浏览器上字体实际显示位置与FairyGUI中字体位置不一致，位置会偏上

具体表现如图所示。
CCC在不设置ttf字体的情况下默认使用Arial字体，所以这里文本字体设置成Arial消除字体的影响。
问题产生的原因在于CCC的字体渲染是通过canvas画布画出来的，先预留一行行高的空间，然后顶着画一行字体，再预留一行再画一行

_updateTexture: function() {

        _context.clearRect(0, 0, _canvas.width, _canvas.height);

        _context.font = _fontDesc;

        var startPosition = this._calculateFillTextStartPosition();

        var lineHeight = this._getLineHeight();

        _context.lineJoin = "round";

        _context.fillStyle = "rgba(" + _color.r + ", " + _color.g + ", " + _color.b + ", " + _color.a / 255 + ")";

        var underlineStartPosition = void 0;

        for (var i = 0; i < _splitedStrings.length; ++i) {

          if (_isOutlined) {

            var strokeColor = _outlineColor || WHITE;

            _context.strokeStyle = "rgba(" + strokeColor.r + ", " + strokeColor.g + ", " + strokeColor.b + ", " + strokeColor.a / 255 + ")";

            _context.lineWidth = 2 * _outlineWidth;

            _context.strokeText(_splitedStrings[i], startPosition.x, startPosition.y + i * lineHeight);

          }

          //这里以lineHeight来定位画笔的起始位置

          _context.fillText(_splitedStrings[i], startPosition.x, startPosition.y + i * lineHeight);

          if (_isUnderline) {

            underlineStartPosition = this._calculateUnderlineStartPosition();

            _context.save();

            _context.beginPath();

            _context.lineWidth = _fontSize / 8;

            _context.strokeStyle = "rgba(" + _color.r + ", " + _color.g + ", " + _color.b + ", " + _color.a / 255 + ")";

            _context.moveTo(underlineStartPosition.x, underlineStartPosition.y + i * lineHeight - 1);

            _context.lineTo(underlineStartPosition.x + _canvas.width, underlineStartPosition.y + i * lineHeight - 1);

            _context.stroke();

            _context.restore();

          }

        }

        _texture.handleLoadedTexture();

      }[/i][/i]

[i]fgui给ccc label设定的行高是[/i]

[i][i]this._label.lineHeight = fontSize + this._leading;[/i][/i]

[i]然后在FairyGUI编辑器里面,文本显示时是有默认的上下留白的,即使留白设置为0也有，导致编辑器显示和浏览器显示不一致
这个问题有没有什么解决方案啊[/i]