gistfile1.txt

from kivy.uix.widget import Widget
from kivy.properties import ListProperty
from kivy.properties import FloatProperty


class GraphicsElement(Widget):

    label = StringProperty('')

    # label_containment is either ``inside`` or ``outside`` the element.
    label_containment = OptionProperty(['inside', 'outside'])

    # label_anchor is the anchor position, relative to the bounding box of the
    # label text.
    label_anchor = OptionProperty(['center', 'top_center', 'bottom_center',
        'left_center', 'right_center', 'nw_corner', 'ne_corner', 'se_corner',
        'sw_corner'])

    # label_origin is the position of the label_anchor relative to the bounding
    # box of the element.
    label_origin = OptionProperty(['center', 'top_center', 'bottom_center',
        'left_center', 'right_center', 'nw_corner', 'ne_corner', 'se_corner',
        'sw_corner'])

    # label_azimuth is the angle of the an imaginary line starting at
    # label_origin, from 0 to 360 degrees, in the fashion of compass
    # directions. The label_anchor is placed somewhere on this line.
    label_azimuth = FloatProperty(0.0)

    # label_margin is the distance from the element to the label_anchor along
    # the label_azimuth line. The label positioning algorithm will place the
    # label along the label_azimuth line, depending on 
    label_margin = FloatProperty(20.0)

    line_color = ListProperty([0, 0, 0, 0])
    fill_color = ListProperty([0, 0, 0, 0])

    x = FloatProperty(10.0)
    y = FloatProperty(10.0)
    width = FloatProperty(10.0)
    height = FloatProperty(10.0)

    def __init__(self, **kwargs):

        super(GraphicsElement, self).__init__(**kwargs)

        self.bind(label_origin=self.reposition_label)
        self.bind(label_azimuth=self.reposition_label)
        self.bind(label_margin=self.reposition_label)

        self.size_hint = (None, None)

    def reposition_label(self, *args):

        # Strike a line from label_origin at an angle of label_azimuth,
        # attempting to place the label, using some increment. Find the place
        # along the line that is optimal for label_containment, label_margin,
        # etc.
        pass