Commit a merge to trunk, with probabal errors

(bzr r11073.1.36)

1 files changed, 868 insertions, 0 deletions

diff --git a/src/ui/tools/pencil-tool.cpp b/src/ui/tools/pencil-tool.cpp
new file mode 100644
index 000000000..230ec62af
--- /dev/null
+++ b/src/ui/tools/pencil-tool.cpp
@@ -0,0 +1,868 @@
+/** \file
+ * Pencil event context implementation.
+ */
+
+/*
+ * Authors:
+ *   Lauris Kaplinski <lauris@kaplinski.com>
+ *   bulia byak <buliabyak@users.sf.net>
+ *   Jon A. Cruz <jon@joncruz.org>
+ *
+ * Copyright (C) 2000 Lauris Kaplinski
+ * Copyright (C) 2000-2001 Ximian, Inc.
+ * Copyright (C) 2002 Lauris Kaplinski
+ * Copyright (C) 2004 Monash University
+ *
+ * Released under GNU GPL, read the file 'COPYING' for more information
+ */
+
+#include <gdk/gdkkeysyms.h>
+
+#include "ui/tools/pencil-tool.h"
+#include "desktop.h"
+#include "desktop-handles.h"
+#include "selection.h"
+#include "selection-chemistry.h"
+#include "draw-anchor.h"
+#include "message-stack.h"
+#include "message-context.h"
+#include "modifier-fns.h"
+#include "sp-path.h"
+#include "preferences.h"
+#include "snap.h"
+#include "pixmaps/cursor-pencil.xpm"
+#include <2geom/sbasis-to-bezier.h>
+#include <2geom/bezier-utils.h>
+#include "display/canvas-bpath.h"
+#include <glibmm/i18n.h>
+#include "context-fns.h"
+#include "sp-namedview.h"
+#include "xml/repr.h"
+#include "document.h"
+#include "desktop-style.h"
+#include "macros.h"
+#include "display/sp-canvas.h"
+#include "display/curve.h"
+#include "livarot/Path.h"
+#include "tool-factory.h"
+
+namespace Inkscape {
+namespace UI {
+namespace Tools {
+
+static Geom::Point pencil_drag_origin_w(0, 0);
+static bool pencil_within_tolerance = false;
+
+static bool in_svg_plane(Geom::Point const &p) { return Geom::LInfty(p) < 1e18; }
+
+namespace {
+	ToolBase* createPencilContext() {
+		return new PencilTool();
+	}
+
+	bool pencilContextRegistered = ToolFactory::instance().registerObject("/tools/freehand/pencil", createPencilContext);
+}
+
+const std::string& PencilTool::getPrefsPath() {
+	return PencilTool::prefsPath;
+}
+
+const std::string PencilTool::prefsPath = "/tools/freehand/pencil";
+
+PencilTool::PencilTool()
+    : FreehandBase(cursor_pencil_xpm, 4, 4)
+    , p()
+    , npoints(0)
+    , state(SP_PENCIL_CONTEXT_IDLE)
+    , req_tangent(0, 0)
+    , is_drawing(false)
+    , sketch_n(0)
+{
+}
+
+void PencilTool::setup() {
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    if (prefs->getBool("/tools/freehand/pencil/selcue")) {
+        this->enableSelectionCue();
+    }
+
+    FreehandBase::setup();
+
+    this->is_drawing = false;
+    this->anchor_statusbar = false;
+}
+
+PencilTool::~PencilTool() {
+}
+
+/** Snaps new node relative to the previous node. */
+void PencilTool::_endpointSnap(Geom::Point &p, guint const state) {
+    if ((state & GDK_CONTROL_MASK)) { //CTRL enables constrained snapping
+        if (this->npoints > 0) {
+            spdc_endpoint_snap_rotation(this, p, this->p[0], state);
+        }
+    } else {
+        if (!(state & GDK_SHIFT_MASK)) { //SHIFT disables all snapping, except the angular snapping above
+                                         //After all, the user explicitely asked for angular snapping by
+                                         //pressing CTRL
+            boost::optional<Geom::Point> origin = this->npoints > 0 ? this->p[0] : boost::optional<Geom::Point>();
+            spdc_endpoint_snap_free(this, p, origin, state);
+        }
+    }
+}
+
+/**
+ * Callback for handling all pencil context events.
+ */
+bool PencilTool::root_handler(GdkEvent* event) {
+    gint ret = FALSE;
+
+    switch (event->type) {
+        case GDK_BUTTON_PRESS:
+            ret = this->_handleButtonPress(event->button);
+            break;
+
+        case GDK_MOTION_NOTIFY:
+            ret = this->_handleMotionNotify(event->motion);
+            break;
+
+        case GDK_BUTTON_RELEASE:
+            ret = this->_handleButtonRelease(event->button);
+            break;
+
+        case GDK_KEY_PRESS:
+            ret = this->_handleKeyPress(get_group0_keyval (&event->key), event->key.state);
+            break;
+
+        case GDK_KEY_RELEASE:
+            ret = this->_handleKeyRelease(get_group0_keyval (&event->key), event->key.state);
+            break;
+
+        default:
+            break;
+    }
+
+    if (!ret) {
+    	ret = FreehandBase::root_handler(event);
+    }
+
+    return ret;
+}
+
+gint PencilTool::_handleButtonPress(GdkEventButton const &bevent) {
+    gint ret = FALSE;
+    ToolBase *event_context = SP_EVENT_CONTEXT(this);
+    if ( bevent.button == 1  && !event_context->space_panning) {
+
+        FreehandBase *dc = SP_DRAW_CONTEXT (this);
+        SPDesktop *desktop = dc->desktop;
+        Inkscape::Selection *selection = sp_desktop_selection(desktop);
+
+        if (Inkscape::have_viable_layer(desktop, dc->message_context) == false) {
+            return TRUE;
+        }
+
+        if (!this->grab) {
+            /* Grab mouse, so release will not pass unnoticed */
+            this->grab = SP_CANVAS_ITEM(desktop->acetate);
+            sp_canvas_item_grab(this->grab, ( GDK_KEY_PRESS_MASK | GDK_BUTTON_PRESS_MASK   |
+                                            GDK_BUTTON_RELEASE_MASK |
+                                            GDK_POINTER_MOTION_MASK  ),
+                                NULL, bevent.time);
+        }
+
+        Geom::Point const button_w(bevent.x, bevent.y);
+
+        /* Find desktop coordinates */
+        Geom::Point p = this->desktop->w2d(button_w);
+
+        /* Test whether we hit any anchor. */
+        SPDrawAnchor *anchor = spdc_test_inside(this, button_w);
+
+        pencil_drag_origin_w = Geom::Point(bevent.x,bevent.y);
+        pencil_within_tolerance = true;
+
+        switch (this->state) {
+            case SP_PENCIL_CONTEXT_ADDLINE:
+                /* Current segment will be finished with release */
+                ret = TRUE;
+                break;
+            default:
+                /* Set first point of sequence */
+                SnapManager &m = desktop->namedview->snap_manager;
+
+                if (bevent.state & GDK_CONTROL_MASK) {
+                    m.setup(desktop);
+                    if (!(bevent.state & GDK_SHIFT_MASK)) {
+                        m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
+                      }
+                    spdc_create_single_dot(event_context, p, "/tools/freehand/pencil", bevent.state);
+                    m.unSetup();
+                    ret = true;
+                    break;
+                }
+                if (anchor) {
+                    p = anchor->dp;
+                    desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Continuing selected path"));
+                } else {
+                    m.setup(desktop);
+                    if (!(bevent.state & GDK_SHIFT_MASK)) {
+                        // This is the first click of a new curve; deselect item so that
+                        // this curve is not combined with it (unless it is drawn from its
+                        // anchor, which is handled by the sibling branch above)
+                        selection->clear();
+                        desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Creating new path"));
+                        m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
+                    } else if (selection->singleItem() && SP_IS_PATH(selection->singleItem())) {
+                        desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Appending to selected path"));
+                        m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
+                    }
+                    m.unSetup();
+                }
+                this->sa = anchor;
+                this->_setStartpoint(p);
+                ret = TRUE;
+                break;
+        }
+
+        this->is_drawing = true;
+    }
+    return ret;
+}
+
+gint PencilTool::_handleMotionNotify(GdkEventMotion const &mevent) {
+    SPDesktop *const dt = this->desktop;
+
+    if ((mevent.state & GDK_CONTROL_MASK) && (mevent.state & GDK_BUTTON1_MASK)) {
+        // mouse was accidentally moved during Ctrl+click;
+        // ignore the motion and create a single point
+        this->is_drawing = false;
+        return TRUE;
+    }
+    gint ret = FALSE;
+
+    ToolBase *event_context = SP_EVENT_CONTEXT(this);
+    if (event_context->space_panning || mevent.state & GDK_BUTTON2_MASK || mevent.state & GDK_BUTTON3_MASK) {
+        // allow scrolling
+        return FALSE;
+    }
+
+    if ( ( mevent.state & GDK_BUTTON1_MASK ) && !this->grab && this->is_drawing) {
+        /* Grab mouse, so release will not pass unnoticed */
+        this->grab = SP_CANVAS_ITEM(dt->acetate);
+        sp_canvas_item_grab(this->grab, ( GDK_KEY_PRESS_MASK | GDK_BUTTON_PRESS_MASK   |
+                                        GDK_BUTTON_RELEASE_MASK |
+                                        GDK_POINTER_MOTION_MASK  ),
+                            NULL, mevent.time);
+    }
+
+    /* Find desktop coordinates */
+    Geom::Point p = dt->w2d(Geom::Point(mevent.x, mevent.y));
+
+    /* Test whether we hit any anchor. */
+    SPDrawAnchor *anchor = spdc_test_inside(this, Geom::Point(mevent.x, mevent.y));
+
+    if (pencil_within_tolerance) {
+        Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+        gint const tolerance = prefs->getIntLimited("/options/dragtolerance/value", 0, 0, 100);
+        if ( Geom::LInfty( Geom::Point(mevent.x,mevent.y) - pencil_drag_origin_w ) < tolerance ) {
+            return FALSE;   // Do not drag if we're within tolerance from origin.
+        }
+    }
+
+    // Once the user has moved farther than tolerance from the original location
+    // (indicating they intend to move the object, not click), then always process the
+    // motion notify coordinates as given (no snapping back to origin)
+    pencil_within_tolerance = false;
+
+    switch (this->state) {
+        case SP_PENCIL_CONTEXT_ADDLINE:
+            /* Set red endpoint */
+            if (anchor) {
+                p = anchor->dp;
+            } else {
+                Geom::Point ptnr(p);
+                this->_endpointSnap(ptnr, mevent.state);
+                p = ptnr;
+            }
+            this->_setEndpoint(p);
+            ret = TRUE;
+            break;
+        default:
+            /* We may be idle or already freehand */
+            if ( mevent.state & GDK_BUTTON1_MASK && this->is_drawing ) {
+                if (this->state == SP_PENCIL_CONTEXT_IDLE) {
+                    sp_event_context_discard_delayed_snap_event(event_context);
+                }
+                this->state = SP_PENCIL_CONTEXT_FREEHAND;
+
+                if ( !this->sa && !this->green_anchor ) {
+                    /* Create green anchor */
+                    this->green_anchor = sp_draw_anchor_new(this, this->green_curve, TRUE, this->p[0]);
+                }
+                if (anchor) {
+                    p = anchor->dp;
+                }
+
+                if ( this->npoints != 0) { // buttonpress may have happened before we entered draw context!
+                    if (this->ps.empty()) {
+                        // Only in freehand mode we have to add the first point also to pc->ps (apparently)
+                        // - We cannot add this point in spdc_set_startpoint, because we only need it for freehand
+                        // - We cannot do this in the button press handler because at that point we don't know yet
+                        //   wheter we're going into freehand mode or not
+                        this->ps.push_back(this->p[0]);
+                    }
+                    this->_addFreehandPoint(p, mevent.state);
+                    ret = TRUE;
+                }
+
+                if (anchor && !this->anchor_statusbar) {
+                    this->message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Release</b> here to close and finish the path."));
+                    this->anchor_statusbar = true;
+                } else if (!anchor && this->anchor_statusbar) {
+                    this->message_context->clear();
+                    this->anchor_statusbar = false;
+                } else if (!anchor) {
+                    this->message_context->set(Inkscape::NORMAL_MESSAGE, _("Drawing a freehand path"));
+                }
+
+            } else {
+                if (anchor && !this->anchor_statusbar) {
+                    this->message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drag</b> to continue the path from this point."));
+                    this->anchor_statusbar = true;
+                } else if (!anchor && this->anchor_statusbar) {
+                    this->message_context->clear();
+                    this->anchor_statusbar = false;
+                }
+            }
+
+            // Show the pre-snap indicator to communicate to the user where we would snap to if he/she were to
+            // a) press the mousebutton to start a freehand drawing, or
+            // b) release the mousebutton to finish a freehand drawing
+            if (!this->sp_event_context_knot_mouseover()) {
+                SnapManager &m = dt->namedview->snap_manager;
+                m.setup(dt);
+                m.preSnap(Inkscape::SnapCandidatePoint(p, Inkscape::SNAPSOURCE_NODE_HANDLE));
+                m.unSetup();
+            }
+            break;
+    }
+    return ret;
+}
+
+gint PencilTool::_handleButtonRelease(GdkEventButton const &revent) {
+    gint ret = FALSE;
+
+    ToolBase *event_context = SP_EVENT_CONTEXT(this);
+    if ( revent.button == 1 && this->is_drawing && !event_context->space_panning) {
+        SPDesktop *const dt = this->desktop;
+
+        this->is_drawing = false;
+
+        /* Find desktop coordinates */
+        Geom::Point p = dt->w2d(Geom::Point(revent.x, revent.y));
+
+        /* Test whether we hit any anchor. */
+        SPDrawAnchor *anchor = spdc_test_inside(this, Geom::Point(revent.x,
+                                                              revent.y));
+
+        switch (this->state) {
+            case SP_PENCIL_CONTEXT_IDLE:
+                /* Releasing button in idle mode means single click */
+                /* We have already set up start point/anchor in button_press */
+                if (!(revent.state & GDK_CONTROL_MASK)) {
+                    // Ctrl+click creates a single point so only set context in ADDLINE mode when Ctrl isn't pressed
+                    this->state = SP_PENCIL_CONTEXT_ADDLINE;
+                }
+                ret = TRUE;
+                break;
+            case SP_PENCIL_CONTEXT_ADDLINE:
+                /* Finish segment now */
+                if (anchor) {
+                    p = anchor->dp;
+                } else {
+                    this->_endpointSnap(p, revent.state);
+                }
+                this->ea = anchor;
+                this->_setEndpoint(p);
+                this->_finishEndpoint();
+                this->state = SP_PENCIL_CONTEXT_IDLE;
+                sp_event_context_discard_delayed_snap_event(event_context);
+                ret = TRUE;
+                break;
+            case SP_PENCIL_CONTEXT_FREEHAND:
+                if (revent.state & GDK_MOD1_MASK) {
+                    /* sketch mode: interpolate the sketched path and improve the current output path with the new interpolation. don't finish sketch */
+
+                    this->_sketchInterpolate();
+
+                    if (this->green_anchor) {
+                        this->green_anchor = sp_draw_anchor_destroy(this->green_anchor);
+                    }
+
+                    this->state = SP_PENCIL_CONTEXT_SKETCH;
+                } else {
+                    /* Finish segment now */
+                    /// \todo fixme: Clean up what follows (Lauris)
+                    if (anchor) {
+                        p = anchor->dp;
+                    } else {
+                        Geom::Point p_end = p;
+                        this->_endpointSnap(p_end, revent.state);
+                        if (p_end != p) {
+                            // then we must have snapped!
+                            this->_addFreehandPoint(p_end, revent.state);
+                        }
+                    }
+
+                    this->ea = anchor;
+                    /* Write curves to object */
+
+                    dt->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Finishing freehand"));
+
+                    this->_interpolate();
+                    spdc_concat_colors_and_flush(this, FALSE);
+                    this->sa = NULL;
+                    this->ea = NULL;
+                    if (this->green_anchor) {
+                        this->green_anchor = sp_draw_anchor_destroy(this->green_anchor);
+                    }
+                    this->state = SP_PENCIL_CONTEXT_IDLE;
+                    // reset sketch mode too
+                    this->sketch_n = 0;
+                }
+                ret = TRUE;
+                break;
+            case SP_PENCIL_CONTEXT_SKETCH:
+            default:
+                break;
+        }
+
+        if (this->grab) {
+            /* Release grab now */
+            sp_canvas_item_ungrab(this->grab, revent.time);
+            this->grab = NULL;
+        }
+
+        ret = TRUE;
+    }
+    return ret;
+}
+
+void PencilTool::_cancel() {
+    if (this->grab) {
+        /* Release grab now */
+        sp_canvas_item_ungrab(this->grab, 0);
+        this->grab = NULL;
+    }
+
+    this->is_drawing = false;
+    this->state = SP_PENCIL_CONTEXT_IDLE;
+    sp_event_context_discard_delayed_snap_event(SP_EVENT_CONTEXT(this));
+
+    this->red_curve->reset();
+    sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(this->red_bpath), NULL);
+    while (this->green_bpaths) {
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(this->green_bpaths->data));
+        this->green_bpaths = g_slist_remove(this->green_bpaths, this->green_bpaths->data);
+    }
+    this->green_curve->reset();
+    if (this->green_anchor) {
+        this->green_anchor = sp_draw_anchor_destroy(this->green_anchor);
+    }
+
+    this->message_context->clear();
+    this->message_context->flash(Inkscape::NORMAL_MESSAGE, _("Drawing cancelled"));
+
+    this->desktop->canvas->endForcedFullRedraws();
+}
+
+gint PencilTool::_handleKeyPress(guint const keyval, guint const state) {
+    gint ret = FALSE;
+    switch (keyval) {
+        case GDK_KEY_Up:
+        case GDK_KEY_Down:
+        case GDK_KEY_KP_Up:
+        case GDK_KEY_KP_Down:
+            // Prevent the zoom field from activation.
+            if (!mod_ctrl_only(state)) {
+                ret = TRUE;
+            }
+            break;
+        case GDK_KEY_Escape:
+            if (this->npoints != 0) {
+                // if drawing, cancel, otherwise pass it up for deselecting
+                if (this->state != SP_PENCIL_CONTEXT_IDLE) {
+                    this->_cancel();
+                    ret = TRUE;
+                }
+            }
+            break;
+        case GDK_KEY_z:
+        case GDK_KEY_Z:
+            if (mod_ctrl_only(state) && this->npoints != 0) {
+                // if drawing, cancel, otherwise pass it up for undo
+                if (this->state != SP_PENCIL_CONTEXT_IDLE) {
+                    this->_cancel();
+                    ret = TRUE;
+                }
+            }
+            break;
+        case GDK_KEY_g:
+        case GDK_KEY_G:
+            if (mod_shift_only(state)) {
+                sp_selection_to_guides(SP_EVENT_CONTEXT(this)->desktop);
+                ret = true;
+            }
+            break;
+        case GDK_KEY_Alt_L:
+        case GDK_KEY_Alt_R:
+        case GDK_KEY_Meta_L:
+        case GDK_KEY_Meta_R:
+            if (this->state == SP_PENCIL_CONTEXT_IDLE) {
+                this->desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("<b>Sketch mode</b>: holding <b>Alt</b> interpolates between sketched paths. Release <b>Alt</b> to finalize."));
+            }
+            break;
+        default:
+            break;
+    }
+    return ret;
+}
+
+gint PencilTool::_handleKeyRelease(guint const keyval, guint const /*state*/) {
+    gint ret = FALSE;
+    switch (keyval) {
+        case GDK_KEY_Alt_L:
+        case GDK_KEY_Alt_R:
+        case GDK_KEY_Meta_L:
+        case GDK_KEY_Meta_R:
+            if (this->state == SP_PENCIL_CONTEXT_SKETCH) {
+                spdc_concat_colors_and_flush(this, FALSE);
+                this->sketch_n = 0;
+                this->sa = NULL;
+                this->ea = NULL;
+                if (this->green_anchor) {
+                    this->green_anchor = sp_draw_anchor_destroy(this->green_anchor);
+                }
+                this->state = SP_PENCIL_CONTEXT_IDLE;
+                sp_event_context_discard_delayed_snap_event(SP_EVENT_CONTEXT(this));
+                this->desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Finishing freehand sketch"));
+                ret = TRUE;
+            }
+            break;
+        default:
+            break;
+    }
+    return ret;
+}
+
+/**
+ * Reset points and set new starting point.
+ */
+void PencilTool::_setStartpoint(Geom::Point const &p) {
+    this->npoints = 0;
+    this->red_curve_is_valid = false;
+    if (in_svg_plane(p)) {
+        this->p[this->npoints++] = p;
+    }
+}
+
+/**
+ * Change moving endpoint position.
+ * <ul>
+ * <li>Ctrl constrains to moving to H/V direction, snapping in given direction.
+ * <li>Otherwise we snap freely to whatever attractors are available.
+ * </ul>
+ *
+ * Number of points is (re)set to 2 always, 2nd point is modified.
+ * We change RED curve.
+ */
+void PencilTool::_setEndpoint(Geom::Point const &p) {
+    if (this->npoints == 0) {
+        return;
+        /* May occur if first point wasn't in SVG plane (e.g. weird w2d transform, perhaps from bad
+         * zoom setting).
+         */
+    }
+    g_return_if_fail( this->npoints > 0 );
+
+    this->red_curve->reset();
+    if ( ( p == this->p[0] )
+         || !in_svg_plane(p) )
+    {
+        this->npoints = 1;
+    } else {
+        this->p[1] = p;
+        this->npoints = 2;
+
+        this->red_curve->moveto(this->p[0]);
+        this->red_curve->lineto(this->p[1]);
+        this->red_curve_is_valid = true;
+
+        sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(this->red_bpath), this->red_curve);
+    }
+}
+
+/**
+ * Finalize addline.
+ *
+ * \todo
+ * fixme: I'd like remove red reset from concat colors (lauris).
+ * Still not sure, how it will make most sense.
+ */
+void PencilTool::_finishEndpoint() {
+    if ( ( this->red_curve->is_empty() )
+         || ( *(this->red_curve->first_point()) == *(this->red_curve->second_point())   ) )
+    {
+        this->red_curve->reset();
+        sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(this->red_bpath), NULL);
+    } else {
+        /* Write curves to object. */
+        spdc_concat_colors_and_flush(this, FALSE);
+        this->sa = NULL;
+        this->ea = NULL;
+    }
+}
+
+void PencilTool::_addFreehandPoint(Geom::Point const &p, guint /*state*/) {
+    g_assert( this->npoints > 0 );
+    g_return_if_fail(unsigned(this->npoints) < G_N_ELEMENTS(this->p));
+
+    if ( ( p != this->p[ this->npoints - 1 ] )
+         && in_svg_plane(p) )
+    {
+        this->ps.push_back(p);
+        this->p[this->npoints++] = p;
+        this->_fitAndSplit();
+    }
+}
+
+static inline double
+square(double const x)
+{
+    return x * x;
+}
+
+void PencilTool::_interpolate() {
+    if ( this->ps.size() <= 1 ) {
+        return;
+    }
+
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    double const tol = prefs->getDoubleLimited("/tools/freehand/pencil/tolerance", 10.0, 1.0, 100.0) * 0.4;
+    double const tolerance_sq = 0.02 * square( this->desktop->w2d().descrim() *
+                                               tol) * exp(0.2*tol - 2);
+
+    g_assert(is_zero(this->req_tangent)
+             || is_unit_vector(this->req_tangent));
+    Geom::Point const tHatEnd(0, 0);
+
+    guint n_points  = this->ps.size();
+    this->green_curve->reset();
+    this->red_curve->reset();
+    this->red_curve_is_valid = false;
+
+    Geom::Point * b = g_new(Geom::Point, 4*n_points);
+    Geom::Point * points = g_new(Geom::Point, 4*n_points);
+    for (unsigned int i = 0; i < this->ps.size(); i++) {
+        points[i] = this->ps[i];
+    }
+
+    // worst case gives us a segment per point
+    int max_segs = 4*n_points;
+
+    int const n_segs = Geom::bezier_fit_cubic_r(b, points, n_points,
+                                             tolerance_sq, max_segs);
+
+    if ( n_segs > 0)
+    {
+        /* Fit and draw and reset state */
+        this->green_curve->moveto(b[0]);
+        for (int c = 0; c < n_segs; c++) {
+            this->green_curve->curveto(b[4*c+1], b[4*c+2], b[4*c+3]);
+        }
+        sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(this->red_bpath), this->green_curve);
+
+        /* Fit and draw and copy last point */
+        g_assert(!this->green_curve->is_empty());
+
+        /* Set up direction of next curve. */
+        {
+            Geom::Curve const * last_seg = this->green_curve->last_segment();
+            g_assert( last_seg );      // Relevance: validity of (*last_seg)
+            this->p[0] = last_seg->finalPoint();
+            this->npoints = 1;
+            Geom::Curve *last_seg_reverse = last_seg->reverse();
+            Geom::Point const req_vec( -last_seg_reverse->unitTangentAt(0) );
+            delete last_seg_reverse;
+            this->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
+                                ? Geom::Point(0, 0)
+                                : Geom::unit_vector(req_vec) );
+        }
+    }
+    g_free(b);
+    g_free(points);
+    this->ps.clear();
+}
+
+
+/* interpolates the sketched curve and tweaks the current sketch interpolation*/
+void PencilTool::_sketchInterpolate() {
+    if ( this->ps.size() <= 1 ) {
+        return;
+    }
+
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    double const tol = prefs->getDoubleLimited("/tools/freehand/pencil/tolerance", 10.0, 1.0, 100.0) * 0.4;
+    double const tolerance_sq = 0.02 * square( this->desktop->w2d().descrim() *
+                                               tol) * exp(0.2*tol - 2);
+
+    bool average_all_sketches = prefs->getBool("/tools/freehand/pencil/average_all_sketches", true);
+
+    g_assert(is_zero(this->req_tangent)
+             || is_unit_vector(this->req_tangent));
+    Geom::Point const tHatEnd(0, 0);
+
+    guint n_points  = this->ps.size();
+    this->red_curve->reset();
+    this->red_curve_is_valid = false;
+
+    Geom::Point * b = g_new(Geom::Point, 4*n_points);
+    Geom::Point * points = g_new(Geom::Point, 4*n_points);
+    for (unsigned i = 0; i < this->ps.size(); i++) {
+        points[i] = this->ps[i];
+    }
+
+    // worst case gives us a segment per point
+    int max_segs = 4*n_points;
+
+    int const n_segs = Geom::bezier_fit_cubic_r(b, points, n_points,
+                                             tolerance_sq, max_segs);
+
+    if ( n_segs > 0)
+    {
+        Geom::Path fit(b[0]);
+        for (int c = 0; c < n_segs; c++) {
+            fit.appendNew<Geom::CubicBezier>(b[4*c+1], b[4*c+2], b[4*c+3]);
+        }
+        Geom::Piecewise<Geom::D2<Geom::SBasis> > fit_pwd2 = fit.toPwSb();
+
+        if ( this->sketch_n > 0 ) {
+            double t =0.;
+            if (average_all_sketches) {
+                // Average = (sum of all) / n
+                //         = (sum of all + new one) / n+1
+                //         = ((old average)*n + new one) / n+1
+                t = this->sketch_n / (this->sketch_n + 1.);
+            } else {
+                t = 0.5;
+            }
+            this->sketch_interpolation = Geom::lerp(t, fit_pwd2, this->sketch_interpolation);
+            // simplify path, to eliminate small segments
+            Path *path = new Path;
+            path->LoadPathVector(Geom::path_from_piecewise(this->sketch_interpolation, 0.01));
+            path->Simplify(0.5);
+            Geom::PathVector *pathv = path->MakePathVector();
+            this->sketch_interpolation = (*pathv)[0].toPwSb();
+            delete path;
+            delete pathv;
+        } else {
+            this->sketch_interpolation = fit_pwd2;
+        }
+        this->sketch_n++;
+
+        this->green_curve->reset();
+        this->green_curve->set_pathvector(Geom::path_from_piecewise(this->sketch_interpolation, 0.01));
+        sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(this->red_bpath), this->green_curve);
+
+        /* Fit and draw and copy last point */
+        g_assert(!this->green_curve->is_empty());
+
+        /* Set up direction of next curve. */
+        {
+            Geom::Curve const * last_seg = this->green_curve->last_segment();
+            g_assert( last_seg );      // Relevance: validity of (*last_seg)
+            this->p[0] = last_seg->finalPoint();
+            this->npoints = 1;
+            Geom::Curve *last_seg_reverse = last_seg->reverse();
+            Geom::Point const req_vec( -last_seg_reverse->unitTangentAt(0) );
+            delete last_seg_reverse;
+            this->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
+                                ? Geom::Point(0, 0)
+                                : Geom::unit_vector(req_vec) );
+        }
+    }
+    g_free(b);
+    g_free(points);
+    this->ps.clear();
+}
+
+void PencilTool::_fitAndSplit() {
+    g_assert( this->npoints > 1 );
+
+    double const tolerance_sq = 0;
+
+    Geom::Point b[4];
+    g_assert(is_zero(this->req_tangent)
+             || is_unit_vector(this->req_tangent));
+    Geom::Point const tHatEnd(0, 0);
+    int const n_segs = Geom::bezier_fit_cubic_full(b, NULL, this->p, this->npoints,
+                                                this->req_tangent, tHatEnd,
+                                                tolerance_sq, 1);
+    if ( n_segs > 0
+         && unsigned(this->npoints) < G_N_ELEMENTS(this->p) )
+    {
+        /* Fit and draw and reset state */
+        this->red_curve->reset();
+        this->red_curve->moveto(b[0]);
+        this->red_curve->curveto(b[1], b[2], b[3]);
+        sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(this->red_bpath), this->red_curve);
+        this->red_curve_is_valid = true;
+    } else {
+        /* Fit and draw and copy last point */
+
+        g_assert(!this->red_curve->is_empty());
+
+        /* Set up direction of next curve. */
+        {
+            Geom::Curve const * last_seg = this->red_curve->last_segment();
+            g_assert( last_seg );      // Relevance: validity of (*last_seg)
+            this->p[0] = last_seg->finalPoint();
+            this->npoints = 1;
+            Geom::Curve *last_seg_reverse = last_seg->reverse();
+            Geom::Point const req_vec( -last_seg_reverse->unitTangentAt(0) );
+            delete last_seg_reverse;
+            this->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
+                                ? Geom::Point(0, 0)
+                                : Geom::unit_vector(req_vec) );
+        }
+
+
+        this->green_curve->append_continuous(this->red_curve, 0.0625);
+        SPCurve *curve = this->red_curve->copy();
+
+        /// \todo fixme:
+        SPCanvasItem *cshape = sp_canvas_bpath_new(sp_desktop_sketch(this->desktop), curve);
+        curve->unref();
+        sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cshape), this->green_color, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
+
+        this->green_bpaths = g_slist_prepend(this->green_bpaths, cshape);
+
+        this->red_curve_is_valid = false;
+    }
+}
+
+}
+}
+}
+
+/*
+  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 :