kivyforms/formcanvas.py

   1 from kivy.graphics import Color, Line
   2 from kivy.uix.boxlayout import BoxLayout
   3 from kivy.uix.button import Button
   4 from kivy.uix.label import Label
   5 from kivy.uix.stacklayout import StackLayout
   6
   7
   8 """
   9 Some common methods
  10 """
  11 def get_form_canvas(widget):
  12     parent = widget.parent
  13     while parent and not isinstance(parent, FormCanvas):
  14         if parent is parent.parent:
  15             raise Exception("Infinite loop when searching FormCanvas")
  16         parent = parent.parent
  17     return parent
  18
  19 def get_index(widget):
  20     for idx in range(len(widget.parent.children)):
  21         if widget.parent.children[idx] is widget:
  22             return idx
  23     return None
  24
  25 def get_zone(widget, x, y):
  26     side = widget.x + widget.width / 4
  27     if x > side * 3:
  28         return 'right'
  29     elif x < side:
  30         return 'left'
  31     elif y > widget.y + widget.height / 2:
  32         return 'top'
  33     else:
  34         return 'bottom'
  35
  36
  37 class Destination(Label):
  38     def __init__(self, **kwargs):
  39         super(Destination, self).__init__(**kwargs)
  40         self.text = 'Widget goes here'
  41         self.color = [1, 1, 0, 1]
  42         with self.canvas.after:
  43             Color(1, 1, 0, 1)
  44             self.box = Line(dash_length=8, dash_offset=4)
  45
  46     def update_box(self):
  47         self.box.points = [
  48             self.x, self.y,
  49             self.x, self.y + self.height,
  50             self.x + self.width, self.y + self.height,
  51             self.x + self.width, self.y,
  52             self.x, self.y
  53         ]
  54
  55     def on_pos(self, instance, value):
  56         self.update_box()
  57
  58     def on_size(self, instance, value):
  59         self.update_box()
  60
  61
  62 class Grabbable(BoxLayout):
  63     def __init__(self, **kwargs):
  64         super(Grabbable, self).__init__(**kwargs)
  65         self.detached = False
  66
  67     def point(self, touch):
  68         get_form_canvas(self).point_widget(self, touch.pos)
  69
  70     def detach(self):
  71         self.detached = True
  72         get_form_canvas(self).detach_widget(self)
  73
  74     def attach(self, touch):
  75         if self.detached:
  76             form_canvas = None
  77             for widget in self.get_root_window().children[1].walk():
  78                 if isinstance(widget, FormCanvas) and widget.collide_point(*touch.pos):
  79                     form_canvas = widget
  80                     break
  81             else:
  82                 raise Exception("FormCanvas not found")
  83             form_canvas.attach_widget(self)
  84             self.detached = False
  85
  86     def move(self, x, y):
  87         self.pos = [x - self.width / 2, y - self.height / 2]
  88
  89     def on_touch_down(self, touch):
  90         if self.collide_point(*touch.pos):
  91             if touch.grab_current is None:
  92                 touch.grab(self)
  93                 self.detach()
  94                 self.move(*touch.pos)
  95                 return True
  96         return super(Grabbable, self).on_touch_down(touch)
  97
  98     def on_touch_move(self, touch):
  99         if touch.grab_current is self:
 100             self.move(*touch.pos)
 101         else:
 102             if self.parent and self.parent != self.get_root_window():
 103                 if self.collide_point(touch.x, touch.y):
 104                     self.point(touch)
 105
 106     def on_touch_up(self, touch):
 107         if touch.grab_current is self:
 108             touch.ungrab(self)
 109             self.attach(touch)
 110
 111
 112 class FormCanvas(BoxLayout):
 113     def __init__(self, *args, **kwargs):
 114         super(FormCanvas, self).__init__(*args, **kwargs)
 115
 116         self._canvas = StackLayout(
 117             orientation='lr-tb',
 118             padding=[10, 10, 10, 10],
 119             spacing=[10, 10]
 120         )
 121         super(FormCanvas, self).add_widget(self._canvas)
 122
 123         self.widgets_height = 40
 124         self.widgets_size_hint = (1, None)
 125
 126     def add_widget(self, widget):
 127         g = Grabbable(
 128             height=self.widgets_height,
 129             size_hint=self.widgets_size_hint
 130         )
 131         widget.height = self.widgets_height
 132         widget.size_hint = self.widgets_size_hint
 133         g.add_widget(widget)
 134         self._canvas.add_widget(g)
 135
 136     def detach_widget(self, widget):
 137         "Detach grabbable widget from canvas and show widget destination"
 138
 139         # Show widget destination
 140         self.destination = Destination()
 141         self.destination.height = self.widgets_height
 142         self.destination.size_hint = self.widgets_size_hint
 143         widget.parent.add_widget(self.destination, index=get_index(widget))
 144
 145         # Place widget in the root window
 146         widget.parent.remove_widget(widget)
 147         widget.size_hint = (None, None)
 148         widget.width = 150
 149         widget.height = 50
 150         self.get_root_window().add_widget(widget)
 151
 152     def point_widget(self, widget, position):
 153         if not self.destination:
 154             raise Exception("Wrong status: destination point not specified")
 155
 156         # Widget info about destination
 157         widget_idx = get_index(widget)
 158         zone = get_zone(widget, *position)
 159
 160         # Remove destination
 161         box = self.destination.parent
 162         box.remove_widget(self.destination)
 163
 164         # Put destination in the right place
 165         if zone in ('left', 'right') and widget.parent.orientation != 'horizontal':
 166             parent = widget.parent
 167             box = self.create_box()
 168             parent.add_widget(box, index=widget_idx)
 169             parent.remove_widget(widget)
 170             box.add_widget(widget)
 171             if zone == 'left':
 172                 box.add_widget(self.destination, index=1)
 173             else:
 174                 box.add_widget(self.destination, index=0)
 175         else:
 176             widget.parent.add_widget(self.destination, index=widget_idx)
 177
 178         # Remove useless boxes
 179         if isinstance(box, BoxLayout) and len(box.children) == 1:
 180             child = box.children[0]
 181             box.remove_widget(child)
 182             box.parent.add_widget(child, index=get_index(box))
 183             box.parent.remove_widget(box)
 184
 185     def attach_widget(self, widget):
 186         """
 187         Attach grabbable widget to the destination
 188         """
 189         widget.parent.remove_widget(widget)
 190         widget.height = self.widgets_height
 191         widget.size_hint = self.widgets_size_hint
 192
 193         dest_idx = get_index(self.destination)
 194         self.destination.parent.add_widget(widget, index=dest_idx)
 195         self.destination.parent.remove_widget(self.destination)
 196         self.destination = None
 197
 198     def create_box(self):
 199         return BoxLayout(
 200             orientation='horizontal',
 201             height=self.widgets_height,
 202             size_hint=self.widgets_size_hint,
 203             spacing=self._canvas.spacing[0]
 204         )
 205
 206     def export_to_kv(self):
 207         kv = """StackLayout:
 208     orientation: '{orientation}'
 209     padding: {padding}
 210     spacing: {spacing}
 211 """.format(orientation=self._canvas.orientation, padding=self._canvas.padding, spacing=self._canvas.spacing)
 212
 213         indent = '    '
 214         stack = [self._canvas]
 215
 216         widgets = self.walk(restrict=True)
 217         next(widgets)    # the first widget is the FormCanvas
 218         next(widgets)    # and the second is the inner StackLayout
 219         for widget in widgets:
 220             if not isinstance(widget, Grabbable):
 221                 # Look for the widget position inside the tree
 222                 parent = widget.parent
 223                 if isinstance(parent, Grabbable):
 224                     parent = parent.parent
 225                 while not parent is stack[-1]:
 226                     stack.pop()
 227
 228                 # Widget header
 229                 kv += '{indent}{widget}:\n'.format(indent=indent*len(stack), widget=type(widget).__name__)
 230
 231                 stack.append(widget)
 232
 233                 # Widget attributes
 234                 for attr in ('height', 'size_hint', 'text', 'spacing'):
 235                     if hasattr(widget, attr):
 236                         value = getattr(widget, attr)
 237                         if type(value) is str:
 238                             value = "'" + value + "'"
 239                         kv += "{indent}{attr}: {value}\n".format(
 240                             indent=indent*len(stack),
 241                             attr=attr,
 242                             value=value
 243                         )
 244
 245         return kv