~centralelyon2010/inkscape/imagelinks2

/*

 * Eraser drawing mode

 *

 * Authors:

 *   Mitsuru Oka <oka326@parkcity.ne.jp>

 *   Lauris Kaplinski <lauris@kaplinski.com>

 *   bulia byak <buliabyak@users.sf.net>

 *   MenTaLguY <mental@rydia.net>

 *   Jon A. Cruz <jon@joncruz.org>

 *   Abhishek Sharma

 *

 * The original dynadraw code:

 *   Paul Haeberli <paul@sgi.com>

 *

 * Copyright (C) 1998 The Free Software Foundation

 * Copyright (C) 1999-2005 authors

 * Copyright (C) 2001-2002 Ximian, Inc.

 * Copyright (C) 2005-2007 bulia byak

 * Copyright (C) 2006 MenTaLguY

 * Copyright (C) 2008 Jon A. Cruz

 *

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

 */

#define noERASER_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/sp-canvas.h"

#include "display/canvas-bpath.h"

#include <2geom/bezier-utils.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-style.h"

#include "message-context.h"

#include "preferences.h"

#include "pixmaps/cursor-eraser.xpm"

#include "xml/repr.h"

#include "context-fns.h"

#include "sp-item.h"

#include "color.h"

#include "rubberband.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 <2geom/math-utils.h>

#include <2geom/pathvector.h>

#include "eraser-context.h"

using Inkscape::DocumentUndo;

#define ERC_RED_RGBA 0xff0000ff

#define TOLERANCE_ERASER 0.1

#define ERASER_EPSILON 0.5e-6

#define ERASER_EPSILON_START 0.5e-2

#define ERASER_VEL_START 1e-5

#define DRAG_MIN 0.0

#define DRAG_DEFAULT 1.0

#define DRAG_MAX 1.0

static void sp_eraser_context_class_init(SPEraserContextClass *klass);

static void sp_eraser_context_init(SPEraserContext *erc);

static void sp_eraser_context_dispose(GObject *object);

static void sp_eraser_context_setup(SPEventContext *ec);

static void sp_eraser_context_set(SPEventContext *ec, Inkscape::Preferences::Entry *val);

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

static void clear_current(SPEraserContext *dc);

static void set_to_accumulated(SPEraserContext *dc);

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

static void accumulate_eraser(SPEraserContext *dc);

static void fit_and_split(SPEraserContext *erc, gboolean release);

static void sp_eraser_reset(SPEraserContext *erc, Geom::Point p);

static Geom::Point sp_eraser_get_npoint(SPEraserContext const *erc, Geom::Point v);

static Geom::Point sp_eraser_get_vpoint(SPEraserContext const *erc, Geom::Point n);

static void draw_temporary_box(SPEraserContext *dc);

static SPEventContextClass *eraser_parent_class = 0;

GType sp_eraser_context_get_type(void)

{

    static GType type = 0;

    if (!type) {

        GTypeInfo info = {

            sizeof(SPEraserContextClass),

            0, // base_init

            0, // base_finalize

            (GClassInitFunc)sp_eraser_context_class_init,

            0, // class_finalize

            0, // class_data

            sizeof(SPEraserContext),

            0, // n_preallocs

            (GInstanceInitFunc)sp_eraser_context_init,

            0 // value_table

        };

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

    }

    return type;

}

static void

sp_eraser_context_class_init(SPEraserContextClass *klass)

{

    GObjectClass *object_class = (GObjectClass *) klass;

    SPEventContextClass *event_context_class = (SPEventContextClass *) klass;

    eraser_parent_class = (SPEventContextClass*)g_type_class_peek_parent(klass);

    object_class->dispose = sp_eraser_context_dispose;

    event_context_class->setup = sp_eraser_context_setup;

    event_context_class->set = sp_eraser_context_set;

    event_context_class->root_handler = sp_eraser_context_root_handler;

}

static void

sp_eraser_context_init(SPEraserContext *erc)

{

    erc->cursor_shape = cursor_eraser_xpm;

    erc->hot_x = 4;

    erc->hot_y = 4;

}

static void

sp_eraser_context_dispose(GObject *object)

{

    //SPEraserContext *erc = SP_ERASER_CONTEXT(object);

    G_OBJECT_CLASS(eraser_parent_class)->dispose(object);

}

static void

sp_eraser_context_setup(SPEventContext *ec)

{

    SPEraserContext *erc = SP_ERASER_CONTEXT(ec);

    SPDesktop *desktop = ec->desktop;

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

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

    erc->accumulated = new SPCurve();

    erc->currentcurve = new SPCurve();

    erc->cal1 = new SPCurve();

    erc->cal2 = new SPCurve();

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

    sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(erc->currentshape), ERC_RED_RGBA, SP_WIND_RULE_EVENODD);

    sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(erc->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(erc->currentshape), "event", G_CALLBACK(sp_desktop_root_handler), desktop);

/*

static ProfileFloatElement f_profile[PROFILE_FLOAT_SIZE] = {

    {"mass",0.02, 0.0, 1.0},

    {"wiggle",0.0, 0.0, 1.0},

    {"angle",30.0, -90.0, 90.0},

    {"thinning",0.1, -1.0, 1.0},

    {"tremor",0.0, 0.0, 1.0},

    {"flatness",0.9, 0.0, 1.0},

    {"cap_rounding",0.0, 0.0, 5.0}

};

*/

    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, "cap_rounding");

    erc->is_drawing = false;

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

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

    if (prefs->getBool("/tools/eraser/selcue", 0) != 0) {

        ec->enableSelectionCue();

    }

// TODO temp force:

    ec->enableSelectionCue();

}

static void

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

{

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

    if ( eraser_parent_class->set ) {

        eraser_parent_class->set(ec, val);

    }

}

static double

flerp(double f0, double f1, double p)

{

    return f0 + ( f1 - f0 ) * p;

}

/* Get normalized point */

static Geom::Point

sp_eraser_get_npoint(SPEraserContext 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);

}

/* Get view point */

static Geom::Point

sp_eraser_get_vpoint(SPEraserContext 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_eraser_reset(SPEraserContext *dc, Geom::Point p)

{

    dc->last = dc->cur = sp_eraser_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_eraser_extinput(SPEraserContext *dc, GdkEvent *event)

{

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

        dc->pressure = CLAMP (dc->pressure, ERC_MIN_PRESSURE, ERC_MAX_PRESSURE);

    else

        dc->pressure = ERC_DEFAULT_PRESSURE;

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

        dc->xtilt = CLAMP (dc->xtilt, ERC_MIN_TILT, ERC_MAX_TILT);

    else

        dc->xtilt = ERC_DEFAULT_TILT;

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

        dc->ytilt = CLAMP (dc->ytilt, ERC_MIN_TILT, ERC_MAX_TILT);

    else

        dc->ytilt = ERC_DEFAULT_TILT;

}

static gboolean

sp_eraser_apply(SPEraserContext *dc, Geom::Point p)

{

    Geom::Point n = sp_eraser_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 ERASER_EPSILON,

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

    // _and_ the force is below the (higher) ERASER_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) < ERASER_EPSILON || (dc->vel_max < ERASER_VEL_START && Geom::L2(force) < ERASER_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 < ERASER_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));

//    g_print ("force %g  acc %g  vel_max %g  vel %g  a1 %g  a2 %g  new_ang %g\n", Geom::L2(force), Geom::L2(dc->acc), dc->vel_max, Geom::L2(dc->vel), a1, a2, new_ang);

    /* Apply drag */

    dc->vel *= 1.0 - drag;

    /* Update position */

    dc->last = dc->cur;

    dc->cur += dc->vel;

    return TRUE;

}

static void

sp_eraser_brush(SPEraserContext *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_eraser_get_vpoint(dc, dc->cur);

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

    double trace_thick = 1;

    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++;

}

void

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

{

    desktop->setToolboxAdjustmentValue (id, value);

}

static void

eraser_cancel(SPEraserContext *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;

            }

}

gint

sp_eraser_context_root_handler(SPEventContext *event_context,

                                  GdkEvent *event)

{

    SPEraserContext *dc = SP_ERASER_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) {

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

                    return TRUE;

                }

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

                                         event->button.y);

                Geom::Point const button_dt(desktop->w2d(button_w));

                sp_eraser_reset(dc, button_dt);

                sp_eraser_extinput(dc, event);

                sp_eraser_apply(dc, button_dt);

                dc->accumulated->reset();

                if (dc->repr) {

                    dc->repr = NULL;

                }

                Inkscape::Rubberband::get(desktop)->start(desktop, button_dt);

                Inkscape::Rubberband::get(desktop)->setMode(RUBBERBAND_MODE_TOUCHPATH);

                /* 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;

            }

            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_eraser_extinput(dc, event);

            dc->_message_context->clear();

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

                dc->dragging = TRUE;

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

                if (!sp_eraser_apply(dc, motion_dt)) {

                    ret = TRUE;

                    break;

                }

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

                    sp_eraser_brush(dc);

                    g_assert( dc->npoints > 0 );

                    fit_and_split(dc, FALSE);

                }

                ret = TRUE;

            }

            Inkscape::Rubberband::get(desktop)->move(motion_dt);

        }

        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_eraser_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);

            accumulate_eraser(dc);

            set_to_accumulated(dc); // performs document_done

            /* reset accumulated curve */

            dc->accumulated->reset();

            clear_current(dc);

            if (dc->repr) {

                dc->repr = NULL;

            }

            dc->_message_context->clear();

            ret = TRUE;

        }

        if (Inkscape::Rubberband::get(desktop)->is_started()) {

            Inkscape::Rubberband::get(desktop)->stop();

        }

        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_erc_update_toolbox (desktop, "eraser-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_erc_update_toolbox (desktop, "eraser-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_erc_update_toolbox (desktop, "altx-eraser", 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_erc_update_toolbox (desktop, "altx-eraser", dc->width * 100);

                ret = TRUE;

            }

            break;

        case GDK_Home:

        case GDK_KP_Home:

            dc->width = 0.01;

            sp_erc_update_toolbox (desktop, "altx-eraser", dc->width * 100);

            ret = TRUE;

            break;

        case GDK_End:

        case GDK_KP_End:

            dc->width = 1.0;

            sp_erc_update_toolbox (desktop, "altx-eraser", dc->width * 100);

            ret = TRUE;

            break;

        case GDK_x:

        case GDK_X:

            if (MOD__ALT_ONLY) {

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

                ret = TRUE;

            }

            break;

        case GDK_Escape:

            Inkscape::Rubberband::get(desktop)->stop();

            if (dc->is_drawing) {

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

                eraser_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

                eraser_cancel (dc);

                ret = TRUE;

            }

            break;

        default:

            break;

        }

        break;