ui/widget/rotateable.cpp

	rotateable.cpp revision 2429c5413c8d0d76b2ae660e54a0bbe7b88dee24
/**
 * \brief widget adjustable by dragging it to rotate away from a zero-change axis
 *
 * Authors:
 *   buliabyak@gmail.com
 *
 * Copyright (C) 2007 authors
 *
 * Released under GNU GPL.  Read the file 'COPYING' for more information.
 */

#include "event-context.h"
#include "rotateable.h"
#include "libnr/nr-point.h"
#include "libnr/nr-point-fns.h"
#include <gtkmm/box.h>
#include <gtkmm/eventbox.h>
#include <glibmm/i18n.h>

namespace Inkscape {
namespace UI {
namespace Widget {

    Rotateable::Rotateable():
    axis(-M_PI/4),
    maxdecl(M_PI/4)
  {
        dragging = false;
        working = false;
        modifier = 0;
        current_axis = axis;

    signal_button_press_event().connect(sigc::mem_fun(*this, &Rotateable::on_click));
    signal_motion_notify_event().connect(sigc::mem_fun(*this, &Rotateable::on_motion));
    signal_button_release_event().connect(sigc::mem_fun(*this, &Rotateable::on_release));
    }

  bool Rotateable::on_click(GdkEventButton *event) {
        if (event->button == 1) {
            drag_started_x = event->x;
            drag_started_y = event->y;
            modifier = get_single_modifier(modifier, event->state);
        dragging = true;
        working = false;
            current_axis = axis;
      return true;
        }
        return false;
    }

  guint Rotateable::get_single_modifier(guint old, guint state) {

        if (old == 0) {
            if (state & GDK_CONTROL_MASK)
                return 1; // ctrl
            if (state & GDK_SHIFT_MASK)
                return 2; // shift
            return 0;
        } else {
            if (!(state & GDK_CONTROL_MASK) && !(state & GDK_SHIFT_MASK))
                return 0; // none
            if (old == 1)
            if (state & GDK_SHIFT_MASK && !(state & GDK_CONTROL_MASK))
                return 2; // shift
        else
          return 1;
            if (old == 2)
            if (state & GDK_CONTROL_MASK && !(state & GDK_SHIFT_MASK))
                return 1; // ctrl
        else
          return 2;
        return old;
        }
    }


  bool Rotateable::on_motion(GdkEventMotion *event) {
        if (dragging) {
            double dist = NR::L2(NR::Point(event->x, event->y) - NR::Point(drag_started_x, drag_started_y));
            double angle = atan2(event->y - drag_started_y, event->x - drag_started_x);
            if (dist > 20) {
                working = true;
            double force = CLAMP (-(angle - current_axis)/maxdecl, -1, 1);
            if (fabs(force) < 0.002)
                force = 0; // snap to zero
                if (modifier != get_single_modifier(modifier, event->state)) {
          // user has switched modifiers in mid drag, close past drag and start a new
          // one, redefining axis temporarily
                do_release(force, modifier);
                    current_axis = angle;
                modifier = get_single_modifier(modifier, event->state);
                } else {
                do_motion(force, modifier);
                }
            }
      gobble_motion_events(GDK_BUTTON1_MASK);
        return true;
        }
        return false;
    }


  bool Rotateable::on_release(GdkEventButton *event) {
        if (dragging && working) {
            double angle = atan2(event->y - drag_started_y, event->x - drag_started_x);
            double force = CLAMP (-(angle - current_axis)/maxdecl, -1, 1);
            if (fabs(force) < 0.002)
                force = 0; // snap to zero
            do_release(force, modifier);
            dragging = false;
            working = false;
            current_axis = axis;
            return true;
        }
        return false;
    }


    Rotateable::~Rotateable() {
    }


} // namespace Widget
} // namespace UI
} // namespace Inkscape

/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: filetype=c++:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :