From cca66b9ec4e494c1d919bff0f71a820d8afab1fa Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 7 Apr 2024 20:24:48 +0200
Subject: Adding upstream version 1.2.2.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 src/object/algorithms/graphlayout.cpp | 216 ++++++++++++++++++++++++++++++++++
 1 file changed, 216 insertions(+)
 create mode 100644 src/object/algorithms/graphlayout.cpp

(limited to 'src/object/algorithms/graphlayout.cpp')

diff --git a/src/object/algorithms/graphlayout.cpp b/src/object/algorithms/graphlayout.cpp
new file mode 100644
index 0000000..b31454f
--- /dev/null
+++ b/src/object/algorithms/graphlayout.cpp
@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/**
+ * @file
+ * Interface between Inkscape code (SPItem) and graphlayout functions.
+ */
+/*
+ * Authors:
+ *   Tim Dwyer <Tim.Dwyer@infotech.monash.edu.au>
+ *   Abhishek Sharma
+ *
+ * Copyright (C) 2005 Authors
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include <algorithm>
+#include <cstring>
+#include <iostream>
+#include <list>
+#include <map>
+#include <string>
+#include <valarray>
+#include <vector>
+
+#include <2geom/transforms.h>
+
+#include "conn-avoid-ref.h"
+#include "desktop.h"
+#include "graphlayout.h"
+#include "inkscape.h"
+
+#include "3rdparty/adaptagrams/libavoid/router.h"
+
+#include "3rdparty/adaptagrams/libcola/cola.h"
+#include "3rdparty/adaptagrams/libcola/connected_components.h"
+
+#include "object/sp-item-transform.h"
+#include "object/sp-namedview.h"
+#include "object/sp-path.h"
+#include "style.h"
+
+using namespace cola;
+using namespace vpsc;
+
+/**
+ * Returns true if item is a connector
+ */
+bool isConnector(SPItem const * const item) {
+    auto path = dynamic_cast<SPPath const *>(item);
+    return path && path->connEndPair.isAutoRoutingConn();
+}
+
+struct CheckProgress: TestConvergence {
+    CheckProgress(double d, unsigned i, std::list<SPItem*> & selected, Rectangles & rs,
+            std::map<std::string, unsigned> & nodelookup)
+        : TestConvergence(d, i)
+        , selected(selected)
+        , rs(rs)
+        , nodelookup(nodelookup)
+    {}
+    bool operator()(const double new_stress, std::valarray<double> & X, std::valarray<double> & Y) override {
+        /* This is where, if we wanted to animate the layout, we would need to update
+         * the positions of all objects and redraw the canvas and maybe sleep a bit
+         cout << "stress="<<new_stress<<endl;
+        cout << "x[0]="<<rs[0]->getMinX()<<endl;
+        for (std::list<SPItem *>::iterator it(selected.begin());
+            it != selected.end();
+            ++it)
+        {
+            SPItem *u=*it;
+            if(!isConnector(u)) {
+                Rectangle* r=rs[nodelookup[u->id]];
+                Geom::Rect const item_box(sp_item_bbox_desktop(u));
+                Geom::Point const curr(item_box.midpoint());
+                Geom::Point const dest(r->getCentreX(),r->getCentreY());
+                u->move_rel(Geom::Translate(dest - curr));
+            }
+        }
+        */
+        return TestConvergence::operator()(new_stress, X, Y);
+    }
+    std::list<SPItem*> & selected;
+    Rectangles & rs;
+    std::map<std::string, unsigned> & nodelookup;
+};
+
+/**
+ * Scans the items list and places those items that are
+ * not connectors in filtered
+ */
+void filterConnectors(std::vector<SPItem*> const & items, std::list<SPItem*> & filtered) {
+    for (SPItem * item: items) {
+        if (!isConnector(item)) {
+            filtered.push_back(item);
+        }
+    }
+}
+
+/**
+ * Takes a list of inkscape items, extracts the graph defined by
+ * connectors between them, and uses graph layout techniques to find
+ * a nice layout
+ */
+void graphlayout(std::vector<SPItem*> const & items) {
+    if (items.empty()) return;
+
+    std::list<SPItem*> selected;
+    filterConnectors(items, selected);
+    std::vector<SPItem*> connectors;
+    std::copy_if(items.begin(), items.end(), std::back_inserter(connectors), [](SPItem* item){return isConnector(item); });
+
+    if (selected.size() < 2) return;
+
+    // add the connector spacing to the size of node bounding boxes
+    // so that connectors can always be routed between shapes
+    SPDesktop * desktop = SP_ACTIVE_DESKTOP;
+    double spacing = 0;
+    if (desktop) spacing = desktop->namedview->connector_spacing + 0.1;
+
+    std::map<std::string, unsigned> nodelookup;
+    Rectangles rs;
+    std::vector<Edge> es;
+    for (SPItem * item: selected) {
+        Geom::OptRect const item_box = item->desktopVisualBounds();
+        if (item_box) {
+            Geom::Point ll(item_box->min());
+            Geom::Point ur(item_box->max());
+            nodelookup[item->getId()] = rs.size();
+            rs.push_back(new Rectangle(ll[0] - spacing, ur[0] + spacing,
+                    ll[1] - spacing, ur[1] + spacing));
+        } else {
+            // I'm not actually sure if it's possible for something with a
+            // NULL item-box to be attached to a connector in which case we
+            // should never get to here... but if such a null box can occur it's
+            // probably pretty safe to simply ignore
+            //fprintf(stderr, "NULL item_box found in graphlayout, ignoring!\n");
+        }
+    }
+
+    Inkscape::Preferences * prefs = Inkscape::Preferences::get();
+    CompoundConstraints constraints;
+    double ideal_connector_length = prefs->getDouble("/tools/connector/length", 100.0);
+    double directed_edge_height_modifier = 1.0;
+
+    bool directed       = prefs->getBool("/tools/connector/directedlayout");
+    bool avoid_overlaps = prefs->getBool("/tools/connector/avoidoverlaplayout");
+
+    for (SPItem* conn: connectors) {
+        SPPath* path = SP_PATH(conn);
+        std::array<SPItem*, 2> attachedItems;
+        path->connEndPair.getAttachedItems(attachedItems.data());
+        if (attachedItems[0] == nullptr) continue;
+        if (attachedItems[1] == nullptr) continue;
+        std::map<std::string, unsigned>::iterator i_iter=nodelookup.find(attachedItems[0]->getId());
+        if (i_iter == nodelookup.end()) continue;
+        unsigned rect_index_first = i_iter->second;
+        i_iter = nodelookup.find(attachedItems[1]->getId());
+        if (i_iter == nodelookup.end()) continue;
+        unsigned rect_index_second = i_iter->second;
+        es.emplace_back(rect_index_first, rect_index_second);
+
+        if (conn->style->marker_end.set) {
+            if (directed && strcmp(conn->style->marker_end.value(), "none")) {
+                constraints.push_back(new SeparationConstraint(YDIM, rect_index_first, rect_index_second,
+                                                               ideal_connector_length * directed_edge_height_modifier));
+            }
+        }
+    }
+
+    EdgeLengths elengths(es.size(), 1);
+    std::vector<Component*> cs;
+    connectedComponents(rs, es, cs);
+    for (Component * c: cs) {
+        if (c->edges.size() < 2) continue;
+        CheckProgress test(0.0001, 100, selected, rs, nodelookup);
+        ConstrainedMajorizationLayout alg(c->rects, c->edges, nullptr, ideal_connector_length, elengths, &test);
+        if (avoid_overlaps) alg.setAvoidOverlaps();
+        alg.setConstraints(&constraints);
+        alg.run();
+    }
+    separateComponents(cs);
+
+    for (SPItem * item: selected) {
+        if (!isConnector(item)) {
+            std::map<std::string, unsigned>::iterator i = nodelookup.find(item->getId());
+            if (i != nodelookup.end()) {
+                Rectangle * r = rs[i->second];
+                Geom::OptRect item_box = item->desktopVisualBounds();
+                if (item_box) {
+                    Geom::Point const curr(item_box->midpoint());
+                    Geom::Point const dest(r->getCentreX(),r->getCentreY());
+                    item->move_rel(Geom::Translate(dest - curr));
+                }
+            }
+        }
+    }
+    for (CompoundConstraint * c: constraints) {
+        delete c;
+    }
+    for (Rectangle * r: rs) {
+        delete r;
+    }
+}
+// vim: set cindent
+// vim: ts=4 sw=4 et tw=0 wm=0
+
+/*
+  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 :
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