func (gc *GraphicContext) Translate(tx, ty float64) {
	gc.StackGraphicContext.Translate(tx, ty)
	gc.pdf.TransformTranslate(tx, ty)
}
func (gc *GraphicContext) Translate(tx, ty float64) {
	gc.StackGraphicContext.Translate(tx, ty)
	gc.pdf.TransformTranslate(tx, ty)
}
// Translate moves the following text, drawings and images
// horizontally and vertically by the amounts specified by tx and ty.
// This must be placed between gc.Save() and gc.Restore(), otherwise
// the pdf is invalid.