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LibWeb: Skip over grapheme clusters on left/right arrow key presses

Currently, if you use the left/right arrow keys to move over a multi-
code point glyph, we will move through that glyph one code point at a
time. This means you can "pause" your movement in the middle of a glyph
and delete a subsection of a grapheme cluster. This now moves the cursor
across the entire cluster.
This commit is contained in:
Timothy Flynn 2023-03-01 07:20:36 -05:00 committed by Linus Groh
parent 2c4acba883
commit 4734214ac1

View file

@ -6,6 +6,7 @@
*/
#include <AK/Utf8View.h>
#include <LibUnicode/Segmentation.h>
#include <LibWeb/DOM/Node.h>
#include <LibWeb/DOM/Position.h>
#include <LibWeb/DOM/Text.h>
@ -33,38 +34,30 @@ bool Position::increment_offset()
auto& node = verify_cast<DOM::Text>(*m_node);
auto text = Utf8View(node.data());
for (auto iterator = text.begin(); !iterator.done(); ++iterator) {
if (text.byte_offset_of(iterator) >= m_offset) {
// NOTE: If the current offset is inside a multi-byte code point, it will be moved to the start of the next code point.
m_offset = text.byte_offset_of(++iterator);
return true;
}
if (auto offset = Unicode::next_grapheme_segmentation_boundary(text, m_offset); offset.has_value()) {
m_offset = *offset;
return true;
}
// NOTE: Already at end of current node.
return false;
}
bool Position::decrement_offset()
{
if (m_offset == 0 || !is<DOM::Text>(*m_node))
if (!is<DOM::Text>(*m_node))
return false;
auto& node = verify_cast<DOM::Text>(*m_node);
auto text = Utf8View(node.data());
size_t last_smaller_offset = 0;
for (auto iterator = text.begin(); !iterator.done(); ++iterator) {
auto byte_offset = text.byte_offset_of(iterator);
if (byte_offset >= m_offset) {
break;
}
last_smaller_offset = text.byte_offset_of(iterator);
if (auto offset = Unicode::previous_grapheme_segmentation_boundary(text, m_offset); offset.has_value()) {
m_offset = *offset;
return true;
}
// NOTE: If the current offset is inside a multi-byte code point, it will be moved to the start of that code point.
m_offset = last_smaller_offset;
return true;
// NOTE: Already at beginning of current node.
return false;
}
bool Position::offset_is_at_end_of_node() const