1 files changed, 196 insertions, 0 deletions
diff --git a/src/ui/tool/curve-drag-point.cpp b/src/ui/tool/curve-drag-point.cpp
new file mode 100644
index 000000000..e761daf20
--- /dev/null
+++ b/src/ui/tool/curve-drag-point.cpp
@@ -0,0 +1,196 @@
+/** @file
+ * Control point that is dragged during path drag
+ */
+/* Authors:
+ *   Krzysztof Kosiński <tweenk.pl@gmail.com>
+ *
+ * Copyright (C) 2009 Authors
+ * Released under GNU GPL, read the file 'COPYING' for more information
+ */
+
+#include <glib/gi18n.h>
+#include <2geom/bezier-curve.h>
+#include "desktop.h"
+#include "ui/tool/control-point-selection.h"
+#include "ui/tool/curve-drag-point.h"
+#include "ui/tool/event-utils.h"
+#include "ui/tool/multi-path-manipulator.h"
+#include "ui/tool/path-manipulator.h"
+#include "ui/tool/node.h"
+
+namespace Inkscape {
+namespace UI {
+
+/**
+ * @class CurveDragPoint
+ * An invisible point used to drag curves. This point is used by PathManipulator to allow editing
+ * of path segments by dragging them. It is defined in a separate file so that the node tool
+ * can check if the mouseovered control point is a curve drag point and update the cursor
+ * accordingly, without the need to drag in the full PathManipulator header.
+ */
+
+// This point should be invisible to the user - use the invisible_cset from control-point.h
+// TODO make some methods from path-manipulator.cpp public so that this point doesn't have
+// to be declared as a friend
+
+bool CurveDragPoint::_drags_stroke = false;
+
+CurveDragPoint::CurveDragPoint(PathManipulator &pm)
+    : ControlPoint(pm._multi_path_manipulator._path_data.node_data.desktop, Geom::Point(),
+        Gtk::ANCHOR_CENTER, SP_CTRL_SHAPE_CIRCLE, 1.0, &invisible_cset,
+        pm._multi_path_manipulator._path_data.dragpoint_group)
+    , _pm(pm)
+{
+    setVisible(false);
+}
+
+bool CurveDragPoint::_eventHandler(GdkEvent *event)
+{
+    // do not process any events when the manipulator is empty
+    if (_pm.empty()) {
+        setVisible(false);
+        return false;
+    }
+    return ControlPoint::_eventHandler(event);
+}
+
+bool CurveDragPoint::grabbed(GdkEventMotion */*event*/)
+{
+    _pm._selection.hideTransformHandles();
+    NodeList::iterator second = first.next();
+
+    // move the handles to 1/3 the length of the segment for line segments
+    if (first->front()->isDegenerate() && second->back()->isDegenerate()) {
+
+        // delta is a vector equal 1/3 of distance from first to second
+        Geom::Point delta = (second->position() - first->position()) / 3.0;
+        first->front()->move(first->front()->position() + delta);
+        second->back()->move(second->back()->position() - delta);
+
+        _pm.update();
+    }
+    return false;
+}
+
+void CurveDragPoint::dragged(Geom::Point &new_pos, GdkEventMotion *)
+{
+    NodeList::iterator second = first.next();
+    // Magic Bezier Drag Equations follow!
+    // "weight" describes how the influence of the drag should be distributed
+    // among the handles; 0 = front handle only, 1 = back handle only.
+    double weight, t = _t;
+    if (t <= 1.0 / 6.0) weight = 0;
+    else if (t <= 0.5) weight = (pow((6 * t - 1) / 2.0, 3)) / 2;
+    else if (t <= 5.0 / 6.0) weight = (1 - pow((6 * (1-t) - 1) / 2.0, 3)) / 2 + 0.5;
+    else weight = 1;
+
+    Geom::Point delta = new_pos - position();
+    Geom::Point offset0 = ((1-weight)/(3*t*(1-t)*(1-t))) * delta;
+    Geom::Point offset1 = (weight/(3*t*t*(1-t))) * delta;
+
+    first->front()->move(first->front()->position() + offset0);
+    second->back()->move(second->back()->position() + offset1);
+
+    _pm.update();
+}
+
+void CurveDragPoint::ungrabbed(GdkEventButton *)
+{
+    _pm._updateDragPoint(_desktop->d2w(position()));
+    _pm._commit(_("Drag curve"));
+    _pm._selection.restoreTransformHandles();
+}
+
+bool CurveDragPoint::clicked(GdkEventButton *event)
+{
+    // This check is probably redundant
+    if (!first || event->button != 1) return false;
+    // the next iterator can be invalid if we click very near the end of path
+    NodeList::iterator second = first.next();
+    if (!second) return false;
+
+    // insert nodes on Ctrl+Alt+click
+    if (held_control(*event) && held_alt(*event)) {
+        _insertNode(false);
+        return true;
+    }
+
+    if (held_shift(*event)) {
+        // if both nodes of the segment are selected, deselect;
+        // otherwise add to selection
+        if (first->selected() && second->selected())  {
+            _pm._selection.erase(first.ptr());
+            _pm._selection.erase(second.ptr());
+        } else {
+            _pm._selection.insert(first.ptr());
+            _pm._selection.insert(second.ptr());
+        }
+    } else {
+        // without Shift, take selection
+        _pm._selection.clear();
+        _pm._selection.insert(first.ptr());
+        _pm._selection.insert(second.ptr());
+    }
+    return true;
+}
+
+bool CurveDragPoint::doubleclicked(GdkEventButton *event)
+{
+    if (event->button != 1 || !first || !first.next()) return false;
+    _insertNode(true);
+    return true;
+}
+
+void CurveDragPoint::_insertNode(bool take_selection)
+{
+    // The purpose of this call is to make way for the just created node.
+    // Otherwise clicks on the new node would only work after the user moves the mouse a bit.
+    // PathManipulator will restore visibility when necessary.
+    setVisible(false);
+    NodeList::iterator inserted = _pm.subdivideSegment(first, _t);
+    if (take_selection) {
+        _pm._selection.clear();
+    }
+    _pm._selection.insert(inserted.ptr());
+
+    _pm.update();
+    _pm._commit(_("Add node"));
+}
+
+Glib::ustring CurveDragPoint::_getTip(unsigned state)
+{
+    if (_pm.empty()) return "";
+    if (!first || !first.next()) return "";
+    bool linear = first->front()->isDegenerate() && first.next()->back()->isDegenerate();
+    if (state_held_shift(state)) {
+        return C_("Path segment tip",
+            "<b>Shift:</b> click to toggle segment selection");
+    }
+    if (state_held_control(state) && state_held_alt(state)) {
+        return C_("Path segment tip",
+            "<b>Ctrl+Alt:</b> click to insert a node");
+    }
+    if (linear) {
+        return C_("Path segment tip",
+            "<b>Linear segment:</b> drag to convert to a Bezier segment, "
+            "doubleclick to insert node, click to select (more: Shift, Ctrl+Alt)");
+    } else {
+        return C_("Path segment tip",
+            "<b>Bezier segment:</b> drag to shape the segment, doubleclick to insert node, "
+            "click to select (more: Shift, Ctrl+Alt)");
+    }
+}
+
+} // namespace UI
+} // 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:encoding=utf-8:textwidth=99 :