#ifdef HAVE_CONFIG_H

# include <config.h>

#endif

#include <map>

#include <string>

#include "ui/dialog/guides.h"

#include <2geom/line.h>

#include <2geom/angle.h>

#include <glibmm/i18n.h>

#include "desktop.h"

#include "desktop-events.h"

#include "desktop-handles.h"

#include "dialogs/dialog-events.h"

#include "display/canvas-axonomgrid.h"

#include "display/canvas-grid.h"

#include "display/guideline.h"

#include "display/snap-indicator.h"

#include "document.h"

#include "document-undo.h"

#include "ui/tools/tool-base.h"

#include "helper/action.h"

#include "message-context.h"

#include "preferences.h"

#include "snap.h"

#include "display/sp-canvas.h"

#include "sp-guide.h"

#include "sp-namedview.h"

#include "tools-switch.h"

#include "verbs.h"

#include "widgets/desktop-widget.h"

#include "xml/repr.h"

using Inkscape::DocumentUndo;

static void snoop_extended(GdkEvent* event, SPDesktop *desktop);

static void init_extended();

void sp_dt_ruler_snap_new_guide(SPDesktop *desktop, SPCanvasItem *guide, Geom::Point &event_dt, Geom::Point &normal);

int sp_desktop_root_handler(SPCanvasItem */*item*/, GdkEvent *event, SPDesktop *desktop)

{

static bool watch = false;

static bool first = true;

if ( first ) {

Inkscape::Preferences *prefs = Inkscape::Preferences::get();

if ( prefs->getBool("/options/useextinput/value", true)

&& prefs->getBool("/options/switchonextinput/value") ) {

watch = true;

init_extended();

}

first = false;

}

if ( watch ) {

snoop_extended(event, desktop);

}

return sp_event_context_root_handler(desktop->event_context, event);

}

static gint sp_dt_ruler_event(GtkWidget *widget, GdkEvent *event, SPDesktopWidget *dtw, bool horiz)

{

static bool clicked = false;

static bool dragged = false;

static SPCanvasItem *guide = NULL;

static Geom::Point normal;

int wx, wy;

static gint xp = 0, yp = 0; // where drag started

SPDesktop *desktop = dtw->desktop;

GdkWindow *window = gtk_widget_get_window(GTK_WIDGET(dtw->canvas));

gint width, height;

#if GTK_CHECK_VERSION(3,0,0)

GdkDevice *device = gdk_event_get_device(event);

gdk_window_get_device_position(window, device, &wx, &wy, NULL);

gdk_window_get_geometry(window, NULL /*x*/, NULL /*y*/, &width, &height);

#else

gdk_window_get_pointer(window, &wx, &wy, NULL);

gdk_window_get_geometry(window, NULL /*x*/, NULL /*y*/, &width, &height, NULL/*depth*/);

#endif

Geom::Point const event_win(wx, wy);

switch (event->type) {

case GDK_BUTTON_PRESS:

if (event->button.button == 1) {

clicked = true;

dragged = false;

// save click origin

xp = (gint) event->button.x;

yp = (gint) event->button.y;

Geom::Point const event_w(sp_canvas_window_to_world(dtw->canvas, event_win));

Geom::Point const event_dt(desktop->w2d(event_w));

// calculate the normal of the guidelines when dragged from the edges of rulers.

Geom::Point normal_bl_to_tr(-1.,1.); //bottomleft to topright

Geom::Point normal_tr_to_bl(1.,1.); //topright to bottomleft

normal_bl_to_tr.normalize();

normal_tr_to_bl.normalize();

Inkscape::CanvasGrid * grid = sp_namedview_get_first_enabled_grid(desktop->namedview);

if (grid){

if (grid->getGridType() == Inkscape::GRID_AXONOMETRIC ) {

Inkscape::CanvasAxonomGrid *axonomgrid = dynamic_cast<Inkscape::CanvasAxonomGrid *>(grid);

if (event->button.state & GDK_CONTROL_MASK) {

// guidelines normal to gridlines

normal_bl_to_tr = Geom::Point::polar(-axonomgrid->angle_rad[0], 1.0);

normal_tr_to_bl = Geom::Point::polar(axonomgrid->angle_rad[2], 1.0);

} else {

normal_bl_to_tr = rot90(Geom::Point::polar(axonomgrid->angle_rad[2], 1.0));

normal_tr_to_bl = rot90(Geom::Point::polar(-axonomgrid->angle_rad[0], 1.0));

}

}

}

if (horiz) {

if (wx < 50) {

normal = normal_bl_to_tr;

} else if (wx > width - 50) {

normal = normal_tr_to_bl;

} else {

normal = Geom::Point(0.,1.);

}

} else {

if (wy < 50) {

normal = normal_bl_to_tr;

} else if (wy > height - 50) {

normal = normal_tr_to_bl;

} else {

normal = Geom::Point(1.,0.);

}

}

guide = sp_guideline_new(desktop->guides, NULL, event_dt, normal);

sp_guideline_set_color(SP_GUIDELINE(guide), desktop->namedview->guidehicolor);

#if GTK_CHECK_VERSION(3,0,0)

gdk_device_grab(device,

gtk_widget_get_window(widget),

GDK_OWNERSHIP_NONE,

FALSE,

(GdkEventMask)(GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK ),

NULL,

event->button.time);

#else

gdk_pointer_grab(gtk_widget_get_window (widget), FALSE,

(GdkEventMask)(GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK ),

NULL, NULL,

event->button.time);

#endif

}

break;

case GDK_MOTION_NOTIFY:

if (clicked) {

Geom::Point const event_w(sp_canvas_window_to_world(dtw->canvas, event_win));

Geom::Point event_dt(desktop->w2d(event_w));

Inkscape::Preferences *prefs = Inkscape::Preferences::get();

gint tolerance = prefs->getIntLimited("/options/dragtolerance/value", 0, 0, 100);

if ( ( abs( (gint) event->motion.x - xp ) < tolerance )

&& ( abs( (gint) event->motion.y - yp ) < tolerance ) ) {

break;

}

dragged = true;

// explicitly show guidelines; if I draw a guide, I want them on

if ((horiz ? wy : wx) >= 0) {

desktop->namedview->setGuides(true);

}

if (!(event->motion.state & GDK_SHIFT_MASK)) {

sp_dt_ruler_snap_new_guide(desktop, guide, event_dt, normal);

}

sp_guideline_set_normal(SP_GUIDELINE(guide), normal);

sp_guideline_set_position(SP_GUIDELINE(guide), event_dt);

desktop->set_coordinate_status(event_dt);

}

break;

case GDK_BUTTON_RELEASE:

if (clicked && event->button.button == 1) {

sp_event_context_discard_delayed_snap_event(desktop->event_context);

#if GTK_CHECK_VERSION(3,0,0)

gdk_device_ungrab(device, event->button.time);

#else

gdk_pointer_ungrab(event->button.time);

#endif

Geom::Point const event_w(sp_canvas_window_to_world(dtw->canvas, event_win));

Geom::Point event_dt(desktop->w2d(event_w));

if (!(event->button.state & GDK_SHIFT_MASK)) {

sp_dt_ruler_snap_new_guide(desktop, guide, event_dt, normal);

}

sp_canvas_item_destroy(guide);

guide = NULL;

if ((horiz ? wy : wx) >= 0) {

Inkscape::XML::Document *xml_doc = desktop->doc()->getReprDoc();

Inkscape::XML::Node *repr = xml_doc->createElement("sodipodi:guide");

sp_repr_set_point(repr, "orientation", normal);

sp_repr_set_point(repr, "position", event_dt);

desktop->namedview->appendChild(repr);

Inkscape::GC::release(repr);

DocumentUndo::done(sp_desktop_document(desktop), SP_VERB_NONE,

_("Create guide"));

}

desktop->set_coordinate_status(event_dt);

if (!dragged) {

// Ruler click (without drag) toggle the guide visibility on and off

Inkscape::XML::Node *repr = desktop->namedview->getRepr();

sp_namedview_toggle_guides(sp_desktop_document(desktop), repr);

}

clicked = false;

dragged = false;

}

default:

break;

}

return FALSE;

}

int sp_dt_hruler_event(GtkWidget *widget, GdkEvent *event, SPDesktopWidget *dtw)

{

if (event->type == GDK_MOTION_NOTIFY) {

sp_event_context_snap_delay_handler(dtw->desktop->event_context, (gpointer) widget, (gpointer) dtw, (GdkEventMotion *)event, Inkscape::UI::Tools::DelayedSnapEvent::GUIDE_HRULER);

}

return sp_dt_ruler_event(widget, event, dtw, true);

}

int sp_dt_vruler_event(GtkWidget *widget, GdkEvent *event, SPDesktopWidget *dtw)

{

if (event->type == GDK_MOTION_NOTIFY) {

sp_event_context_snap_delay_handler(dtw->desktop->event_context, (gpointer) widget, (gpointer) dtw, (GdkEventMotion *)event, Inkscape::UI::Tools::DelayedSnapEvent::GUIDE_VRULER);

}

return sp_dt_ruler_event(widget, event, dtw, false);

}

static Geom::Point drag_origin;

static SPGuideDragType drag_type = SP_DRAG_NONE;

#define tol 40.0

gint sp_dt_guide_event(SPCanvasItem *item, GdkEvent *event, gpointer data)

{

static bool moved = false;

gint ret = FALSE;

SPGuide *guide = SP_GUIDE(data);

SPDesktop *desktop = static_cast<SPDesktop*>(g_object_get_data(G_OBJECT(item->canvas), "SPDesktop"));

switch (event->type) {

case GDK_2BUTTON_PRESS:

if (event->button.button == 1) {

drag_type = SP_DRAG_NONE;

sp_event_context_discard_delayed_snap_event(desktop->event_context);

sp_canvas_item_ungrab(item, event->button.time);

Inkscape::UI::Dialogs::GuidelinePropertiesDialog::showDialog(guide, desktop);

ret = TRUE;

}

break;

case GDK_BUTTON_PRESS:

if (event->button.button == 1) {

Geom::Point const event_w(event->button.x, event->button.y);

Geom::Point const event_dt(desktop->w2d(event_w));

// Due to the tolerance allowed when grabbing a guide, event_dt will generally

// be close to the guide but not just exactly on it. The drag origin calculated

// here must be exactly on the guide line though, otherwise

// small errors will occur once we snap, see

// https://bugs.launchpad.net/inkscape/+bug/333762

drag_origin = Geom::projection(event_dt, Geom::Line(guide->point_on_line, guide->angle()));

if (event->button.state & GDK_SHIFT_MASK) {

// with shift we rotate the guide

drag_type = SP_DRAG_ROTATE;

} else {

if (event->button.state & GDK_CONTROL_MASK) {

drag_type = SP_DRAG_MOVE_ORIGIN;

} else {

drag_type = SP_DRAG_TRANSLATE;

}

}

if (drag_type == SP_DRAG_ROTATE || drag_type == SP_DRAG_TRANSLATE) {

sp_canvas_item_grab(item,

( GDK_BUTTON_RELEASE_MASK |

GDK_BUTTON_PRESS_MASK |

GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK ),

NULL,

event->button.time);

}

ret = TRUE;

}

break;

case GDK_MOTION_NOTIFY:

if (drag_type != SP_DRAG_NONE) {

Geom::Point const motion_w(event->motion.x,

event->motion.y);

Geom::Point motion_dt(desktop->w2d(motion_w));

sp_event_context_snap_delay_handler(desktop->event_context, (gpointer) item, data, (GdkEventMotion *)event, Inkscape::UI::Tools::DelayedSnapEvent::GUIDE_HANDLER);

// This is for snapping while dragging existing guidelines. New guidelines,

// which are dragged off the ruler, are being snapped in sp_dt_ruler_event

SnapManager &m = desktop->namedview->snap_manager;

m.setup(desktop, true, NULL, NULL, guide);

if (drag_type == SP_DRAG_MOVE_ORIGIN) {

// If we snap in guideConstrainedSnap() below, then motion_dt will

// be forced to be on the guide. If we don't snap however, then

// the origin should still be constrained to the guide. So let's do

// that explicitly first:

Geom::Line line(guide->point_on_line, guide->angle());

Geom::Coord t = line.nearestPoint(motion_dt);

motion_dt = line.pointAt(t);

if (!(event->motion.state & GDK_SHIFT_MASK)) {

m.guideConstrainedSnap(motion_dt, *guide);

}

} else if (!((drag_type == SP_DRAG_ROTATE) && (event->motion.state & GDK_CONTROL_MASK))) {

// cannot use shift here to disable snapping, because we already use it for rotating the guide

if (drag_type == SP_DRAG_ROTATE) {

m.guideFreeSnap(motion_dt, guide->point_on_line, true, false);

} else {

m.guideFreeSnap(motion_dt, guide->normal_to_line, false, true);

}

}

m.unSetup();

switch (drag_type) {

case SP_DRAG_TRANSLATE:

{

sp_guide_moveto(*guide, motion_dt, false);

break;

}

case SP_DRAG_ROTATE:

{

Geom::Point pt = motion_dt - guide->point_on_line;

Geom::Angle angle(pt);

if (event->motion.state & GDK_CONTROL_MASK) {

Inkscape::Preferences *prefs = Inkscape::Preferences::get();

unsigned const snaps = abs(prefs->getInt("/options/rotationsnapsperpi/value", 12));

bool const relative_snaps = abs(prefs->getBool("/options/relativeguiderotationsnap/value", false));

if (snaps) {

if (relative_snaps) {

Geom::Angle orig_angle(guide->normal_to_line);

Geom::Angle snap_angle = angle - orig_angle;

double sections = floor(snap_angle.radians0() * snaps / M_PI + .5);

angle = (M_PI / snaps) * sections + orig_angle.radians0();

} else {

double sections = floor(angle.radians0() * snaps / M_PI + .5);

angle = (M_PI / snaps) * sections;

}

}

}

sp_guide_set_normal(*guide, Geom::Point::polar(angle).cw(), false);

break;

}

case SP_DRAG_MOVE_ORIGIN:

{

sp_guide_moveto(*guide, motion_dt, false);

break;

}

case SP_DRAG_NONE:

g_assert_not_reached();

break;

}

moved = true;

desktop->set_coordinate_status(motion_dt);

ret = TRUE;

}

break;

case GDK_BUTTON_RELEASE:

if (drag_type != SP_DRAG_NONE && event->button.button == 1) {

sp_event_context_discard_delayed_snap_event(desktop->event_context);

if (moved) {

Geom::Point const event_w(event->button.x,

event->button.y);

Geom::Point event_dt(desktop->w2d(event_w));

SnapManager &m = desktop->namedview->snap_manager;

m.setup(desktop, true, NULL, NULL, guide);

if (drag_type == SP_DRAG_MOVE_ORIGIN) {

// If we snap in guideConstrainedSnap() below, then motion_dt will

// be forced to be on the guide. If we don't snap however, then

// the origin should still be constrained to the guide. So let's

// do that explicitly first:

Geom::Line line(guide->point_on_line, guide->angle());

Geom::Coord t = line.nearestPoint(event_dt);

event_dt = line.pointAt(t);

if (!(event->button.state & GDK_SHIFT_MASK)) {

m.guideConstrainedSnap(event_dt, *guide);

}

} else if (!((drag_type == SP_DRAG_ROTATE) && (event->motion.state & GDK_CONTROL_MASK))) {

// cannot use shift here to disable snapping, because we already use it for rotating the guide

if (drag_type == SP_DRAG_ROTATE) {

m.guideFreeSnap(event_dt, guide->point_on_line, true, false);

} else {

m.guideFreeSnap(event_dt, guide->normal_to_line, false, true);

}

}

m.unSetup();

if (sp_canvas_world_pt_inside_window(item->canvas, event_w)) {

switch (drag_type) {

case SP_DRAG_TRANSLATE:

{

sp_guide_moveto(*guide, event_dt, true);

break;

}

case SP_DRAG_ROTATE:

{

Geom::Point pt = event_dt - guide->point_on_line;

Geom::Angle angle(pt);

if (event->motion.state & GDK_CONTROL_MASK) {

Inkscape::Preferences *prefs = Inkscape::Preferences::get();

unsigned const snaps = abs(prefs->getInt("/options/rotationsnapsperpi/value", 12));

bool const relative_snaps = abs(prefs->getBool("/options/relativeguiderotationsnap/value", false));

if (snaps) {

if (relative_snaps) {

Geom::Angle orig_angle(guide->normal_to_line);

Geom::Angle snap_angle = angle - orig_angle;

double sections = floor(snap_angle.radians0() * snaps / M_PI + .5);

angle = (M_PI / snaps) * sections + orig_angle.radians0();

} else {

double sections = floor(angle.radians0() * snaps / M_PI + .5);

angle = (M_PI / snaps) * sections;

}

}

}

sp_guide_set_normal(*guide, Geom::Point::polar(angle).cw(), true);

break;

}

case SP_DRAG_MOVE_ORIGIN:

{

sp_guide_moveto(*guide, event_dt, true);

break;

}

case SP_DRAG_NONE:

g_assert_not_reached();

break;

}

DocumentUndo::done(sp_desktop_document(desktop), SP_VERB_NONE,

_("Move guide"));

} else {

/* Undo movement of any attached shapes. */

sp_guide_moveto(*guide, guide->point_on_line, false);

sp_guide_set_normal(*guide, guide->normal_to_line, false);

sp_guide_remove(guide);

DocumentUndo::done(sp_desktop_document(desktop), SP_VERB_NONE,

_("Delete guide"));

}

moved = false;

desktop->set_coordinate_status(event_dt);

}

drag_type = SP_DRAG_NONE;

sp_canvas_item_ungrab(item, event->button.time);

ret=TRUE;

}

break;

case GDK_ENTER_NOTIFY:

{

sp_guideline_set_color(SP_GUIDELINE(item), guide->hicolor);

// set move or rotate cursor

Geom::Point const event_w(event->crossing.x, event->crossing.y);

Geom::Point const event_dt(desktop->w2d(event_w));

if ((event->crossing.state & GDK_SHIFT_MASK) && (drag_type != SP_DRAG_MOVE_ORIGIN)) {

GdkCursor *guide_cursor;

guide_cursor = gdk_cursor_new (GDK_EXCHANGE);

gdk_window_set_cursor(gtk_widget_get_window (GTK_WIDGET(sp_desktop_canvas(desktop))), guide_cursor);

#if GTK_CHECK_VERSION(3,0,0)

g_object_unref(guide_cursor);

#else

gdk_cursor_unref(guide_cursor);

#endif

} else {

GdkCursor *guide_cursor;

guide_cursor = gdk_cursor_new (GDK_HAND1);

gdk_window_set_cursor(gtk_widget_get_window (GTK_WIDGET(sp_desktop_canvas(desktop))), guide_cursor);

#if GTK_CHECK_VERSION(3,0,0)

g_object_unref(guide_cursor);

#else

gdk_cursor_unref(guide_cursor);

#endif

}

char *guide_description = sp_guide_description(guide);

desktop->guidesMessageContext()->setF(Inkscape::NORMAL_MESSAGE, _("<b>Guideline</b>: %s"), guide_description);

g_free(guide_description);

break;

}

case GDK_LEAVE_NOTIFY:

sp_guideline_set_color(SP_GUIDELINE(item), guide->color);

// restore event context's cursor

gdk_window_set_cursor(gtk_widget_get_window (GTK_WIDGET(sp_desktop_canvas(desktop))), desktop->event_context->cursor);

desktop->guidesMessageContext()->clear();

break;

case GDK_KEY_PRESS:

switch (Inkscape::UI::Tools::get_group0_keyval (&event->key)) {

case GDK_KEY_Delete:

case GDK_KEY_KP_Delete:

case GDK_KEY_BackSpace:

{

SPDocument *doc = guide->document;

sp_guide_remove(guide);

DocumentUndo::done(doc, SP_VERB_NONE, _("Delete guide"));

ret = TRUE;

sp_event_context_discard_delayed_snap_event(desktop->event_context);

break;

}

case GDK_KEY_Shift_L:

case GDK_KEY_Shift_R:

if (drag_type != SP_DRAG_MOVE_ORIGIN) {

GdkCursor *guide_cursor;

guide_cursor = gdk_cursor_new (GDK_EXCHANGE);

gdk_window_set_cursor(gtk_widget_get_window (GTK_WIDGET(sp_desktop_canvas(desktop))), guide_cursor);

#if GTK_CHECK_VERSION(3,0,0)

g_object_unref(guide_cursor);

#else

gdk_cursor_unref(guide_cursor);

#endif

ret = TRUE;

break;

}

default:

// do nothing;

break;

}

break;

case GDK_KEY_RELEASE:

switch (Inkscape::UI::Tools::get_group0_keyval (&event->key)) {

case GDK_KEY_Shift_L:

case GDK_KEY_Shift_R:

GdkCursor *guide_cursor;

guide_cursor = gdk_cursor_new (GDK_EXCHANGE);

gdk_window_set_cursor(gtk_widget_get_window (GTK_WIDGET(sp_desktop_canvas(desktop))), guide_cursor);

#if GTK_CHECK_VERSION(3,0,0)

g_object_unref(guide_cursor);

#else

gdk_cursor_unref(guide_cursor);

#endif

break;

default:

// do nothing;

break;

}

break;

default:

break;

}

return ret;

}

static std::map<std::string, int> toolToUse;

static std::string lastName;

static GdkInputSource lastType = GDK_SOURCE_MOUSE;

static void init_extended()

{

std::string avoidName = "pad";

#if GTK_CHECK_VERSION(3,0,0)

GdkDisplay *display = gdk_display_get_default();

GdkDeviceManager *dm = gdk_display_get_device_manager(display);

GList* devices = gdk_device_manager_list_devices(dm, GDK_DEVICE_TYPE_SLAVE);

#else

GList* devices = gdk_devices_list();

#endif

if ( devices ) {

for ( GList* curr = devices; curr; curr = g_list_next(curr) ) {

GdkDevice* dev = reinterpret_cast<GdkDevice*>(curr->data);

gchar const *devName = gdk_device_get_name(dev);

GdkInputSource devSrc = gdk_device_get_source(dev);

if ( devName

&& (avoidName != devName)

&& (devSrc != GDK_SOURCE_MOUSE) ) {

// Set the initial tool for the device

switch ( devSrc ) {

case GDK_SOURCE_PEN:

toolToUse[devName] = TOOLS_CALLIGRAPHIC;

break;

case GDK_SOURCE_ERASER:

toolToUse[devName] = TOOLS_ERASER;

break;

case GDK_SOURCE_CURSOR:

toolToUse[devName] = TOOLS_SELECT;

break;

default:

; // do not add

}

}

}

}

#if GTK_CHECK_VERSION(3,0,0)

g_list_free(devices);

#endif

}

void snoop_extended(GdkEvent* event, SPDesktop *desktop)

{

GdkInputSource source = GDK_SOURCE_MOUSE;

std::string name;

switch ( event->type ) {

case GDK_MOTION_NOTIFY:

{

GdkEventMotion* event2 = reinterpret_cast<GdkEventMotion*>(event);

if ( event2->device ) {

source = gdk_device_get_source(event2->device);

name = gdk_device_get_name(event2->device);

}

}

break;

case GDK_BUTTON_PRESS:

case GDK_2BUTTON_PRESS:

case GDK_3BUTTON_PRESS:

case GDK_BUTTON_RELEASE:

{

GdkEventButton* event2 = reinterpret_cast<GdkEventButton*>(event);

if ( event2->device ) {

source = gdk_device_get_source(event2->device);

name = gdk_device_get_name(event2->device);

}

}

break;

case GDK_SCROLL:

{

GdkEventScroll* event2 = reinterpret_cast<GdkEventScroll*>(event);

if ( event2->device ) {

source = gdk_device_get_source(event2->device);

name = gdk_device_get_name(event2->device);

}

}

break;

case GDK_PROXIMITY_IN:

case GDK_PROXIMITY_OUT:

{

GdkEventProximity* event2 = reinterpret_cast<GdkEventProximity*>(event);

if ( event2->device ) {

source = gdk_device_get_source(event2->device);

name = gdk_device_get_name(event2->device);

}

}

break;

default:

;

}

if (!name.empty()) {

if ( lastType != source || lastName != name ) {

// The device switched. See if it is one we 'count'

//g_message("Changed device %s -> %s", lastName.c_str(), name.c_str());

std::map<std::string, int>::iterator it = toolToUse.find(lastName);

if (it != toolToUse.end()) {

// Save the tool currently selected for next time the input

// device shows up.

it->second = tools_active(desktop);

}

it = toolToUse.find(name);

if (it != toolToUse.end() ) {

tools_switch(desktop, it->second);

}

lastName = name;

lastType = source;

}

}

}

void sp_dt_ruler_snap_new_guide(SPDesktop *desktop, SPCanvasItem * /*guide*/, Geom::Point &event_dt, Geom::Point &normal)

{

SnapManager &m = desktop->namedview->snap_manager;

m.setup(desktop);

// We're dragging a brand new guide, just pulled of the rulers seconds ago. When snapping to a

// path this guide will change it slope to become either tangential or perpendicular to that path. It's

// therefore not useful to try tangential or perpendicular snapping, so this will be disabled temporarily

bool pref_perp = m.snapprefs.getSnapPerp();

bool pref_tang = m.snapprefs.getSnapTang();

m.snapprefs.setSnapPerp(false);

m.snapprefs.setSnapTang(false);

// We only have a temporary guide which is not stored in our document yet.

// Because the guide snapper only looks in the document for guides to snap to,

// we don't have to worry about a guide snapping to itself here

Geom::Point normal_orig = normal;

m.guideFreeSnap(event_dt, normal, false, false);

// After snapping, both event_dt and normal have been modified accordingly; we'll take the normal (of the

// curve we snapped to) to set the normal the guide. And rotate it by 90 deg. if needed

if (pref_perp) { // Perpendicular snapping to paths is requested by the user, so let's do that

if (normal != normal_orig) {

normal = Geom::rot90(normal);

}

}

if (!(pref_tang || pref_perp)) { // if we don't want to snap either perpendicularly or tangentially, then

normal = normal_orig; // we must restore the normal to it's original state

}

// Restore the preferences

m.snapprefs.setSnapPerp(pref_perp);

m.snapprefs.setSnapTang(pref_tang);

m.unSetup();

}