Adding upstream version 1.2.2.upstream/1.2.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1966 insertions, 0 deletions

diff --git a/src/gradient-chemistry.cpp b/src/gradient-chemistry.cpp
new file mode 100644
index 0000000..680b097
--- /dev/null
+++ b/src/gradient-chemistry.cpp
@@ -0,0 +1,1966 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Various utility methods for gradients
+ *
+ * Authors:
+ *   Lauris Kaplinski <lauris@kaplinski.com>
+ *   bulia byak
+ *   Johan Engelen <j.b.c.engelen@ewi.utwente.nl>
+ *   Jon A. Cruz <jon@joncruz.org>
+ *   Abhishek Sharma
+ *   Tavmjong Bah <tavmjong@free.fr>
+ *
+ * Copyright (C) 2012 Tavmjong Bah
+ * Copyright (C) 2010 Authors
+ * Copyright (C) 2007 Johan Engelen
+ * Copyright (C) 2001-2005 authors
+ * Copyright (C) 2001 Ximian, Inc.
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include <glibmm/i18n.h>
+
+#include <2geom/transforms.h>
+#include <2geom/bezier-curve.h>
+#include <2geom/crossing.h>
+#include <2geom/line.h>
+
+#include "desktop-style.h"
+#include "desktop.h"
+#include "document-undo.h"
+#include "gradient-chemistry.h"
+#include "gradient-drag.h"
+#include "selection.h"
+
+#include "object/sp-defs.h"
+#include "object/sp-gradient-reference.h"
+#include "object/sp-linear-gradient.h"
+#include "object/sp-mesh-gradient.h"
+#include "object/sp-radial-gradient.h"
+#include "object/sp-stop.h"
+#include "object/sp-text.h"
+#include "object/sp-tspan.h"
+#include "object/sp-root.h"
+#include "style.h"
+
+#include "svg/svg.h"
+#include "svg/svg-color.h"
+#include "svg/css-ostringstream.h"
+
+#include "ui/icon-names.h"
+#include "ui/tools/tool-base.h"
+#include "ui/widget/gradient-vector-selector.h"
+
+#define noSP_GR_VERBOSE
+
+using Inkscape::DocumentUndo;
+
+namespace {
+
+Inkscape::PaintTarget paintTargetItems[] = {Inkscape::FOR_FILL, Inkscape::FOR_STROKE};
+
+std::vector<Inkscape::PaintTarget> vectorOfPaintTargets(paintTargetItems, paintTargetItems + (sizeof(paintTargetItems) / sizeof(paintTargetItems[0])));
+
+} // namespace
+
+namespace Inkscape {
+
+std::vector<PaintTarget> const &allPaintTargets()
+{
+    return vectorOfPaintTargets;
+}
+
+} // namespace Inkscape
+
+// Terminology:
+//
+// "vector" is a gradient that has stops but not position coords. It can be referenced by one or
+// more privates. Objects should not refer to it directly. It has no radial/linear distinction.
+//
+// "array" is a gradient that has mesh rows and patches. It may or may not have "x" and "y" attributes.
+// An array does have spacial information so it cannot be normalized like a "vector".
+//
+// "shared" is either a "vector" or "array" that is shared between multiple objects.
+//
+// "private" is a gradient that is not shared. A private linear or radial gradient has no stops but
+// has position coords (e.g. center, radius etc for a radial); it references a "vector" for the
+// actual colors. A mesh may or may not reference an array. Each private is only used by one object.
+
+static void sp_gradient_repr_set_link(Inkscape::XML::Node *repr, SPGradient *gr);
+
+SPGradient *sp_gradient_ensure_vector_normalized(SPGradient *gr)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_gradient_ensure_vector_normalized(%p)", gr);
+#endif
+    g_return_val_if_fail(gr != nullptr, NULL);
+    g_return_val_if_fail(SP_IS_GRADIENT(gr), NULL);
+    g_return_val_if_fail(!SP_IS_MESHGRADIENT(gr), NULL);
+
+    /* If we are already normalized vector, just return */
+    if (gr->state == SP_GRADIENT_STATE_VECTOR) return gr;
+    /* Fail, if we have wrong state set */
+    if (gr->state != SP_GRADIENT_STATE_UNKNOWN) {
+        g_warning("file %s: line %d: Cannot normalize private gradient to vector (%s)", __FILE__, __LINE__, gr->getId());
+        return nullptr;
+    }
+
+    /* First make sure we have vector directly defined (i.e. gr has its own stops) */
+    if ( !gr->hasStops() ) {
+        /* We do not have stops ourselves, so flatten stops as well */
+        gr->ensureVector();
+        g_assert(gr->vector.built);
+        // this adds stops from gr->vector as children to gr
+        gr->repr_write_vector ();
+    }
+
+    /* If gr hrefs some other gradient, remove the href */
+    if (gr->ref){
+        if (gr->ref->getObject()) {
+            // We are hrefing someone, so require flattening
+            gr->updateRepr(SP_OBJECT_WRITE_EXT | SP_OBJECT_WRITE_ALL);
+            sp_gradient_repr_set_link(gr->getRepr(), nullptr);
+        }
+    }
+
+    /* Everything is OK, set state flag */
+    gr->state = SP_GRADIENT_STATE_VECTOR;
+    return gr;
+}
+
+/**
+ * Creates new private gradient for the given shared gradient.
+ */
+
+static SPGradient *sp_gradient_get_private_normalized(SPDocument *document, SPGradient *shared, SPGradientType type)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_gradient_get_private_normalized(%p, %p, %d)", document, shared, type);
+#endif
+
+    g_return_val_if_fail(document != nullptr, NULL);
+    g_return_val_if_fail(shared != nullptr, NULL);
+    g_return_val_if_fail(SP_IS_GRADIENT(shared), NULL);
+    g_return_val_if_fail(shared->hasStops() || shared->hasPatches(), NULL);
+
+    SPDefs *defs = document->getDefs();
+
+    Inkscape::XML::Document *xml_doc = document->getReprDoc();
+    // create a new private gradient of the requested type
+    Inkscape::XML::Node *repr;
+    if (type == SP_GRADIENT_TYPE_LINEAR) {
+        repr = xml_doc->createElement("svg:linearGradient");
+    } else if(type == SP_GRADIENT_TYPE_RADIAL) {
+        repr = xml_doc->createElement("svg:radialGradient");
+    } else {
+        repr = xml_doc->createElement("svg:meshgradient");
+    }
+
+    // make auto collection optional
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    if (prefs->getBool("/option/gradient/auto_collect", true)) {
+        repr->setAttribute("inkscape:collect", "always");
+    } else {
+        repr->setAttribute("inkscape:collect", "never");
+    }
+
+    // link to shared
+    sp_gradient_repr_set_link(repr, shared);
+
+    /* Append the new private gradient to defs */
+    defs->getRepr()->appendChild(repr);
+    Inkscape::GC::release(repr);
+
+    // get corresponding object
+    SPGradient *gr = static_cast<SPGradient *>(document->getObjectByRepr(repr));
+    g_assert(gr != nullptr);
+    g_assert(SP_IS_GRADIENT(gr));
+
+    return gr;
+}
+
+/**
+Count how many times gr is used by the styles of o and its descendants
+*/
+static guint count_gradient_hrefs(SPObject *o, SPGradient *gr)
+{
+    if (!o)
+        return 1;
+
+    guint i = 0;
+
+    SPStyle *style = o->style;
+    if (style
+        && style->fill.isPaintserver()
+        && SP_IS_GRADIENT(SP_STYLE_FILL_SERVER(style))
+        && SP_GRADIENT(SP_STYLE_FILL_SERVER(style)) == gr)
+    {
+        i ++;
+    }
+    if (style
+        && style->stroke.isPaintserver()
+        && SP_IS_GRADIENT(SP_STYLE_STROKE_SERVER(style))
+        && SP_GRADIENT(SP_STYLE_STROKE_SERVER(style)) == gr)
+    {
+        i ++;
+    }
+
+    for (auto& child: o->children) {
+        i += count_gradient_hrefs(&child, gr);
+    }
+
+    return i;
+}
+
+
+/**
+ * If gr has other users, create a new shared; also check if gr links to shared, relink if not
+ */
+static SPGradient *sp_gradient_fork_private_if_necessary(SPGradient *gr, SPGradient *shared,
+                                                         SPGradientType type, SPObject *o)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_gradient_fork_private_if_necessary(%p, %p, %d, %p)", gr, shared, type, o);
+#endif
+    g_return_val_if_fail(gr != nullptr, NULL);
+    g_return_val_if_fail(SP_IS_GRADIENT(gr), NULL);
+
+    // Orphaned gradient, no shared with stops or patches at the end of the line; this used to be
+    // an assert
+    if ( !shared || !(shared->hasStops() || shared->hasPatches()) ) {
+        std::cerr << "sp_gradient_fork_private_if_necessary: Orphaned gradient" << std::endl;
+        return (gr);
+    }
+
+    // user is the object that uses this gradient; normally it's item but for tspans, we
+    // check its ancestor text so that tspans don't get different gradients from their
+    // texts.
+    SPObject *user = o;
+    while (SP_IS_TSPAN(user)) {
+        user = user->parent;
+    }
+
+    // Check the number of uses of the gradient within this object;
+    // if we are private and there are no other users,
+    if (!shared->isSwatch() && (gr->hrefcount <= count_gradient_hrefs(user, gr))) {
+        // check shared
+        if ( gr != shared && gr->ref->getObject() != shared ) {
+            /* our href is not the shared, and shared is different from gr; relink */
+            sp_gradient_repr_set_link(gr->getRepr(), shared);
+        }
+        return gr;
+    }
+
+    SPDocument *doc = gr->document;
+    SPObject *defs = doc->getDefs();
+
+    if ((gr->hasStops()) ||
+        (gr->hasPatches()) ||
+        (gr->state != SP_GRADIENT_STATE_UNKNOWN) ||
+        (gr->parent != defs) ||
+        (gr->hrefcount > 1)) {
+
+        // we have to clone a fresh new private gradient for the given shared
+
+        // create an empty one
+        SPGradient *gr_new = sp_gradient_get_private_normalized(doc, shared, type);
+
+        // copy all the attributes to it
+        Inkscape::XML::Node *repr_new = gr_new->getRepr();
+        Inkscape::XML::Node *repr = gr->getRepr();
+        repr_new->setAttribute("gradientUnits", repr->attribute("gradientUnits"));
+        repr_new->setAttribute("gradientTransform", repr->attribute("gradientTransform"));
+        if (SP_IS_RADIALGRADIENT(gr)) {
+            repr_new->setAttribute("cx", repr->attribute("cx"));
+            repr_new->setAttribute("cy", repr->attribute("cy"));
+            repr_new->setAttribute("fx", repr->attribute("fx"));
+            repr_new->setAttribute("fy", repr->attribute("fy"));
+            repr_new->setAttribute("r",  repr->attribute("r" ));
+            repr_new->setAttribute("fr", repr->attribute("fr"));
+            repr_new->setAttribute("spreadMethod", repr->attribute("spreadMethod"));
+        } else if (SP_IS_LINEARGRADIENT(gr)) {
+            repr_new->setAttribute("x1", repr->attribute("x1"));
+            repr_new->setAttribute("y1", repr->attribute("y1"));
+            repr_new->setAttribute("x2", repr->attribute("x2"));
+            repr_new->setAttribute("y2", repr->attribute("y2"));
+            repr_new->setAttribute("spreadMethod", repr->attribute("spreadMethod"));
+        } else { // Mesh
+            repr_new->setAttribute("x", repr->attribute("x"));
+            repr_new->setAttribute("y", repr->attribute("y"));
+            repr_new->setAttribute("type", repr->attribute("type"));
+
+            // We probably want a completely separate mesh gradient so
+            // copy the children and unset the link to the shared.
+            for ( Inkscape::XML::Node *child = repr->firstChild() ; child ; child = child->next() ) {
+                Inkscape::XML::Node *copy = child->duplicate(doc->getReprDoc());
+                repr_new->appendChild( copy );
+                Inkscape::GC::release( copy );
+            }
+            sp_gradient_repr_set_link(repr_new, nullptr);
+        }
+        return gr_new;
+    } else {
+        return gr;
+    }
+}
+
+SPGradient *sp_gradient_fork_vector_if_necessary(SPGradient *gr)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_gradient_fork_vector_if_necessary(%p)", gr);
+#endif
+    // Some people actually prefer their gradient vectors to be shared...
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    if (!prefs->getBool("/options/forkgradientvectors/value", true))
+        return gr;
+
+    if (gr->hrefcount > 1) {
+        SPDocument *doc = gr->document;
+        Inkscape::XML::Document *xml_doc = doc->getReprDoc();
+
+        Inkscape::XML::Node *repr = gr->getRepr()->duplicate(xml_doc);
+        doc->getDefs()->getRepr()->addChild(repr, nullptr);
+        SPGradient *gr_new = static_cast<SPGradient *>(doc->getObjectByRepr(repr));
+        gr_new = sp_gradient_ensure_vector_normalized (gr_new);
+        Inkscape::GC::release(repr);
+        return gr_new;
+    }
+    return gr;
+}
+
+/**
+ *  Obtain the vector from the gradient. A forked vector will be created and linked to this gradient if another gradient uses it.
+ */
+SPGradient *sp_gradient_get_forked_vector_if_necessary(SPGradient *gradient, bool force_vector)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_gradient_get_forked_vector_if_necessary(%p, %d)", gradient, force_vector);
+#endif
+    SPGradient *vector = gradient->getVector(force_vector);
+    vector = sp_gradient_fork_vector_if_necessary (vector);
+    if ( gradient != vector && gradient->ref->getObject() != vector ) {
+        sp_gradient_repr_set_link(gradient->getRepr(), vector);
+    }
+    return vector;
+}
+
+
+/**
+ * Convert an item's gradient to userspace _without_ preserving coords, setting them to defaults
+ * instead. No forking or reapplying is done because this is only called for newly created privates.
+ * @return The new gradient.
+ */
+SPGradient *sp_gradient_reset_to_userspace(SPGradient *gr, SPItem *item)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_gradient_reset_to_userspace(%p, %p)", gr, item);
+#endif
+    Inkscape::XML::Node *repr = gr->getRepr();
+
+    // calculate the bbox of the item
+    item->document->ensureUpToDate();
+    Geom::OptRect bbox = item->visualBounds(); // we need "true" bbox without item_i2d_affine
+
+    if (!bbox)
+        return gr;
+
+    Geom::Coord const width = bbox->dimensions()[Geom::X];
+    Geom::Coord const height = bbox->dimensions()[Geom::Y];
+
+    Geom::Point const center = bbox->midpoint();
+
+    if (SP_IS_RADIALGRADIENT(gr)) {
+        repr->setAttributeSvgDouble("cx", center[Geom::X]);
+        repr->setAttributeSvgDouble("cy", center[Geom::Y]);
+        repr->setAttributeSvgDouble("fx", center[Geom::X]);
+        repr->setAttributeSvgDouble("fy", center[Geom::Y]);
+        repr->setAttributeSvgDouble("r", width/2);
+
+        // we want it to be elliptic, not circular
+        Geom::Affine squeeze = Geom::Translate (-center) *
+            Geom::Scale(1, height/width) *
+            Geom::Translate (center);
+
+        gr->gradientTransform = squeeze;
+        gr->setAttributeOrRemoveIfEmpty("gradientTransform", sp_svg_transform_write(gr->gradientTransform));
+    } else if (SP_IS_LINEARGRADIENT(gr)) {
+
+        // Assume horizontal gradient by default (as per SVG 1.1)
+        Geom::Point pStart = center - Geom::Point(width/2, 0);
+        Geom::Point pEnd = center + Geom::Point(width/2, 0);
+
+        // Get the preferred gradient angle from prefs
+        Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+        double angle = prefs->getDouble("/dialogs/gradienteditor/angle", 0.0);
+
+        if (angle != 0.0) {
+
+            Geom::Line grl(center, Geom::rad_from_deg(angle));
+            Geom::LineSegment bbl1(bbox->corner(0), bbox->corner(1));
+            Geom::LineSegment bbl2(bbox->corner(1), bbox->corner(2));
+            Geom::LineSegment bbl3(bbox->corner(2), bbox->corner(3));
+            Geom::LineSegment bbl4(bbox->corner(3), bbox->corner(0));
+
+            // Find where our gradient line intersects the bounding box.
+            if (!bbl1.isDegenerate() && intersection(bbl1, grl)) {
+                pStart = bbl1.pointAt((*intersection(bbl1, grl)).ta);
+                pEnd = bbl3.pointAt((*intersection(bbl3, grl)).ta);
+                if (intersection(bbl1, grl.ray(grl.angle()))) {
+                    std::swap(pStart, pEnd);
+                }
+            } else if (!bbl2.isDegenerate() && intersection(bbl2, grl)) {
+                pStart = bbl2.pointAt((*intersection(bbl2, grl)).ta);
+                pEnd = bbl4.pointAt((*intersection(bbl4, grl)).ta);
+                if (intersection(bbl2, grl.ray(grl.angle()))) {
+                    std::swap(pStart, pEnd);
+                }
+            }
+
+        }
+
+        repr->setAttributeSvgDouble("x1", pStart[Geom::X]);
+        repr->setAttributeSvgDouble("y1", pStart[Geom::Y]);
+        repr->setAttributeSvgDouble("x2", pEnd[Geom::X]);
+        repr->setAttributeSvgDouble("y2", pEnd[Geom::Y]);
+
+    } else {
+        // Mesh
+        // THIS IS BEING CALLED TWICE WHENEVER A NEW GRADIENT IS CREATED, WRITING HERE CAUSES PROBLEMS
+        // IN SPMeshNodeArray::create()
+        //repr->setAttributeSvgDouble("x", bbox->min()[Geom::X]);
+        //repr->setAttributeSvgDouble("y", bbox->min()[Geom::Y]);
+
+        // We don't create a shared array gradient.
+        SPMeshGradient* mg = SP_MESHGRADIENT( gr );
+        mg->array.create( mg, item, bbox );
+    }
+
+    // set the gradientUnits
+    repr->setAttribute("gradientUnits", "userSpaceOnUse");
+
+    return gr;
+}
+
+/**
+ * Convert an item's gradient to userspace if necessary, also fork it if necessary.
+ * @return The new gradient.
+ */
+SPGradient *sp_gradient_convert_to_userspace(SPGradient *gr, SPItem *item, gchar const *property)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_gradient_convert_to_userspace(%p, %p, \"%s\")", gr, item, property);
+#endif
+    g_return_val_if_fail(SP_IS_GRADIENT(gr), NULL);
+
+    if ( gr && gr->isSolid() ) {
+        return gr;
+    }
+
+    // First, fork it if it is shared
+    if (SP_IS_LINEARGRADIENT(gr)) {
+        gr = sp_gradient_fork_private_if_necessary(gr, gr->getVector(), SP_GRADIENT_TYPE_LINEAR, item);
+    } else if (SP_IS_RADIALGRADIENT(gr)) {
+        gr = sp_gradient_fork_private_if_necessary(gr, gr->getVector(), SP_GRADIENT_TYPE_RADIAL, item);
+    } else {
+        gr = sp_gradient_fork_private_if_necessary(gr, gr->getArray(),  SP_GRADIENT_TYPE_MESH,   item);
+    }
+
+    if (gr->getUnits() == SP_GRADIENT_UNITS_OBJECTBOUNDINGBOX) {
+
+        Inkscape::XML::Node *repr = gr->getRepr();
+
+        // calculate the bbox of the item
+        item->document->ensureUpToDate();
+        Geom::Affine bbox2user;
+        Geom::OptRect bbox = item->visualBounds(); // we need "true" bbox without item_i2d_affine
+        if ( bbox ) {
+            bbox2user = Geom::Affine(bbox->dimensions()[Geom::X], 0,
+                                   0, bbox->dimensions()[Geom::Y],
+                                   bbox->min()[Geom::X], bbox->min()[Geom::Y]);
+        } else {
+            // would be degenerate otherwise
+            bbox2user = Geom::identity();
+        }
+
+        /* skew is the additional transform, defined by the proportions of the item, that we need
+         * to apply to the gradient in order to work around this weird bit from SVG 1.1
+         * (http://www.w3.org/TR/SVG11/pservers.html#LinearGradients):
+         *
+         *   When gradientUnits="objectBoundingBox" and gradientTransform is the identity
+         *   matrix, the stripes of the linear gradient are perpendicular to the gradient
+         *   vector in object bounding box space (i.e., the abstract coordinate system where
+         *   (0,0) is at the top/left of the object bounding box and (1,1) is at the
+         *   bottom/right of the object bounding box). When the object's bounding box is not
+         *   square, the stripes that are conceptually perpendicular to the gradient vector
+         *   within object bounding box space will render non-perpendicular relative to the
+         *   gradient vector in user space due to application of the non-uniform scaling
+         *   transformation from bounding box space to user space.
+         */
+        Geom::Affine skew = bbox2user;
+        double exp = skew.descrim();
+        skew[0] /= exp;
+        skew[1] /= exp;
+        skew[2] /= exp;
+        skew[3] /= exp;
+        skew[4] = 0;
+        skew[5] = 0;
+
+        // apply skew to the gradient
+        gr->gradientTransform = skew;
+        gr->setAttributeOrRemoveIfEmpty("gradientTransform", sp_svg_transform_write(gr->gradientTransform));
+
+        // Matrix to convert points to userspace coords; postmultiply by inverse of skew so
+        // as to cancel it out when it's applied to the gradient during rendering
+        Geom::Affine point_convert = bbox2user * skew.inverse();
+
+        if (SP_IS_LINEARGRADIENT(gr)) {
+            SPLinearGradient *lg = SP_LINEARGRADIENT(gr);
+
+            Geom::Point p1_b = Geom::Point(lg->x1.computed, lg->y1.computed);
+            Geom::Point p2_b = Geom::Point(lg->x2.computed, lg->y2.computed);
+
+            Geom::Point p1_u = p1_b * point_convert;
+            Geom::Point p2_u = p2_b * point_convert;
+
+            repr->setAttributeSvgDouble("x1", p1_u[Geom::X]);
+            repr->setAttributeSvgDouble("y1", p1_u[Geom::Y]);
+            repr->setAttributeSvgDouble("x2", p2_u[Geom::X]);
+            repr->setAttributeSvgDouble("y2", p2_u[Geom::Y]);
+
+            // set the gradientUnits
+            repr->setAttribute("gradientUnits", "userSpaceOnUse");
+
+        } else if (SP_IS_RADIALGRADIENT(gr)) {
+            SPRadialGradient *rg = SP_RADIALGRADIENT(gr);
+
+            // original points in the bbox coords
+            Geom::Point c_b = Geom::Point(rg->cx.computed, rg->cy.computed);
+            Geom::Point f_b = Geom::Point(rg->fx.computed, rg->fy.computed);
+            double r_b = rg->r.computed;
+
+            // converted points in userspace coords
+            Geom::Point c_u = c_b * point_convert;
+            Geom::Point f_u = f_b * point_convert;
+            double r_u = r_b * point_convert.descrim();
+
+            repr->setAttributeSvgDouble("cx", c_u[Geom::X]);
+            repr->setAttributeSvgDouble("cy", c_u[Geom::Y]);
+            repr->setAttributeSvgDouble("fx", f_u[Geom::X]);
+            repr->setAttributeSvgDouble("fy", f_u[Geom::Y]);
+            repr->setAttributeSvgDouble("r", r_u);
+
+            // set the gradientUnits
+            repr->setAttribute("gradientUnits", "userSpaceOnUse");
+
+        } else {
+            std::cerr << "sp_gradient_convert_to_userspace: Conversion of mesh to userspace not implemented" << std::endl;
+        }
+    }
+
+    // apply the gradient to the item (may be necessary if we forked it); not recursive
+    // generally because grouped items will be taken care of later (we're being called
+    // from sp_item_adjust_paint_recursive); however text and all its children should all
+    // refer to one gradient, hence the recursive call for text (because we can't/don't
+    // want to access tspans and set gradients on them separately)
+    if (SP_IS_TEXT(item)) {
+        sp_style_set_property_url(item, property, gr, true);
+    } else {
+        sp_style_set_property_url(item, property, gr, false);
+    }
+
+    return gr;
+}
+
+void sp_gradient_transform_multiply(SPGradient *gradient, Geom::Affine postmul, bool set)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_gradient_transform_multiply(%p, , %d)", gradient, set);
+#endif
+    if (set) {
+        gradient->gradientTransform = postmul;
+    } else {
+        gradient->gradientTransform *= postmul; // fixme: get gradient transform by climbing to hrefs?
+    }
+    gradient->gradientTransform_set = TRUE;
+
+    auto c = sp_svg_transform_write(gradient->gradientTransform);
+    gradient->setAttributeOrRemoveIfEmpty("gradientTransform", c);
+}
+
+SPGradient *getGradient(SPItem *item, Inkscape::PaintTarget fill_or_stroke)
+{
+    SPStyle *style = item->style;
+    SPGradient *gradient = nullptr;
+
+    switch (fill_or_stroke)
+    {
+        case Inkscape::FOR_FILL:
+            if (style && (style->fill.isPaintserver())) {
+                SPPaintServer *server = item->style->getFillPaintServer();
+                if ( SP_IS_GRADIENT(server) ) {
+                    gradient = SP_GRADIENT(server);
+                }
+            }
+            break;
+        case Inkscape::FOR_STROKE:
+            if (style && (style->stroke.isPaintserver())) {
+                SPPaintServer *server = item->style->getStrokePaintServer();
+                if ( SP_IS_GRADIENT(server) ) {
+                    gradient = SP_GRADIENT(server);
+                }
+            }
+            break;
+    }
+
+   return gradient;
+}
+
+SPStop *sp_last_stop(SPGradient *gradient)
+{
+    for (SPStop *stop = gradient->getFirstStop(); stop != nullptr; stop = stop->getNextStop()) {
+        if (stop->getNextStop() == nullptr)
+            return stop;
+    }
+    return nullptr;
+}
+
+std::pair<SPStop*, SPStop*> sp_get_before_after_stops(SPStop* stop) {
+   SPStop* before = nullptr;
+   SPStop* after = nullptr;
+
+   if (stop) {
+      before = stop->getPrevStop();
+      after = stop->getNextStop();
+   }
+
+   return std::make_pair(before, after);
+}
+
+static std::pair<SPStop*, SPStop*> get_before_after_stops(SPGradient* gradient, double offset) {
+   SPStop* before = nullptr;
+   SPStop* after = nullptr;
+
+   SPStop* stop = gradient->getFirstStop();
+   while (stop && stop->offset < offset) {
+      before = stop;
+      stop = stop->getNextStop();
+   }
+
+   if (stop && stop->offset > offset) {
+      after = stop;
+   }
+
+   return std::make_pair(before, after);
+}
+
+guint sp_number_of_stops_before_stop(SPGradient* gradient, SPStop* target) {
+    if (!gradient) return 0;
+
+    guint n = 0;
+    for (SPStop* stop = gradient->getFirstStop(); stop != nullptr; stop = stop->getNextStop()) {
+        if (stop == target) {
+            return n;
+        }
+        n++;
+    }
+    return n;
+} 
+
+
+SPStop* sp_get_nth_stop(SPGradient* gradient, guint index) {
+    SPStop* stop = gradient->getFirstStop();
+    if (!stop) return nullptr;
+
+    for (guint i = 0; i < index; ++i) {
+        if (!stop) return nullptr;
+
+        stop = stop->getNextStop();
+    }
+
+    return stop;
+}
+
+
+SPStop *sp_get_stop_i(SPGradient *gradient, guint stop_i)
+{
+    SPStop *stop = gradient->getFirstStop();
+    if (!stop) {
+        return nullptr;
+    }
+
+    // if this is valid but weird gradient without an offset-zero stop element,
+    // inkscape has created a handle for the start of gradient anyway,
+    // so when it asks for stop N that corresponds to stop element N-1
+    if (stop->offset != 0)
+    {
+        stop_i--;
+    }
+    
+    for (guint i = 0; i < stop_i; i++) {
+        if (!stop) {
+            return nullptr;
+        }
+        stop = stop->getNextStop();
+    }
+
+    return stop;
+}
+
+guint32 average_color(guint32 c1, guint32 c2, gdouble p)
+{
+    guint32 r = static_cast<guint32>(SP_RGBA32_R_U (c1) * (1 - p) + SP_RGBA32_R_U (c2) * p);
+    guint32 g = static_cast<guint32>(SP_RGBA32_G_U (c1) * (1 - p) + SP_RGBA32_G_U (c2) * p);
+    guint32 b = static_cast<guint32>(SP_RGBA32_B_U (c1) * (1 - p) + SP_RGBA32_B_U (c2) * p);
+    guint32 a = static_cast<guint32>(SP_RGBA32_A_U (c1) * (1 - p) + SP_RGBA32_A_U (c2) * p);
+
+    return SP_RGBA32_U_COMPOSE(r, g, b, a);
+}
+
+void sp_repr_set_css_double(Inkscape::XML::Node* node, const char* key, double value) {
+    if (node) {
+        node->setAttributeCssDouble(key, value);
+    }
+}
+
+SPStop *sp_vector_add_stop(SPGradient *vector, SPStop* prev_stop, SPStop* next_stop, gfloat offset)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_vector_add_stop(%p, %p, %p, %f)", vector, prev_stop, next_stop, offset);
+#endif
+    SPStop* newstop = nullptr;
+    // this function doesn't deal with empty gradients
+    if (!prev_stop && !next_stop) return newstop;
+
+    guint cnew = 0; // new color
+    Inkscape::XML::Node *new_stop_repr = nullptr;
+
+    if (!prev_stop || !next_stop) {
+       // inserting stop past next or before previous is supported
+       SPStop* stop = prev_stop ? prev_stop : next_stop;
+       auto repr = stop->getRepr();
+       new_stop_repr = repr->duplicate(vector->getRepr()->document());
+       vector->getRepr()->addChild(new_stop_repr, prev_stop ? repr : nullptr);
+
+       cnew = stop->get_rgba32();
+    }
+    else {
+        auto repr = prev_stop->getRepr();
+        new_stop_repr = repr->duplicate(vector->getRepr()->document());
+        vector->getRepr()->addChild(new_stop_repr, repr);
+
+        guint32 const c1 = prev_stop->get_rgba32();
+        guint32 const c2 = next_stop->get_rgba32();
+        cnew = average_color (c1, c2, (offset - prev_stop->offset) / (next_stop->offset - prev_stop->offset));
+    }
+
+    newstop = reinterpret_cast<SPStop *>(vector->document->getObjectByRepr(new_stop_repr));
+    newstop->offset = offset;
+    newstop->getRepr()->setAttributeCssDouble("offset", (double)offset);
+    Inkscape::CSSOStringStream os;
+    gchar c[64];
+    sp_svg_write_color (c, sizeof(c), cnew);
+    gdouble opacity = (gdouble) SP_RGBA32_A_F (cnew);
+    os << "stop-color:" << c << ";stop-opacity:" << opacity <<";";
+    newstop->setAttributeOrRemoveIfEmpty("style", os.str());
+    Inkscape::GC::release(new_stop_repr);
+
+    return newstop;
+}
+
+// delete gradient's stop
+void sp_gradient_delete_stop(SPGradient* gradient, SPStop* stop) {
+
+    if (!stop || !gradient) {
+        return;
+    }
+
+    if (gradient->getStopCount() > 2) { // 2 is the minimum
+        gradient->getRepr()->removeChild(stop->getRepr());
+        DocumentUndo::done(gradient->document, _("Delete gradient stop"), INKSCAPE_ICON("color-gradient"));
+    }
+}
+
+// make gradient well-formed if needed; from gradient-vector.cpp
+static bool verify_grad(SPGradient* gradient) {
+    bool modified = false;
+    int i = 0;
+    SPStop *stop = nullptr;
+    /* count stops */
+    for (auto& ochild: gradient->children) {
+        if (SP_IS_STOP(&ochild)) {
+            i++;
+            stop = SP_STOP(&ochild);
+        }
+    }
+
+    Inkscape::XML::Document *xml_doc;
+    xml_doc = gradient->getRepr()->document();
+
+    if (i < 1) {
+        Inkscape::CSSOStringStream os;
+        os << "stop-color: #000000;stop-opacity:" << 1.0 << ";";
+
+        Inkscape::XML::Node *child;
+
+        child = xml_doc->createElement("svg:stop");
+        sp_repr_set_css_double(child, "offset", 0.0);
+        child->setAttribute("style", os.str());
+        gradient->getRepr()->addChild(child, nullptr);
+        Inkscape::GC::release(child);
+
+        child = xml_doc->createElement("svg:stop");
+        sp_repr_set_css_double(child, "offset", 1.0);
+        child->setAttribute("style", os.str());
+        gradient->getRepr()->addChild(child, nullptr);
+        Inkscape::GC::release(child);
+        modified = true;
+    }
+    else if (i < 2) {
+        sp_repr_set_css_double(stop->getRepr(), "offset", 0.0);
+        Inkscape::XML::Node *child = stop->getRepr()->duplicate(gradient->getRepr()->document());
+        sp_repr_set_css_double(child, "offset", 1.0);
+        gradient->getRepr()->addChild(child, stop->getRepr());
+        Inkscape::GC::release(child);
+        modified = true;
+    }
+
+    return modified;
+}
+
+// add new stop to a gradient; function lifted from gradient-vector.cpp
+SPStop* sp_gradient_add_stop(SPGradient* gradient, SPStop* current) {
+    if (!gradient || !current) return nullptr;
+
+    if (verify_grad(gradient)) {
+        // gradient has been fixed by adding stop(s), don't insert another one
+        return nullptr;
+    }
+
+    SPStop *stop = current;
+    Inkscape::XML::Node *new_stop_repr = nullptr;
+    SPStop *next = stop->getNextStop();
+
+    if (next == nullptr) {
+        SPStop *prev = stop->getPrevStop();
+        if (prev != nullptr) {
+            next = stop;
+            stop = prev;
+        }
+    }
+
+    if (next != nullptr) {
+        new_stop_repr = stop->getRepr()->duplicate(gradient->getRepr()->document());
+        gradient->getRepr()->addChild(new_stop_repr, stop->getRepr());
+    } else {
+        next = stop;
+        new_stop_repr = stop->getPrevStop()->getRepr()->duplicate(gradient->getRepr()->document());
+        gradient->getRepr()->addChild(new_stop_repr, stop->getPrevStop()->getRepr());
+    }
+
+    SPStop *newstop = reinterpret_cast<SPStop *>(gradient->document->getObjectByRepr(new_stop_repr));
+
+    newstop->offset = (stop->offset + next->offset) * 0.5 ;
+
+    guint32 const c1 = stop->get_rgba32();
+    guint32 const c2 = next->get_rgba32();
+    guint32 cnew = average_color(c1, c2);
+
+    Inkscape::CSSOStringStream os;
+    gchar c[64];
+    sp_svg_write_color(c, sizeof(c), cnew);
+    gdouble opacity = static_cast<gdouble>(SP_RGBA32_A_F(cnew));
+    os << "stop-color:" << c << ";stop-opacity:" << opacity <<";";
+    newstop->setAttribute("style", os.str());
+    sp_repr_set_css_double(newstop->getRepr(), "offset", (double)newstop->offset);
+    Inkscape::GC::release(new_stop_repr);
+    DocumentUndo::done(gradient->document, _("Add gradient stop"), INKSCAPE_ICON("color-gradient"));
+
+    return newstop;
+}
+
+SPStop* sp_gradient_add_stop_at(SPGradient* gradient, double offset) {
+    if (!gradient) return nullptr;
+
+    verify_grad(gradient);
+
+    // find stops before and after given offset
+
+    std::pair<SPStop*, SPStop*> stops = get_before_after_stops(gradient, offset);
+
+    if (stops.first || stops.second) {
+        auto stop = sp_vector_add_stop(gradient, stops.first, stops.second, offset);
+        if (stop) {
+           DocumentUndo::done(gradient->document, _("Add gradient stop"), INKSCAPE_ICON("color-gradient"));
+        }
+        return stop;
+    }
+    else {
+        return nullptr;
+    }
+}
+
+void sp_set_gradient_stop_color(SPDocument* document, SPStop* stop, SPColor color, double opacity) {
+   sp_repr_set_css_double(stop->getRepr(), "offset", stop->offset);
+   Inkscape::CSSOStringStream os;
+   os << "stop-color:" << color.toString() << ";stop-opacity:" << opacity <<";";
+   stop->setAttribute("style", os.str());
+
+   DocumentUndo::done(document, _("Change gradient stop color"), INKSCAPE_ICON("color-gradient"));
+}
+
+SPStop* sp_item_gradient_get_stop(SPItem *item, GrPointType point_type, guint point_i, Inkscape::PaintTarget fill_or_stroke) {
+    SPGradient *gradient = getGradient(item, fill_or_stroke);
+
+    if (!gradient || !SP_IS_GRADIENT(gradient)) {
+        return nullptr;
+    }
+
+    if (SP_IS_LINEARGRADIENT(gradient) || SP_IS_RADIALGRADIENT(gradient) ) {
+
+        SPGradient *vector = gradient->getVector();
+
+        if (!vector) // orphan!
+            return nullptr;
+
+        switch (point_type) {
+            case POINT_LG_BEGIN:
+            case POINT_RG_CENTER:
+            case POINT_RG_FOCUS:
+                return vector->getFirstStop();
+
+            case POINT_LG_END:
+            case POINT_RG_R1:
+            case POINT_RG_R2:
+                return sp_last_stop (vector);
+
+            case POINT_LG_MID:
+            case POINT_RG_MID1:
+            case POINT_RG_MID2:
+                return sp_get_stop_i (vector, point_i);
+
+            default:
+                g_warning( "Bad linear/radial gradient handle type" );
+                break;
+        }
+    }
+    return nullptr;
+}
+
+guint32 sp_item_gradient_stop_query_style(SPItem *item, GrPointType point_type, guint point_i, Inkscape::PaintTarget fill_or_stroke)
+{
+    SPGradient *gradient = getGradient(item, fill_or_stroke);
+
+    if (!gradient || !SP_IS_GRADIENT(gradient)) {
+        return 0;
+    }
+
+    if (SP_IS_LINEARGRADIENT(gradient) || SP_IS_RADIALGRADIENT(gradient) ) {
+
+        SPGradient *vector = gradient->getVector();
+
+        if (!vector) // orphan!
+            return 0; // what else to do?
+
+        switch (point_type) {
+            case POINT_LG_BEGIN:
+            case POINT_RG_CENTER:
+            case POINT_RG_FOCUS:
+            {
+                SPStop *first = vector->getFirstStop();
+                if (first) {
+                    return first->get_rgba32();
+                }
+            }
+            break;
+
+            case POINT_LG_END:
+            case POINT_RG_R1:
+            case POINT_RG_R2:
+            {
+                SPStop *last = sp_last_stop (vector);
+                if (last) {
+                    return last->get_rgba32();
+                }
+            }
+            break;
+
+            case POINT_LG_MID:
+            case POINT_RG_MID1:
+            case POINT_RG_MID2:
+            {
+                SPStop *stopi = sp_get_stop_i (vector, point_i);
+                if (stopi) {
+                    return stopi->get_rgba32();
+                }
+            }
+            break;
+
+            default:
+                g_warning( "Bad linear/radial gradient handle type" );
+                break;
+        }
+        return 0;
+    } else if (SP_IS_MESHGRADIENT(gradient)) {
+
+        // Mesh gradient
+        SPMeshGradient *mg = SP_MESHGRADIENT(gradient);
+
+        switch (point_type) {
+            case POINT_MG_CORNER: {
+                if (point_i >= mg->array.corners.size()) {
+                    return 0;
+                }
+                SPMeshNode const* cornerpoint = mg->array.corners[ point_i ];
+
+                if (cornerpoint) {
+                    SPColor color  = cornerpoint->color;
+                    double opacity = cornerpoint->opacity;
+                    return  color.toRGBA32( opacity );
+                } else {
+                    return 0;
+                }
+                break;
+            }
+
+            case POINT_MG_HANDLE:
+            case POINT_MG_TENSOR:
+            {
+                // Do nothing. Handles and tensors don't have color
+                break;
+            }
+
+            default:
+                g_warning( "Bad mesh handle type" );
+        }
+        return 0;
+    }
+
+    return 0;
+}
+
+void sp_item_gradient_stop_set_style(SPItem *item, GrPointType point_type, guint point_i, Inkscape::PaintTarget fill_or_stroke, SPCSSAttr *stop)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_item_gradient_stop_set_style(%p, %d, %d, %d, %p)", item, point_type, point_i, fill_or_stroke, stop);
+#endif
+    SPGradient *gradient = getGradient(item, fill_or_stroke);
+
+    if (!gradient || !SP_IS_GRADIENT(gradient))
+        return;
+
+    if (SP_IS_LINEARGRADIENT(gradient) || SP_IS_RADIALGRADIENT(gradient) ) {
+
+        SPGradient *vector = gradient->getVector();
+
+        if (!vector) // orphan!
+            return;
+
+        vector = sp_gradient_fork_vector_if_necessary (vector);
+        if ( gradient != vector && gradient->ref->getObject() != vector ) {
+            sp_gradient_repr_set_link(gradient->getRepr(), vector);
+        }
+
+        switch (point_type) {
+            case POINT_LG_BEGIN:
+            case POINT_RG_CENTER:
+            case POINT_RG_FOCUS:
+            {
+                SPStop *first = vector->getFirstStop();
+                if (first) {
+                    sp_repr_css_change(first->getRepr(), stop, "style");
+                }
+            }
+            break;
+
+            case POINT_LG_END:
+            case POINT_RG_R1:
+            case POINT_RG_R2:
+            {
+                SPStop *last = sp_last_stop (vector);
+                if (last) {
+                    sp_repr_css_change(last->getRepr(), stop, "style");
+                }
+            }
+            break;
+
+            case POINT_LG_MID:
+            case POINT_RG_MID1:
+            case POINT_RG_MID2:
+            {
+                SPStop *stopi = sp_get_stop_i (vector, point_i);
+                if (stopi) {
+                    sp_repr_css_change(stopi->getRepr(), stop, "style");
+                }
+            }
+            break;
+
+            default:
+                g_warning( "Bad linear/radial gradient handle type" );
+                break;
+        }
+    } else {
+
+        // Mesh gradient
+        SPMeshGradient *mg = SP_MESHGRADIENT(gradient);
+
+        bool changed = false;
+        switch (point_type) {
+            case POINT_MG_CORNER: {
+
+                // Update mesh array (which is not updated automatically when stop is changed?)
+                gchar const* color_str = sp_repr_css_property( stop, "stop-color", nullptr );
+                if( color_str ) {
+                    SPColor color( 0 );
+                    SPIPaint paint;
+                    paint.read( color_str );
+                    if( paint.isColor() ) {
+                        color = paint.value.color;
+                    }
+                    mg->array.corners[ point_i ]->color = color;
+                    changed = true;
+                }
+                gchar const* opacity_str = sp_repr_css_property( stop, "stop-opacity", nullptr );
+                if( opacity_str ) {
+                    std::stringstream os( opacity_str );
+                    double opacity = 1.0;
+                    os >> opacity;
+                    mg->array.corners[ point_i ]->opacity = opacity;
+                    changed = true;
+                }
+                // Update stop
+                if( changed ) {
+                    SPStop *stopi = mg->array.corners[ point_i ]->stop;
+                    if (stopi) {
+                        sp_repr_css_change(stopi->getRepr(), stop, "style");
+                    } else {
+                        std::cerr << "sp_item_gradient_stop_set_style: null stopi" << std::endl;
+                    }
+                }
+                break;
+            }
+
+            case POINT_MG_HANDLE:
+            case POINT_MG_TENSOR:
+            {
+                // Do nothing. Handles and tensors don't have colors.
+                break;
+            }
+
+            default:
+                g_warning( "Bad mesh handle type" );
+        }
+    }
+}
+
+void sp_item_gradient_reverse_vector(SPItem *item, Inkscape::PaintTarget fill_or_stroke)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_item_gradient_reverse_vector(%p, %d)", item, fill_or_stroke);
+#endif
+    SPGradient *gradient = getGradient(item, fill_or_stroke);
+    sp_gradient_reverse_vector(gradient);
+}
+
+void sp_gradient_reverse_vector(SPGradient* gradient) {
+    if (!gradient || !SP_IS_GRADIENT(gradient))
+        return;
+
+    SPGradient *vector = gradient->getVector();
+    if (!vector) // orphan!
+        return;
+
+    vector = sp_gradient_fork_vector_if_necessary (vector);
+    if ( gradient != vector && gradient->ref->getObject() != vector ) {
+        sp_gradient_repr_set_link(gradient->getRepr(), vector);
+    }
+
+    std::vector<SPObject *> child_objects;
+    std::vector<Inkscape::XML::Node *>child_reprs;
+    std::vector<double> offsets;
+    double offset;
+    for (auto& child: vector->children) {
+        child_reprs.push_back(child.getRepr());
+        child_objects.push_back(&child);
+        offset = child.getRepr()->getAttributeDouble("offset", 0);
+        offsets.push_back(offset);
+    }
+
+    std::vector<Inkscape::XML::Node *> child_copies;
+    for (auto repr:child_reprs) {
+        Inkscape::XML::Document *xml_doc = vector->getRepr()->document();
+        child_copies.push_back(repr->duplicate(xml_doc));
+    }
+
+
+    for (auto i:child_objects) {
+        i->deleteObject();
+    }
+
+    std::vector<double>::reverse_iterator o_it = offsets.rbegin();
+    for (auto c_it = child_copies.rbegin(); c_it != child_copies.rend(); ++c_it, ++o_it) {
+        vector->appendChildRepr(*c_it);
+        (*c_it)->setAttributeSvgDouble("offset", 1 - *o_it);
+        Inkscape::GC::release(*c_it);
+    }
+}
+
+void sp_item_gradient_invert_vector_color(SPItem *item, Inkscape::PaintTarget fill_or_stroke)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_item_gradient_invert_vector_color(%p, %d)", item, fill_or_stroke);
+#endif
+    SPGradient *gradient = getGradient(item, fill_or_stroke);
+    if (!gradient || !SP_IS_GRADIENT(gradient))
+        return;
+
+    SPGradient *vector = gradient->getVector();
+    if (!vector) // orphan!
+        return;
+
+    vector = sp_gradient_fork_vector_if_necessary (vector);
+    if ( gradient != vector && gradient->ref->getObject() != vector ) {
+        sp_gradient_repr_set_link(gradient->getRepr(), vector);
+    }
+
+    for (auto& child: vector->children) {
+        if (SP_IS_STOP(&child)) {
+            guint32 color =  SP_STOP(&child)->get_rgba32();
+            //g_message("Stop color %d", color);
+            gchar c[64];
+            sp_svg_write_color (c, sizeof(c),
+                SP_RGBA32_U_COMPOSE(
+                        (255 - SP_RGBA32_R_U(color)),
+                        (255 - SP_RGBA32_G_U(color)),
+                        (255 - SP_RGBA32_B_U(color)),
+                        SP_RGBA32_A_U(color)
+                )
+            );
+            SPCSSAttr *css = sp_repr_css_attr_new ();
+            sp_repr_css_set_property (css, "stop-color", c);
+            sp_repr_css_change(child.getRepr(), css, "style");
+            sp_repr_css_attr_unref (css);
+        }
+    }
+}
+
+// HACK: linear and radial gradients may have first and/or last stops moved from their default positions
+// of 0 and 1 respectively; this is not what gradient tool was built to handle; instead of making extensive
+// changes to try to fix it, this hack just makes sure that midpoint draggers don't move to the true 0/1 limits;
+// with that, code relying on sp_get_stop_i will work correctly
+double midpoint_offset_hack(double offset) {
+    const double EPS = 0.0001;
+
+    if (offset <= 0) {
+        offset = EPS;
+    }
+    else if (offset >= 1) {
+        offset = 1 - EPS;
+    }
+
+    return offset;
+}
+
+/**
+Set the position of point point_type of the gradient applied to item (either fill_or_stroke) to
+p_w (in desktop coordinates). Write_repr if you want the change to become permanent.
+*/
+void sp_item_gradient_set_coords(SPItem *item, GrPointType point_type, guint point_i, Geom::Point p_w, Inkscape::PaintTarget fill_or_stroke, bool write_repr, bool scale)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_item_gradient_set_coords(%p, %d, %d, (%f, %f), ...)", item, point_type, point_i, p_w[Geom::X], p_w[Geom::Y] );
+#endif
+    SPGradient *gradient = getGradient(item, fill_or_stroke);
+
+    if (!gradient || !SP_IS_GRADIENT(gradient))
+        return;
+
+    // Needed only if units are set to SP_GRADIENT_UNITS_OBJECTBOUNDINGBOX
+    gradient = sp_gradient_convert_to_userspace(gradient, item, (fill_or_stroke == Inkscape::FOR_FILL) ? "fill" : "stroke");
+
+    Geom::Affine i2d (item->i2dt_affine ());
+    Geom::Point p = p_w * i2d.inverse();
+    p *= (gradient->gradientTransform).inverse();
+    // now p is in gradient's original coordinates
+
+    Inkscape::XML::Node *repr = gradient->getRepr();
+
+    if (SP_IS_LINEARGRADIENT(gradient)) {
+        SPLinearGradient *lg = SP_LINEARGRADIENT(gradient);
+        switch (point_type) {
+            case POINT_LG_BEGIN:
+                if (scale) {
+                    lg->x2.computed += (lg->x1.computed - p[Geom::X]);
+                    lg->y2.computed += (lg->y1.computed - p[Geom::Y]);
+                }
+                lg->x1.computed = p[Geom::X];
+                lg->y1.computed = p[Geom::Y];
+                if (write_repr) {
+                    if (scale) {
+                        repr->setAttributeSvgDouble("x2", lg->x2.computed);
+                        repr->setAttributeSvgDouble("y2", lg->y2.computed);
+                    }
+                    repr->setAttributeSvgDouble("x1", lg->x1.computed);
+                    repr->setAttributeSvgDouble("y1", lg->y1.computed);
+                } else {
+                    gradient->requestModified(SP_OBJECT_MODIFIED_FLAG);
+                }
+                break;
+            case POINT_LG_END:
+                if (scale) {
+                    lg->x1.computed += (lg->x2.computed - p[Geom::X]);
+                    lg->y1.computed += (lg->y2.computed - p[Geom::Y]);
+                }
+                lg->x2.computed = p[Geom::X];
+                lg->y2.computed = p[Geom::Y];
+                if (write_repr) {
+                    if (scale) {
+                        repr->setAttributeSvgDouble("x1", lg->x1.computed);
+                        repr->setAttributeSvgDouble("y1", lg->y1.computed);
+                    }
+                    repr->setAttributeSvgDouble("x2", lg->x2.computed);
+                    repr->setAttributeSvgDouble("y2", lg->y2.computed);
+                } else {
+                    gradient->requestModified(SP_OBJECT_MODIFIED_FLAG);
+                }
+                break;
+            case POINT_LG_MID:
+            {
+                // using X-coordinates only to determine the offset, assuming p has been snapped to the vector from begin to end.
+                Geom::Point begin(lg->x1.computed, lg->y1.computed);
+                Geom::Point end(lg->x2.computed, lg->y2.computed);
+                double offset = Geom::LineSegment(begin, end).nearestTime(p);
+                offset = midpoint_offset_hack(offset);
+                SPGradient *vector = sp_gradient_get_forked_vector_if_necessary (lg, false);
+                lg->ensureVector();
+                lg->vector.stops.at(point_i).offset = offset;
+                if (SPStop* stopi = sp_get_stop_i(vector, point_i)) {
+                    stopi->offset = offset;
+                    if (write_repr) {
+                        stopi->getRepr()->setAttributeCssDouble("offset", stopi->offset);
+                    } else {
+                        stopi->requestModified(SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_STYLE_MODIFIED_FLAG);
+                    }
+                }
+            }
+            break;
+            default:
+                g_warning( "Bad linear gradient handle type" );
+                break;
+        }
+    } else if (SP_IS_RADIALGRADIENT(gradient)) {
+        SPRadialGradient *rg = SP_RADIALGRADIENT(gradient);
+        Geom::Point c (rg->cx.computed, rg->cy.computed);
+        Geom::Point c_w = c * gradient->gradientTransform * i2d; // now in desktop coords
+        if ((point_type == POINT_RG_R1 || point_type == POINT_RG_R2) && Geom::L2 (p_w - c_w) < 1e-3) {
+            // prevent setting a radius too close to the center
+            return;
+        }
+        Geom::Affine new_transform;
+        bool transform_set = false;
+
+        switch (point_type) {
+            case POINT_RG_CENTER:
+                rg->fx.computed = p[Geom::X] + (rg->fx.computed - rg->cx.computed);
+                rg->fy.computed = p[Geom::Y] + (rg->fy.computed - rg->cy.computed);
+                rg->cx.computed = p[Geom::X];
+                rg->cy.computed = p[Geom::Y];
+                if (write_repr) {
+                    repr->setAttributeSvgDouble("fx", rg->fx.computed);
+                    repr->setAttributeSvgDouble("fy", rg->fy.computed);
+                    repr->setAttributeSvgDouble("cx", rg->cx.computed);
+                    repr->setAttributeSvgDouble("cy", rg->cy.computed);
+                } else {
+                    gradient->requestModified(SP_OBJECT_MODIFIED_FLAG);
+                }
+                break;
+            case POINT_RG_FOCUS:
+                rg->fx.computed = p[Geom::X];
+                rg->fy.computed = p[Geom::Y];
+                if (write_repr) {
+                    repr->setAttributeSvgDouble("fx", rg->fx.computed);
+                    repr->setAttributeSvgDouble("fy", rg->fy.computed);
+                } else {
+                    gradient->requestModified(SP_OBJECT_MODIFIED_FLAG);
+                }
+                break;
+            case POINT_RG_R1:
+            {
+                Geom::Point r1_w = (c + Geom::Point(rg->r.computed, 0)) * gradient->gradientTransform * i2d;
+                double r1_angle = Geom::atan2(r1_w - c_w);
+                double move_angle = Geom::atan2(p_w - c_w) - r1_angle;
+                double move_stretch = Geom::L2(p_w - c_w) / Geom::L2(r1_w - c_w);
+
+                Geom::Affine move = Geom::Affine (Geom::Translate (-c_w)) *
+                    Geom::Affine (Geom::Rotate(-r1_angle)) *
+                    Geom::Affine (Geom::Scale(move_stretch, scale? move_stretch : 1)) *
+                    Geom::Affine (Geom::Rotate(r1_angle)) *
+                    Geom::Affine (Geom::Rotate(move_angle)) *
+                    Geom::Affine (Geom::Translate (c_w));
+
+                new_transform = gradient->gradientTransform * i2d * move * i2d.inverse();
+                transform_set = true;
+
+                break;
+            }
+            case POINT_RG_R2:
+            {
+                Geom::Point r2_w = (c + Geom::Point(0, -rg->r.computed)) * gradient->gradientTransform * i2d;
+                double r2_angle = Geom::atan2(r2_w - c_w);
+                double move_angle = Geom::atan2(p_w - c_w) - r2_angle;
+                double move_stretch = Geom::L2(p_w - c_w) / Geom::L2(r2_w - c_w);
+
+                Geom::Affine move = Geom::Affine (Geom::Translate (-c_w)) *
+                    Geom::Affine (Geom::Rotate(-r2_angle)) *
+                    Geom::Affine (Geom::Scale(move_stretch, scale? move_stretch : 1)) *
+                    Geom::Affine (Geom::Rotate(r2_angle)) *
+                    Geom::Affine (Geom::Rotate(move_angle)) *
+                    Geom::Affine (Geom::Translate (c_w));
+
+                new_transform = gradient->gradientTransform * i2d * move * i2d.inverse();
+                transform_set = true;
+
+                break;
+            }
+            case POINT_RG_MID1:
+            {
+                Geom::Point start = Geom::Point (rg->cx.computed, rg->cy.computed);
+                Geom::Point end   = Geom::Point (rg->cx.computed + rg->r.computed, rg->cy.computed);
+                double offset = Geom::LineSegment(start, end).nearestTime(p);
+                offset = midpoint_offset_hack(offset);
+                SPGradient *vector = sp_gradient_get_forked_vector_if_necessary (rg, false);
+                rg->ensureVector();
+                rg->vector.stops.at(point_i).offset = offset;
+                if (SPStop* stopi = sp_get_stop_i(vector, point_i)) {
+                    stopi->offset = offset;
+                    if (write_repr) {
+                        stopi->getRepr()->setAttributeCssDouble("offset", stopi->offset);
+                    } else {
+                        stopi->requestModified(SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_STYLE_MODIFIED_FLAG);
+                    }
+                }
+                break;
+            }
+            case POINT_RG_MID2:
+            {
+                Geom::Point start = Geom::Point (rg->cx.computed, rg->cy.computed);
+                Geom::Point end   = Geom::Point (rg->cx.computed, rg->cy.computed - rg->r.computed);
+                double offset = Geom::LineSegment(start, end).nearestTime(p);
+                offset = midpoint_offset_hack(offset);
+                SPGradient *vector = sp_gradient_get_forked_vector_if_necessary(rg, false);
+                rg->ensureVector();
+                rg->vector.stops.at(point_i).offset = offset;
+                if (SPStop* stopi = sp_get_stop_i(vector, point_i)) {
+                    stopi->offset = offset;
+                    if (write_repr) {
+                        stopi->getRepr()->setAttributeCssDouble("offset", stopi->offset);
+                    } else {
+                        stopi->requestModified(SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_STYLE_MODIFIED_FLAG);
+                    }
+                }
+                break;
+            }
+            default:
+                g_warning( "Bad radial gradient handle type" );
+                break;
+        }
+
+        if (transform_set) {
+            gradient->gradientTransform = new_transform;
+            gradient->gradientTransform_set = TRUE;
+            if (write_repr) {
+                auto s = sp_svg_transform_write(gradient->gradientTransform);
+                gradient->setAttributeOrRemoveIfEmpty("gradientTransform", s);
+            } else {
+                gradient->requestModified(SP_OBJECT_MODIFIED_FLAG);
+            }
+        }
+    } else if (SP_IS_MESHGRADIENT(gradient)) {
+        SPMeshGradient *mg = SP_MESHGRADIENT(gradient);
+        //Geom::Affine new_transform;
+        //bool transform_set = false;
+
+        switch (point_type) {
+            case POINT_MG_CORNER:
+            {
+                mg->array.corners[ point_i ]->p = p;
+                // Handles are moved in gradient-drag.cpp
+                gradient->requestModified(SP_OBJECT_MODIFIED_FLAG);
+                break;
+            }
+
+            case POINT_MG_HANDLE: {
+                mg->array.handles[ point_i ]->p = p;
+                gradient->requestModified(SP_OBJECT_MODIFIED_FLAG);
+                break;
+            }
+
+            case POINT_MG_TENSOR: {
+                mg->array.tensors[ point_i ]->p = p;
+                gradient->requestModified(SP_OBJECT_MODIFIED_FLAG);
+                break;
+            }
+
+            default:
+                g_warning( "Bad mesh handle type" );
+        }
+        if( write_repr ) {
+            //std::cout << "Write mesh repr" << std::endl;
+            mg->array.write( mg );
+        }
+    }
+
+}
+
+SPGradient *sp_item_gradient_get_vector(SPItem *item, Inkscape::PaintTarget fill_or_stroke)
+{
+    SPGradient *gradient = getGradient(item, fill_or_stroke);
+
+    if (gradient) {
+        return gradient->getVector();
+    }
+    return nullptr;
+}
+
+SPGradientSpread sp_item_gradient_get_spread(SPItem *item, Inkscape::PaintTarget fill_or_stroke)
+{
+    SPGradientSpread spread = SP_GRADIENT_SPREAD_PAD;
+    SPGradient *gradient = getGradient(item, fill_or_stroke);
+
+    if (gradient) {
+        spread = gradient->fetchSpread();
+    }
+    return spread;
+}
+
+
+/**
+Returns the position of point point_type of the gradient applied to item (either fill_or_stroke),
+in desktop coordinates.
+*/
+Geom::Point getGradientCoords(SPItem *item, GrPointType point_type, guint point_i, Inkscape::PaintTarget fill_or_stroke)
+{
+    SPGradient *gradient = getGradient(item, fill_or_stroke);
+#ifdef SP_GR_VERBOSE
+    g_message("getGradientCoords(%p, %d, %d, %d, %p)", item, point_type, point_i, fill_or_stroke, gradient);
+#endif
+
+    Geom::Point p (0, 0);
+
+    if (!gradient)
+        return p;
+
+    if (SP_IS_LINEARGRADIENT(gradient)) {
+        SPLinearGradient *lg = SP_LINEARGRADIENT(gradient);
+        switch (point_type) {
+            case POINT_LG_BEGIN:
+                p = Geom::Point (lg->x1.computed, lg->y1.computed);
+                break;
+            case POINT_LG_END:
+                p = Geom::Point (lg->x2.computed, lg->y2.computed);
+                break;
+            case POINT_LG_MID:
+                {
+                    if (lg->vector.stops.size() < point_i) {
+                        g_message("POINT_LG_MID bug trigger, see LP bug #453067");
+                        break;
+                    }
+                    gdouble offset = lg->vector.stops.at(point_i).offset;
+                    p = (1-offset) * Geom::Point(lg->x1.computed, lg->y1.computed) + offset * Geom::Point(lg->x2.computed, lg->y2.computed);
+                }
+                break;
+            default:
+                g_warning( "Bad linear gradient handle type" );
+                break;
+        }
+    } else     if (SP_IS_RADIALGRADIENT(gradient)) {
+        SPRadialGradient *rg = SP_RADIALGRADIENT(gradient);
+        switch (point_type) {
+            case POINT_RG_CENTER:
+                p = Geom::Point (rg->cx.computed, rg->cy.computed);
+                break;
+            case POINT_RG_FOCUS:
+                p = Geom::Point (rg->fx.computed, rg->fy.computed);
+                break;
+            case POINT_RG_R1:
+                p = Geom::Point (rg->cx.computed + rg->r.computed, rg->cy.computed);
+                break;
+            case POINT_RG_R2:
+                p = Geom::Point (rg->cx.computed, rg->cy.computed - rg->r.computed);
+                break;
+            case POINT_RG_MID1:
+                {
+                    if (rg->vector.stops.size() < point_i) {
+                        g_message("POINT_RG_MID1 bug trigger, see LP bug #453067");
+                        break;
+                    }
+                    gdouble offset = rg->vector.stops.at(point_i).offset;
+                    p = (1-offset) * Geom::Point (rg->cx.computed, rg->cy.computed) + offset * Geom::Point(rg->cx.computed + rg->r.computed, rg->cy.computed);
+                }
+                break;
+            case POINT_RG_MID2:
+                {
+                    if (rg->vector.stops.size() < point_i) {
+                        g_message("POINT_RG_MID2 bug trigger, see LP bug #453067");
+                        break;
+                    }
+                    gdouble offset = rg->vector.stops.at(point_i).offset;
+                    p = (1-offset) * Geom::Point (rg->cx.computed, rg->cy.computed) + offset * Geom::Point(rg->cx.computed, rg->cy.computed - rg->r.computed);
+                }
+                break;
+            default:
+                g_warning( "Bad radial gradient handle type" );
+                break;
+        }
+    } else     if (SP_IS_MESHGRADIENT(gradient)) {
+        SPMeshGradient *mg = SP_MESHGRADIENT(gradient);
+        switch (point_type) {
+
+            case POINT_MG_CORNER:
+                p = mg->array.corners[ point_i ]->p;
+                break;
+
+            case POINT_MG_HANDLE: {
+                p = mg->array.handles[ point_i ]->p;
+                break;
+            }
+
+            case POINT_MG_TENSOR: {
+                p = mg->array.tensors[ point_i ]->p;
+                break;
+            }
+
+            default:
+                g_warning( "Bad mesh handle type" );
+        }
+    }
+
+
+    if (gradient->getUnits() == SP_GRADIENT_UNITS_OBJECTBOUNDINGBOX) {
+        item->document->ensureUpToDate();
+        Geom::OptRect bbox = item->visualBounds(); // we need "true" bbox without item_i2d_affine
+        if (bbox) {
+            p *= Geom::Affine(bbox->dimensions()[Geom::X], 0,
+                            0, bbox->dimensions()[Geom::Y],
+                            bbox->min()[Geom::X], bbox->min()[Geom::Y]);
+        }
+    }
+    p *= Geom::Affine(gradient->gradientTransform) * (Geom::Affine)item->i2dt_affine();
+    return p;
+}
+
+/**
+ * Sets item fill or stroke to the gradient of the specified type with given vector, creating
+ * new private gradient, if needed.
+ * gr has to be a normalized vector.
+ */
+
+SPGradient *sp_item_set_gradient(SPItem *item, SPGradient *gr, SPGradientType type, Inkscape::PaintTarget fill_or_stroke)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_item_set_gradient(%p, %p, %d, %d)", item, gr, type, fill_or_stroke);
+#endif
+    g_return_val_if_fail(item != nullptr, NULL);
+    g_return_val_if_fail(SP_IS_ITEM(item), NULL);
+    g_return_val_if_fail(gr != nullptr, NULL);
+    g_return_val_if_fail(SP_IS_GRADIENT(gr), NULL);
+    g_return_val_if_fail(gr->state == SP_GRADIENT_STATE_VECTOR, NULL);
+
+    SPStyle *style = item->style;
+    g_assert(style != nullptr);
+
+    SPPaintServer *ps = nullptr;
+    if ((fill_or_stroke == Inkscape::FOR_FILL) ? style->fill.isPaintserver() : style->stroke.isPaintserver()) {
+        ps = (fill_or_stroke == Inkscape::FOR_FILL) ? SP_STYLE_FILL_SERVER(style) : SP_STYLE_STROKE_SERVER(style);
+    }
+
+    if (ps
+        && ( (type == SP_GRADIENT_TYPE_LINEAR && SP_IS_LINEARGRADIENT(ps)) ||
+             (type == SP_GRADIENT_TYPE_RADIAL && SP_IS_RADIALGRADIENT(ps))   ) )
+    {
+
+        /* Current fill style is the gradient of the required type */
+        SPGradient *current = SP_GRADIENT(ps);
+
+        //g_message("hrefcount %d   count %d\n", current->hrefcount, count_gradient_hrefs(item, current));
+
+        if (!current->isSwatch()
+            && (current->hrefcount == 1 ||
+            current->hrefcount == count_gradient_hrefs(item, current))) {
+
+            // current is private and it's either used once, or all its uses are by children of item;
+            // so just change its href to vector
+
+            if ( current != gr && current->getVector() != gr ) {
+                // href is not the vector
+                sp_gradient_repr_set_link(current->getRepr(), gr);
+            }
+            item->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_STYLE_MODIFIED_FLAG);
+            return current;
+
+        } else {
+
+            // the gradient is not private, or it is shared with someone else;
+            // normalize it (this includes creating new private if necessary)
+            SPGradient *normalized = sp_gradient_fork_private_if_necessary(current, gr, type, item);
+
+            g_return_val_if_fail(normalized != nullptr, NULL);
+
+            if (normalized != current) {
+
+                /* We have to change object style here; recursive because this is used from
+                 * fill&stroke and must work for groups etc. */
+                sp_style_set_property_url(item, (fill_or_stroke == Inkscape::FOR_FILL) ? "fill" : "stroke", normalized, true);
+            }
+            item->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_STYLE_MODIFIED_FLAG);
+            return normalized;
+        }
+
+    } else {
+        /* Current fill style is not a gradient or wrong type, so construct everything */
+        /* This is where mesh gradients are constructed. */
+        g_assert(SP_IS_GRADIENT(gr)); // TEMP
+        SPGradient *constructed = sp_gradient_get_private_normalized(item->document, gr, type);
+        constructed = sp_gradient_reset_to_userspace(constructed, item);
+        sp_style_set_property_url(item, ( (fill_or_stroke == Inkscape::FOR_FILL) ? "fill" : "stroke" ), constructed, true);
+        item->requestDisplayUpdate(( SP_OBJECT_MODIFIED_FLAG |
+                                     SP_OBJECT_STYLE_MODIFIED_FLAG ));
+        return constructed;
+    }
+}
+
+static void sp_gradient_repr_set_link(Inkscape::XML::Node *repr, SPGradient *link)
+{
+#ifdef SP_GR_VERBOSE
+    g_message("sp_gradient_repr_set_link(%p, %p)", repr, link);
+#endif
+    g_return_if_fail(repr != nullptr);
+    if (link) {
+        g_return_if_fail(SP_IS_GRADIENT(link));
+    }
+
+    if (link) {
+        Glib::ustring ref("#");
+        ref += link->getId();
+        repr->setAttribute("xlink:href", ref);
+    } else {
+        repr->removeAttribute("xlink:href");
+    }
+}
+
+
+static void addStop( Inkscape::XML::Node *parent, Glib::ustring const &color, gint opacity, gchar const *offset )
+{
+#ifdef SP_GR_VERBOSE
+    g_message("addStop(%p, %s, %d, %s)", parent, color.c_str(), opacity, offset);
+#endif
+    Inkscape::XML::Node *stop = parent->document()->createElement("svg:stop");
+    {
+        gchar *tmp = g_strdup_printf( "stop-color:%s;stop-opacity:%d;", color.c_str(), opacity );
+        stop->setAttribute( "style", tmp );
+        g_free(tmp);
+    }
+
+    stop->setAttribute( "offset", offset );
+
+    parent->appendChild(stop);
+    Inkscape::GC::release(stop);
+}
+
+/*
+ * Get default normalized gradient vector of document, create if there is none
+ */
+SPGradient *sp_document_default_gradient_vector( SPDocument *document, SPColor const &color, bool singleStop )
+{
+    SPDefs *defs = document->getDefs();
+    Inkscape::XML::Document *xml_doc = document->getReprDoc();
+
+    Inkscape::XML::Node *repr = xml_doc->createElement("svg:linearGradient");
+
+    if ( !singleStop ) {
+        // make auto collection optional
+        Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+        if (prefs->getBool("/option/gradient/auto_collect", true)) {
+            repr->setAttribute("inkscape:collect", "always");
+        } else {
+            repr->setAttribute("inkscape:collect", "never");
+        }
+
+        // set here, but removed when it's edited in the gradient editor
+        // to further reduce clutter, we could
+        // (1) here, search gradients by color and return what is found without duplication
+        // (2) in fill & stroke, show only one copy of each gradient in list
+    }
+
+    Glib::ustring colorStr = color.toString();
+    addStop( repr, colorStr, 1, "0" );
+    if ( !singleStop ) {
+        addStop( repr, colorStr, 0, "1" );
+    }
+
+    defs->getRepr()->addChild(repr, nullptr);
+    Inkscape::GC::release(repr);
+
+    /* fixme: This does not look like nice */
+    SPGradient *gr = static_cast<SPGradient *>(document->getObjectByRepr(repr));
+    g_assert(gr != nullptr);
+    g_assert(SP_IS_GRADIENT(gr));
+    /* fixme: Maybe add extra sanity check here */
+    gr->state = SP_GRADIENT_STATE_VECTOR;
+
+    return gr;
+}
+
+SPGradient *sp_gradient_vector_for_object( SPDocument *const doc, SPDesktop *const desktop,
+                                           SPObject *const o, Inkscape::PaintTarget const fill_or_stroke, bool singleStop )
+{
+    SPColor color;
+    if ( (o == nullptr) || (o->style == nullptr) ) {
+        color = sp_desktop_get_color(desktop, (fill_or_stroke == Inkscape::FOR_FILL));
+    } else {
+        // take the color of the object
+        SPStyle const &style = *(o->style);
+        SPIPaint const &paint = *style.getFillOrStroke(fill_or_stroke == Inkscape::FOR_FILL);
+        if (paint.isPaintserver()) {
+            SPObject *server = (fill_or_stroke == Inkscape::FOR_FILL) ? o->style->getFillPaintServer() : o->style->getStrokePaintServer();
+            if ( SP_IS_LINEARGRADIENT(server) || SP_IS_RADIALGRADIENT(server) ) {
+                return SP_GRADIENT(server)->getVector(true);
+            } else {
+                color = sp_desktop_get_color(desktop, (fill_or_stroke == Inkscape::FOR_FILL));
+            }
+        } else if (paint.isColor()) {
+            color = paint.value.color;
+        } else {
+            // if o doesn't use flat color, then take current color of the desktop.
+            color = sp_desktop_get_color(desktop, (fill_or_stroke == Inkscape::FOR_FILL));
+        }
+    }
+
+    return sp_document_default_gradient_vector( doc, color, singleStop );
+}
+
+void sp_gradient_invert_selected_gradients(SPDesktop *desktop, Inkscape::PaintTarget fill_or_stroke)
+{
+    Inkscape::Selection *selection = desktop->getSelection();
+
+    auto list= selection->items();
+    for (auto i = list.begin(); i != list.end(); ++i) {
+        sp_item_gradient_invert_vector_color(*i, fill_or_stroke);
+    }
+
+    // we did an undoable action
+    DocumentUndo::done(desktop->getDocument(), _("Invert gradient colors"), INKSCAPE_ICON("color-gradient"));
+}
+
+void sp_gradient_reverse_selected_gradients(SPDesktop *desktop)
+{
+    Inkscape::Selection *selection = desktop->getSelection();
+    Inkscape::UI::Tools::ToolBase *ev = desktop->getEventContext();
+
+    if (!ev) {
+        return;
+    }
+
+    GrDrag *drag = ev->get_drag();
+
+    // First try selected dragger
+    if (drag && !drag->selected.empty()) {
+        drag->selected_reverse_vector();
+    } else { // If no drag or no dragger selected, act on selection (both fill and stroke gradients)
+        auto list= selection->items();
+        for (auto i = list.begin(); i != list.end(); ++i) {
+            sp_item_gradient_reverse_vector(*i, Inkscape::FOR_FILL);
+            sp_item_gradient_reverse_vector(*i, Inkscape::FOR_STROKE);
+        }
+    }
+
+    // we did an undoable action
+    DocumentUndo::done(desktop->getDocument(), _("Reverse gradient"), INKSCAPE_ICON("color-gradient"));
+}
+
+void sp_gradient_unset_swatch(SPDesktop *desktop, std::string const &id)
+{
+    SPDocument *doc = desktop ? desktop->doc() : nullptr;
+
+    if (doc) {
+        const std::vector<SPObject *> gradients = doc->getResourceList("gradient");
+        for (auto gradient : gradients) {
+            SPGradient* grad = SP_GRADIENT(gradient);
+            if ( id == grad->getId() ) {
+                grad->setSwatch(false);
+                DocumentUndo::done(doc, _("Delete swatch"), INKSCAPE_ICON("color-gradient"));
+                break;
+            }
+        }
+    }
+}
+
+/*
+ * Return a SPItem's gradient
+ */
+SPGradient* sp_item_get_gradient(SPItem *item, bool fillorstroke)
+{
+    SPIPaint *item_paint = item->style->getFillOrStroke(fillorstroke);
+    if (item_paint->isPaintserver()) {
+
+        SPPaintServer *item_server = fillorstroke ? item->style->getFillPaintServer() : item->style->getStrokePaintServer();
+
+        if (SP_IS_LINEARGRADIENT(item_server) || SP_IS_RADIALGRADIENT(item_server) ||
+                (SP_IS_GRADIENT(item_server) && SP_GRADIENT(item_server)->getVector()->isSwatch()))  {
+
+            return SP_GRADIENT(item_server)->getVector();
+        }
+    }
+
+    return nullptr;
+}
+
+static void get_all_doc_items(std::vector<SPItem*> &list, SPObject *from)
+{
+    for (auto& child: from->children) {
+        if (SP_IS_ITEM(&child)) {
+            list.push_back(SP_ITEM(&child));
+        }
+        get_all_doc_items(list, &child);
+    }
+}
+
+std::vector<SPItem*> sp_get_all_document_items(SPDocument* document) {
+    std::vector<SPItem*> items;
+    if (document) {
+        get_all_doc_items(items, document->getRoot());
+    }
+    return items;
+}
+
+int sp_get_gradient_refcount(SPDocument* document, SPGradient* gradient) {
+    if (!document || !gradient) return 0;
+
+    int count = 0;
+    for (auto item : sp_get_all_document_items(document)) {
+        if (!item->getId()) {
+            continue;
+        }
+        SPGradient* fill = sp_item_get_gradient(item, true); // fill
+        if (fill == gradient) {
+            ++count;
+        }
+        SPGradient* stroke = sp_item_get_gradient(item, false); // stroke
+        if (stroke == gradient) {
+            ++count;
+        }
+    }
+
+    return count;
+}
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :