src/ui/widget/rotateable.cpp

   1 /**
   2  * \brief widget adjustable by dragging it to rotate away from a zero-change axis
   3  *
   4  * Authors:
   5  *   buliabyak@gmail.com
   6  *
   7  * Copyright (C) 2007 authors
   8  *
   9  * Released under GNU GPL.  Read the file 'COPYING' for more information.
  10  */
  11
  12 #include "event-context.h"
  13 #include "rotateable.h"
  14 #include "libnr/nr-point.h"
  15 #include "libnr/nr-point-fns.h"
  16 #include <gtkmm/box.h>
  17 #include <gtkmm/eventbox.h>
  18 #include <glibmm/i18n.h>
  19
  20 namespace Inkscape {
  21 namespace UI {
  22 namespace Widget {
  23
  24         Rotateable::Rotateable():
  25     axis(-M_PI/4),
  26     maxdecl(M_PI/4)
  27   {
  28                 dragging = false;
  29                 working = false;
  30                 modifier = 0;
  31                 current_axis = axis;
  32
  33     signal_button_press_event().connect(sigc::mem_fun(*this, &Rotateable::on_click));
  34     signal_motion_notify_event().connect(sigc::mem_fun(*this, &Rotateable::on_motion));
  35     signal_button_release_event().connect(sigc::mem_fun(*this, &Rotateable::on_release));
  36         }
  37
  38   bool Rotateable::on_click(GdkEventButton *event) {
  39                 if (event->button == 1) {
  40                         drag_started_x = event->x;
  41                         drag_started_y = event->y;
  42                         modifier = get_single_modifier(modifier, event->state);
  43                 dragging = true;
  44                 working = false;
  45                         current_axis = axis;
  46           return true;
  47                 }
  48                 return false;
  49         }
  50
  51   guint Rotateable::get_single_modifier(guint old, guint state) {
  52
  53                 if (old == 0) {
  54                         if (state & GDK_CONTROL_MASK)
  55                                 return 1; // ctrl
  56                         if (state & GDK_SHIFT_MASK)
  57                                 return 2; // shift
  58                         return 0;
  59                 } else {
  60                         if (!(state & GDK_CONTROL_MASK) && !(state & GDK_SHIFT_MASK))
  61                                 return 0; // none
  62                         if (old == 1)
  63                         if (state & GDK_SHIFT_MASK && !(state & GDK_CONTROL_MASK))
  64                                 return 2; // shift
  65         else
  66           return 1;
  67                         if (old == 2)
  68                         if (state & GDK_CONTROL_MASK && !(state & GDK_SHIFT_MASK))
  69                                 return 1; // ctrl
  70         else
  71           return 2;
  72                 return old;
  73                 }
  74         }
  75
  76
  77   bool Rotateable::on_motion(GdkEventMotion *event) {
  78                 if (dragging) {
  79                         double dist = NR::L2(NR::Point(event->x, event->y) - NR::Point(drag_started_x, drag_started_y));
  80                         double angle = atan2(event->y - drag_started_y, event->x - drag_started_x);
  81                         if (dist > 20) {
  82                                 working = true;
  83                         double force = CLAMP (-(angle - current_axis)/maxdecl, -1, 1);
  84                         if (fabs(force) < 0.002)
  85                                 force = 0; // snap to zero
  86                                 if (modifier != get_single_modifier(modifier, event->state)) {
  87           // user has switched modifiers in mid drag, close past drag and start a new
  88           // one, redefining axis temporarily
  89                                 do_release(force, modifier);
  90                                         current_axis = angle;
  91                         modifier = get_single_modifier(modifier, event->state);
  92                                 } else {
  93                                 do_motion(force, modifier);
  94                                 }
  95                         }
  96       gobble_motion_events(GDK_BUTTON1_MASK);
  97                 return true;
  98                 }
  99                 return false;
 100         }
 101
 102
 103   bool Rotateable::on_release(GdkEventButton *event) {
 104                 if (dragging && working) {
 105                         double angle = atan2(event->y - drag_started_y, event->x - drag_started_x);
 106                         double force = CLAMP (-(angle - current_axis)/maxdecl, -1, 1);
 107                         if (fabs(force) < 0.002)
 108                                 force = 0; // snap to zero
 109                         do_release(force, modifier);
 110                         dragging = false;
 111                         working = false;
 112                         current_axis = axis;
 113                         return true;
 114                 }
 115                 return false;
 116         }
 117
 118
 119         Rotateable::~Rotateable() {
 120         }
 121
 122
 123
 124 } // namespace Widget
 125 } // namespace UI
 126 } // namespace Inkscape
 127
 128 /*
 129   Local Variables:
 130   mode:c++
 131   c-file-style:"stroustrup"
 132   c-file-offsets:((innamespace . 0)(inline-open . 0))
 133   indent-tabs-mode:nil
 134   fill-column:99
 135   End:
 136 */
 137 // vim: filetype=c++:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :