Fileman copy/paste support (#970)

* Add copy/paste UI instead of file save

firmware/common/ui_widget.cpp

@@ -1535,6 +1535,137 @@ bool OptionsField::on_touch(const TouchEvent event) {
 	return true;
 }
 
+/* TextField ***********************************************************/
+
+TextField::TextField(
+	std::string& str,
+	size_t max_length,
+	Point position,
+	uint32_t length
+) : Widget{ { position, { 8 * static_cast<int>(length), 16 } } },
+	text_{ str },
+	max_length_{ std::max<size_t>(max_length, str.length()) },
+	char_count_{ std::max<uint32_t>(length, 1) },
+	cursor_pos_{ text_.length() },
+	insert_mode_{ true }
+{
+	set_focusable(true);
+}
+
+const std::string& TextField::value() const {
+	return text_;
+}
+
+void TextField::set_cursor(uint32_t pos) {
+	cursor_pos_ = std::min<size_t>(pos, text_.length());
+	set_dirty();
+}
+
+void TextField::set_insert_mode() {
+	insert_mode_ = true;
+}
+
+void TextField::set_overwrite_mode() {
+	insert_mode_ = false;
+}
+
+void TextField::char_add(char c) {
+	// Don't add if inserting and at max_length and
+	// don't overwrite if past the end of the text.
+	if ((text_.length() >= max_length_ && insert_mode_) ||
+		(cursor_pos_ >= text_.length() && !insert_mode_))
+		return;
+
+	if (insert_mode_)
+		text_.insert(cursor_pos_, 1, c);
+	else
+		text_[cursor_pos_] = c;
+
+	cursor_pos_++;
+	set_dirty();
+}
+
+void TextField::char_delete() {
+	if (cursor_pos_ == 0)
+		return;
+
+	cursor_pos_--;
+	text_.erase(cursor_pos_, 1);
+	set_dirty();
+}
+
+void TextField::paint(Painter& painter) {
+	constexpr int char_width = 8;
+
+	auto rect = screen_rect();
+	auto text_style = has_focus() ? style().invert() : style();
+	auto offset = 0;
+
+	// Does the string need to be shifted?
+	if (cursor_pos_ >= char_count_)
+		offset = cursor_pos_ - char_count_ + 1;
+
+	// Clear the control.
+	painter.fill_rectangle(rect, text_style.background);
+
+	// Draw the text starting at the offset.
+	for (uint32_t i = 0; i < char_count_ && i + offset < text_.length(); i++) {
+		painter.draw_char(
+			{ rect.location().x() + (static_cast<int>(i) * char_width), rect.location().y() },
+			text_style,
+			text_[i + offset]
+		);
+	}
+
+	// Determine cursor position on screen (either the cursor position or the last char).
+	int32_t cursor_x = char_width * (offset > 0 ? char_count_ - 1 : cursor_pos_);
+	Point cursor_point{ screen_pos().x() + cursor_x, screen_pos().y() };
+	auto cursor_style = text_style.invert();
+
+	// Invert the cursor character when in overwrite mode.
+	if (!insert_mode_ && (cursor_pos_) < text_.length())
+		painter.draw_char(cursor_point, cursor_style, text_[cursor_pos_]);
+
+	// Draw the cursor.
+	Rect cursor_box{ cursor_point, { char_width, 16 } };
+	painter.draw_rectangle(cursor_box, cursor_style.background);
+}
+
+bool TextField::on_key(const KeyEvent key) {
+	if (key == KeyEvent::Left && cursor_pos_ > 0)
+		cursor_pos_--;
+	else if (key == KeyEvent::Right && cursor_pos_ < text_.length())
+		cursor_pos_++;
+	else if (key == KeyEvent::Select)
+		insert_mode_ = !insert_mode_;
+	else
+		return false;
+
+	set_dirty();
+	return true;
+}
+
+bool TextField::on_encoder(const EncoderEvent delta) {
+	int32_t new_pos = cursor_pos_ + delta;
+
+	// Let the encoder wrap around the ends of the text.
+	if (new_pos < 0)
+		new_pos = text_.length();
+	else if (static_cast<size_t>(new_pos) > text_.length())
+		new_pos = 0;
+
+	set_cursor(new_pos);
+	return true;
+}
+
+bool TextField::on_touch(const TouchEvent event) {
+	if (event.type == TouchEvent::Type::Start)
+		focus();
+
+	set_dirty();
+	return true;
+}
+
 /* NumberField ***********************************************************/
 
 NumberField::NumberField(