Adding upstream version 1.2.2.upstream/1.2.2upstream

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

1 files changed, 1120 insertions, 0 deletions

diff --git a/src/display/control/canvas-grid.cpp b/src/display/control/canvas-grid.cpp
new file mode 100644
index 0000000..8ca17e0
--- /dev/null
+++ b/src/display/control/canvas-grid.cpp
@@ -0,0 +1,1120 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
+ * Cartesian grid item for the Inkscape canvas.
+ *//*
+ * Authors:
+ * see git history
+ * Copyright (C) Johan Engelen 2006-2007 <johan@shouraizou.nl>
+ * Copyright (C) Lauris Kaplinski 2000
+ *   Abhishek Sharma
+ *   Jon A. Cruz <jon@joncruz.org>
+ * Copyright (C) Tavmong Bah 2017 <tavmjong@free.fr>
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+/* As a general comment, I am not exactly proud of how things are done.
+ * (for example the 'enable' widget and readRepr things)
+ * It does seem to work however. I intend to clean up and sort things out later, but that can take forever...
+ * Don't be shy to correct things.
+ */
+
+#include <gtkmm/box.h>
+#include <gtkmm/label.h>
+#include <gtkmm/grid.h>
+
+#include <glibmm/i18n.h>
+
+#include "canvas-grid.h"
+#include "canvas-axonomgrid.h"
+#include "canvas-item-grid.h"
+
+#include "desktop.h"
+#include "document.h"
+#include "inkscape.h"
+#include "preferences.h"
+
+#include "display/cairo-utils.h"
+
+#include "helper/mathfns.h"
+
+#include "object/sp-namedview.h"
+#include "object/sp-object.h"
+#include "object/sp-root.h"
+
+#include "svg/stringstream.h"
+#include "svg/svg-color.h"
+
+#include "ui/icon-names.h"
+#include "ui/widget/canvas.h"
+
+#include "util/units.h"
+
+#include "xml/node-event-vector.h"
+
+using Inkscape::DocumentUndo;
+using Inkscape::Util::unit_table;
+
+namespace Inkscape {
+
+static gchar const *const grid_name[] = {
+    N_("Rectangular grid"),
+    N_("Axonometric grid")
+};
+
+static gchar const *const grid_svgname[] = {
+    "xygrid",
+    "axonomgrid"
+};
+
+// ##########################################################
+//   CanvasGrid
+
+    static Inkscape::XML::NodeEventVector const _repr_events = {
+        nullptr, /* child_added */
+        nullptr, /* child_removed */
+        CanvasGrid::on_repr_attr_changed,
+        nullptr, /* content_changed */
+        nullptr  /* order_changed */
+    };
+
+CanvasGrid::CanvasGrid(SPNamedView * nv, Inkscape::XML::Node * in_repr, SPDocument *in_doc, GridType type)
+    : visible(true), gridtype(type), legacy(false), pixel(false)
+{
+    repr = in_repr;
+    doc = in_doc;
+    if (repr) {
+        repr->addListener (&_repr_events, this);
+    }
+
+    namedview = nv;
+}
+
+CanvasGrid::~CanvasGrid()
+{
+    if (repr) {
+        repr->removeListenerByData (this);
+    }
+
+    if (_rcb_enabled) {
+        _rcb_enabled->remove_destroy_notify_callback(this);
+    }
+
+    for (auto grid : canvas_item_grids) {
+        delete grid;
+    }
+    canvas_item_grids.clear();
+}
+
+const char *
+CanvasGrid::getName() const
+{
+    return _(grid_name[gridtype]);
+}
+
+const char *
+CanvasGrid::getSVGName() const
+{
+    return grid_svgname[gridtype];
+}
+
+GridType
+CanvasGrid::getGridType() const
+{
+    return gridtype;
+}
+
+
+char const *
+CanvasGrid::getName(GridType type)
+{
+    return _(grid_name[type]);
+}
+
+char const *
+CanvasGrid::getSVGName(GridType type)
+{
+    return grid_svgname[type];
+}
+
+GridType
+CanvasGrid::getGridTypeFromSVGName(char const *typestr)
+{
+    if (!typestr) return GRID_RECTANGULAR;
+
+    gint t = 0;
+    for (t = GRID_MAXTYPENR; t >= 0; t--) {  //this automatically defaults to grid0 which is rectangular grid
+        if (!strcmp(typestr, grid_svgname[t])) break;
+    }
+    return (GridType) t;
+}
+
+GridType
+CanvasGrid::getGridTypeFromName(char const *typestr)
+{
+    if (!typestr) return GRID_RECTANGULAR;
+
+    gint t = 0;
+    for (t = GRID_MAXTYPENR; t >= 0; t--) {  //this automatically defaults to grid0 which is rectangular grid
+        if (!strcmp(typestr, _(grid_name[t]))) break;
+    }
+    return (GridType) t;
+}
+
+
+/*
+*  writes an <inkscape:grid> child to repr.
+*/
+void
+CanvasGrid::writeNewGridToRepr(Inkscape::XML::Node * repr, SPDocument * doc, GridType gridtype)
+{
+    if (!repr) return;
+    if (gridtype > GRID_MAXTYPENR) return;
+
+    // first create the child xml node, then hook it to repr. This order is important, to not set off listeners to repr before the new node is complete.
+
+    Inkscape::XML::Document *xml_doc = doc->getReprDoc();
+    Inkscape::XML::Node *newnode;
+    newnode = xml_doc->createElement("inkscape:grid");
+    newnode->setAttribute("type", getSVGName(gridtype));
+
+    repr->appendChild(newnode);
+    Inkscape::GC::release(newnode);
+
+    DocumentUndo::done(doc, _("Create new grid"), INKSCAPE_ICON("document-properties"));
+}
+
+/*
+* Creates a new CanvasGrid object of type gridtype
+*/
+CanvasGrid*
+CanvasGrid::NewGrid(SPNamedView * nv, Inkscape::XML::Node * repr, SPDocument * doc, GridType gridtype)
+{
+    if (!repr) return nullptr;
+    if (!doc) {
+        g_error("CanvasGrid::NewGrid - doc==NULL");
+        return nullptr;
+    }
+
+    switch (gridtype) {
+        case GRID_RECTANGULAR:
+            return new CanvasXYGrid(nv, repr, doc);
+        case GRID_AXONOMETRIC:
+            return new CanvasAxonomGrid(nv, repr, doc);
+    }
+
+    return nullptr;
+}
+
+
+/**
+*  creates a new grid canvasitem for the SPDesktop given as parameter. Keeps a link to this canvasitem in the canvas_item_grids list.
+*/
+Inkscape::CanvasItemGrid *
+CanvasGrid::createCanvasItem(SPDesktop * desktop)
+{
+    if (!desktop) return nullptr;
+//    Johan: I think for multiple desktops it is best if each has their own canvasitem,
+//           but share the same CanvasGrid object; that is what this function is for.
+
+    // check if there is already a canvasitem on this desktop linking to this grid
+    for (auto grid : canvas_item_grids) {
+        if ( desktop->getCanvasGrids() == grid->get_parent() ) {
+            return nullptr;
+        }
+    }
+
+    Inkscape::CanvasItemGrid *grid = new Inkscape::CanvasItemGrid(desktop->getCanvasGrids(), this);
+    grid->show();
+    canvas_item_grids.push_back(grid);
+    return grid;
+}
+
+/**
+ * Remove a CanvasGridItem from vector. Does NOT delete CanvasGridItem.
+ * This is used by the CanvasGridItem destructor to ensure no dangling pointer is left.
+ */
+void
+CanvasGrid::removeCanvasItem(Inkscape::CanvasItemGrid *item)
+{
+    auto it = std::find(canvas_item_grids.begin(), canvas_item_grids.end(), item);
+    if (it != canvas_item_grids.end()) {
+        canvas_item_grids.erase(it);
+    }
+}
+
+Gtk::Widget *
+CanvasGrid::newWidget()
+{
+    Gtk::Box * vbox = Gtk::manage( new Gtk::Box(Gtk::ORIENTATION_VERTICAL) );
+    Gtk::Label * namelabel = Gtk::manage(new Gtk::Label("", Gtk::ALIGN_CENTER) );
+
+    Glib::ustring str("<b>");
+    str += getName();
+    str += "</b>";
+    namelabel->set_markup(str);
+    vbox->pack_start(*namelabel, false, false);
+
+    _rcb_enabled = Gtk::manage( new Inkscape::UI::Widget::RegisteredCheckButton(
+            _("_Enabled"),
+            _("Makes the grid available for working with on the canvas."),
+            "enabled", _wr, false, repr, doc) );
+    // _rcb_enabled serves as a canary that tells us that the widgets have been destroyed
+    _rcb_enabled->add_destroy_notify_callback(this, &CanvasGrid::notifyWidgetsDestroyed);
+
+    _rcb_snap_visible_only = Gtk::manage( new Inkscape::UI::Widget::RegisteredCheckButton(
+            _("Snap to visible _grid lines only"),
+            _("When zoomed out, not all grid lines will be displayed. Only the visible ones will be snapped to"),
+            "snapvisiblegridlinesonly", _wr, false, repr, doc) );
+
+    _rcb_visible = Gtk::manage( new Inkscape::UI::Widget::RegisteredCheckButton(
+            _("_Visible"),
+            _("Determines whether the grid is displayed or not. Objects are still snapped to invisible grids."),
+            "visible", _wr, false, repr, doc) );
+
+    _as_alignment = Gtk::manage( new Inkscape::UI::Widget::AlignmentSelector() );
+    _as_alignment->on_alignmentClicked().connect(sigc::mem_fun(*this, &CanvasGrid::align_clicked));
+
+    Gtk::Box *left = Gtk::manage(new Gtk::Box(Gtk::ORIENTATION_VERTICAL, 4));
+    left->pack_start(*_rcb_enabled, false, false);
+    left->pack_start(*_rcb_visible, false, false);
+    left->pack_start(*_rcb_snap_visible_only, false, false);
+
+    if (getGridType() == GRID_RECTANGULAR) {
+        _rcb_dotted = Gtk::manage( new Inkscape::UI::Widget::RegisteredCheckButton(
+                _("_Show dots instead of lines"), _("If set, displays dots at gridpoints instead of gridlines"),
+                "dotted", _wr, false, repr, doc) );
+        _rcb_dotted->setActive(render_dotted);
+        left->pack_start(*_rcb_dotted, false, false);
+    }
+
+    left->pack_start(*Gtk::manage(new Gtk::Label(_("Align to page:"))), false, false);
+    left->pack_start(*_as_alignment, false, false);
+
+    auto right = newSpecificWidget();
+    right->set_hexpand(false);
+
+    Gtk::Box *inner = Gtk::manage(new Gtk::Box(Gtk::ORIENTATION_HORIZONTAL, 4));
+    inner->pack_start(*left, true, true);
+    inner->pack_start(*right, false, false);
+    vbox->pack_start(*inner, false, false);
+    vbox->set_border_width(4);
+
+    std::list<Gtk::Widget*> slaves;
+    for (auto &item : left->get_children()) {
+        if (item != _rcb_enabled) {
+            slaves.push_back(item);
+        }
+    }
+    slaves.push_back(right);
+    _rcb_enabled->setSlaveWidgets(slaves);
+
+    // set widget values
+    _wr.setUpdating (true);
+    _rcb_visible->setActive(visible);
+    if (snapper != nullptr) {
+        _rcb_enabled->setActive(snapper->getEnabled());
+        _rcb_snap_visible_only->setActive(snapper->getSnapVisibleOnly());
+    }
+    _wr.setUpdating (false);
+    return dynamic_cast<Gtk::Widget *> (vbox);
+}
+
+/**
+ * @brief Zeroes out our pointers to the widgets when the widgets are destroyed
+ * @param data - a pointer to the CanvasGrid object holding the widget pointers
+ * @return always returns nullptr
+ */
+void *CanvasGrid::notifyWidgetsDestroyed(void *data)
+{
+    CanvasGrid *obj = (CanvasGrid *)(data);
+    obj->_rcb_enabled = nullptr;
+    obj->_rcb_snap_visible_only = nullptr;
+    obj->_rcb_visible = nullptr;
+    obj->_rcb_dotted = nullptr;
+    obj->_as_alignment = nullptr;
+    return nullptr;
+}
+
+void
+CanvasGrid::on_repr_attr_changed(Inkscape::XML::Node *repr, gchar const *key, gchar const *oldval, gchar const *newval, bool is_interactive, void *data)
+{
+    if (!data)
+        return;
+
+    (static_cast<CanvasGrid*>(data))->onReprAttrChanged(repr, key, oldval, newval, is_interactive);
+}
+
+bool CanvasGrid::isEnabled() const
+{
+    if (snapper == nullptr) {
+       return false;
+    }
+
+    return snapper->getEnabled();
+}
+
+// Used to shift origin when page size changed to fit drawing.
+void CanvasGrid::setOrigin(Geom::Point const &origin_px)
+{
+    SPRoot *root = doc->getRoot();
+    double scale_x = 1.0;
+    double scale_y = 1.0;
+    if( root->viewBox_set ) {
+        scale_x = root->viewBox.width()  / root->width.computed;
+        scale_y = root->viewBox.height() / root->height.computed;
+    }
+
+    // Write out in 'user-units'
+    Inkscape::SVGOStringStream os_x, os_y;
+    os_x << origin_px[Geom::X] * scale_x;
+    os_y << origin_px[Geom::Y] * scale_y;
+    repr->setAttribute("originx", os_x.str());
+    repr->setAttribute("originy", os_y.str());
+}
+
+void CanvasGrid::align_clicked(int align)
+{
+    Geom::Point dimensions = doc->getDimensions();
+    dimensions[Geom::X] *= align % 3 * 0.5;
+    dimensions[Geom::Y] *= align / 3 * 0.5;
+    dimensions *= doc->doc2dt();
+    setOrigin(dimensions);
+}
+
+
+
+// ##########################################################
+//   CanvasXYGrid
+
+CanvasXYGrid::CanvasXYGrid (SPNamedView * nv, Inkscape::XML::Node * in_repr, SPDocument * in_doc)
+    : CanvasGrid(nv, in_repr, in_doc, GRID_RECTANGULAR)
+{
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    gridunit = unit_table.getUnit(prefs->getString("/options/grids/xy/units"));
+    if (!gridunit) {
+        gridunit = unit_table.getUnit("px");
+    }
+    origin[Geom::X] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/xy/origin_x", 0.0), gridunit, "px");
+    origin[Geom::Y] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/xy/origin_y", 0.0), gridunit, "px");
+    color = prefs->getInt("/options/grids/xy/color", GRID_DEFAULT_COLOR);
+    empcolor = prefs->getInt("/options/grids/xy/empcolor", GRID_DEFAULT_EMPCOLOR);
+    empspacing = prefs->getInt("/options/grids/xy/empspacing", 5);
+    spacing[Geom::X] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/xy/spacing_x", 0.0), gridunit, "px");
+    spacing[Geom::Y] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/xy/spacing_y", 0.0), gridunit, "px");
+    render_dotted = prefs->getBool("/options/grids/xy/dotted", false);
+
+    snapper = new CanvasXYGridSnapper(this, &namedview->snap_manager, 0);
+
+    if (repr) readRepr();
+}
+
+CanvasXYGrid::~CanvasXYGrid ()
+{
+   if (snapper) delete snapper;
+}
+
+static gboolean sp_nv_read_opacity(gchar const *str, guint32 *color)
+{
+    if (!str) {
+        return FALSE;
+    }
+
+    gchar *u;
+    gdouble v = g_ascii_strtod(str, &u);
+    if (!u) {
+        return FALSE;
+    }
+    v = CLAMP(v, 0.0, 1.0);
+
+    *color = (*color & 0xffffff00) | (guint32) floor(v * 255.9999);
+
+    return TRUE;
+}
+
+/** If the passed int is invalid (<=0), then set the widget and the int
+    to use the given old value.
+
+    @param oldVal Old value to use if the new one is invalid.
+    @param pTarget The int to validate.
+    @param widget Widget associated with the int.
+*/
+static void validateInt(gint oldVal,
+                        gint* pTarget)
+{
+    // Avoid nullness.
+    if ( pTarget == nullptr )
+        return;
+
+    // Invalid new value?
+    if ( *pTarget <= 0 ) {
+        // If the old value is somehow invalid as well, then default to 1.
+        if ( oldVal <= 0 )
+            oldVal = 1;
+
+        // Reset the int and associated widget to the old value.
+        *pTarget = oldVal;
+    } //if
+
+} //validateInt
+
+void
+CanvasXYGrid::readRepr()
+{
+    SPRoot *root = doc->getRoot();
+    double scale_x = 1.0;
+    double scale_y = 1.0;
+    if( root->viewBox_set ) {
+        scale_x = root->width.computed  / root->viewBox.width();
+        scale_y = root->height.computed / root->viewBox.height();
+        if (Geom::are_near(scale_x / scale_y, 1.0, Geom::EPSILON)) {
+            // scaling is uniform, try to reduce numerical error
+            scale_x = (scale_x + scale_y)/2.0;
+            double scale_none = Inkscape::Util::Quantity::convert(1, doc->getDisplayUnit(), "px");
+            if (Geom::are_near(scale_x / scale_none, 1.0, Geom::EPSILON))
+                scale_x = scale_none; // objects are same size, reduce numerical error
+            scale_y = scale_x;
+        }
+    }
+
+    gchar const *value;
+
+    if ( (value = repr->attribute("originx")) ) {
+
+        Inkscape::Util::Quantity q = unit_table.parseQuantity(value);
+
+        if( q.unit->type == UNIT_TYPE_LINEAR ) {
+            // Legacy grid not in 'user units'
+            origin[Geom::X] = q.value("px");
+            legacy = true;
+            if (q.unit->abbr == "px" ) {
+                pixel = true;
+            }
+        } else {
+            // Grid in 'user units'
+            origin[Geom::X] = q.quantity * scale_x;
+        }
+    }
+
+    if ( (value = repr->attribute("originy")) ) {
+
+        Inkscape::Util::Quantity q = unit_table.parseQuantity(value);
+
+        if( q.unit->type == UNIT_TYPE_LINEAR ) {
+            // Legacy grid not in 'user units'
+            origin[Geom::Y] = q.value("px");
+            legacy = true;
+            if (q.unit->abbr == "px" ) {
+                pixel = true;
+            }
+        } else {
+            // Grid in 'user units'
+            origin[Geom::Y] = q.quantity * scale_y;
+        }
+    }
+
+    if ( (value = repr->attribute("spacingx")) ) {
+
+        // Ensure a valid default value
+        if( spacing[Geom::X] <= 0.0 )
+            spacing[Geom::X] = 1.0;
+
+        Inkscape::Util::Quantity q = unit_table.parseQuantity(value);
+        // Ensure a valid new value
+        if( q.quantity > 0 ) {
+            if( q.unit->type == UNIT_TYPE_LINEAR ) {
+                // Legacy grid not in 'user units'
+                spacing[Geom::X] = q.value("px");
+                legacy = true;
+                if (q.unit->abbr == "px" ) {
+                    pixel = true;
+                }
+            } else {
+                // Grid in 'user units'
+                spacing[Geom::X] = q.quantity * scale_x;
+            }
+        }
+    }
+
+    if ( (value = repr->attribute("spacingy")) ) {
+
+        // Ensure a valid default value
+        if( spacing[Geom::Y] <= 0.0 )
+            spacing[Geom::Y] = 1.0;
+
+        Inkscape::Util::Quantity q = unit_table.parseQuantity(value);
+        // Ensure a valid new value
+        if( q.quantity > 0 ) {
+            if( q.unit->type == UNIT_TYPE_LINEAR ) {
+                // Legacy grid not in 'user units'
+                spacing[Geom::Y] = q.value("px");
+                legacy = true;
+                if (q.unit->abbr == "px" ) {
+                    pixel = true;
+                }
+            } else {
+                // Grid in 'user units'
+                spacing[Geom::Y] = q.quantity * scale_y;
+            }
+        }
+    }
+
+    if ( (value = repr->attribute("color")) ) {
+        color = (color & 0xff) | sp_svg_read_color(value, color);
+    }
+
+    if ( (value = repr->attribute("empcolor")) ) {
+        empcolor = (empcolor & 0xff) | sp_svg_read_color(value, empcolor);
+    }
+
+    if ( (value = repr->attribute("opacity")) ) {
+        sp_nv_read_opacity(value, &color);
+    }
+    if ( (value = repr->attribute("empopacity")) ) {
+        sp_nv_read_opacity(value, &empcolor);
+    }
+
+    if ( (value = repr->attribute("empspacing")) ) {
+        gint oldVal = empspacing;
+        empspacing = atoi(value);
+        validateInt( oldVal, &empspacing);
+    }
+
+    if ( (value = repr->attribute("dotted")) ) {
+        render_dotted = (strcmp(value,"false") != 0 && strcmp(value, "0") != 0);
+    }
+
+    if ( (value = repr->attribute("visible")) ) {
+        visible = (strcmp(value,"false") != 0 && strcmp(value, "0") != 0);
+    }
+
+    if ( (value = repr->attribute("enabled")) ) {
+        g_assert(snapper != nullptr);
+        snapper->setEnabled(strcmp(value,"false") != 0 && strcmp(value, "0") != 0);
+    }
+
+    if ( (value = repr->attribute("snapvisiblegridlinesonly")) ) {
+        g_assert(snapper != nullptr);
+        snapper->setSnapVisibleOnly(strcmp(value,"false") != 0 && strcmp(value, "0") != 0);
+    }
+
+    if ( (value = repr->attribute("units")) ) {
+        gridunit = unit_table.getUnit(value); // Display unit identifier in grid menu
+    }
+
+    for (auto grid : canvas_item_grids) {
+        grid->request_update();
+    }
+
+    return;
+}
+
+/**
+ * Called when XML node attribute changed; updates dialog widgets if change was not done by widgets themselves.
+ */
+void
+CanvasXYGrid::onReprAttrChanged(Inkscape::XML::Node */*repr*/, gchar const */*key*/, gchar const */*oldval*/, gchar const */*newval*/, bool /*is_interactive*/)
+{
+    readRepr();
+    updateWidgets();
+}
+
+
+Gtk::Widget *
+CanvasXYGrid::newSpecificWidget()
+{
+    _rumg = Gtk::manage( new Inkscape::UI::Widget::RegisteredUnitMenu(
+            _("Grid _units:"), "units", _wr, repr, doc) );
+    _rsu_ox = Gtk::manage( new Inkscape::UI::Widget::RegisteredScalarUnit(
+            _("_Origin X:"), _("X coordinate of grid origin"), "originx",
+            *_rumg, _wr, repr, doc, Inkscape::UI::Widget::RSU_x) );
+    _rsu_oy = Gtk::manage( new Inkscape::UI::Widget::RegisteredScalarUnit(
+            _("O_rigin Y:"), _("Y coordinate of grid origin"), "originy",
+            *_rumg, _wr, repr, doc, Inkscape::UI::Widget::RSU_y) );
+    _rsu_sx = Gtk::manage( new Inkscape::UI::Widget::RegisteredScalarUnit(
+            _("Spacing _X:"), _("Distance between vertical grid lines"), "spacingx",
+            *_rumg, _wr, repr, doc, Inkscape::UI::Widget::RSU_x) );
+    _rsu_sy = Gtk::manage( new Inkscape::UI::Widget::RegisteredScalarUnit(
+            _("Spacing _Y:"), _("Distance between horizontal grid lines"), "spacingy",
+            *_rumg, _wr, repr, doc, Inkscape::UI::Widget::RSU_y) );
+
+    _rcp_gcol = Gtk::manage( new Inkscape::UI::Widget::RegisteredColorPicker(
+            _("Minor grid line _color:"), _("Minor grid line color"), _("Color of the minor grid lines"),
+            "color", "opacity", _wr, repr, doc) );
+
+    _rcp_gmcol = Gtk::manage( new Inkscape::UI::Widget::RegisteredColorPicker(
+            _("Ma_jor grid line color:"), _("Major grid line color"),
+            _("Color of the major (highlighted) grid lines"), "empcolor", "empopacity",
+            _wr, repr, doc) );
+
+    _rsi = Gtk::manage( new Inkscape::UI::Widget::RegisteredSuffixedInteger(
+            _("_Major grid line every:"), "", _("lines"), "empspacing", _wr, repr, doc) );
+
+    _rumg->set_hexpand();
+    _rsu_ox->set_hexpand();
+    _rsu_oy->set_hexpand();
+    _rsu_sx->set_hexpand();
+    _rsu_sy->set_hexpand();
+    _rcp_gcol->set_hexpand();
+    _rcp_gmcol->set_hexpand();
+    _rsi->set_hexpand();
+
+    // set widget values
+    _wr.setUpdating (true);
+
+    _rsu_ox->setDigits(5);
+    _rsu_ox->setIncrements(0.1, 1.0);
+
+    _rsu_oy->setDigits(5);
+    _rsu_oy->setIncrements(0.1, 1.0);
+
+    _rsu_sx->setDigits(5);
+    _rsu_sx->setIncrements(0.1, 1.0);
+
+    _rsu_sy->setDigits(5);
+    _rsu_sy->setIncrements(0.1, 1.0);
+
+    _rumg->setUnit (gridunit->abbr);
+
+    gdouble val;
+    val = origin[Geom::X];
+    val = Inkscape::Util::Quantity::convert(val, "px", gridunit);
+    _rsu_ox->setValue (val);
+    val = origin[Geom::Y];
+    val = Inkscape::Util::Quantity::convert(val, "px", gridunit);
+    _rsu_oy->setValue (val);
+    val = spacing[Geom::X];
+    double gridx = Inkscape::Util::Quantity::convert(val, "px", gridunit);
+    _rsu_sx->setValue (gridx);
+    val = spacing[Geom::Y];
+    double gridy = Inkscape::Util::Quantity::convert(val, "px", gridunit);
+    _rsu_sy->setValue (gridy);
+
+    _rcp_gcol->setRgba32 (color);
+    _rcp_gmcol->setRgba32 (empcolor);
+    _rsi->setValue (empspacing);
+
+    _wr.setUpdating (false);
+
+    _rsu_ox->setProgrammatically = false;
+    _rsu_oy->setProgrammatically = false;
+    _rsu_sx->setProgrammatically = false;
+    _rsu_sy->setProgrammatically = false;
+
+    Gtk::Box *column = Gtk::manage(new Gtk::Box(Gtk::ORIENTATION_VERTICAL, 4));
+    column->pack_start(*_rumg, true, false);
+    column->pack_start(*_rsu_ox, true, false);
+    column->pack_start(*_rsu_oy, true, false);
+    column->pack_start(*_rsu_sx, true, false);
+    column->pack_start(*_rsu_sy, true, false);
+    column->pack_start(*_rcp_gcol, true, false);
+    column->pack_start(*_rcp_gmcol, true, false);
+    column->pack_start(*_rsi, true, false);
+
+    return column;
+}
+
+
+/**
+ * Update dialog widgets from object's values.
+ */
+void
+CanvasXYGrid::updateWidgets()
+{
+    if (_wr.isUpdating()) return;
+
+    //no widgets (grid created with the document, not with the dialog)
+    if (!_rcb_visible) return;
+
+    _wr.setUpdating (true);
+
+    _rcb_visible->setActive(visible);
+    if (snapper != nullptr) {
+        _rcb_enabled->setActive(snapper->getEnabled());
+        _rcb_snap_visible_only->setActive(snapper->getSnapVisibleOnly());
+    }
+
+    _rumg->setUnit (gridunit->abbr);
+
+    gdouble val;
+
+    val = origin[Geom::X];
+    val = Inkscape::Util::Quantity::convert(val, "px", gridunit);
+    _rsu_ox->setValue (val);
+
+    val = origin[Geom::Y];
+    val = Inkscape::Util::Quantity::convert(val, "px", gridunit);
+    _rsu_oy->setValue (val);
+
+    val = spacing[Geom::X];
+    val = Inkscape::Util::Quantity::convert(val, "px", gridunit);
+    _rsu_sx->setValue (val);
+
+    val = spacing[Geom::Y];
+    val = Inkscape::Util::Quantity::convert(val, "px", gridunit);
+    _rsu_sy->setValue (val);
+
+    _rsu_ox->setProgrammatically = false;
+    _rsu_oy->setProgrammatically = false;
+    _rsu_sx->setProgrammatically = false;
+    _rsu_sy->setProgrammatically = false;
+
+    _rcp_gcol->setRgba32 (color);
+    _rcp_gmcol->setRgba32 (empcolor);
+    _rsi->setValue (empspacing);
+    _rcb_dotted->setActive (render_dotted);
+
+    _wr.setUpdating (false);
+}
+
+// For correcting old SVG Inkscape files
+void
+CanvasXYGrid::Scale (Geom::Scale const &scale ) {
+    origin *= scale;
+    spacing *= scale;
+
+    // Write out in 'user-units'
+    Inkscape::SVGOStringStream os_x, os_y, ss_x, ss_y;
+    os_x << origin[Geom::X];
+    os_y << origin[Geom::Y];
+    ss_x << spacing[Geom::X];
+    ss_y << spacing[Geom::Y];
+    repr->setAttribute("originx",  os_x.str());
+    repr->setAttribute("originy",  os_y.str());
+    repr->setAttribute("spacingx", ss_x.str());
+    repr->setAttribute("spacingy", ss_y.str());
+}
+
+void
+CanvasXYGrid::Update (Geom::Affine const &affine, unsigned int /*flags*/)
+{
+    ow = origin * affine;
+    sw[0] = Geom::Point(spacing[0], 0) * affine.withoutTranslation();
+    sw[1] = Geom::Point(0, spacing[1]) * affine.withoutTranslation();
+
+    // Find suitable grid spacing for display
+    for(int dim = 0; dim < 2; dim++) {
+        gint scaling_factor = empspacing;
+
+        if (scaling_factor <= 1)
+            scaling_factor = 5;
+
+        scaled[dim] = false;
+        while (fabs(sw[dim].length()) < 8.0) {
+            scaled[dim] = true;
+            sw[dim] *= scaling_factor;
+            /* First pass, go up to the major line spacing, then
+               keep increasing by two. */
+            scaling_factor = 2;
+        }
+    }
+}
+
+
+// Find intersections of line with rectangle. There should be zero or two.
+// If line is degenerate with rectangle side, two corner points are returned.
+static std::vector<Geom::Point>
+intersect_line_rectangle( Geom::Line const &line, Geom::Rect const &rect )
+{
+    std::vector<Geom::Point> intersections;
+    for (unsigned i = 0; i < 4; ++i) {
+        Geom::LineSegment side( rect.corner(i), rect.corner((i+1)%4) );
+        try {
+            Geom::OptCrossing oc = Geom::intersection(line, side);
+            if (oc) {
+                intersections.push_back( line.pointAt((*oc).ta));
+            }
+        } catch (Geom::InfiniteSolutions) {
+            intersections.clear();
+            intersections.push_back( side.pointAt(0) );
+            intersections.push_back( side.pointAt(1) );
+            return intersections;
+        }
+    }
+    return intersections;
+}
+
+// Find the signed distance of a point to a line. The distance is negative if
+// the point lies to the left of the line considering the line's versor.
+static double
+signed_distance( Geom::Point const &point, Geom::Line const &line ) {
+    Geom::Coord t = line.nearestTime( point );
+    Geom::Point p = line.pointAt(t);
+    double distance = Geom::distance( p, point );
+    if ( Geom::cross( Geom::Line( p, point ).versor(), line.versor() ) < 0.0 ) {
+        distance = -distance;
+    }
+    return distance;
+}
+
+void
+CanvasXYGrid::Render (Inkscape::CanvasItemBuffer *buf)
+{
+
+    // no_emphasize_when_zoomedout determines color (minor or major) when only major grid lines/dots shown.
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    guint32 _empcolor;
+    guint32 _color = color;
+    bool no_emp_when_zoomed_out = prefs->getBool("/options/grids/no_emphasize_when_zoomedout", false);
+    if( (scaled[Geom::X] || scaled[Geom::Y]) && no_emp_when_zoomed_out ) {
+        _empcolor = color;
+    } else {
+        _empcolor = empcolor;
+    }
+
+    bool xrayactive = prefs->getBool("/desktop/xrayactive", false);
+    if (xrayactive) {
+        guint32 bg = 0xffffffff;
+        _color = SP_RGBA32_F_COMPOSE(
+                CLAMP(((1 - SP_RGBA32_A_F(_color)) * SP_RGBA32_R_F(bg)) + (SP_RGBA32_A_F(_color) * SP_RGBA32_R_F(_color)), 0.0, 1.0),
+                CLAMP(((1 - SP_RGBA32_A_F(_color)) * SP_RGBA32_G_F(bg)) + (SP_RGBA32_A_F(_color) * SP_RGBA32_G_F(_color)), 0.0, 1.0),
+                CLAMP(((1 - SP_RGBA32_A_F(_color)) * SP_RGBA32_B_F(bg)) + (SP_RGBA32_A_F(_color) * SP_RGBA32_B_F(_color)), 0.0, 1.0),
+                1.0);
+        _empcolor = SP_RGBA32_F_COMPOSE(
+                CLAMP(((1 - SP_RGBA32_A_F(_empcolor)) * SP_RGBA32_R_F(bg)) + (SP_RGBA32_A_F(_empcolor) * SP_RGBA32_R_F(_empcolor)), 0.0, 1.0),
+                CLAMP(((1 - SP_RGBA32_A_F(_empcolor)) * SP_RGBA32_G_F(bg)) + (SP_RGBA32_A_F(_empcolor) * SP_RGBA32_G_F(_empcolor)), 0.0, 1.0),
+                CLAMP(((1 - SP_RGBA32_A_F(_empcolor)) * SP_RGBA32_B_F(bg)) + (SP_RGBA32_A_F(_empcolor) * SP_RGBA32_B_F(_empcolor)), 0.0, 1.0),
+                1.0);
+    }
+
+    buf->cr->save();
+    buf->cr->translate(-buf->rect.left(), -buf->rect.top());
+    buf->cr->set_line_width(1.0);
+    buf->cr->set_line_cap(Cairo::LINE_CAP_SQUARE);
+
+    // Adding a 2 px margin to the buffer rectangle to avoid missing intersections (in case of rounding errors, and due to adding 0.5 below)
+    Geom::IntRect buf_rect_with_margin = buf->rect;
+    buf_rect_with_margin.expandBy(2);
+
+    for (unsigned dim = 0; dim < 2; ++dim) {
+
+        // std::cout << "\n  " << (dim==0?"Horizontal":"Vertical") << "   ------------" << std::endl;
+
+        // Construct an axis line through origin with direction normal to grid spacing.
+        Geom::Line axis = Geom::Line::from_origin_and_vector( ow, sw[dim]       );
+        Geom::Line orth = Geom::Line::from_origin_and_vector( ow, sw[(dim+1)%2] );
+
+        double spacing = sw[(dim+1)%2].length();  // Spacing between grid lines.
+        double dash    = sw[dim].length();        // Total length of dash pattern.
+
+        // std::cout << "  axis: " << axis.origin() << ", " << axis.vector() << std::endl;
+        // std::cout << "  spacing: " << spacing << std::endl;
+        // std::cout << "  dash period: " << dash << std::endl;
+
+        // Find the minimum and maximum distances of the buffer corners from axis.
+        double min =  Geom::infinity();
+        double max = -Geom::infinity();
+        for (unsigned c = 0; c < 4; ++c) {
+
+            // We need signed distance... lib2geom offers only positive distance.
+            double distance = signed_distance( buf_rect_with_margin.corner(c), axis );
+
+            // Correct it for coordinate flips (inverts handedness).
+            if (Geom::cross( axis.vector(), orth.vector() ) > 0 ) {
+                distance = -distance;
+            }
+
+            if (distance < min)
+                min = distance;
+            if (distance > max)
+                max = distance;
+        }
+        int start = floor( min/spacing );
+        int stop  = floor( max/spacing );
+
+        // std::cout << "  rect: " << buf->rect << std::endl;
+        // std::cout << "  min: " << min << "  max: " << max << std::endl;
+        // std::cout << "  start: " << start << "  stop: " << stop << std::endl;
+
+        // Loop over grid lines that intersected buf rectangle.
+        for (int j = start+1; j <= stop; ++j) {
+
+            Geom::Line grid_line = Geom::make_parallel_line( ow + j * sw[(dim+1)%2], axis );
+
+            std::vector<Geom::Point> x = intersect_line_rectangle( grid_line, buf_rect_with_margin );
+
+            // If we have two intersections, grid line intersects buffer rectangle.
+            if (x.size() == 2 ) {
+                // Make sure lines are always drawn in the same direction (or dashes misplaced).
+                Geom::Line vector( x[0], x[1]);
+                if (Geom::dot( vector.vector(), axis.vector() ) < 0.0) {
+                    std::swap(x[0], x[1]);
+                }
+
+                // Set up line. Need to use floor()+0.5 such that Cairo will draw us lines with a width of a single pixel, without any aliasing.
+                // For this we need to position the lines at exactly half pixels, see https://www.cairographics.org/FAQ/#sharp_lines
+                // Must be consistent with the pixel alignment of the guide lines, see CanvasXYGrid::Render(), and the drawing of the rulers
+                buf->cr->move_to(floor(x[0][Geom::X]) + 0.5, floor(x[0][Geom::Y]) + 0.5);
+                buf->cr->line_to(floor(x[1][Geom::X]) + 0.5, floor(x[1][Geom::Y]) + 0.5);
+                
+                // Set dash pattern and color.
+                if (render_dotted) {
+                    // alpha needs to be larger than in the line case to maintain a similar
+                    // visual impact but setting it to the maximal value makes the dots
+                    // dominant in some cases. Solution, increase the alpha by a factor of
+                    // 4. This then allows some user adjustment.
+                    guint32 _empdot = (_empcolor & 0xff) << 2;
+                    if (_empdot > 0xff)
+                        _empdot = 0xff;
+                    _empdot += (_empcolor & 0xffffff00);
+
+                    guint32 _colordot = (_color & 0xff) << 2;
+                    if (_colordot > 0xff)
+                        _colordot = 0xff;
+                    _colordot += (_color & 0xffffff00);
+
+                    // Dash pattern must use spacing from orthogonal direction.
+                    // Offset is to center dash on orthogonal lines.
+                    double offset = fmod( signed_distance( x[0], orth ), sw[dim].length());
+                    if (Geom::cross( axis.vector(), orth.vector() ) > 0 ) {
+                        offset = -offset;
+                    }
+
+                    std::vector<double> dashes;
+                    if (!scaled[dim] && (j % empspacing) != 0) {
+                        // Minor lines
+                        dashes.push_back(1.0);
+                        dashes.push_back(dash - 1.0);
+                        offset -= 0.5;
+                        buf->cr->set_source_rgba(SP_RGBA32_R_F(_colordot), SP_RGBA32_G_F(_colordot),
+                                                 SP_RGBA32_B_F(_colordot), SP_RGBA32_A_F(_colordot));
+                    } else {
+                        // Major lines
+                        dashes.push_back(3.0);
+                        dashes.push_back(dash - 3.0);
+                        offset -= 1.5; // Center dash on intersection.
+                        buf->cr->set_source_rgba(SP_RGBA32_R_F(_empdot), SP_RGBA32_G_F(_empdot),
+                                                 SP_RGBA32_B_F(_empdot), SP_RGBA32_A_F(_empdot));
+                    }
+
+                    buf->cr->set_line_cap(Cairo::LINE_CAP_BUTT);
+                    buf->cr->set_dash(dashes, -offset);
+
+                } else {
+
+                    // Solid lines
+
+                    // Set color
+                    if (!scaled[dim] && (j % empspacing) != 0) {
+                        buf->cr->set_source_rgba(SP_RGBA32_R_F(_color), SP_RGBA32_G_F(_color),
+                                                 SP_RGBA32_B_F(_color), SP_RGBA32_A_F(_color));
+                    } else {
+                        buf->cr->set_source_rgba(SP_RGBA32_R_F(_empcolor), SP_RGBA32_G_F(_empcolor),
+                                                 SP_RGBA32_B_F(_empcolor), SP_RGBA32_A_F(_empcolor));
+                    }
+                }
+
+                buf->cr->stroke();
+
+            } else {
+                std::cerr << "CanvasXYGrid::render: Grid line doesn't intersect!" << std::endl;
+            }
+        }
+    }
+
+    buf->cr->restore();
+}
+
+CanvasXYGridSnapper::CanvasXYGridSnapper(CanvasXYGrid *grid, SnapManager *sm, Geom::Coord const d) : LineSnapper(sm, d)
+{
+    this->grid = grid;
+}
+
+/**
+ *  \return Snap tolerance (desktop coordinates); depends on current zoom so that it's always the same in screen pixels
+ */
+Geom::Coord CanvasXYGridSnapper::getSnapperTolerance() const
+{
+    SPDesktop const *dt = _snapmanager->getDesktop();
+    double const zoom =  dt ? dt->current_zoom() : 1;
+    return _snapmanager->snapprefs.getGridTolerance() / zoom;
+}
+
+bool CanvasXYGridSnapper::getSnapperAlwaysSnap() const
+{
+    return _snapmanager->snapprefs.getGridTolerance() == 10000; //TODO: Replace this threshold of 10000 by a constant; see also tolerance-slider.cpp
+}
+
+LineSnapper::LineList
+CanvasXYGridSnapper::_getSnapLines(Geom::Point const &p) const
+{
+    LineList s;
+
+    if ( grid == nullptr ) {
+        return s;
+    }
+
+    for (unsigned int i = 0; i < 2; ++i) {
+
+        double spacing;
+
+        if (getSnapVisibleOnly()) {
+            // Only snapping to visible grid lines
+            spacing = grid->sw[i].length(); // this is the spacing of the visible grid lines measured in screen pixels
+            // convert screen pixels to px
+            // FIXME: after we switch to snapping dist in screen pixels, this will be unnecessary
+            SPDesktop const *dt = _snapmanager->getDesktop();
+            if (dt) {
+                spacing /= dt->current_zoom();
+            }
+        } else {
+            // Snapping to any grid line, whether it's visible or not
+            spacing = grid->spacing[i];
+        }
+
+        Geom::Coord rounded;
+        Geom::Point point_on_line;
+        Geom::Point cvec(0.,0.);
+        cvec[i] = 1.;
+
+        rounded = Inkscape::Util::round_to_upper_multiple_plus(p[i], spacing, grid->origin[i]);
+        point_on_line = i ? Geom::Point(0, rounded) : Geom::Point(rounded, 0);
+        s.push_back(std::make_pair(cvec, point_on_line));
+
+        rounded = Inkscape::Util::round_to_lower_multiple_plus(p[i], spacing, grid->origin[i]);
+        point_on_line = i ? Geom::Point(0, rounded) : Geom::Point(rounded, 0);
+        s.push_back(std::make_pair(cvec, point_on_line));
+    }
+
+    return s;
+}
+
+void CanvasXYGridSnapper::_addSnappedLine(IntermSnapResults &isr, Geom::Point const &snapped_point, Geom::Coord const &snapped_distance,  SnapSourceType const &source, long source_num, Geom::Point const &normal_to_line, Geom::Point const &point_on_line) const
+{
+    SnappedLine dummy = SnappedLine(snapped_point, snapped_distance, source, source_num, Inkscape::SNAPTARGET_GRID, getSnapperTolerance(), getSnapperAlwaysSnap(), normal_to_line, point_on_line);
+    isr.grid_lines.push_back(dummy);
+}
+
+void CanvasXYGridSnapper::_addSnappedPoint(IntermSnapResults &isr, Geom::Point const &snapped_point, Geom::Coord const &snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const
+{
+    SnappedPoint dummy = SnappedPoint(snapped_point, source, source_num, Inkscape::SNAPTARGET_GRID, snapped_distance, getSnapperTolerance(), getSnapperAlwaysSnap(), constrained_snap, true);
+    isr.points.push_back(dummy);
+}
+
+void CanvasXYGridSnapper::_addSnappedLinePerpendicularly(IntermSnapResults &isr, Geom::Point const &snapped_point, Geom::Coord const &snapped_distance, SnapSourceType const &source, long source_num, bool constrained_snap) const
+{
+    SnappedPoint dummy = SnappedPoint(snapped_point, source, source_num, Inkscape::SNAPTARGET_GRID_PERPENDICULAR, snapped_distance, getSnapperTolerance(), getSnapperAlwaysSnap(), constrained_snap, true);
+    isr.points.push_back(dummy);
+}
+
+/**
+ *  \return true if this Snapper will snap at least one kind of point.
+ */
+bool CanvasXYGridSnapper::ThisSnapperMightSnap() const
+{
+    return _snap_enabled && _snapmanager->snapprefs.isTargetSnappable(Inkscape::SNAPTARGET_GRID);
+}
+
+} // namespace Inkscape
+
+
+/*
+  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 :