Added new manim checkhealth CLI subcommand

manim/__main__.py

@@ -7,6 +7,7 @@
 
 from . import __version__, cli_ctx_settings, console
 from .cli.cfg.group import cfg
+from .cli.checkhealth.commands import checkhealth
 from .cli.default_group import DefaultGroup
 from .cli.init.commands import init
 from .cli.new.group import new
@@ -48,6 +49,7 @@ def main(ctx):
     pass
 
 
+main.add_command(checkhealth)
 main.add_command(cfg)
 main.add_command(plugins)
 main.add_command(init)

manim/cli/checkhealth/checks.py

@@ -0,0 +1,173 @@
+"""Auxiliary module for the checkhealth subcommand, contains
+the actual check implementations."""
+
+from __future__ import annotations
+
+import os
+import shutil
+import subprocess
+from typing import Callable
+
+from ..._config import config
+
+HEALTH_CHECKS = []
+
+
+def healthcheck(
+    description: str,
+    recommendation: str,
+    skip_on_failed: list[Callable | str] | None = None,
+    post_fail_fix_hook: Callable | None = None,
+):
+    """Decorator used for declaring health checks.
+
+    This decorator attaches some data to a function,
+    which is then added to a list containing all checks.
+
+    Parameters
+    ----------
+    description
+        A brief description of this check, displayed when
+        the checkhealth subcommand is run.
+    recommendation
+        Help text which is displayed in case the check fails.
+    skip_on_failed
+        A list of check functions which, if they fail, cause
+        the current check to be skipped.
+    post_fail_fix_hook
+        A function that is supposed to (interactively) help
+        to fix the detected problem, if possible. This is
+        only called upon explicit confirmation of the user.
+
+    Returns
+    -------
+    A check function, as required by the checkhealth subcommand.
+    """
+    if skip_on_failed is None:
+        skip_on_failed = []
+    skip_on_failed = [
+        skip.__name__ if callable(skip) else skip for skip in skip_on_failed
+    ]
+
+    def decorator(func):
+        func.description = description
+        func.recommendation = recommendation
+        func.skip_on_failed = skip_on_failed
+        func.post_fail_fix_hook = post_fail_fix_hook
+        HEALTH_CHECKS.append(func)
+        return func
+
+    return decorator
+
+
+@healthcheck(
+    description="Checking whether manim is on your PATH",
+    recommendation=(
+        "The command <manim> is currently not on your system's PATH.\n\n"
+        "You can work around this by calling the manim module directly "
+        "via <python -m manim> instead of just <manim>.\n\n"
+        "To fix the PATH issue properly: "
+        "Usually, the Python package installer pip issues a warning "
+        "during the installation which contains more information. "
+        "Consider reinstalling manim via <pip uninstall manim> "
+        "followed by <pip install manim> to see the warning again, "
+        "then consult the internet on how to modify your system's "
+        "PATH variable."
+    ),
+)
+def is_manim_on_path():
+    path_to_manim = shutil.which("manim")
+    return path_to_manim is not None
+
+
+@healthcheck(
+    description="Checking whether the executable belongs to manim",
+    recommendation=(
+        "The command <manim> does not belong to your installed version "
+        "of this library, it likely belongs to manimgl / manimlib.\n\n"
+        "Run manim via <python -m manim> or via <manimce>, or uninstall "
+        "and reinstall manim via <pip install --upgrade "
+        "--force-reinstall manim> to fix this."
+    ),
+    skip_on_failed=[is_manim_on_path],
+)
+def is_manim_executable_associated_to_this_library():
+    path_to_manim = shutil.which("manim")
+    with open(path_to_manim, "rb") as f:
+        manim_exec = f.read()
+
+    # first condition below corresponds to the executable being
+    # some sort of python script. second condition happens when
+    # the executable is actually a Windows batch file.
+    return b"manim.__main__" in manim_exec or b'"%~dp0\\manim"' in manim_exec
+
+
+@healthcheck(
+    description="Checking whether ffmpeg is available",
+    recommendation=(
+        "Manim does not work without ffmpeg. Please follow our "
+        "installation instructions "
+        "at https://docs.manim.community/en/stable/installation.html "
+        "to download ffmpeg. Then, either ...\n\n"
+        "(a) ... make the ffmpeg executable available to your system's PATH,\n"
+        "(b) or, alternatively, use <manim cfg write --open> to create a "
+        "custom configuration and set the ffmpeg_executable variable to the "
+        "full absolute path to the ffmpeg executable."
+    ),
+)
+def is_ffmpeg_available():
+    path_to_ffmpeg = shutil.which(config.ffmpeg_executable)
+    return path_to_ffmpeg is not None and os.access(path_to_ffmpeg, os.X_OK)
+
+
+@healthcheck(
+    description="Checking whether ffmpeg is working",
+    recommendation=(
+        "Your installed version of ffmpeg does not support x264 encoding, "
+        "which manim requires. Please follow our installation instructions "
+        "at https://docs.manim.community/en/stable/installation.html "
+        "to download and install a newer version of ffmpeg."
+    ),
+    skip_on_failed=[is_ffmpeg_available],
+)
+def is_ffmpeg_working():
+    ffmpeg_version = subprocess.run(
+        [config.ffmpeg_executable, "-version"],
+        stdout=subprocess.PIPE,
+    ).stdout.decode()
+    return (
+        ffmpeg_version.startswith("ffmpeg version")
+        and "--enable-libx264" in ffmpeg_version
+    )
+
+
+@healthcheck(
+    description="Checking whether latex is available",
+    recommendation=(
+        "Manim cannot find <latex> on your system's PATH. "
+        "You will not be able to use Tex and MathTex mobjects "
+        "in your scenes.\n\n"
+        "Consult our installation instructions "
+        "at https://docs.manim.community/en/stable/installation.html "
+        "or search the web for instructions on how to install a "
+        "LaTeX distribution on your operating system."
+    ),
+)
+def is_latex_available():
+    path_to_latex = shutil.which("latex")
+    return path_to_latex is not None and os.access(path_to_latex, os.X_OK)
+
+
+@healthcheck(
+    description="Checking whether dvisvgm is available",
+    recommendation=(
+        "Manim could find <latex>, but not <dvisvgm> on your system's "
+        "PATH. Make sure your installed LaTeX distribution comes with "
+        "dvisvgm and consider installing a larger distribution if it "
+        "does not."
+    ),
+    skip_on_failed=[is_latex_available],
+)
+def is_dvisvgm_available():
+    path_to_dvisvgm = shutil.which("dvisvgm")
+    return path_to_dvisvgm is not None and os.access(path_to_dvisvgm, os.X_OK)

manim/cli/checkhealth/commands.py

@@ -0,0 +1,81 @@
+"""A CLI utility helping to diagnose problems with
+your Manim installation.
+
+"""
+
+from __future__ import annotations
+
+import sys
+
+import click
+import cloup
+
+from .checks import HEALTH_CHECKS
+
+
+@cloup.command(
+    context_settings=None,
+)
+def checkhealth():
+    """This subcommand checks whether Manim is installed correctly
+    and has access to its required (and optional) system dependencies.
+    """
+    click.echo(f"Python executable: {sys.executable}\n")
+    click.echo("Checking whether your installation of Manim Community is healthy...")
+    failed_checks = []
+
+    for check in HEALTH_CHECKS:
+        click.echo(f"- {check.description} ... ", nl=False)
+        if any(
+            failed_check.__name__ in check.skip_on_failed
+            for failed_check in failed_checks
+        ):
+            click.secho("SKIPPED", fg="blue")
+            continue
+        check_result = check()
+        if check_result:
+            click.secho("PASSED", fg="green")
+        else:
+            click.secho("FAILED", fg="red")
+            failed_checks.append(check)
+
+    click.echo()
+
+    if failed_checks:
+        click.echo(
+            "There are problems with your installation, "
+            "here are some recommendations to fix them:"
+        )
+        for ind, failed_check in enumerate(failed_checks):
+            click.echo(failed_check.recommendation)
+            if ind + 1 < len(failed_checks):
+                click.confirm("Continue with next recommendation?")
+
+    else:  # no problems detected!
+        click.echo("No problems detected, your installation seems healthy!")
+        render_test_scene = click.confirm(
+            "Would you like to render and preview a test scene?"
+        )
+        if render_test_scene:
+            import manim as mn
+
+            class CheckHealthDemo(mn.Scene):
+                def construct(self):
+                    banner = mn.ManimBanner().shift(mn.UP * 0.5)
+                    self.play(banner.create())
+                    self.wait(0.5)
+                    self.play(banner.expand())
+                    self.wait(0.5)
+                    text_left = mn.Text("All systems operational!")
+                    formula_right = mn.MathTex(r"\oint_{\gamma} f(z)~dz = 0")
+                    text_tex_group = mn.VGroup(text_left, formula_right)
+                    text_tex_group.arrange(mn.RIGHT, buff=1).next_to(banner, mn.DOWN)
+                    self.play(mn.Write(text_tex_group))
+                    self.wait(0.5)
+                    self.play(
+                        mn.FadeOut(banner, shift=mn.UP),
+                        mn.FadeOut(text_tex_group, shift=mn.DOWN),
+                    )
+
+            with mn.tempconfig({"preview": True, "disable_caching": True}):
+                CheckHealthDemo().render()

manim/constants.py

@@ -62,6 +62,7 @@
     "DEFAULT_POINT_DENSITY_1D",
     "DEFAULT_STROKE_WIDTH",
     "DEFAULT_FONT_SIZE",
+    "SCALE_FACTOR_PER_FONT_POINT",
     "PI",
     "TAU",
     "DEGREES",
@@ -183,6 +184,7 @@
 DEFAULT_POINT_DENSITY_1D: int = 10
 DEFAULT_STROKE_WIDTH: int = 4
 DEFAULT_FONT_SIZE: float = 48
+SCALE_FACTOR_PER_FONT_POINT: float = 1 / 960
 
 # Mathematical constants
 PI: float = np.pi