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// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "third_party/blink/renderer/platform/fonts/shaping/shape_result_spacing.h"
#include "third_party/blink/renderer/platform/fonts/font.h"
#include "third_party/blink/renderer/platform/fonts/font_description.h"
#include "third_party/blink/renderer/platform/text/text_run.h"
namespace blink {
template <typename TextContainerType>
bool ShapeResultSpacing<TextContainerType>::SetSpacing(
const FontDescription& font_description) {
return SetSpacing(TextRunLayoutUnit(font_description.LetterSpacing()),
TextRunLayoutUnit(font_description.WordSpacing()));
}
template <typename TextContainerType>
bool ShapeResultSpacing<TextContainerType>::SetSpacing(
TextRunLayoutUnit letter_spacing,
TextRunLayoutUnit word_spacing) {
if (!letter_spacing && !word_spacing) {
has_spacing_ = false;
return false;
}
letter_spacing_ = letter_spacing;
word_spacing_ = word_spacing;
DCHECK(!normalize_space_);
allow_tabs_ = true;
has_spacing_ = true;
return true;
}
template <typename TextContainerType>
void ShapeResultSpacing<TextContainerType>::SetExpansion(
InlineLayoutUnit expansion,
TextDirection direction,
bool allows_leading_expansion,
bool allows_trailing_expansion) {
DCHECK_GT(expansion, InlineLayoutUnit());
expansion_ = expansion;
ComputeExpansion(allows_leading_expansion, allows_trailing_expansion,
direction);
has_spacing_ |= HasExpansion();
}
template <typename TextContainerType>
void ShapeResultSpacing<TextContainerType>::SetSpacingAndExpansion(
const FontDescription& font_description) {
// Available only for TextRun since it has expansion data.
NOTREACHED();
}
template <>
void ShapeResultSpacing<TextRun>::SetSpacingAndExpansion(
const FontDescription& font_description) {
SetSpacingAndExpansion(font_description, text_.NormalizeSpace());
}
template <typename TextContentType>
void ShapeResultSpacing<TextContentType>::SetSpacingAndExpansion(
const FontDescription& font_description,
bool normalize_space) {
letter_spacing_ = TextRunLayoutUnit(font_description.LetterSpacing());
word_spacing_ = TextRunLayoutUnit(font_description.WordSpacing());
expansion_ = InlineLayoutUnit();
has_spacing_ = letter_spacing_ || word_spacing_;
if (!has_spacing_)
return;
normalize_space_ = normalize_space;
allow_tabs_ = false;
}
template <typename TextContainerType>
void ShapeResultSpacing<TextContainerType>::ComputeExpansion(
bool allows_leading_expansion,
bool allows_trailing_expansion,
TextDirection direction) {
DCHECK_GT(expansion_, InlineLayoutUnit());
is_after_expansion_ = !allows_leading_expansion;
bool is_after_expansion = is_after_expansion_;
if (text_.Is8Bit()) {
expansion_opportunity_count_ = Character::ExpansionOpportunityCount(
text_.Span8(), direction, is_after_expansion);
} else {
expansion_opportunity_count_ = Character::ExpansionOpportunityCount(
text_.Span16(), direction, is_after_expansion);
}
if (is_after_expansion && !allows_trailing_expansion &&
expansion_opportunity_count_ > 0) {
--expansion_opportunity_count_;
}
if (expansion_opportunity_count_) {
expansion_per_opportunity_ =
(expansion_ / expansion_opportunity_count_).To<TextRunLayoutUnit>();
}
}
template <typename TextContainerType>
TextRunLayoutUnit ShapeResultSpacing<TextContainerType>::NextExpansion() {
if (!expansion_opportunity_count_) {
NOTREACHED();
}
is_after_expansion_ = true;
if (!--expansion_opportunity_count_) [[unlikely]] {
const TextRunLayoutUnit remaining = expansion_.To<TextRunLayoutUnit>();
expansion_ = InlineLayoutUnit();
return remaining;
}
expansion_ -= expansion_per_opportunity_.To<InlineLayoutUnit>();
return expansion_per_opportunity_;
}
template <typename TextContainerType>
TextRunLayoutUnit ShapeResultSpacing<TextContainerType>::ComputeSpacing(
const ComputeSpacingParameters& parameters,
float& offset,
bool is_cursive_script) {
DCHECK(has_spacing_);
unsigned index = parameters.index;
UChar32 character = text_[index];
bool treat_as_space =
(Character::TreatAsSpace(character) ||
(normalize_space_ &&
Character::IsNormalizedCanvasSpaceCharacter(character))) &&
(character != '\t' || !allow_tabs_);
if (treat_as_space && character != kNoBreakSpaceCharacter)
character = kSpaceCharacter;
TextRunLayoutUnit spacing;
bool has_letter_spacing = letter_spacing_;
bool apply_letter_spacing =
RuntimeEnabledFeatures::IgnoreLetterSpacingInCursiveScriptsEnabled()
? !is_cursive_script
: true;
if (has_letter_spacing && !Character::TreatAsZeroWidthSpace(character) &&
apply_letter_spacing) {
spacing += letter_spacing_;
is_letter_spacing_applied_ = true;
}
if (treat_as_space && (allow_word_spacing_anywhere_ || index ||
character == kNoBreakSpaceCharacter)) {
spacing += word_spacing_;
is_word_spacing_applied_ = true;
}
if (!HasExpansion())
return spacing;
if (treat_as_space)
return spacing + NextExpansion();
if (text_.Is8Bit())
return spacing;
// isCJKIdeographOrSymbol() has expansion opportunities both before and
// after each character.
// http://www.w3.org/TR/jlreq/#line_adjustment
if (U16_IS_LEAD(character) && index + 1 < text_.length() &&
U16_IS_TRAIL(text_[index + 1]))
character = U16_GET_SUPPLEMENTARY(character, text_[index + 1]);
if (!Character::IsCJKIdeographOrSymbol(character)) {
if (!Character::IsDefaultIgnorable(character)) {
is_after_expansion_ = false;
}
return spacing;
}
if (!is_after_expansion_) {
// Take the expansion opportunity before this ideograph.
TextRunLayoutUnit expand_before = NextExpansion();
if (expand_before) {
offset += expand_before.ToFloat();
spacing += expand_before;
}
if (!HasExpansion())
return spacing;
}
return spacing + NextExpansion();
}
// Instantiate the template class.
template class ShapeResultSpacing<TextRun>;
template class ShapeResultSpacing<String>;
} // namespace blink
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