN_TOP:
offset.set_y(0);
break;
case ALIGN_MIDDLE:
if (multiline_)
offset.set_y((display_rect_.height() - GetStringSize().height()) / 2);
else
offset.set_y(GetBaseline() - GetDisplayTextBaseline());
break;
case ALIGN_BOTTOM:
offset.set_y(display_rect_.height() - GetStringSize().height());
break;
}
return offset;
}
void RenderText::ApplyFadeEffects(internal::SkiaTextRenderer* renderer) {
const int width = display_rect().width();
if (multiline() || elide_behavior_ != FADE_TAIL || GetContentWidth() <= width)
return;
const int gradient_width = CalculateFadeGradientWidth(font_list(), width);
if (gradient_width == 0)
return;
HorizontalAlignment horizontal_alignment = GetCurrentHorizontalAlignment();
Rect solid_part = display_rect();
Rect left_part;
Rect right_part;
if (horizontal_alignment != ALIGN_LEFT) {
left_part = solid_part;
left_part.Inset(
gfx::Insets::TLBR(0, 0, 0, solid_part.width() - gradient_width));
solid_part.Inset(gfx::Insets::TLBR(0, gradient_width, 0, 0));
}
if (horizontal_alignment != ALIGN_RIGHT) {
right_part = solid_part;
right_part.Inset(
gfx::Insets::TLBR(0, solid_part.width() - gradient_width, 0, 0));
solid_part.Inset(gfx::Insets::TLBR(0, 0, 0, gradient_width));
}
// CreateFadeShader() expects at least one part to not be empty.
// See https://crbug.com/706835.
if (left_part.IsEmpty() && right_part.IsEmpty())
return;
Rect text_rect = display_rect();
text_rect.Inset(gfx::Insets::TLBR(0, GetAlignmentOffset(0).x(), 0, 0));
// TODO(msw): Use the actual text colors corresponding to each faded part.
renderer->SetShader(
CreateFadeShader(font_list(), text_rect, left_part, right_part,
SkColorSetA(colors_.breaks().front().second, 0xff)));
}
void RenderText::ApplyTextShadows(internal::SkiaTextRenderer* renderer) {
renderer->SetDrawLooper(CreateShadowDrawLooper(shadows_));
}
base::i18n::TextDirection RenderText::GetTextDirectionForGivenText(
const std::u16string& text) const {
switch (directionality_mode_) {
case DIRECTIONALITY_FROM_TEXT:
// Derive the direction from the display text, which differs from text()
// in the case of obscured (password) textfields.
return base::i18n::GetFirstStrongCharacterDirection(text);
case DIRECTIONALITY_FROM_UI:
return base::i18n::IsRTL() ? base::i18n::RIGHT_TO_LEFT
: base::i18n::LEFT_TO_RIGHT;
case DIRECTIONALITY_FORCE_LTR:
return base::i18n::LEFT_TO_RIGHT;
case DIRECTIONALITY_FORCE_RTL:
return base::i18n::RIGHT_TO_LEFT;
case DIRECTIONALITY_AS_URL:
// Rendering as a URL implies left-to-right paragraph direction.
// URL Standard specifies that a URL "should be rendered as if it were
// in a left-to-right embedding".
// https://url.spec.whatwg.org/#url-rendering
//
// Consider logical string for domain "ABC.com/hello" (where ABC are
// Hebrew (RTL) characters). The normal Bidi algorithm renders this as
// "com/hello.CBA"; by forcing LTR, it is rendered as "CBA.com/hello".
//
// Note that this only applies a LTR embedding at the top level; it
// doesn't change the Bidi algorithm, so there are still some URLs that
// will render in a confusing order. Consider the logical string
// "abc.COM/HELLO/world", which will render as "abc.OLLEH/MOC/world".
// See https://crbug.com/351639.
//
// Note that the LeftToRightUrls feature flag enables additional
// behaviour for DIRECTIONALITY_AS_URL, but the left-to-right embedding
// behaviour is always enabled, regardless of the flag.
return base::i18n::LEFT_TO_RIGHT;
default:
NOTREACHED();
return base::i18n::UNKNOWN_DIRECTION;
}
}
void RenderText::UpdateStyleLengths() {
const size_t text_length = text_.length();
colors_.SetMax(text_length);
baselines_.SetMax(text_length);
font_size_overrides_.SetMax(text_length);
weights_.SetMax(text_length);
for (auto& style : styles_)
style.SetMax(text_length);
}
void RenderText::UpdateLayoutStyleLengths(size_t max_length) const {
layout_colors_.SetMax(max_length);
layout_baselines_.SetMax(max_length);
layout_font_size_overrides_.SetMax(max_length);
layout_weights_.SetMax(max_length);
for (auto& layout_style : layout_styles_)
layout_style.SetMax(max_length);
}
int RenderText::GetLineContainingYCoord(float text_y) {
if (text_y < 0)
return -1;
internal::ShapedText* shaper_text = GetShapedText();
for (size_t i = 0; i < shaper_text->lines().size(); i++) {
const internal::Line& line = shaper_text->lines()[i];
if (text_y <= line.size.height())
return i;
text_y -= line.size.height();
}
return shaper_text->lines().size();
}
// static
bool RenderText::RangeContainsCaret(const Range& range,
size_t caret_pos,
LogicalCursorDirection caret_affinity) {
if (caret_pos == 0 && caret_affinity == CURSOR_BACKWARD)
return false;
size_t adjacent = (caret_affinity == CURSOR_BACKWARD) ?
caret_pos - 1 : caret_pos + 1;
return range.Contains(Range(caret_pos, adjacent));
}
// static
int RenderText::DetermineBaselineCenteringText(const int display_height,
const FontList& font_list) {
const int font_height = font_list.GetHeight();
// Lower and upper bound of baseline shift as we try to show as much area of
// text as possible. In particular case of |display_height| == |font_height|,
// we do not want to shift the baseline.
const int min_shift = std::min(0, display_height - font_height);
const int max_shift = std::abs(display_height - font_height);
const int baseline = font_list.GetBaseline();
const int cap_height = font_list.GetCapHeight();
const int internal_leading = baseline - cap_height;
// Some platforms don't support getting the cap height, and simply return
// the entire font ascent from GetCapHeight(). Centering the ascent makes
// the font look too low, so if GetCapHeight() returns the ascent, center
// the entire font height instead.
const int space =
display_height - ((internal_leading != 0) ? cap_height : font_height);
const int baseline_shift = space / 2 - internal_leading;
return baseline + std::clamp(baseline_shift, min_shift, max_shift);
}
// static
Rect RenderText::ExpandToBeVerticallySymmetric(const Rect& rect,
const Rect& display_rect) {
// Mirror |rect| across the horizontal line dividing |display_rect| in half.
Rect result = rect;
int mid_y = display_rect.CenterPoint().y();
// The top of the mirror rect must be equidistant with the bottom of the
// original rect from the mid-line.
result.set_y(mid_y + (mid_y - rect.bottom()));
// Now make a union with the original rect to ensure we are encompassing both.
result.Union(rect);
return result;
}
// static
void RenderText::MergeIntersectingRects(std::vector<Rect>& rects) {
if (rects.size() < 2)
return;
std::sort(rects.begin(), rects.end(),
[](const Rect& a, const Rect& b) { return a.x() < b.x(); });
size_t merge_candidate = 0;
for (size_t i = 1; i < rects.size(); i++) {
if (rects[i].Intersects(rects[merge_candidate]) ||
rects[i].SharesEdgeWith(rects[merge_candidate])) {
DCHECK_EQ(rects[i].y(), rects[merge_candidate].y());
DCHECK_EQ(rects[i].height(), rects[merge_candidate].height());
rects[merge_candidate].Union(rects[i]);
} else {
merge_candidate++;
if (merge_candidate != i)
rects[merge_candidate] = rects[i];
}
}
rects.resize(merge_candidate + 1);
}
void RenderText::OnTextAttributeChanged() {
layout_text_.clear();
display_text_.clear();
text_elided_ = false;
layout_text_up_to_date_ = false;
OnLayoutTextAttributeChanged(true);
}
std::u16string RenderText::Elide(const std::u16string& text,
float text_width,
float available_width,
ElideBehavior behavior) {
if (available_width <= 0 || text.empty())
return std::u16string();
if (behavior == ELIDE_EMAIL)
return ElideEmail(text, available_width);
if (text_width > 0 && text_width <= available_width)
return text;
TRACE_EVENT0("ui", "RenderText::Elide");
// Create a RenderText copy with attributes that affect the rendering width.
std::unique_ptr<RenderText> render_text = CreateInstanceOfSameStyle(text);
render_text->UpdateStyleLengths();
if (text_width == 0)
text_width = render_text->GetContentWidthF();
if (text_width <= available_width)
return text;
const std::u16string ellipsis = std::u16string(kEllipsisUTF16);
const bool insert_ellipsis = (behavior != TRUNCATE);
const bool elide_in_middle = (behavior == ELIDE_MIDDLE);
const bool elide_at_beginning = (behavior == ELIDE_HEAD);
if (insert_ellipsis) {
render_text->SetText(ellipsis);
const float ellipsis_width = render_text->GetContentWidthF();
if (ellipsis_width > available_width)
return std::u16string();
}
StringSlicer slicer(text, ellipsis, elide_in_middle, elide_at_beginning,
whitespace_elision_);
// Use binary(-like) search to compute the elided text. In particular, do
// an interpolation search, which is a binary search in which each guess
// is an attempt to smartly calculate the right point rather than blindly
// guessing midway between the endpoints.
size_t lo = 0;
size_t hi = text.length() - 1;
size_t guess = std::string::npos;
// These two widths are not exactly right but they're good enough to provide
// some guidance to the search. For example, |text_width| is actually the
// length of text.length(), not text.length()-1.
float lo_width = 0;
float hi_width = text_width;
const base::i18n::TextDirection text_direction = GetTextDirection();
while (lo <= hi) {
// Linearly interpolate between |lo| and |hi|, which correspond to widths
// of |lo_width| and |hi_width| to estimate at what position
// |available_width| would be at. Because |lo_width| and |hi_width| are
// both estimates (may be off by a little because, for example, |lo_width|
// may have been calculated from |lo| minus one, not |lo|), we clamp to the
// the valid range.
// |last_guess| is merely used to verify that we're not repeating guesses.
const size_t last_guess = guess;
if (hi_width != lo_width) {
guess = lo + base::ClampRound<size_t>((available_width - lo_width) *
(hi - lo) / (hi_width - lo_width));
}
guess = std::clamp(guess, lo, hi);
DCHECK_NE(last_guess, guess);
// Restore colors. They will be truncated to size by SetText.
render_text->colors_ = colors_;
std::u16string new_text =
slicer.CutString(guess, insert_ellipsis && behavior != ELIDE_TAIL);
// This has to be an additional step so that the ellipsis is rendered with
// same style as trailing part of the text.
if (insert_ellipsis && behavior == ELIDE_TAIL) {
// When ellipsis follows text whose directionality is not the same as that
// of the whole text, it will be rendered with the directionality of the
// whole text. Since we want ellipsis to indicate continuation of the
// preceding text, we force the directionality of ellipsis to be same as
// the preceding text using LTR or RTL markers.
base::i18n::TextDirection trailing_text_direction =
base::i18n::GetLastStrongCharacterDirection(new_text);
// Ensures that the |new_text| will always be smaller or equal to the
// original text. There is a corner case when only one character is elided
// and two characters are added back (ellipsis and directional marker).
if (trailing_text_direction != text_direction &&
new_text.length() + 2 > text.length() && guess >= 1) {
new_text = slicer.CutString(guess - 1, false);
trailing_text_direction =
base::i18n::GetLastStrongCharacterDirection(new_text);
}
// Append the ellipsis and the optional directional marker characters.
// Do not append the BiDi marker if the only codepoint in the text is
// an ellipsis.
new_text.append(ellipsis);
if (new_text.size() != 1 && trailing_text_direction != text_direction) {
if (trailing_text_direction == base::i18n::LEFT_TO_RIGHT)
new_text += base::i18n::kLeftToRightMark;
else
new_text += base::i18n::kRightToLeftMark;
}
}
// The elided text must be smaller in bytes. Otherwise, break-lists are not
// consistent and the characters after the last range are not styled.
DCHECK_LE(new_text.size(), text.size());
render_text->SetText(new_text);
// Restore styles and baselines without breaking multi-character graphemes.
render_text->styles_ = styles_;
for (auto& style : render_text->styles_)
RestoreBreakList(render_text.get(), &style);
RestoreBreakList(render_text.get(), &render_text->baselines_);
RestoreBreakList(render_text.get(), &render_text->font_size_overrides_);
render_text->weights_ = weights_;
RestoreBreakList(render_text.get(), &render_text->weights_);
// We check the width of the whole desired string at once to ensure we
// handle kerning/ligatures/etc. correctly.
const float guess_width = render_text->GetContentWidthF();
if (guess_width == available_width)
break;
if (guess_width > available_width) {
hi = guess - 1;
hi_width = guess_width;
// Move back on the loop terminating condition when the guess is too wide.
if (hi < lo) {
lo = hi;
lo_width = guess_width;
}
} else {
lo = guess + 1;
lo_width = guess_width;
}
}
return render_text->text();
}
std::u16string RenderText::ElideEmail(const std::u16string& email,
float available_width) {
// The returned string will have at least one character besides the ellipsis
// on either side of '@'; if that's impossible, a single ellipsis is returned.
// If possible, only the username is elided. Otherwise, the domain is elided
// in the middle, splitting available width equally with the elided username.
// If the username is short enough that it doesn't need half the available
// width, the elided domain will occupy that extra width.
// Split the email into its local-part (username) and domain-part. The email
// spec allows for @ symbols in the username under some special requirements,
// but not in the domain part, so splitting at the last @ symbol is safe.
const size_t split_index = email.find_last_of('@');
if (split_index == std::u16string::npos)
return Elide(email, 0, available_width, ELIDE_TAIL);
std::u16string username = email.substr(0, split_index);
std::u16string domain = email.substr(split_index + 1);
// TODO(http://crbug.com/1085014): Fix eliding of text with styles.
DCHECK(IsHomogeneous())
<< "ElideEmail(...) doesn't work with non homogeneous styles.";
auto render_text = CreateInstanceOfSameStyle(std::u16string());
auto get_string_width = [&](const std::u16string& text) {
render_text->SetText(text);
return render_text->GetStringSizeF().width();
};
// Subtract the @ symbol from the available width as it is mandatory.
const std::u16string kAtSignUTF16 = u"@";
float at_width = get_string_width(kAtSignUTF16);
if (available_width < at_width)
return Elide(kEllipsisUTF16, 0, available_width, ELIDE_TAIL);
const float remaining_width = available_width - at_width;
// Handle corner cases where one of username or domain is empty.
if (username.empty() && domain.empty()) {
return Elide(email, 0, available_width, ELIDE_TAIL);
} else if (username.empty()) {
domain = Elide(domain, 0, remaining_width, ELIDE_MIDDLE);
if (domain.empty() || domain == kEllipsisUTF16)
return Elide(kEllipsisUTF16, 0, available_width, ELIDE_TAIL);
return kAtSignUTF16 + domain;
} else if (domain.empty()) {
username = Elide(username, 0, remaining_width, ELIDE_TAIL);
if (username.empty() || username == kEllipsisUTF16)
return Elide(kEllipsisUTF16, 0, available_width, ELIDE_TAIL);
return username + kAtSignUTF16;
}
// Check whether eliding the domain is necessary: if eliding the username
// is sufficient, the domain will not be elided.
const float full_username_width = get_string_width(username);
const float available_domain_width =
remaining_width -
std::min(full_username_width,
get_string_width(username.substr(0, 1) + kEllipsisUTF16));
if (get_string_width(domain) > available_domain_width) {
// Elide the domain so that it only takes half of the available width.
// Should the username not need all the width available in its half, the
// domain will occupy the leftover width.
// If |desired_domain_width| is greater than |available_domain_width|: the
// minimal username elision allowed by the specifications will not fit; thus
// |desired_domain_width| must be <= |available_domain_width| at all cost.
const float desired_domain_width =
std::min<float>(available_domain_width,
std::max<float>(remaining_width - full_username_width,
remaining_width / 2));
domain = Elide(domain, 0, desired_domain_width, ELIDE_MIDDLE);
// Failing to elide the domain such that at least one character remains
// (other than the ellipsis itself) remains: return a single ellipsis.
if (domain.empty() || domain == kEllipsisUTF16)
return Elide(kEllipsisUTF16, 0, available_width, ELIDE_TAIL);
}
// Fit the username in the remaining width (at this point the elided username
// is guaranteed to fit with at least one character remaining given all the
// precautions taken earlier).
const float domain_width = get_string_width(domain);
const float available_username_width = remaining_width - domain_width;
username = Elide(username, 0, available_username_width, ELIDE_TAIL);
return username + kAtSignUTF16 + domain;
}
void RenderText::UpdateCachedBoundsAndOffset() {
if (cached_bounds_and_offset_valid_)
return;
int delta_x = 0;
int delta_y = 0;
if (cursor_enabled()) {
// When cursor is enabled, ensure it is visible. For this, set the valid
// flag true and calculate the current cursor bounds using the stale
// |display_offset_|. Then calculate the change in offset needed to move the
// cursor into the visible area.
cached_bounds_and_offset_valid_ = true;
cursor_bounds_ = GetCursorBounds(selection_model_, true);
// TODO(bidi): Show RTL glyphs at the cursor position for ALIGN_LEFT, etc.
if (cursor_bounds_.right() > display_rect_.right())
delta_x = display_rect_.right() - cursor_bounds_.right();
else if (cursor_bounds_.x() < display_rect_.x())
delta_x = display_rect_.x() - cursor_bounds_.x();
if (vertical_alignment_ == ALIGN_TOP) {
if (cursor_bounds_.bottom() > display_rect_.bottom())
delta_y = display_rect_.bottom() - cursor_bounds_.bottom();
else if (cursor_bounds_.y() < display_rect_.y())
delta_y = display_rect_.y() - cursor_bounds_.y();
}
}
SetDisplayOffset(display_offset_ + Vector2d(delta_x, delta_y));
}
internal::GraphemeIterator RenderText::GetGraphemeIteratorAtIndex(
const std::u16string& text,
const size_t internal::TextToDisplayIndex::*field,
size_t index) const {
DCHECK_LE(index, text.length());
if (index == text.length())
return text_to_display_indices_.end();
DCHECK(layout_text_up_to_date_);
DCHECK(!text_to_display_indices_.empty());
// The function std::lower_bound(...) finds the first not less than |index|.
internal::GraphemeIterator iter = std::lower_bound(
text_to_display_indices_.begin(), text_to_display_indices_.end(), index,
[field](const internal::TextToDisplayIndex& lhs, size_t rhs) {
return lhs.*field < rhs;
});
if (iter == text_to_display_indices_.end() || *iter.*field != index) {
DCHECK(iter != text_to_display_indices_.begin());
--iter;
}
return iter;
}
void RenderText::DrawSelections(Canvas* canvas,
const std::vector<Range>& selections) {
for (auto selection : selections) {
if (!selection.is_empty()) {
for (Rect s : GetSubstringBounds(selection)) {
if (symmetric_selection_visual_bounds() && !multiline())
s = ExpandToBeVerticallySymmetric(s, display_rect());
canvas->FillRect(s, selection_background_focused_color_);
}
}
}
}
size_t RenderText::GetNearestWordStartBoundary(size_t index) const {
const size_t length = text().length();
if (obscured() || length == 0)
return length;
base::i18n::BreakIterator iter(text(), base::i18n::BreakIterator::BREAK_WORD);
const bool success = iter.Init();
DCHECK(success);
if (!success)
return length;
// First search for the word start boundary in the CURSOR_BACKWARD direction,
// then in the CURSOR_FORWARD direction.
for (int i = static_cast<int>(std::min(index, length - 1)); i >= 0; i--)
if (iter.IsStartOfWord(i))
return i;
for (size_t i = index + 1; i < length; i++)
if (iter.IsStartOfWord(i))
return i;
return length;
}
} // namespace gfx