Method deleteBackward

core/2d/TextFieldTTF.cpp:315–379

}

void TextFieldTTF::deleteBackward(size_t numChars)
{
    size_t len = _inputText.length();
    if (!len)
    {
        // there is no string
        return;
    }

    // Length of characters to delete is based on input editor, but the actual
    // length of the displayed text may be less
    numChars = std::min(numChars, len);

    size_t totalDeleteLen = 0;
    for (auto i = 0; i < numChars; ++i)
    {
        // get the delete byte number
        size_t deleteLen = 1;  // default, erase 1 byte

        // Calculate the actual number of bytes to delete for a specific character
        while (0x80 == (0xC0 & _inputText.at(len - totalDeleteLen - deleteLen)))
        {
            ++deleteLen;
        }
        totalDeleteLen += deleteLen;
    }

    if (_delegate &&
        _delegate->onTextFieldDeleteBackward(this, _inputText.c_str() + len - totalDeleteLen, static_cast<int>(totalDeleteLen)))
    {
        // delegate doesn't want to delete backwards
        return;
    }

    // if all text deleted, show placeholder string
    if (len <= totalDeleteLen)
    {
        _inputText = "";
        _charCount = 0;
        setCursorPosition(0);
        setString(_inputText);
        return;
    }

    // set new input text
    if (_cursorEnabled)
    {
        if (_cursorPosition)
        {
            setCursorPosition(_cursorPosition - 1);

            std::string sText(_inputText);
            auto nb = StringUtils::eraseUTF8CharAt(sText, _cursorPosition);
            if (nb)
                --_charCount;

            setString(sText);
        }