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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021, sin-ack <sin-ack@protonmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "TextLayout.h"
namespace Gfx {
enum class BlockType {
Newline,
Whitespace,
Word
};
struct Block {
BlockType type;
Utf8View characters;
};
IntRect TextLayout::bounding_rect(TextWrapping wrapping, int line_spacing) const
{
auto lines = wrap_lines(TextElision::None, wrapping, line_spacing, FitWithinRect::No);
if (!lines.size()) {
return {};
}
IntRect bounding_rect = {
0, 0, 0, static_cast<int>((lines.size() * (m_font->pixel_size() + line_spacing)) - line_spacing)
};
for (auto& line : lines) {
auto line_width = m_font->width(line);
if (line_width > bounding_rect.width())
bounding_rect.set_width(line_width);
}
return bounding_rect;
}
Vector<String, 32> TextLayout::wrap_lines(TextElision elision, TextWrapping wrapping, int line_spacing, FitWithinRect fit_within_rect) const
{
Vector<Block> blocks;
Optional<BlockType> current_block_type;
size_t block_start_offset = 0;
size_t offset = 0;
for (auto it = m_text.begin(); !it.done(); ++it) {
offset = m_text.iterator_offset(it);
switch (*it) {
case '\t':
case ' ': {
if (current_block_type.has_value() && current_block_type.value() != BlockType::Whitespace) {
blocks.append({
current_block_type.value(),
m_text.substring_view(block_start_offset, offset - block_start_offset),
});
current_block_type.clear();
}
if (!current_block_type.has_value()) {
current_block_type = BlockType::Whitespace;
block_start_offset = offset;
}
continue;
}
case '\n':
case '\r': {
if (current_block_type.has_value()) {
blocks.append({
current_block_type.value(),
m_text.substring_view(block_start_offset, offset - block_start_offset),
});
current_block_type.clear();
}
blocks.append({ BlockType::Newline, Utf8View {} });
continue;
}
default: {
if (current_block_type.has_value() && current_block_type.value() != BlockType::Word) {
blocks.append({
current_block_type.value(),
m_text.substring_view(block_start_offset, offset - block_start_offset),
});
current_block_type.clear();
}
if (!current_block_type.has_value()) {
current_block_type = BlockType::Word;
block_start_offset = offset;
}
}
}
}
if (current_block_type.has_value()) {
blocks.append({
current_block_type.value(),
m_text.substring_view(block_start_offset, m_text.byte_length() - block_start_offset),
});
}
size_t max_lines_that_can_fit = 0;
if (m_rect.height() >= m_font->glyph_height()) {
// NOTE: If glyph height is 10 and line spacing is 1, we can fit a
// single line into a 10px rect and a 20px rect, but 2 lines into a
// 21px rect.
max_lines_that_can_fit = 1 + (m_rect.height() - m_font->glyph_height()) / (m_font->glyph_height() + line_spacing);
}
if (max_lines_that_can_fit == 0)
return {};
Vector<String> lines;
StringBuilder builder;
size_t line_width = 0;
size_t current_block = 0;
bool did_not_finish = false;
for (Block& block : blocks) {
switch (block.type) {
case BlockType::Newline: {
lines.append(builder.to_string());
builder.clear();
line_width = 0;
if (lines.size() == max_lines_that_can_fit && fit_within_rect == FitWithinRect::Yes) {
did_not_finish = true;
goto blocks_processed;
}
current_block++;
continue;
}
case BlockType::Whitespace:
case BlockType::Word: {
size_t block_width = font().width(block.characters);
// FIXME: This should look at the specific advance amount of the
// last character, but we don't support that yet.
if (current_block != blocks.size() - 1) {
block_width += font().glyph_spacing();
}
if (wrapping == TextWrapping::Wrap && line_width + block_width > static_cast<unsigned>(m_rect.width())) {
lines.append(builder.to_string());
builder.clear();
line_width = 0;
}
if (lines.size() == max_lines_that_can_fit && fit_within_rect == FitWithinRect::Yes) {
did_not_finish = true;
goto blocks_processed;
}
builder.append(block.characters.as_string());
line_width += block_width;
current_block++;
}
}
}
blocks_processed:
if (!did_not_finish) {
auto last_line = builder.to_string();
if (!last_line.is_empty())
lines.append(last_line);
}
switch (elision) {
case TextElision::None:
break;
case TextElision::Right: {
lines.at(lines.size() - 1) = elide_text_from_right(Utf8View { lines.at(lines.size() - 1) }, did_not_finish);
break;
}
}
return lines;
}
String TextLayout::elide_text_from_right(Utf8View text, bool force_elision) const
{
size_t text_width = m_font->width(text);
if (force_elision || text_width > static_cast<unsigned>(m_rect.width())) {
size_t ellipsis_width = m_font->width("...");
size_t current_width = ellipsis_width;
size_t glyph_spacing = m_font->glyph_spacing();
// FIXME: This code will break when the font has glyphs with advance
// amounts different from the actual width of the glyph
// (which is the case with many TrueType fonts).
if (ellipsis_width < text_width) {
size_t offset = 0;
for (auto it = text.begin(); !it.done(); ++it) {
auto code_point = *it;
int glyph_width = m_font->glyph_or_emoji_width(code_point);
// NOTE: Glyph spacing should not be added after the last glyph on the line,
// but since we are here because the last glyph does not actually fit on the line,
// we don't have to worry about spacing.
int width_with_this_glyph_included = current_width + glyph_width + glyph_spacing;
if (width_with_this_glyph_included > m_rect.width())
break;
current_width += glyph_width + glyph_spacing;
offset = text.iterator_offset(it);
}
StringBuilder builder;
builder.append(text.substring_view(0, offset).as_string());
builder.append("...");
return builder.to_string();
}
}
return text.as_string();
}
}
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