ManimCommunity / ManimCommunity/manim
SVGMobject passing NoneType to svgelements
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Description
Description of bug / unexpected behavior
When using an SVG plot with a legend (below), Manim passes a NoneType to svgelements. This results in an error:
TypeError: object of type 'NoneType' has no len()
When using an otherwise identical plot with no legend (below), there is no such error and Manim is able to parse the SVG image successfully.
I'm unsure if this is fundamentally an issue with Manim or svgelements.
Expected behavior
Both plots should be easily parsable without modifying svgelements.
How to reproduce the issue
Create the following simple scene with Manim using the two attached plots.
Code for reproducing the problem
class LoadSVGPlots(Scene):
def construct(self):
plot0 = SVGMobject('plot_without_legend.svg')
print('loaded plot_without_legend')
plot1 = SVGMobject('plot_with_legend.svg')
print('loaded plot_with_legend')
Additional media files
Images/GIFs
Logs
Terminal output
After running the command: manim -qh -v DEBUG scene.py LoadSVGPlotsmanim -qh -v DEBUG scene.py LoadSVGPlots
Manim Community v0.18.1
loaded plot_without_legend
╭─────────────────────────────── Traceback (most recent call last) ────────────────────────────────╮
│ /home/mikhailj/Downloads/anaconda3/envs/my-manim-environment/lib/python3.10/site-packages/manim/ │
│ cli/render/commands.py:120 in render │
│ │
│ 117 │ │ │ try: │
│ 118 │ │ │ │ with tempconfig({}): │
│ 119 │ │ │ │ │ scene = SceneClass() │
│ ❱ 120 │ │ │ │ │ scene.render() │
│ 121 │ │ │ except Exception: │
│ 122 │ │ │ │ error_console.print_exception() │
│ 123 │ │ │ │ sys.exit(1) │
│ │
│ /home/mikhailj/Downloads/anaconda3/envs/my-manim-environment/lib/python3.10/site-packages/manim/ │
│ scene/scene.py:229 in render │
│ │
│ 226 │ │ """ │
│ 227 │ │ self.setup() │
│ 228 │ │ try: │
│ ❱ 229 │ │ │ self.construct() │
│ 230 │ │ except EndSceneEarlyException: │
│ 231 │ │ │ pass │
│ 232 │ │ except RerunSceneException as e: │
│ │
│ /home/mikhailj/Videos/Manim/uniform_combination/scene.py:331 in construct │
│ │
│ 328 │ def construct(self): │
│ 329 │ │ plot0 = SVGMobject('plot_without_legend.svg') │
│ 330 │ │ print('loaded plot_without_legend') │
│ ❱ 331 │ │ plot1 = SVGMobject('plot_with_legend.svg') │
│ 332 │ │ print('loaded plot_with_legend') │
│ 333 │
│ 334 ##################### │
│ │
│ /home/mikhailj/Downloads/anaconda3/envs/my-manim-environment/lib/python3.10/site-packages/manim/ │
│ mobject/svg/svg_mobject.py:145 in __init__ │
│ │
│ 142 │ │ │ path_string_config = {} │
│ 143 │ │ self.path_string_config = path_string_config │
│ 144 │ │ │
│ ❱ 145 │ │ self.init_svg_mobject(use_svg_cache=use_svg_cache) │
│ 146 │ │ │
│ 147 │ │ self.set_style( │
│ 148 │ │ │ fill_color=fill_color, │
│ │
│ /home/mikhailj/Downloads/anaconda3/envs/my-manim-environment/lib/python3.10/site-packages/manim/ │
│ mobject/svg/svg_mobject.py:171 in init_svg_mobject │
│ │
│ 168 │ │ │ │ self.add(*mob) │
│ 169 │ │ │ │ return │
│ 170 │ │ │
│ ❱ 171 │ │ self.generate_mobject() │
│ 172 │ │ if use_svg_cache: │
│ 173 │ │ │ SVG_HASH_TO_MOB_MAP[hash_val] = self.copy() │
│ 174 │
│ │
│ /home/mikhailj/Downloads/anaconda3/envs/my-manim-environment/lib/python3.10/site-packages/manim/ │
│ mobject/svg/svg_mobject.py:199 in generate_mobject │
│ │
│ 196 │ │ modified_file_path = file_path.with_name(f"{file_path.stem}_{file_path.suffix}") │
│ 197 │ │ new_tree.write(modified_file_path) │
│ 198 │ │ │
│ ❱ 199 │ │ svg = se.SVG.parse(modified_file_path) │
│ 200 │ │ modified_file_path.unlink() │
│ 201 │ │ │
│ 202 │ │ mobjects = self.get_mobjects_from(svg) │
│ │
│ /home/mikhailj/Downloads/anaconda3/envs/my-manim-environment/lib/python3.10/site-packages/svgele │
│ ments/svgelements.py:9236 in parse │
│ │
│ 9233 │ │ │ │ │ │ if SVG_TAG_PATH == tag: │
│ 9234 │ │ │ │ │ │ │ # Delayed path parsing, for partial paths. │
│ 9235 │ │ │ │ │ │ │ s = Path(values, pathd_loaded=True) │
│ ❱ 9236 │ │ │ │ │ │ │ s.parse(values.get(SVG_ATTR_DATA)) │
│ 9237 │ │ │ │ │ │ elif SVG_TAG_CIRCLE == tag: │
│ 9238 │ │ │ │ │ │ │ s = Circle(values) │
│ 9239 │ │ │ │ │ │ elif SVG_TAG_ELLIPSE == tag: │
│ │
│ /home/mikhailj/Downloads/anaconda3/envs/my-manim-environment/lib/python3.10/site-packages/svgele │
│ ments/svgelements.py:5969 in parse │
│ │
│ 5966 │ def parse(self, pathdef): │
│ 5967 │ │ """Parses the SVG path.""" │
│ 5968 │ │ tokens = SVGLexicalParser() │
│ ❱ 5969 │ │ tokens.parse(self, pathdef) │
│ 5970 │ │
│ 5971 │ def validate_connections(self): │
│ 5972 │ │ """ │
│ │
│ /home/mikhailj/Downloads/anaconda3/envs/my-manim-environment/lib/python3.10/site-packages/svgele │
│ ments/svgelements.py:347 in parse │
│ │
│ 344 │ │ self.parser.start() │
│ 345 │ │ self.pathd = pathd │
│ 346 │ │ self.pos = 0 │
│ ❱ 347 │ │ self.limit = len(pathd) │
│ 348 │ │ while True: │
│ 349 │ │ │ cmd = self._command() │
│ 350 │ │ │ if cmd is None: │
╰──────────────────────────────────────────────────────────────────────────────────────────────────╯
TypeError: object of type 'NoneType' has no len()
System specifications
System Details
- OS (with version, e.g., Windows 10 v2004 or macOS 10.15 (Catalina)): Debian GNU/Linux 10 (buster)
- RAM:
- Python version (
python/py/python3 --version): Python 3.10.14 - Installed modules (provide output from
pip list):
Package Version
-------------------- -----------
Brotli 1.1.0
build 1.2.2
CacheControl 0.14.0
certifi 2024.8.30
cffi 1.17.1
charset-normalizer 3.3.2
cleo 2.1.0
click 8.1.7
click-default-group 1.2.4
cloup 3.0.5
colorama 0.4.6
crashtest 0.4.1
cryptography 43.0.1
decorator 5.1.1
distlib 0.3.8
dulwich 0.21.7
fastjsonschema 2.20.0
filelock 3.16.0
future 1.0.0
glcontext 3.0.0
h2 4.1.0
hpack 4.0.0
hyperframe 6.0.1
idna 3.10
importlib_metadata 8.5.0
installer 0.7.0
isosurfaces 0.1.2
jaraco.classes 3.4.0
jeepney 0.8.0
keyring 24.3.1
manim 0.18.1
ManimPango 0.6.0
mapbox_earcut 1.0.1
markdown-it-py 3.0.0
mdurl 0.1.2
moderngl 5.10.0
moderngl-window 2.4.1
more-itertools 10.5.0
msgpack 1.1.0
multipledispatch 0.6.0
networkx 3.3
numpy 1.26.4
packaging 24.1
pexpect 4.9.0
pillow 10.4.0
pip 24.2
pkginfo 1.11.1
platformdirs 4.3.3
poetry 1.8.3
poetry-core 1.9.0
poetry-plugin-export 1.8.0
ptyprocess 0.7.0
pycairo 1.27.0
pycparser 2.22
pydub 0.25.1
pyglet 1.5.16
Pygments 2.18.0
pyproject_hooks 1.1.0
pyrr 0.10.3
PySocks 1.7.1
PyYAML 6.0.2
rapidfuzz 3.9.7
requests 2.32.3
requests-toolbelt 1.0.0
rich 13.8.1
scipy 1.14.1
screeninfo 0.8.1
SecretStorage 3.3.3
setuptools 73.0.1
shellingham 1.5.4
six 1.16.0
skia-pathops 0.8.0.post1
srt 3.5.3
svg.path 6.3
svgelements 1.9.6
tomli 2.0.1
tomlkit 0.13.2
tqdm 4.66.5
trove-classifiers 2024.9.12
typing_extensions 4.12.2
urllib3 2.2.3
virtualenv 20.26.4
watchdog 5.0.2
wheel 0.44.0
zipp 3.20.2
zstandard 0.23.0
LaTeX details
- LaTeX distribution (e.g. TeX Live 2020):
- Installed LaTeX packages:
Additional comments
I was able to avoid the error by modifying svgelements/svgelements.py class SVGLexicalParser method parse. I replaced
def parse(self, parser, pathd):
self.parser = parser
self.parser.start()
self.pathd = pathd
self.pos = 0
self.limit = len(pathd)
# the rest of the method
with
def parse(self, parser, pathd):
self.parser = parser
self.parser.start()
self.pathd = pathd
self.pos = 0
if pathd is not None:
self.limit = len(pathd)
else:
self.limit = 0
# the rest of the method
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the failure with the LoadSVGPlots scene and compare the two supplied SVG plots. Start in manim/mobject/svg/svg_mobject.py at generate_mobject(), then inspect the svgelements SVG.parse and Path.parse calls shown in the traceback; done means the legend plot loads without the NoneType len() error.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- computer-graphics
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100