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# (C) Copyright 2004-2023 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!
""" Trait definition for a null-based (i.e., no UI) font.
"""
from traits.api import Trait, TraitHandler, TraitError
# ------------------------------------------------------------------------------
# Convert a string into a valid 'wxFont' object (if possible):
# ------------------------------------------------------------------------------
# Mapping of strings to valid wxFont families
font_families = ["default", "decorative", "roman", "script", "swiss", "modern"]
# Mapping of strings to wxFont styles
font_styles = ["slant", "italic"]
# Mapping of strings wxFont weights
font_weights = ["light", "bold"]
# Strings to ignore in text representations of fonts
font_noise = ["pt", "point", "family"]
# ------------------------------------------------------------------------------
# 'TraitFont' class'
# ------------------------------------------------------------------------------
class TraitFont(TraitHandler):
"""Ensures that values assigned to a trait attribute are valid font
descriptor strings; the value actually assigned is the corresponding
canonical font descriptor string.
"""
def validate(self, object, name, value):
"""Validates that the value is a valid font descriptor string."""
try:
point_size = family = style = weight = underline = ""
facename = [""]
for word in value.split():
lword = word.lower()
if lword in font_families:
family = " " + lword
elif lword in font_styles:
style = " " + lword
elif lword in font_weights:
weight = " " + lword
elif lword == "underline":
underline = " " + lword
elif lword not in font_noise:
try:
int(lword)
point_size = lword + " pt"
except:
facename.append(word)
fontstr = (
"%s%s%s%s%s%s"
% (
point_size,
family,
style,
weight,
underline,
" ".join(facename),
)
).strip()
return fontstr
except Exception:
pass
raise TraitError(object, name, "a font descriptor string", repr(value))
def info(self):
return (
"a string describing a font (e.g. '12 pt bold italic "
"swiss family Arial' or 'default 12')"
)
# ------------------------------------------------------------------------------
# Define a 'null' specific font trait:
# ------------------------------------------------------------------------------
### Note: Declare the editor to be a function which returns the FontEditor
# class from traits ui to avoid circular import issues. For backwards
# compatibility with previous Traits versions, the 'editors' folder in Traits
# project declares 'from api import *' in its __init__.py. The 'api' in turn
# can contain classes that have a Font trait which lead to this file getting
# imported. This leads to a circular import when declaring a Font trait.
def get_font_editor(*args, **traits):
from ..api import FontEditor
return FontEditor(*args, **traits)
fh = TraitFont()
NullFont = Trait(
fh.validate(None, None, "Arial 10"), fh, editor=get_font_editor
)
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