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// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40285824): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif
#include "ui/base/ime/linux/composition_text_util_pango.h"
#include <pango/pango-attributes.h>
#include <stddef.h>
#include <algorithm>
#include <string>
#include "base/i18n/char_iterator.h"
#include "base/strings/utf_string_conversions.h"
#include "ui/base/ime/composition_text.h"
namespace ui {
void ExtractCompositionTextFromGtkPreedit(const char* utf8_text,
PangoAttrList* attrs,
int cursor_position,
CompositionText* composition) {
*composition = CompositionText();
composition->text = base::UTF8ToUTF16(utf8_text);
if (composition->text.empty())
return;
// Gtk/Pango uses character index for cursor position and byte index for
// attribute range, but we use char16 offset for them. So we need to do
// conversion here.
std::vector<size_t> char16_offsets;
size_t length = composition->text.length();
for (base::i18n::UTF16CharIterator char_iterator(composition->text);
!char_iterator.end(); char_iterator.Advance()) {
char16_offsets.push_back(char_iterator.array_pos());
}
// The text length in Unicode characters.
int char_length = static_cast<int>(char16_offsets.size());
// Make sure we can convert the value of |char_length| as well.
char16_offsets.push_back(length);
size_t cursor_offset =
char16_offsets[std::clamp(cursor_position, 0, char_length)];
composition->selection = gfx::Range(cursor_offset);
if (attrs) {
int utf8_length = strlen(utf8_text);
PangoAttrIterator* iter = pango_attr_list_get_iterator(attrs);
// We only care about underline and background attributes and convert
// background attribute into selection if possible.
do {
gint start, end;
pango_attr_iterator_range(iter, &start, &end);
start = std::min(start, utf8_length);
end = std::min(end, utf8_length);
if (start >= end)
continue;
start = g_utf8_pointer_to_offset(utf8_text, utf8_text + start);
end = g_utf8_pointer_to_offset(utf8_text, utf8_text + end);
// Double check, in case |utf8_text| is not a valid utf-8 string.
start = std::min(start, char_length);
end = std::min(end, char_length);
if (start >= end)
continue;
PangoAttribute* background_attr =
pango_attr_iterator_get(iter, PANGO_ATTR_BACKGROUND);
PangoAttribute* underline_attr =
pango_attr_iterator_get(iter, PANGO_ATTR_UNDERLINE);
if (background_attr || underline_attr) {
// Use a thin underline with text color by default.
ImeTextSpan ime_text_span(
ImeTextSpan::Type::kComposition, char16_offsets[start],
char16_offsets[end], ImeTextSpan::Thickness::kThin,
ImeTextSpan::UnderlineStyle::kSolid, SK_ColorTRANSPARENT);
// Always use thick underline for a range with background color, which
// is usually the selection range.
if (background_attr) {
ime_text_span.thickness = ImeTextSpan::Thickness::kThick;
// If the cursor is at start or end of this underline, then we treat
// it as the selection range as well, but make sure to set the cursor
// position to the selection end.
if (ime_text_span.start_offset == cursor_offset) {
composition->selection.set_start(ime_text_span.end_offset);
composition->selection.set_end(cursor_offset);
} else if (ime_text_span.end_offset == cursor_offset) {
composition->selection.set_start(ime_text_span.start_offset);
composition->selection.set_end(cursor_offset);
}
}
if (underline_attr) {
int type = reinterpret_cast<PangoAttrInt*>(underline_attr)->value;
if (type == PANGO_UNDERLINE_DOUBLE)
ime_text_span.thickness = ImeTextSpan::Thickness::kThick;
else if (type == PANGO_UNDERLINE_ERROR)
ime_text_span.underline_color = SK_ColorRED;
}
composition->ime_text_spans.push_back(ime_text_span);
}
} while (pango_attr_iterator_next(iter));
pango_attr_iterator_destroy(iter);
}
// Use a thin underline with text color by default.
if (composition->ime_text_spans.empty()) {
composition->ime_text_spans.push_back(
ImeTextSpan(ImeTextSpan::Type::kComposition, 0, length,
ImeTextSpan::Thickness::kThin,
ImeTextSpan::UnderlineStyle::kSolid, SK_ColorTRANSPARENT));
}
}
} // namespace ui
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