Adding upstream version 1.2.2.upstream/1.2.2upstream

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

1 files changed, 172 insertions, 0 deletions

diff --git a/src/line-snapper.cpp b/src/line-snapper.cpp
new file mode 100644
index 0000000..6882132
--- /dev/null
+++ b/src/line-snapper.cpp
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * LineSnapper class.
+ *
+ * Authors:
+ *   Diederik van Lierop <mail@diedenrezi.nl>
+ *   And others...
+ *
+ * Copyright (C) 1999-2012 Authors
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include <2geom/line.h>
+
+#include "line-snapper.h"
+#include "snap.h"
+
+Inkscape::LineSnapper::LineSnapper(SnapManager *sm, Geom::Coord const d) : Snapper(sm, d)
+{
+}
+
+void Inkscape::LineSnapper::freeSnap(IntermSnapResults &isr,
+                                                    Inkscape::SnapCandidatePoint const &p,
+                                                    Geom::OptRect const &/*bbox_to_snap*/,
+                                                    std::vector<SPObject const *> const */*it*/,
+                                                    std::vector<Inkscape::SnapCandidatePoint> */*unselected_nodes*/) const
+{
+    if (!(_snap_enabled && _snapmanager->snapprefs.isSourceSnappable(p.getSourceType())) ) {
+        return;
+    }
+
+    /* Get the lines that we will try to snap to */
+    const LineList lines = _getSnapLines(p.getPoint());
+
+    for (const auto & line : lines) {
+        Geom::Point const p1 = line.second; // point at guide/grid line
+        Geom::Point const p2 = p1 + Geom::rot90(line.first); // 2nd point at guide/grid line
+        assert(line.first != Geom::Point(0,0)); // we cannot project on an linesegment of zero length
+
+        Geom::Point const p_proj = Geom::projection(p.getPoint(), Geom::Line(p1, p2));
+        Geom::Coord const dist = Geom::L2(p_proj - p.getPoint());
+        //Store any line that's within snapping range
+        if (dist < getSnapperTolerance()) {
+            _addSnappedLine(isr, p_proj, dist, p.getSourceType(), p.getSourceNum(), line.first, line.second);
+            // For any line that's within range, we will also look at it's "point on line" p1. For guides
+            // this point coincides with its origin; for grids this is of no use, but we cannot
+            // discern between grids and guides here
+            Geom::Coord const dist_p1 = Geom::L2(p1 - p.getPoint());
+            if (dist_p1 < getSnapperTolerance()) {
+                _addSnappedLinesOrigin(isr, p1, dist_p1, p.getSourceType(), p.getSourceNum(), false);
+                // Only relevant for guides; grids don't have an origin per line
+                // Therefore _addSnappedLinesOrigin() will only be implemented for guides
+            }
+
+            // Here we will try to snap either tangentially or perpendicularly to a grid/guide line
+            // For this we need to know where the origin is located of the line that is currently being rotated,
+            std::vector<std::pair<Geom::Point, bool> > const origins_and_vectors = p.getOriginsAndVectors();
+            // Now we will iterate over all the origins and vectors and see which of these will get use a tangential or perpendicular snap
+            for (const auto & origins_and_vector : origins_and_vectors) {
+                if (origins_and_vector.second) { // if "second" is true then "first" is a vector, otherwise it's a point
+                    // When snapping a line with a constant vector (constant direction) to a guide or grid line,
+                    // then either all points will be perpendicular/tangential or none at all. This is not very useful
+                    continue;
+                }
+
+                //Geom::Point origin_doc = _snapmanager->getDesktop()->dt2doc((*it_origin_or_vector).first); // "first" contains a Geom::Point, denoting either a point
+                Geom::Point origin = origins_and_vector.first; // "first" contains a Geom::Point, denoting either a point
+
+                // We won't try to snap tangentially; a line being tangential to another line can be achieved by snapping both its endpoints
+                // individually to the other line. There's no need to have an explicit tangential snap here, that would be redundant
+
+                if (_snapmanager->snapprefs.isTargetSnappable(Inkscape::SNAPTARGET_PATH_PERPENDICULAR)) { // Find the point that leads to a perpendicular snap
+                    Geom::Point const origin_proj = Geom::projection(origin, Geom::Line(p1, p2));
+                    Geom::Coord dist = Geom::L2(origin_proj - p.getPoint());
+                    if (dist < getSnapperTolerance()) {
+                        _addSnappedLinePerpendicularly(isr, origin_proj, dist, p.getSourceType(), p.getSourceNum(), false);
+                    }
+                }
+            }
+        }
+    }
+}
+
+void Inkscape::LineSnapper::constrainedSnap(IntermSnapResults &isr,
+                                               Inkscape::SnapCandidatePoint const &p,
+                                               Geom::OptRect const &/*bbox_to_snap*/,
+                                               SnapConstraint const &c,
+                                               std::vector<SPObject const *> const */*it*/,
+                                               std::vector<SnapCandidatePoint> */*unselected_nodes*/) const
+
+{
+    if (_snap_enabled == false || _snapmanager->snapprefs.isSourceSnappable(p.getSourceType()) == false) {
+        return;
+    }
+
+    // project the mouse pointer onto the constraint. Only the projected point will be considered for snapping
+    Geom::Point pp = c.projection(p.getPoint());
+
+    /* Get the lines that we will try to snap to */
+    const LineList lines = _getSnapLines(pp);
+
+    for (const auto & line : lines) {
+        Geom::Point const point_on_line = c.hasPoint() ? c.getPoint() : pp;
+        Geom::Line gridguide_line(line.second, line.second + Geom::rot90(line.first));
+
+        if (c.isCircular()) {
+            // Find the intersections between the line and the circular constraint
+            // First, project the origin of the circle onto the line
+            Geom::Point const origin = c.getPoint();
+            Geom::Point const p_proj = Geom::projection(origin, gridguide_line);
+            Geom::Coord dist = Geom::L2(p_proj - origin); // distance from circle origin to constraint line
+            Geom::Coord radius = c.getRadius();
+            if (dist == radius) {
+                // Only one point of intersection;
+                _addSnappedPoint(isr, p_proj, Geom::L2(pp - p_proj), p.getSourceType(), p.getSourceNum(), true);
+            } else if (dist < radius) {
+                // Two points of intersection, symmetrical with respect to the projected point
+                // Calculate half the length of the linesegment between the two points of intersection
+                Geom::Coord l = sqrt(radius*radius - dist*dist);
+                Geom::Coord d = Geom::L2(gridguide_line.versor()); // length of versor, needed to normalize the versor
+                if (d > 0) {
+                    Geom::Point v = l*gridguide_line.versor()/d;
+                    _addSnappedPoint(isr, p_proj + v, Geom::L2(p.getPoint() - (p_proj + v)), p.getSourceType(), p.getSourceNum(), true);
+                    _addSnappedPoint(isr, p_proj - v, Geom::L2(p.getPoint() - (p_proj - v)), p.getSourceType(), p.getSourceNum(), true);
+                }
+            }
+        } else {
+            // Find the intersections between the line and the linear constraint
+            Geom::Line constraint_line(point_on_line, point_on_line + c.getDirection());
+            Geom::OptCrossing inters = Geom::OptCrossing(); // empty by default
+            try
+            {
+                inters = Geom::intersection(constraint_line, gridguide_line);
+            }
+            catch (Geom::InfiniteSolutions &e)
+            {
+                // We're probably dealing with parallel lines, so snapping doesn't make any sense here
+                continue; // jump to the next iterator in the for-loop
+            }
+
+            if (inters) {
+                Geom::Point t = constraint_line.pointAt((*inters).ta);
+                const Geom::Coord dist = Geom::L2(t - p.getPoint());
+                if (dist < getSnapperTolerance()) {
+                    // When doing a constrained snap, we're already at an intersection.
+                    // This snappoint is therefore fully constrained, so there's no need
+                    // to look for additional intersections; just return the snapped point
+                    // and forget about the line
+                    _addSnappedPoint(isr, t, dist, p.getSourceType(), p.getSourceNum(), true);
+                }
+            }
+        }
+    }
+}
+
+// Will only be overridden in the guide-snapper class, because grid lines don't have an origin; the
+// grid-snapper classes will use this default empty method
+void Inkscape::LineSnapper::_addSnappedLinesOrigin(IntermSnapResults &/*isr*/, Geom::Point const &/*origin*/, Geom::Coord const &/*snapped_distance*/, SnapSourceType const &/*source_type*/, long /*source_num*/, bool /*constrained_snap*/) const
+{
+}
+
+/*
+  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 :