mirror of
https://github.com/PiBrewing/craftbeerpi4.git
synced 2024-11-30 10:44:14 +01:00
265 lines
7.8 KiB
Python
265 lines
7.8 KiB
Python
|
"""
|
||
|
|
Utilities for interpreting CSS from Stylers for formatting non-HTML outputs.
|
||
|
|
"""
|
||
|
|
|
||
|
|
import re
|
||
|
|
import warnings
|
||
|
|
|
||
|
|
|
||
|
|
class CSSWarning(UserWarning):
|
||
|
|
"""
|
||
|
|
This CSS syntax cannot currently be parsed.
|
||
|
|
"""
|
||
|
|
|
||
|
|
pass
|
||
|
|
|
||
|
|
|
||
|
|
def _side_expander(prop_fmt: str):
|
||
|
|
def expand(self, prop, value: str):
|
||
|
|
tokens = value.split()
|
||
|
|
try:
|
||
|
|
mapping = self.SIDE_SHORTHANDS[len(tokens)]
|
||
|
|
except KeyError:
|
||
|
|
warnings.warn(
|
||
|
|
f'Could not expand "{prop}: {value}"', CSSWarning,
|
||
|
|
)
|
||
|
|
return
|
||
|
|
for key, idx in zip(self.SIDES, mapping):
|
||
|
|
yield prop_fmt.format(key), tokens[idx]
|
||
|
|
|
||
|
|
return expand
|
||
|
|
|
||
|
|
|
||
|
|
class CSSResolver:
|
||
|
|
"""
|
||
|
|
A callable for parsing and resolving CSS to atomic properties.
|
||
|
|
"""
|
||
|
|
|
||
|
|
def __call__(self, declarations_str, inherited=None):
|
||
|
|
"""
|
||
|
|
The given declarations to atomic properties.
|
||
|
|
|
||
|
|
Parameters
|
||
|
|
----------
|
||
|
|
declarations_str : str
|
||
|
|
A list of CSS declarations
|
||
|
|
inherited : dict, optional
|
||
|
|
Atomic properties indicating the inherited style context in which
|
||
|
|
declarations_str is to be resolved. ``inherited`` should already
|
||
|
|
be resolved, i.e. valid output of this method.
|
||
|
|
|
||
|
|
Returns
|
||
|
|
-------
|
||
|
|
dict
|
||
|
|
Atomic CSS 2.2 properties.
|
||
|
|
|
||
|
|
Examples
|
||
|
|
--------
|
||
|
|
>>> resolve = CSSResolver()
|
||
|
|
>>> inherited = {'font-family': 'serif', 'font-weight': 'bold'}
|
||
|
|
>>> out = resolve('''
|
||
|
|
... border-color: BLUE RED;
|
||
|
|
... font-size: 1em;
|
||
|
|
... font-size: 2em;
|
||
|
|
... font-weight: normal;
|
||
|
|
... font-weight: inherit;
|
||
|
|
... ''', inherited)
|
||
|
|
>>> sorted(out.items()) # doctest: +NORMALIZE_WHITESPACE
|
||
|
|
[('border-bottom-color', 'blue'),
|
||
|
|
('border-left-color', 'red'),
|
||
|
|
('border-right-color', 'red'),
|
||
|
|
('border-top-color', 'blue'),
|
||
|
|
('font-family', 'serif'),
|
||
|
|
('font-size', '24pt'),
|
||
|
|
('font-weight', 'bold')]
|
||
|
|
"""
|
||
|
|
props = dict(self.atomize(self.parse(declarations_str)))
|
||
|
|
if inherited is None:
|
||
|
|
inherited = {}
|
||
|
|
|
||
|
|
# 1. resolve inherited, initial
|
||
|
|
for prop, val in inherited.items():
|
||
|
|
if prop not in props:
|
||
|
|
props[prop] = val
|
||
|
|
|
||
|
|
for prop, val in list(props.items()):
|
||
|
|
if val == "inherit":
|
||
|
|
val = inherited.get(prop, "initial")
|
||
|
|
if val == "initial":
|
||
|
|
val = None
|
||
|
|
|
||
|
|
if val is None:
|
||
|
|
# we do not define a complete initial stylesheet
|
||
|
|
del props[prop]
|
||
|
|
else:
|
||
|
|
props[prop] = val
|
||
|
|
|
||
|
|
# 2. resolve relative font size
|
||
|
|
if props.get("font-size"):
|
||
|
|
if "font-size" in inherited:
|
||
|
|
em_pt = inherited["font-size"]
|
||
|
|
assert em_pt[-2:] == "pt"
|
||
|
|
em_pt = float(em_pt[:-2])
|
||
|
|
else:
|
||
|
|
em_pt = None
|
||
|
|
props["font-size"] = self.size_to_pt(
|
||
|
|
props["font-size"], em_pt, conversions=self.FONT_SIZE_RATIOS
|
||
|
|
)
|
||
|
|
|
||
|
|
font_size = float(props["font-size"][:-2])
|
||
|
|
else:
|
||
|
|
font_size = None
|
||
|
|
|
||
|
|
# 3. TODO: resolve other font-relative units
|
||
|
|
for side in self.SIDES:
|
||
|
|
prop = f"border-{side}-width"
|
||
|
|
if prop in props:
|
||
|
|
props[prop] = self.size_to_pt(
|
||
|
|
props[prop], em_pt=font_size, conversions=self.BORDER_WIDTH_RATIOS
|
||
|
|
)
|
||
|
|
for prop in [
|
||
|
|
f"margin-{side}",
|
||
|
|
f"padding-{side}",
|
||
|
|
]:
|
||
|
|
if prop in props:
|
||
|
|
# TODO: support %
|
||
|
|
props[prop] = self.size_to_pt(
|
||
|
|
props[prop], em_pt=font_size, conversions=self.MARGIN_RATIOS
|
||
|
|
)
|
||
|
|
|
||
|
|
return props
|
||
|
|
|
||
|
|
UNIT_RATIOS = {
|
||
|
|
"rem": ("pt", 12),
|
||
|
|
"ex": ("em", 0.5),
|
||
|
|
# 'ch':
|
||
|
|
"px": ("pt", 0.75),
|
||
|
|
"pc": ("pt", 12),
|
||
|
|
"in": ("pt", 72),
|
||
|
|
"cm": ("in", 1 / 2.54),
|
||
|
|
"mm": ("in", 1 / 25.4),
|
||
|
|
"q": ("mm", 0.25),
|
||
|
|
"!!default": ("em", 0),
|
||
|
|
}
|
||
|
|
|
||
|
|
FONT_SIZE_RATIOS = UNIT_RATIOS.copy()
|
||
|
|
FONT_SIZE_RATIOS.update(
|
||
|
|
{
|
||
|
|
"%": ("em", 0.01),
|
||
|
|
"xx-small": ("rem", 0.5),
|
||
|
|
"x-small": ("rem", 0.625),
|
||
|
|
"small": ("rem", 0.8),
|
||
|
|
"medium": ("rem", 1),
|
||
|
|
"large": ("rem", 1.125),
|
||
|
|
"x-large": ("rem", 1.5),
|
||
|
|
"xx-large": ("rem", 2),
|
||
|
|
"smaller": ("em", 1 / 1.2),
|
||
|
|
"larger": ("em", 1.2),
|
||
|
|
"!!default": ("em", 1),
|
||
|
|
}
|
||
|
|
)
|
||
|
|
|
||
|
|
MARGIN_RATIOS = UNIT_RATIOS.copy()
|
||
|
|
MARGIN_RATIOS.update({"none": ("pt", 0)})
|
||
|
|
|
||
|
|
BORDER_WIDTH_RATIOS = UNIT_RATIOS.copy()
|
||
|
|
BORDER_WIDTH_RATIOS.update(
|
||
|
|
{
|
||
|
|
"none": ("pt", 0),
|
||
|
|
"thick": ("px", 4),
|
||
|
|
"medium": ("px", 2),
|
||
|
|
"thin": ("px", 1),
|
||
|
|
# Default: medium only if solid
|
||
|
|
}
|
||
|
|
)
|
||
|
|
|
||
|
|
def size_to_pt(self, in_val, em_pt=None, conversions=UNIT_RATIOS):
|
||
|
|
def _error():
|
||
|
|
warnings.warn(f"Unhandled size: {repr(in_val)}", CSSWarning)
|
||
|
|
return self.size_to_pt("1!!default", conversions=conversions)
|
||
|
|
|
||
|
|
try:
|
||
|
|
val, unit = re.match(r"^(\S*?)([a-zA-Z%!].*)", in_val).groups()
|
||
|
|
except AttributeError:
|
||
|
|
return _error()
|
||
|
|
if val == "":
|
||
|
|
# hack for 'large' etc.
|
||
|
|
val = 1
|
||
|
|
else:
|
||
|
|
try:
|
||
|
|
val = float(val)
|
||
|
|
except ValueError:
|
||
|
|
return _error()
|
||
|
|
|
||
|
|
while unit != "pt":
|
||
|
|
if unit == "em":
|
||
|
|
if em_pt is None:
|
||
|
|
unit = "rem"
|
||
|
|
else:
|
||
|
|
val *= em_pt
|
||
|
|
unit = "pt"
|
||
|
|
continue
|
||
|
|
|
||
|
|
try:
|
||
|
|
unit, mul = conversions[unit]
|
||
|
|
except KeyError:
|
||
|
|
return _error()
|
||
|
|
val *= mul
|
||
|
|
|
||
|
|
val = round(val, 5)
|
||
|
|
if int(val) == val:
|
||
|
|
size_fmt = f"{int(val):d}pt"
|
||
|
|
else:
|
||
|
|
size_fmt = f"{val:f}pt"
|
||
|
|
return size_fmt
|
||
|
|
|
||
|
|
def atomize(self, declarations):
|
||
|
|
for prop, value in declarations:
|
||
|
|
attr = "expand_" + prop.replace("-", "_")
|
||
|
|
try:
|
||
|
|
expand = getattr(self, attr)
|
||
|
|
except AttributeError:
|
||
|
|
yield prop, value
|
||
|
|
else:
|
||
|
|
for prop, value in expand(prop, value):
|
||
|
|
yield prop, value
|
||
|
|
|
||
|
|
SIDE_SHORTHANDS = {
|
||
|
|
1: [0, 0, 0, 0],
|
||
|
|
2: [0, 1, 0, 1],
|
||
|
|
3: [0, 1, 2, 1],
|
||
|
|
4: [0, 1, 2, 3],
|
||
|
|
}
|
||
|
|
SIDES = ("top", "right", "bottom", "left")
|
||
|
|
|
||
|
|
expand_border_color = _side_expander("border-{:s}-color")
|
||
|
|
expand_border_style = _side_expander("border-{:s}-style")
|
||
|
|
expand_border_width = _side_expander("border-{:s}-width")
|
||
|
|
expand_margin = _side_expander("margin-{:s}")
|
||
|
|
expand_padding = _side_expander("padding-{:s}")
|
||
|
|
|
||
|
|
def parse(self, declarations_str: str):
|
||
|
|
"""
|
||
|
|
Generates (prop, value) pairs from declarations.
|
||
|
|
|
||
|
|
In a future version may generate parsed tokens from tinycss/tinycss2
|
||
|
|
|
||
|
|
Parameters
|
||
|
|
----------
|
||
|
|
declarations_str : str
|
||
|
|
"""
|
||
|
|
for decl in declarations_str.split(";"):
|
||
|
|
if not decl.strip():
|
||
|
|
continue
|
||
|
|
prop, sep, val = decl.partition(":")
|
||
|
|
prop = prop.strip().lower()
|
||
|
|
# TODO: don't lowercase case sensitive parts of values (strings)
|
||
|
|
val = val.strip().lower()
|
||
|
|
if sep:
|
||
|
|
yield prop, val
|
||
|
|
else:
|
||
|
|
warnings.warn(
|
||
|
|
f"Ill-formatted attribute: expected a colon in {repr(decl)}",
|
||
|
|
CSSWarning,
|
||
|
|
)
|