kivyforms/formcanvas.py

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