Snap to intersections of any kind of path (were we previously only could snap to intersections of line-segments)

(bzr r6597)

1 files changed, 146 insertions, 0 deletions

diff --git a/src/snapped-curve.cpp b/src/snapped-curve.cpp
new file mode 100644
index 000000000..c6b7edc8a
--- /dev/null
+++ b/src/snapped-curve.cpp
@@ -0,0 +1,146 @@
+/**

+ *    \file src/snapped-curve.cpp

+ *    \brief SnappedCurve class.

+ *

+ *    Authors:

+ *      Diederik van Lierop <mail@diedenrezi.nl>

+ *

+ *    Released under GNU GPL, read the file 'COPYING' for more information.

+ */

+

+#include "snapped-curve.h"

+#include "libnr/nr-values.h"

+#include <2geom/crossing.h>

+#include <2geom/path-intersection.h>

+#include <libnr/nr-convert2geom.h>

+

+// These two are needed for SP_ACTIVE_DESKTOP; this is a dirty hack

+#include "desktop.h"

+#include "inkscape.h"

+

+Inkscape::SnappedCurve::SnappedCurve(NR::Point const &snapped_point, NR::Coord const &snapped_distance, NR::Coord const &snapped_tolerance, bool const &always_snap, Geom::Curve const *curve)

+{

+	_distance = snapped_distance;

+    _tolerance = snapped_tolerance;

+    _always_snap = always_snap;

+    _curve = curve;

+	_second_distance = NR_HUGE;

+    _second_tolerance = 0;

+    _second_always_snap = false;

+	_point = snapped_point;

+	_at_intersection = false;

+}

+

+Inkscape::SnappedCurve::SnappedCurve() 

+{

+	_distance = NR_HUGE;

+    _tolerance = 0;

+    _always_snap = false;

+    _curve = NULL;

+	_second_distance = NR_HUGE;

+    _second_tolerance = 0;

+    _second_always_snap = false;

+	_point = NR::Point(0,0);

+	_at_intersection = false;

+}

+

+Inkscape::SnappedCurve::~SnappedCurve()

+{

+}

+

+Inkscape::SnappedPoint Inkscape::SnappedCurve::intersect(SnappedCurve const &curve, NR::Point const &p) const 

+{

+    // Calculate the intersections of two curves, which are both within snapping range, and

+    // return only the closest intersection

+    // The point of intersection should be considered for snapping, but might be outside the snapping range

+    // PS: We need p (the location of the mouse pointer) for find out which intersection is the

+    // closest, as there might be multiple intersections of two curves

+    Geom::SimpleCrosser xr;

+    Geom::Crossings cs = xr.crossings(*(this->_curve), *(curve._curve));

+     

+    if (cs.size() > 0) {

+        // There might be multiple intersections: find the closest

+        Geom::Coord best_dist = NR_HUGE;

+        Geom::Point best_p = Geom::Point(NR_HUGE, NR_HUGE);

+        for (std::vector<Geom::Crossing>::const_iterator i = cs.begin(); i != cs.end(); i++) {

+            Geom::Point p_ix = this->_curve->pointAt((*i).ta);

+            Geom::Coord dist = Geom::distance(p_ix, p);

+            if (dist < best_dist) {

+                best_dist = dist;

+                best_p = p_ix;

+            }

+        }

+        

+        // Now we've found the closests intersection, return it as a SnappedPoint

+        bool const use_this_as_primary = _distance < curve.getDistance();

+        Inkscape::SnappedCurve const *primaryC = use_this_as_primary ? this : &curve;

+        Inkscape::SnappedCurve const *secondaryC = use_this_as_primary ? &curve : this;

+        // The intersection should in fact be returned in desktop coordinates, but for this

+        // we need a desktop: this is a dirty hack

+        SPDesktop const *desktop = SP_ACTIVE_DESKTOP;

+        best_p = desktop->dt2doc(best_p);

+        // TODO: Investigate whether it is possible to use document coordinates everywhere

+        // in the snapper code. Only the mouse position should be in desktop coordinates, I guess.

+        // All paths are already in document coords and we are certainly not going to change THAT.

+        return SnappedPoint(from_2geom(best_p), Inkscape::SNAPTARGET_PATH_INTERSECTION, primaryC->getDistance(), primaryC->getTolerance(), primaryC->getAlwaysSnap(), true, 

+                                          secondaryC->getDistance(), secondaryC->getTolerance(), secondaryC->getAlwaysSnap());

+    }

+    

+    // No intersection

+    return SnappedPoint(NR::Point(NR_HUGE, NR_HUGE), SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false, NR_HUGE, 0, false);

+}

+

+// search for the closest snapped line

+bool getClosestCurve(std::list<Inkscape::SnappedCurve> const &list, Inkscape::SnappedCurve &result) 

+{

+    bool success = false;

+    

+    for (std::list<Inkscape::SnappedCurve>::const_iterator i = list.begin(); i != list.end(); i++) {

+        if ((i == list.begin()) || (*i).getDistance() < result.getDistance()) {

+            result = *i;

+            success = true;

+        }   

+    }

+    

+    return success; 

+}

+

+// search for the closest intersection of two snapped curves, which are both member of the same collection

+bool getClosestIntersectionCS(std::list<Inkscape::SnappedCurve> const &list, NR::Point const &p, Inkscape::SnappedPoint &result)

+{

+    bool success = false;

+    

+    for (std::list<Inkscape::SnappedCurve>::const_iterator i = list.begin(); i != list.end(); i++) {

+        std::list<Inkscape::SnappedCurve>::const_iterator j = i;

+        j++;

+        for (; j != list.end(); j++) {

+            Inkscape::SnappedPoint sp = (*i).intersect(*j, p);

+            if (sp.getAtIntersection()) {

+                // if it's the first point

+                bool const c1 = !success;

+                // or, if it's closer             

+                bool const c2 = sp.getDistance() < result.getDistance();

+                // or, if it's just then look at the other distance 

+                // (only relevant for snapped points which are at an intersection

+                bool const c3 = (sp.getDistance() == result.getDistance()) && (sp.getSecondDistance() < result.getSecondDistance()); 

+                // then prefer this point over the previous one

+                if (c1 || c2 || c3) {  

+                    result = sp;

+                    success = true;

+                }

+            }               

+        }

+    }

+    

+    return success; 

+}

+/*

+  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 :