Override Layout Constraints Example

An example which demonstrates overriding layout_constraints.

This example shows how one can override layout_constraints method from enaml syntax to generate custom constraints using procedural code. This can be useful for complex layout scenarios where generating constraints from a single expression would be difficult or impossible.

Tip

To see this example in action, download it from override_layout_constraints and run:

$ enaml-run override_layout_constraints.enaml

Screenshot

Example Enaml Code

#------------------------------------------------------------------------------
# Copyright (c) 2015, Nucleic Development Team.
#
# Distributed under the terms of the Modified BSD License.
#
# The full license is in the file LICENSE, distributed with this software.
#------------------------------------------------------------------------------
""" An example which demonstrates overriding `layout_constraints`.

This example shows how one can override `layout_constraints` method from
enaml syntax to generate custom constraints using procedural code. This
can be useful for complex layout scenarios where generating constraints
from a single expression would be difficult or impossible.

<< autodoc-me >>
"""
from itertools import zip_longest

from enaml.layout.api import align, grid
from enaml.widgets.api import Window, Container, Field, Label, PushButton


enamldef Main(Window):
    title = 'Custom Constraints'
    Container:
        layout_constraints => ():
            rows = []
            widgets = self.visible_widgets()
            row_iters = (iter(widgets),) * 2
            rows = list(zip_longest(*row_iters))
            return [grid(*rows)] + [align('v_center', *row) for row in rows]
        Label:
            text = 'Name'
        Field:
            pass
        Label:
            text = 'Surname'
        Field:
            pass
        PushButton:
            text = 'Click me'