module Magick::RVG::Stretchable

def add_viewbox_primitives(width, height, gc)
    @vbx_width  ||= width
    @vbx_height ||= height
    @vbx_x ||= 0.0
    @vbx_y ||= 0.0
    if @align == 'none'
        sx, sy = set_viewbox_none(width, height)
        tx, ty = 0, 0
    elsif @meet_or_slice == 'meet'
        sx, sy = set_viewbox_meet(width, height)
        tx, ty = align_to_viewport(width, height, sx, sy)
    else
        sx, sy = set_viewbox_slice(width, height)
        tx, ty = align_to_viewport(width, height, sx, sy)
    end
    # Establish clipping path around the current viewport
    name = __id__.to_s
    gc.define_clip_path(name) do
        gc.path("M0,0 l#{width},0 l0,#{height} l-#{width},0 l0,-#{height}z")
    end
    gc.clip_path(name)
    # Add a non-scaled translation if meet or slice
    gc.translate(tx, ty) if tx.abs > 1.0e-10 || ty.abs > 1.0e-10
    # Scale viewbox as necessary
    gc.scale(sx, sy) if sx != 1.0 || sy != 1.0
    # Add a scaled translation if non-0 origin
    gc.translate(-@vbx_x, -@vbx_y) if @vbx_x.abs != 0.0 || @vbx_y.abs != 0
end