From 179fa413b047bede6e32109e2ce82437c5fb8d34 Mon Sep 17 00:00:00 2001
From: MenTaLguY <mental@rydia.net>
Date: Mon, 16 Jan 2006 02:36:01 +0000
Subject: moving trunk for module inkscape

(bzr r1)
---
 src/line-snapper.cpp | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 src/line-snapper.cpp

(limited to 'src/line-snapper.cpp')

diff --git a/src/line-snapper.cpp b/src/line-snapper.cpp
new file mode 100644
index 000000000..383c1fb96
--- /dev/null
+++ b/src/line-snapper.cpp
@@ -0,0 +1,80 @@
+#include "libnr/nr-values.h"
+#include "libnr/nr-point-fns.h"
+#include "geom.h"
+#include "line-snapper.h"
+
+Inkscape::LineSnapper::LineSnapper(SPNamedView const *nv, NR::Coord const d) : Snapper(nv, d)
+{
+
+}
+
+Inkscape::SnappedPoint Inkscape::LineSnapper::_doFreeSnap(NR::Point const &p,
+                                                          std::list<SPItem const *> const &it) const
+{
+    /* Snap along x (ie to vertical lines) */
+    Inkscape::SnappedPoint const v = _doConstrainedSnap(p, component_vectors[NR::X], it);
+    /* Snap along y (ie to horizontal lines) */
+    Inkscape::SnappedPoint const h = _doConstrainedSnap(p, component_vectors[NR::Y], it);
+
+    /* If we snapped to both, combine the two results.  This is so that, for example,
+    ** we snap nicely to the intersection of two guidelines.
+    */
+    if (v.getDistance() < NR_HUGE && h.getDistance() < NR_HUGE) {
+        return SnappedPoint(NR::Point(v.getPoint()[NR::X], h.getPoint()[NR::Y]), hypot(v.getDistance(), h.getDistance()));
+    }
+
+    /* If we snapped to a vertical line, return that */
+    if (v.getDistance() < NR_HUGE) {
+        return v;
+    }
+
+    /* Otherwise just return any horizontal snap; if we didn't snap to that either
+    ** we haven't snapped to anything.
+    */
+    return h;
+}
+
+Inkscape::SnappedPoint Inkscape::LineSnapper::_doConstrainedSnap(NR::Point const &p,
+                                                                 NR::Point const &c,
+                                                                 std::list<SPItem const *> const &it) const
+{
+    Inkscape::SnappedPoint s = SnappedPoint(p, NR_HUGE);
+
+    NR::Point const v = NR::unit_vector(c);
+
+    /* Get the lines that we will try to snap to */
+    const LineList lines = _getSnapLines(p);
+
+    for (LineList::const_iterator i = lines.begin(); i != lines.end(); i++) {
+
+        /* Normal to the line we're trying to snap along */
+        NR::Point const n(NR::rot90(v));
+
+        /* Hence constant term of the line we're trying to snap along */
+        NR::Coord const q = dot(n, p);
+
+        /* Try to intersect this line with the target line */
+        NR::Point t = p;
+        IntersectorKind const k = intersector_line_intersection(n, q, component_vectors[i->first], i->second, t);
+
+        if (k == INTERSECTS) {
+            const NR::Coord dist = L2(t - p);
+            if (dist < getDistance() && dist < s.getDistance() ) {
+                s = SnappedPoint(t, dist);
+            }
+        }
+    }
+
+    return s;
+}
+
+/*
+  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 :
-- 
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