GlyphAsImage export png cropped descent

I want to export png with this method, how do I set it (layerSize and prset) up if I want to export characters that aren’t cropped descent value?

GlyphAsImage.pngDataWithLayer_origSize_settings_(layer, layerSize, preset)

The Glyph as Image filter was written to export icons and those are drawn above the baseline. I’ll have a look if I can fix that. Until then, you could try DrawBot. It is much more flexible.