#define __SP_DYNA_DRAW_CONTEXT_C__

#define noDYNA_DRAW_VERBOSE

#include "config.h"

#include <gtk/gtk.h>

#include <gdk/gdkkeysyms.h>

#include <glibmm/i18n.h>

#include <string>

#include <cstring>

#include <numeric>

#include "svg/svg.h"

#include "display/canvas-bpath.h"

#include <2geom/isnan.h>

#include <2geom/pathvector.h>

#include <2geom/bezier-utils.h>

#include "display/curve.h"

#include <glib/gmem.h>

#include "macros.h"

#include "document.h"

#include "selection.h"

#include "desktop.h"

#include "desktop-events.h"

#include "desktop-handles.h"

#include "desktop-affine.h"

#include "desktop-style.h"

#include "message-context.h"

#include "preferences.h"

#include "pixmaps/cursor-calligraphy.xpm"

#include "xml/repr.h"

#include "context-fns.h"

#include "sp-item.h"

#include "inkscape.h"

#include "color.h"

#include "splivarot.h"

#include "sp-item-group.h"

#include "sp-shape.h"

#include "sp-path.h"

#include "sp-text.h"

#include "display/canvas-bpath.h"

#include "display/canvas-arena.h"

#include "livarot/Shape.h"

#include "dyna-draw-context.h"

#define DDC_RED_RGBA 0xff0000ff

#define TOLERANCE_CALLIGRAPHIC 0.1

#define DYNA_EPSILON 0.5e-6

#define DYNA_EPSILON_START 0.5e-2

#define DYNA_VEL_START 1e-5

#define DYNA_MIN_WIDTH 1.0e-6

static void sp_dyna_draw_context_class_init(SPDynaDrawContextClass *klass);

static void sp_dyna_draw_context_init(SPDynaDrawContext *ddc);

static void sp_dyna_draw_context_dispose(GObject *object);

static void sp_dyna_draw_context_setup(SPEventContext *ec);

static void sp_dyna_draw_context_set(SPEventContext *ec, Inkscape::Preferences::Entry *value);

static gint sp_dyna_draw_context_root_handler(SPEventContext *ec, GdkEvent *event);

static void clear_current(SPDynaDrawContext *dc);

static void set_to_accumulated(SPDynaDrawContext *dc, bool unionize);

static void add_cap(SPCurve *curve, Geom::Point const &from, Geom::Point const &to, double rounding);

static bool accumulate_calligraphic(SPDynaDrawContext *dc);

static void fit_and_split(SPDynaDrawContext *ddc, gboolean release);

static void sp_dyna_draw_reset(SPDynaDrawContext *ddc, Geom::Point p);

static Geom::Point sp_dyna_draw_get_npoint(SPDynaDrawContext const *ddc, Geom::Point v);

static Geom::Point sp_dyna_draw_get_vpoint(SPDynaDrawContext const *ddc, Geom::Point n);

static void draw_temporary_box(SPDynaDrawContext *dc);

static SPEventContextClass *dd_parent_class = 0;

GType sp_dyna_draw_context_get_type(void)

{

static GType type = 0;

if (!type) {

GTypeInfo info = {

sizeof(SPDynaDrawContextClass),

0, // base_init

0, // base_finalize

(GClassInitFunc)sp_dyna_draw_context_class_init,

0, // class_finalize

0, // class_data

sizeof(SPDynaDrawContext),

0, // n_preallocs

(GInstanceInitFunc)sp_dyna_draw_context_init,

0 // value_table

};

type = g_type_register_static(SP_TYPE_COMMON_CONTEXT, "SPDynaDrawContext", &info, static_cast<GTypeFlags>(0));

}

return type;

}

static void

sp_dyna_draw_context_class_init(SPDynaDrawContextClass *klass)

{

GObjectClass *object_class = (GObjectClass *) klass;

SPEventContextClass *event_context_class = (SPEventContextClass *) klass;

dd_parent_class = (SPEventContextClass*)g_type_class_peek_parent(klass);

object_class->dispose = sp_dyna_draw_context_dispose;

event_context_class->setup = sp_dyna_draw_context_setup;

event_context_class->set = sp_dyna_draw_context_set;

event_context_class->root_handler = sp_dyna_draw_context_root_handler;

}

static void

sp_dyna_draw_context_init(SPDynaDrawContext *ddc)

{

ddc->cursor_shape = cursor_calligraphy_xpm;

ddc->hot_x = 4;

ddc->hot_y = 4;

ddc->vel_thin = 0.1;

ddc->flatness = 0.9;

ddc->cap_rounding = 0.0;

ddc->abs_width = false;

ddc->keep_selected = true;

ddc->hatch_spacing = 0;

ddc->hatch_spacing_step = 0;

new (&ddc->hatch_pointer_past) std::list<double>();

new (&ddc->hatch_nearest_past) std::list<double>();

new (&ddc->inertia_vectors) std::list<Geom::Point>();

new (&ddc->hatch_vectors) std::list<Geom::Point>();

ddc->hatch_last_nearest = Geom::Point(0,0);

ddc->hatch_last_pointer = Geom::Point(0,0);

ddc->hatch_escaped = false;

ddc->hatch_area = NULL;

ddc->hatch_item = NULL;

ddc->hatch_livarot_path = NULL;

ddc->trace_bg = false;

ddc->just_started_drawing = false;

}

static void

sp_dyna_draw_context_dispose(GObject *object)

{

SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(object);

if (ddc->hatch_area) {

gtk_object_destroy(GTK_OBJECT(ddc->hatch_area));

ddc->hatch_area = NULL;

}

G_OBJECT_CLASS(dd_parent_class)->dispose(object);

ddc->hatch_pointer_past.~list();

ddc->hatch_nearest_past.~list();

ddc->inertia_vectors.~list();

ddc->hatch_vectors.~list();

}

static void

sp_dyna_draw_context_setup(SPEventContext *ec)

{

SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);

if (((SPEventContextClass *) dd_parent_class)->setup)

((SPEventContextClass *) dd_parent_class)->setup(ec);

ddc->accumulated = new SPCurve();

ddc->currentcurve = new SPCurve();

ddc->cal1 = new SPCurve();

ddc->cal2 = new SPCurve();

ddc->currentshape = sp_canvas_item_new(sp_desktop_sketch(ec->desktop), SP_TYPE_CANVAS_BPATH, NULL);

sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(ddc->currentshape), DDC_RED_RGBA, SP_WIND_RULE_EVENODD);

sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(ddc->currentshape), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);

/* fixme: Cannot we cascade it to root more clearly? */

g_signal_connect(G_OBJECT(ddc->currentshape), "event", G_CALLBACK(sp_desktop_root_handler), ec->desktop);

{

/* TODO: this can be done either with an arcto, and should maybe also be put in a general file (other tools use this as well) */

SPCurve *c = new SPCurve();

const double C1 = 0.552;

c->moveto(-1,0);

c->curveto(-1, C1, -C1, 1, 0, 1 );

c->curveto(C1, 1, 1, C1, 1, 0 );

c->curveto(1, -C1, C1, -1, 0, -1 );

c->curveto(-C1, -1, -1, -C1, -1, 0 );

c->closepath();

ddc->hatch_area = sp_canvas_bpath_new(sp_desktop_controls(ec->desktop), c);

c->unref();

sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(ddc->hatch_area), 0x00000000,(SPWindRule)0);

sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(ddc->hatch_area), 0x0000007f, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);

sp_canvas_item_hide(ddc->hatch_area);

}

sp_event_context_read(ec, "mass");

sp_event_context_read(ec, "wiggle");

sp_event_context_read(ec, "angle");

sp_event_context_read(ec, "width");

sp_event_context_read(ec, "thinning");

sp_event_context_read(ec, "tremor");

sp_event_context_read(ec, "flatness");

sp_event_context_read(ec, "tracebackground");

sp_event_context_read(ec, "usepressure");

sp_event_context_read(ec, "usetilt");

sp_event_context_read(ec, "abs_width");

sp_event_context_read(ec, "keep_selected");

sp_event_context_read(ec, "cap_rounding");

ddc->is_drawing = false;

ddc->_message_context = new Inkscape::MessageContext((ec->desktop)->messageStack());

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

if (prefs->getBool("/tools/calligraphic/selcue")) {

ec->enableSelectionCue();

}

}

static void

sp_dyna_draw_context_set(SPEventContext *ec, Inkscape::Preferences::Entry *val)

{

SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);

Glib::ustring path = val->getEntryName();

if (path == "tracebackground") {

ddc->trace_bg = val->getBool();

} else if (path == "keep_selected") {

ddc->keep_selected = val->getBool();

} else {

//pass on up to parent class to handle common attributes.

if ( dd_parent_class->set ) {

dd_parent_class->set(ec, val);

}

}

//g_print("DDC: %g %g %g %g\n", ddc->mass, ddc->drag, ddc->angle, ddc->width);

}

static double

flerp(double f0, double f1, double p)

{

return f0 + ( f1 - f0 ) * p;

}

static Geom::Point

sp_dyna_draw_get_npoint(SPDynaDrawContext const *dc, Geom::Point v)

{

Geom::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();

double const max = MAX ( drect.dimensions()[Geom::X], drect.dimensions()[Geom::Y] );

return Geom::Point(( v[Geom::X] - drect.min()[Geom::X] ) / max, ( v[Geom::Y] - drect.min()[Geom::Y] ) / max);

}

static Geom::Point

sp_dyna_draw_get_vpoint(SPDynaDrawContext const *dc, Geom::Point n)

{

Geom::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();

double const max = MAX ( drect.dimensions()[Geom::X], drect.dimensions()[Geom::Y] );

return Geom::Point(n[Geom::X] * max + drect.min()[Geom::X], n[Geom::Y] * max + drect.min()[Geom::Y]);

}

static void

sp_dyna_draw_reset(SPDynaDrawContext *dc, Geom::Point p)

{

dc->last = dc->cur = sp_dyna_draw_get_npoint(dc, p);

dc->vel = Geom::Point(0,0);

dc->vel_max = 0;

dc->acc = Geom::Point(0,0);

dc->ang = Geom::Point(0,0);

dc->del = Geom::Point(0,0);

}

static void

sp_dyna_draw_extinput(SPDynaDrawContext *dc, GdkEvent *event)

{

if (gdk_event_get_axis (event, GDK_AXIS_PRESSURE, &dc->pressure))

dc->pressure = CLAMP (dc->pressure, DDC_MIN_PRESSURE, DDC_MAX_PRESSURE);

else

dc->pressure = DDC_DEFAULT_PRESSURE;

if (gdk_event_get_axis (event, GDK_AXIS_XTILT, &dc->xtilt))

dc->xtilt = CLAMP (dc->xtilt, DDC_MIN_TILT, DDC_MAX_TILT);

else

dc->xtilt = DDC_DEFAULT_TILT;

if (gdk_event_get_axis (event, GDK_AXIS_YTILT, &dc->ytilt))

dc->ytilt = CLAMP (dc->ytilt, DDC_MIN_TILT, DDC_MAX_TILT);

else

dc->ytilt = DDC_DEFAULT_TILT;

}

static gboolean

sp_dyna_draw_apply(SPDynaDrawContext *dc, Geom::Point p)

{

Geom::Point n = sp_dyna_draw_get_npoint(dc, p);

/* Calculate mass and drag */

double const mass = flerp(1.0, 160.0, dc->mass);

double const drag = flerp(0.0, 0.5, dc->drag * dc->drag);

/* Calculate force and acceleration */

Geom::Point force = n - dc->cur;

// If force is below the absolute threshold DYNA_EPSILON,

// or we haven't yet reached DYNA_VEL_START (i.e. at the beginning of stroke)

// _and_ the force is below the (higher) DYNA_EPSILON_START threshold,

// discard this move.

// This prevents flips, blobs, and jerks caused by microscopic tremor of the tablet pen,

// especially bothersome at the start of the stroke where we don't yet have the inertia to

// smooth them out.

if ( Geom::L2(force) < DYNA_EPSILON || (dc->vel_max < DYNA_VEL_START && Geom::L2(force) < DYNA_EPSILON_START)) {

return FALSE;

}

dc->acc = force / mass;

/* Calculate new velocity */

dc->vel += dc->acc;

if (Geom::L2(dc->vel) > dc->vel_max)

dc->vel_max = Geom::L2(dc->vel);

/* Calculate angle of drawing tool */

double a1;

if (dc->usetilt) {

// 1a. calculate nib angle from input device tilt:

gdouble length = std::sqrt(dc->xtilt*dc->xtilt + dc->ytilt*dc->ytilt);;

if (length > 0) {

Geom::Point ang1 = Geom::Point(dc->ytilt/length, dc->xtilt/length);

a1 = atan2(ang1);

}

else

a1 = 0.0;

}

else {

// 1b. fixed dc->angle (absolutely flat nib):

double const radians = ( (dc->angle - 90) / 180.0 ) * M_PI;

Geom::Point ang1 = Geom::Point(-sin(radians), cos(radians));

a1 = atan2(ang1);

}

// 2. perpendicular to dc->vel (absolutely non-flat nib):

gdouble const mag_vel = Geom::L2(dc->vel);

if ( mag_vel < DYNA_EPSILON ) {

return FALSE;

}

Geom::Point ang2 = Geom::rot90(dc->vel) / mag_vel;

// 3. Average them using flatness parameter:

// calculate angles

double a2 = atan2(ang2);

// flip a2 to force it to be in the same half-circle as a1

bool flipped = false;

if (fabs (a2-a1) > 0.5*M_PI) {

a2 += M_PI;

flipped = true;

}

// normalize a2

if (a2 > M_PI)

a2 -= 2*M_PI;

if (a2 < -M_PI)

a2 += 2*M_PI;

// find the flatness-weighted bisector angle, unflip if a2 was flipped

// FIXME: when dc->vel is oscillating around the fixed angle, the new_ang flips back and forth. How to avoid this?

double new_ang = a1 + (1 - dc->flatness) * (a2 - a1) - (flipped? M_PI : 0);

// Try to detect a sudden flip when the new angle differs too much from the previous for the

// current velocity; in that case discard this move

double angle_delta = Geom::L2(Geom::Point (cos (new_ang), sin (new_ang)) - dc->ang);

if ( angle_delta / Geom::L2(dc->vel) > 4000 ) {

return FALSE;

}

// convert to point

dc->ang = Geom::Point (cos (new_ang), sin (new_ang));

/* Apply drag */

dc->vel *= 1.0 - drag;

/* Update position */

dc->last = dc->cur;

dc->cur += dc->vel;

return TRUE;

}

static void

sp_dyna_draw_brush(SPDynaDrawContext *dc)

{

g_assert( dc->npoints >= 0 && dc->npoints < SAMPLING_SIZE );

// How much velocity thins strokestyle

double vel_thin = flerp (0, 160, dc->vel_thin);

// Influence of pressure on thickness

double pressure_thick = (dc->usepressure ? dc->pressure : 1.0);

// get the real brush point, not the same as pointer (affected by hatch tracking and/or mass

// drag)

Geom::Point brush = sp_dyna_draw_get_vpoint(dc, dc->cur);

Geom::Point brush_w = SP_EVENT_CONTEXT(dc)->desktop->d2w(brush);

double trace_thick = 1;

if (dc->trace_bg) {

// pick single pixel

NRPixBlock pb;

int x = (int) floor(brush_w[Geom::X]);

int y = (int) floor(brush_w[Geom::Y]);

nr_pixblock_setup_fast(&pb, NR_PIXBLOCK_MODE_R8G8B8A8P, x, y, x+1, y+1, TRUE);

sp_canvas_arena_render_pixblock(SP_CANVAS_ARENA(sp_desktop_drawing(SP_EVENT_CONTEXT(dc)->desktop)), &pb);

const unsigned char *s = NR_PIXBLOCK_PX(&pb);

double R = s[0] / 255.0;

double G = s[1] / 255.0;

double B = s[2] / 255.0;

double A = s[3] / 255.0;

double max = MAX (MAX (R, G), B);

double min = MIN (MIN (R, G), B);

double L = A * (max + min)/2 + (1 - A); // blend with white bg

trace_thick = 1 - L;

//g_print ("L %g thick %g\n", L, trace_thick);

}

double width = (pressure_thick * trace_thick - vel_thin * Geom::L2(dc->vel)) * dc->width;

double tremble_left = 0, tremble_right = 0;

if (dc->tremor > 0) {

// obtain two normally distributed random variables, using polar Box-Muller transform

double x1, x2, w, y1, y2;

do {

x1 = 2.0 * g_random_double_range(0,1) - 1.0;

x2 = 2.0 * g_random_double_range(0,1) - 1.0;

w = x1 * x1 + x2 * x2;

} while ( w >= 1.0 );

w = sqrt( (-2.0 * log( w ) ) / w );

y1 = x1 * w;

y2 = x2 * w;

// deflect both left and right edges randomly and independently, so that:

// (1) dc->tremor=1 corresponds to sigma=1, decreasing dc->tremor narrows the bell curve;

// (2) deflection depends on width, but is upped for small widths for better visual uniformity across widths;

// (3) deflection somewhat depends on speed, to prevent fast strokes looking

// comparatively smooth and slow ones excessively jittery

tremble_left = (y1)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*Geom::L2(dc->vel));

tremble_right = (y2)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*Geom::L2(dc->vel));

}

if ( width < 0.02 * dc->width ) {

width = 0.02 * dc->width;

}

double dezoomify_factor = 0.05 * 1000;

if (!dc->abs_width) {

dezoomify_factor /= SP_EVENT_CONTEXT(dc)->desktop->current_zoom();

}

Geom::Point del_left = dezoomify_factor * (width + tremble_left) * dc->ang;

Geom::Point del_right = dezoomify_factor * (width + tremble_right) * dc->ang;

dc->point1[dc->npoints] = brush + del_left;

dc->point2[dc->npoints] = brush - del_right;

dc->del = 0.5*(del_left + del_right);

dc->npoints++;

}

sp_ddc_update_toolbox (SPDesktop *desktop, const gchar *id, double value)

{

desktop->setToolboxAdjustmentValue (id, value);

}

static void

calligraphic_cancel(SPDynaDrawContext *dc)

{

SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;

dc->dragging = FALSE;

dc->is_drawing = false;

sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), 0);

/* Remove all temporary line segments */

while (dc->segments) {

gtk_object_destroy(GTK_OBJECT(dc->segments->data));

dc->segments = g_slist_remove(dc->segments, dc->segments->data);

}

/* reset accumulated curve */

dc->accumulated->reset();

clear_current(dc);

if (dc->repr) {

dc->repr = NULL;

}

}

sp_dyna_draw_context_root_handler(SPEventContext *event_context,

GdkEvent *event)

{

SPDynaDrawContext *dc = SP_DYNA_DRAW_CONTEXT(event_context);

SPDesktop *desktop = event_context->desktop;

gint ret = FALSE;

switch (event->type) {

case GDK_BUTTON_PRESS:

if (event->button.button == 1 && !event_context->space_panning) {

SPDesktop *desktop = SP_EVENT_CONTEXT_DESKTOP(dc);

if (Inkscape::have_viable_layer(desktop, dc->_message_context) == false) {

return TRUE;

}

dc->accumulated->reset();

if (dc->repr) {

dc->repr = NULL;

}

/* initialize first point */

dc->npoints = 0;

sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),

( GDK_KEY_PRESS_MASK |

GDK_BUTTON_RELEASE_MASK |

GDK_POINTER_MOTION_MASK |

GDK_BUTTON_PRESS_MASK ),

NULL,

event->button.time);

ret = TRUE;

sp_canvas_force_full_redraw_after_interruptions(desktop->canvas, 3);

dc->is_drawing = true;

dc->just_started_drawing = true;

}

break;

case GDK_MOTION_NOTIFY:

{

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

event->motion.y);

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

sp_dyna_draw_extinput(dc, event);

dc->_message_context->clear();

// for hatching:

double hatch_dist = 0;

Geom::Point hatch_unit_vector(0,0);

Geom::Point nearest(0,0);

Geom::Point pointer(0,0);

Geom::Matrix motion_to_curve(Geom::identity());

if (event->motion.state & GDK_CONTROL_MASK) { // hatching - sense the item

SPItem *selected = sp_desktop_selection(desktop)->singleItem();

if (selected && (SP_IS_SHAPE(selected) || SP_IS_TEXT(selected))) {

// One item selected, and it's a path;

// let's try to track it as a guide

if (selected != dc->hatch_item) {

dc->hatch_item = selected;

if (dc->hatch_livarot_path)

delete dc->hatch_livarot_path;

dc->hatch_livarot_path = Path_for_item (dc->hatch_item, true, true);

dc->hatch_livarot_path->ConvertWithBackData(0.01);

}

// calculate pointer point in the guide item's coords

motion_to_curve = sp_item_dt2i_affine(selected) * sp_item_i2doc_affine(selected);

pointer = motion_dt * motion_to_curve;

// calculate the nearest point on the guide path

boost::optional<Path::cut_position> position = get_nearest_position_on_Path(dc->hatch_livarot_path, pointer);

nearest = get_point_on_Path(dc->hatch_livarot_path, position->piece, position->t);

// distance from pointer to nearest

hatch_dist = Geom::L2(pointer - nearest);

// unit-length vector

hatch_unit_vector = (pointer - nearest)/hatch_dist;

dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Guide path selected</b>; start drawing along the guide with <b>Ctrl</b>"));

} else {

dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Select a guide path</b> to track with <b>Ctrl</b>"));

}

}

if ( dc->is_drawing && (event->motion.state & GDK_BUTTON1_MASK) && !event_context->space_panning) {

dc->dragging = TRUE;

if (event->motion.state & GDK_CONTROL_MASK && dc->hatch_item) { // hatching

#define HATCH_VECTOR_ELEMENTS 12

#define INERTIA_ELEMENTS 36

#define SPEED_ELEMENTS 12

#define SPEED_MIN 0.3

#define SPEED_NORMAL 0.3

// speed is the movement of the nearest point along the guide path, divided by

// the movement of the pointer at the same period; it is averaged for the last

// SPEED_ELEMENTS motion events. Normally, as you track the guide path, speed

// is about 1, i.e. the nearest point on the path is moved by about the same

// distance as the pointer. If the speed starts to decrease, we are losing

// contact with the guide; if it drops below SPEED_MIN, we are on our own and

// not attracted to guide anymore. Most often this happens when you have

// tracked to the end of a guide calligraphic stroke and keep moving

// further. We try to handle this situation gracefully: not stick with the

// guide forever but let go of it smoothly and without sharp jerks (non-zero

// mass recommended; with zero mass, jerks are still quite noticeable).

double speed = 1;

if (Geom::L2(dc->hatch_last_nearest) != 0) {

// the distance nearest moved since the last motion event

double nearest_moved = Geom::L2(nearest - dc->hatch_last_nearest);

// the distance pointer moved since the last motion event

double pointer_moved = Geom::L2(pointer - dc->hatch_last_pointer);

// store them in stacks limited to SPEED_ELEMENTS

dc->hatch_nearest_past.push_front(nearest_moved);

if (dc->hatch_nearest_past.size() > SPEED_ELEMENTS)

dc->hatch_nearest_past.pop_back();

dc->hatch_pointer_past.push_front(pointer_moved);

if (dc->hatch_pointer_past.size() > SPEED_ELEMENTS)

dc->hatch_pointer_past.pop_back();

// If the stacks are full,

if (dc->hatch_nearest_past.size() == SPEED_ELEMENTS) {

// calculate the sums of all stored movements

double nearest_sum = std::accumulate (dc->hatch_nearest_past.begin(), dc->hatch_nearest_past.end(), 0.0);

double pointer_sum = std::accumulate (dc->hatch_pointer_past.begin(), dc->hatch_pointer_past.end(), 0.0);

// and divide to get the speed

speed = nearest_sum/pointer_sum;

//g_print ("nearest sum %g pointer_sum %g speed %g\n", nearest_sum, pointer_sum, speed);

}

}

if ( dc->hatch_escaped // already escaped, do not reattach

|| (speed < SPEED_MIN) // stuck; most likely reached end of traced stroke

|| (dc->hatch_spacing > 0 && hatch_dist > 50 * dc->hatch_spacing) // went too far from the guide

) {

// We are NOT attracted to the guide!

//g_print ("\nlast_nearest %g %g nearest %g %g pointer %g %g pos %d %g\n", dc->last_nearest[Geom::X], dc->last_nearest[Geom::Y], nearest[Geom::X], nearest[Geom::Y], pointer[Geom::X], pointer[Geom::Y], position->piece, position->t);

// Remember hatch_escaped so we don't get

// attracted again until the end of this stroke

dc->hatch_escaped = true;

if (dc->inertia_vectors.size() >= INERTIA_ELEMENTS/2) { // move by inertia

Geom::Point moved_past_escape = motion_dt - dc->inertia_vectors.front();

Geom::Point inertia =

dc->inertia_vectors.front() - dc->inertia_vectors.back();

double dot = Geom::dot (moved_past_escape, inertia);

dot /= Geom::L2(moved_past_escape) * Geom::L2(inertia);

if (dot > 0) { // mouse is still moving in approx the same direction

Geom::Point should_have_moved =

(inertia) * (1/Geom::L2(inertia)) * Geom::L2(moved_past_escape);

motion_dt = dc->inertia_vectors.front() + should_have_moved;

}

}

} else {

// Calculate angle cosine of this vector-to-guide and all past vectors

// summed, to detect if we accidentally flipped to the other side of the

// guide

Geom::Point hatch_vector_accumulated = std::accumulate

(dc->hatch_vectors.begin(), dc->hatch_vectors.end(), Geom::Point(0,0));

double dot = Geom::dot (pointer - nearest, hatch_vector_accumulated);

dot /= Geom::L2(pointer - nearest) * Geom::L2(hatch_vector_accumulated);

if (dc->hatch_spacing != 0) { // spacing was already set

double target;

if (speed > SPEED_NORMAL) {

// all ok, strictly obey the spacing

target = dc->hatch_spacing;

} else {

// looks like we're starting to lose speed,

// so _gradually_ let go attraction to prevent jerks

target = (dc->hatch_spacing * speed + hatch_dist * (SPEED_NORMAL - speed))/SPEED_NORMAL;

}

if (!IS_NAN(dot) && dot < -0.5) {// flip

target = -target;

}

// This is the track pointer that we will use instead of the real one

Geom::Point new_pointer = nearest + target * hatch_unit_vector;

// some limited feedback: allow persistent pulling to slightly change

// the spacing

dc->hatch_spacing += (hatch_dist - dc->hatch_spacing)/3500;

// return it to the desktop coords

motion_dt = new_pointer * motion_to_curve.inverse();

if (speed >= SPEED_NORMAL) {

dc->inertia_vectors.push_front(motion_dt);

if (dc->inertia_vectors.size() > INERTIA_ELEMENTS)

dc->inertia_vectors.pop_back();

}

} else {

// this is the first motion event, set the dist

dc->hatch_spacing = hatch_dist;

}

// remember last points

dc->hatch_last_pointer = pointer;

dc->hatch_last_nearest = nearest;

dc->hatch_vectors.push_front(pointer - nearest);

if (dc->hatch_vectors.size() > HATCH_VECTOR_ELEMENTS)

dc->hatch_vectors.pop_back();

}

dc->_message_context->set(Inkscape::NORMAL_MESSAGE, dc->hatch_escaped? _("Tracking: <b>connection to guide path lost!</b>") : _("<b>Tracking</b> a guide path"));

} else {

dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drawing</b> a calligraphic stroke"));

}

if (dc->just_started_drawing) {

dc->just_started_drawing = false;

sp_dyna_draw_reset(dc, motion_dt);

}

if (!sp_dyna_draw_apply(dc, motion_dt)) {

ret = TRUE;

break;

}

if ( dc->cur != dc->last ) {

sp_dyna_draw_brush(dc);

g_assert( dc->npoints > 0 );

fit_and_split(dc, FALSE);

}

ret = TRUE;

}

// Draw the hatching circle if necessary

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

if (dc->hatch_spacing == 0 && hatch_dist != 0) {

// Haven't set spacing yet: gray, center free, update radius live

Geom::Point c = desktop->w2d(motion_w);

Geom::Matrix const sm (Geom::Scale(hatch_dist, hatch_dist) * Geom::Translate(c));

sp_canvas_item_affine_absolute(dc->hatch_area, sm);

sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);

sp_canvas_item_show(dc->hatch_area);

} else if (dc->dragging && !dc->hatch_escaped) {

// Tracking: green, center snapped, fixed radius

Geom::Point c = motion_dt;

Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));

sp_canvas_item_affine_absolute(dc->hatch_area, sm);

sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x00FF00ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);

sp_canvas_item_show(dc->hatch_area);

} else if (dc->dragging && dc->hatch_escaped) {

// Tracking escaped: red, center free, fixed radius

Geom::Point c = motion_dt;

Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));

sp_canvas_item_affine_absolute(dc->hatch_area, sm);

sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0xFF0000ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);

sp_canvas_item_show(dc->hatch_area);

} else {

// Not drawing but spacing set: gray, center snapped, fixed radius

Geom::Point c = (nearest + dc->hatch_spacing * hatch_unit_vector) * motion_to_curve.inverse();

if (!IS_NAN(c[Geom::X]) && !IS_NAN(c[Geom::Y])) {

Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));

sp_canvas_item_affine_absolute(dc->hatch_area, sm);

sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);

sp_canvas_item_show(dc->hatch_area);

}

}

} else {

sp_canvas_item_hide(dc->hatch_area);

}

}

break;

case GDK_BUTTON_RELEASE:

{

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

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

sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), event->button.time);

sp_canvas_end_forced_full_redraws(desktop->canvas);

dc->is_drawing = false;

if (dc->dragging && event->button.button == 1 && !event_context->space_panning) {

dc->dragging = FALSE;

sp_dyna_draw_apply(dc, motion_dt);

/* Remove all temporary line segments */

while (dc->segments) {

gtk_object_destroy(GTK_OBJECT(dc->segments->data));

dc->segments = g_slist_remove(dc->segments, dc->segments->data);

}

/* Create object */

fit_and_split(dc, TRUE);

if (accumulate_calligraphic(dc))

set_to_accumulated(dc, event->button.state & GDK_SHIFT_MASK); // performs document_done

else

g_warning ("Failed to create path: invalid data in dc->cal1 or dc->cal2");

/* reset accumulated curve */

dc->accumulated->reset();

clear_current(dc);

if (dc->repr) {

dc->repr = NULL;

}

if (!dc->hatch_pointer_past.empty()) dc->hatch_pointer_past.clear();

if (!dc->hatch_nearest_past.empty()) dc->hatch_nearest_past.clear();

if (!dc->inertia_vectors.empty()) dc->inertia_vectors.clear();

if (!dc->hatch_vectors.empty()) dc->hatch_vectors.clear();

dc->hatch_last_nearest = Geom::Point(0,0);

dc->hatch_last_pointer = Geom::Point(0,0);

dc->hatch_escaped = false;

dc->hatch_item = NULL;

dc->hatch_livarot_path = NULL;

dc->just_started_drawing = false;

if (dc->hatch_spacing != 0 && !dc->keep_selected) {

// we do not select the newly drawn path, so increase spacing by step

if (dc->hatch_spacing_step == 0) {

dc->hatch_spacing_step = dc->hatch_spacing;

}

dc->hatch_spacing += dc->hatch_spacing_step;

}

dc->_message_context->clear();

ret = TRUE;

}

break;

}

case GDK_KEY_PRESS:

switch (get_group0_keyval (&event->key)) {

case GDK_Up:

case GDK_KP_Up:

if (!MOD__CTRL_ONLY) {

dc->angle += 5.0;

if (dc->angle > 90.0)

dc->angle = 90.0;

sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);

ret = TRUE;

}

break;

case GDK_Down:

case GDK_KP_Down:

if (!MOD__CTRL_ONLY) {

dc->angle -= 5.0;

if (dc->angle < -90.0)

dc->angle = -90.0;

sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);

ret = TRUE;

}

break;

case GDK_Right:

case GDK_KP_Right:

if (!MOD__CTRL_ONLY) {

dc->width += 0.01;

if (dc->width > 1.0)

dc->width = 1.0;

sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100); // the same spinbutton is for alt+x

ret = TRUE;

}

break;

case GDK_Left:

case GDK_KP_Left:

if (!MOD__CTRL_ONLY) {

dc->width -= 0.01;

if (dc->width < 0.01)

dc->width = 0.01;

sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);

ret = TRUE;

}

break;

case GDK_Home:

case GDK_KP_Home:

dc->width = 0.01;

sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);

ret = TRUE;

break;

case GDK_End:

case GDK_KP_End:

dc->width = 1.0;

sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);

ret = TRUE;

break;

case GDK_x:

case GDK_X:

if (MOD__ALT_ONLY) {

desktop->setToolboxFocusTo ("altx-calligraphy");

ret = TRUE;

}

break;

case GDK_Escape:

if (dc->is_drawing) {

// if drawing, cancel, otherwise pass it up for deselecting

calligraphic_cancel (dc);

ret = TRUE;

}

break;

case GDK_z:

case GDK_Z:

if (MOD__CTRL_ONLY && dc->is_drawing) {

// if drawing, cancel, otherwise pass it up for undo

calligraphic_cancel (dc);

ret = TRUE;

}

break;

default:

break;

}

break;

case GDK_KEY_RELEASE:

switch (get_group0_keyval(&event->key)) {

case GDK_Control_L:

case GDK_Control_R:

dc->_message_context->clear();

dc->hatch_spacing = 0;

dc->hatch_spacing_step = 0;

break;

default:

break;

}

default:

break;

}

if (!ret) {

if (((SPEventContextClass *) dd_parent_class)->root_handler) {

ret = ((SPEventContextClass *) dd_parent_class)->root_handler(event_context, event);

}

}

return ret;

}

static void

clear_current(SPDynaDrawContext *dc)

{

/* reset bpath */

sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), NULL);

/* reset curve */

dc->currentcurve->reset();

dc->cal1->reset();

dc->cal2->reset();

/* reset points */

dc->npoints = 0;

}

static void

set_to_accumulated(SPDynaDrawContext *dc, bool unionize)

{

SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;

if (!dc->accumulated->is_empty()) {

if (!dc->repr) {

/* Create object */

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

Inkscape::XML::Node *repr = xml_doc->createElement("svg:path");

/* Set style */

sp_desktop_apply_style_tool (desktop, repr, "/tools/calligraphic", false);

dc->repr = repr;

SPItem *item=SP_ITEM(desktop->currentLayer()->appendChildRepr(dc->repr));

Inkscape::GC::release(dc->repr);

item->transform = sp_item_i2doc_affine(SP_ITEM(desktop->currentLayer())).inverse();

item->updateRepr();

}

Geom::PathVector pathv = dc->accumulated->get_pathvector() * sp_desktop_dt2doc_affine(desktop);

gchar *str = sp_svg_write_path(pathv);

g_assert( str != NULL );

dc->repr->setAttribute("d", str);

g_free(str);

if (unionize) {

sp_desktop_selection(desktop)->add(dc->repr);

sp_selected_path_union_skip_undo(desktop);

} else {

if (dc->keep_selected) {

sp_desktop_selection(desktop)->set(dc->repr);

}

}

} else {

if (dc->repr) {

sp_repr_unparent(dc->repr);

}

dc->repr = NULL;

}

sp_document_done(sp_desktop_document(desktop), SP_VERB_CONTEXT_CALLIGRAPHIC,

_("Draw calligraphic stroke"));

}

static void

add_cap(SPCurve *curve,

Geom::Point const &from,

Geom::Point const &to,

double rounding)

{

if (Geom::L2( to - from ) > DYNA_EPSILON) {

Geom::Point vel = rounding * Geom::rot90( to - from ) / sqrt(2.0);

double mag = Geom::L2(vel);

Geom::Point v = mag * Geom::rot90( to - from ) / Geom::L2( to - from );

curve->curveto(from + v, to + v, to);

}

}

static bool

accumulate_calligraphic(SPDynaDrawContext *dc)

{

if (

dc->cal1->is_empty() ||

dc->cal2->is_empty() ||

(dc->cal1->get_segment_count() <= 0) ||

dc->cal1->first_path()->closed()

) {

dc->cal1->reset();

dc->cal2->reset();

return false; // failure

}

SPCurve *rev_cal2 = dc->cal2->create_reverse();

if (

(rev_cal2->get_segment_count() <= 0) ||

rev_cal2->first_path()->closed()

) {

rev_cal2->unref();

dc->cal1->reset();

dc->cal2->reset();

return false; // failure

}

Geom::CubicBezier const * dc_cal1_firstseg = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->first_segment() );

Geom::CubicBezier const * rev_cal2_firstseg = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->first_segment() );

Geom::CubicBezier const * dc_cal1_lastseg = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->last_segment() );

Geom::CubicBezier const * rev_cal2_lastseg = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->last_segment() );

if (

!dc_cal1_firstseg ||

!rev_cal2_firstseg ||

!dc_cal1_lastseg ||

!rev_cal2_lastseg

) {

rev_cal2->unref();

dc->cal1->reset();

dc->cal2->reset();

return false; // failure

}

dc->accumulated->reset(); /* Is this required ?? */

dc->accumulated->append(dc->cal1, false);

add_cap(dc->accumulated, (*dc_cal1_lastseg)[3], (*rev_cal2_firstseg)[0], dc->cap_rounding);

dc->accumulated->append(rev_cal2, true);

add_cap(dc->accumulated, (*rev_cal2_lastseg)[3], (*dc_cal1_firstseg)[0], dc->cap_rounding);

dc->accumulated->closepath();

rev_cal2->unref();

dc->cal1->reset();

dc->cal2->reset();

return true; // success

}

static double square(double const x)

{

return x * x;

}

static void

fit_and_split(SPDynaDrawContext *dc, gboolean release)

{

SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;

double const tolerance_sq = square( desktop->w2d().descrim() * TOLERANCE_CALLIGRAPHIC );

#ifdef DYNA_DRAW_VERBOSE

g_print("[F&S:R=%c]", release?'T':'F');

#endif

if (!( dc->npoints > 0 && dc->npoints < SAMPLING_SIZE ))

return; // just clicked

if ( dc->npoints == SAMPLING_SIZE - 1 || release ) {

#define BEZIER_SIZE 4

#define BEZIER_MAX_BEZIERS 8

#define BEZIER_MAX_LENGTH ( BEZIER_SIZE * BEZIER_MAX_BEZIERS )

#ifdef DYNA_DRAW_VERBOSE

g_print("[F&S:#] dc->npoints:%d, release:%s\n",

dc->npoints, release ? "TRUE" : "FALSE");

#endif

/* Current calligraphic */

if ( dc->cal1->is_empty() || dc->cal2->is_empty() ) {

/* dc->npoints > 0 */

/* g_print("calligraphics(1|2) reset\n"); */

dc->cal1->reset();

dc->cal2->reset();

dc->cal1->moveto(dc->point1[0]);

dc->cal2->moveto(dc->point2[0]);

}

Geom::Point b1[BEZIER_MAX_LENGTH];

gint const nb1 = Geom::bezier_fit_cubic_r(b1, dc->point1, dc->npoints,

tolerance_sq, BEZIER_MAX_BEZIERS);

g_assert( nb1 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b1)) );

Geom::Point b2[BEZIER_MAX_LENGTH];

gint const nb2 = Geom::bezier_fit_cubic_r(b2, dc->point2, dc->npoints,

tolerance_sq, BEZIER_MAX_BEZIERS);

g_assert( nb2 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b2)) );

if ( nb1 != -1 && nb2 != -1 ) {

/* Fit and draw and reset state */

#ifdef DYNA_DRAW_VERBOSE

g_print("nb1:%d nb2:%d\n", nb1, nb2);

#endif

/* CanvasShape */

if (! release) {

dc->currentcurve->reset();

dc->currentcurve->moveto(b1[0]);

for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {

dc->currentcurve->curveto(bp1[1], bp1[2], bp1[3]);

}

dc->currentcurve->lineto(b2[BEZIER_SIZE*(nb2-1) + 3]);

for (Geom::Point *bp2 = b2 + BEZIER_SIZE * ( nb2 - 1 ); bp2 >= b2; bp2 -= BEZIER_SIZE) {

dc->currentcurve->curveto(bp2[2], bp2[1], bp2[0]);

}

// FIXME: dc->segments is always NULL at this point??

if (!dc->segments) { // first segment

add_cap(dc->currentcurve, b2[0], b1[0], dc->cap_rounding);

}

dc->currentcurve->closepath();

sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);

}

/* Current calligraphic */

for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {

dc->cal1->curveto(bp1[1], bp1[2], bp1[3]);

}

for (Geom::Point *bp2 = b2; bp2 < b2 + BEZIER_SIZE * nb2; bp2 += BEZIER_SIZE) {

dc->cal2->curveto(bp2[1], bp2[2], bp2[3]);

}

} else {

/* fixme: ??? */

#ifdef DYNA_DRAW_VERBOSE

g_print("[fit_and_split] failed to fit-cubic.\n");

#endif

draw_temporary_box(dc);

for (gint i = 1; i < dc->npoints; i++) {

dc->cal1->lineto(dc->point1[i]);

}

for (gint i = 1; i < dc->npoints; i++) {

dc->cal2->lineto(dc->point2[i]);

}

}

/* Fit and draw and copy last point */

#ifdef DYNA_DRAW_VERBOSE

g_print("[%d]Yup\n", dc->npoints);

#endif

if (!release) {

g_assert(!dc->currentcurve->is_empty());

SPCanvasItem *cbp = sp_canvas_item_new(sp_desktop_sketch(desktop),

SP_TYPE_CANVAS_BPATH,

NULL);

SPCurve *curve = dc->currentcurve->copy();

sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH (cbp), curve);

curve->unref();

guint32 fillColor = sp_desktop_get_color_tool (desktop, "/tools/calligraphic", true);

//guint32 strokeColor = sp_desktop_get_color_tool (desktop, "/tools/calligraphic", false);

double opacity = sp_desktop_get_master_opacity_tool (desktop, "/tools/calligraphic");

double fillOpacity = sp_desktop_get_opacity_tool (desktop, "/tools/calligraphic", true);

//double strokeOpacity = sp_desktop_get_opacity_tool (desktop, "/tools/calligraphic", false);

sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(cbp), ((fillColor & 0xffffff00) | SP_COLOR_F_TO_U(opacity*fillOpacity)), SP_WIND_RULE_EVENODD);

//on second thougtht don't do stroke yet because we don't have stoke-width yet and because stoke appears between segments while drawing

//sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cbp), ((strokeColor & 0xffffff00) | SP_COLOR_F_TO_U(opacity*strokeOpacity)), 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);

sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cbp), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);

/* fixme: Cannot we cascade it to root more clearly? */

g_signal_connect(G_OBJECT(cbp), "event", G_CALLBACK(sp_desktop_root_handler), desktop);

dc->segments = g_slist_prepend(dc->segments, cbp);

}

dc->point1[0] = dc->point1[dc->npoints - 1];

dc->point2[0] = dc->point2[dc->npoints - 1];

dc->npoints = 1;

} else {

draw_temporary_box(dc);

}

}

static void

draw_temporary_box(SPDynaDrawContext *dc)

{

dc->currentcurve->reset();

dc->currentcurve->moveto(dc->point2[dc->npoints-1]);

for (gint i = dc->npoints-2; i >= 0; i--) {

dc->currentcurve->lineto(dc->point2[i]);

}

for (gint i = 0; i < dc->npoints; i++) {

dc->currentcurve->lineto(dc->point1[i]);

}

if (dc->npoints >= 2) {

add_cap(dc->currentcurve, dc->point1[dc->npoints-1], dc->point2[dc->npoints-1], dc->cap_rounding);

}

dc->currentcurve->closepath();

sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);

}