Parse <style> tags when loading SVG

This commit is contained in:
Isaiah Odhner 2023-05-19 15:35:43 -04:00
parent f2ac4dc98b
commit 322391544b

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@ -1179,7 +1179,7 @@ class AnsiArtDocument:
- fill or style attributes are used to determine the background/foreground colors.
- text elements are assumed to be belonging to the cell their x/y is within,
without regard to their size/alignment.
- parsing stylesheets is not supported.
- stylesheets are partially supported.
- not all CSS/SVG color formats are supported.
To test the flexibility of this loader, I created pathological_character_grid.svg
@ -1208,6 +1208,67 @@ class AnsiArtDocument:
marker.attrib["stroke-width"] = "0.1"
root.append(marker)
# Parse stylesheets.
# Textual's CSS parser can't handle at-rules like the @font-face in the SVG,
# as of textual 0.24.1, so we either need to parse it manually or remove it.
from textual.css.parse import parse
from textual.css.model import RuleSet
rule_sets: list[RuleSet] = []
# OK this is seriously hacky. It doesn't support browser CSS really at all,
# so I'm rewriting properties as different properties that it does support.
property_map = {
"fill": "color",
}
reverse_property_map = {v: k for k, v in property_map.items()}
def rewrite_property(match: re.Match[str]) -> str:
property_name = match.group(1)
property_value = match.group(2)
if property_name in property_map:
rewritten_name = property_map[property_name]
return f"{rewritten_name}: {property_value}"
return match.group(0) # Return the original match if no rewrite is needed
for style_element in root.findall(".//{http://www.w3.org/2000/svg}style"):
assert style_element.text is not None, "style element has no text"
css = style_element.text
at_rule_pattern = r"\s*@[\w-]+\s*{[^}]+}" # doesn't handle nested braces
css = re.sub(at_rule_pattern, "", css)
property_pattern = r"([\w-]+)\s*:\s*([^;}]+)"
css = re.sub(property_pattern, rewrite_property, css)
for rule_set in parse(css, "inline <style> (modified)"):
rule_sets.append(rule_set)
# Apply stylesheets as inline styles.
for rule_set in rule_sets:
# list[tuple[str, Specificity6, Any]]
rules = rule_set.styles.extract_rules((0, 0, 0))
for css_selector in rule_set.selector_names:
# Just need to handle class and id selectors.
if css_selector.startswith("."):
class_name = css_selector[1:]
# xpath = f".//*[contains(@class, '{class_name}')]" # not supported
xpath = f".//*[@class='{class_name}']"
elif css_selector.startswith("#"):
id = css_selector[1:]
xpath = f".//*[@id='{id}']"
else:
# xpath = "./.." # root's parent never matches
# (absolute xpath is not allowed here, but we're querying from root)
# Alternatively, we could do this:
xpath = ".//*[id='never-match-me-please']"
for element in root.findall(xpath):
for rule in rules:
prop, _, value = rule
prop = reverse_property_map.get(prop, prop)
# it adds auto_color: False when setting a color; hacks on top of hacks
if isinstance(value, str):
element.attrib[prop] = value
elif isinstance(value, Color):
element.attrib[prop] = value.hex
# Search for rect elements to define the background, and the cell locations.
rects = root.findall(".//{http://www.w3.org/2000/svg}rect")
if len(rects) == 0: