void Drawing::render(DrawingContext &ct, Geom::IntRect const &area, unsigned flags) { if (_root) { _root->render(ct, area, flags); } if (colorMode() == COLORMODE_GRAYSCALE) { // apply grayscale filter on top of everything cairo_surface_t *input = ct.rawTarget(); cairo_surface_t *out = ink_cairo_surface_create_identical(input); ink_cairo_surface_filter(input, out, _grayscale_colormatrix); Geom::Point origin = ct.targetLogicalBounds().min(); ct.setSource(out, origin[Geom::X], origin[Geom::Y]); ct.setOperator(CAIRO_OPERATOR_SOURCE); ct.paint(); ct.setOperator(CAIRO_OPERATOR_OVER); cairo_surface_destroy(out); } }