draw2dgl/gc.go
func (gc *GraphicContext) recalc() {
	gc.Current.Scale = gc.Current.FontSize * float64(gc.DPI) * (64.0 / 72.0)
}
func (gc *GraphicContext) recalc() {
	gc.Current.Scale = gc.Current.FontSize * float64(gc.DPI) * (64.0 / 72.0)
}
// recalc recalculates scale and bounds values from the font size, screen
// resolution and font metrics, and invalidates the glyph cache.