Font Utilities

dartwork-mpl provides helper functions and automatic font registration to simplify typography management in your visualizations.

Automatic Font Registration

When you import dartwork-mpl, all bundled fonts are automatically registered with matplotlib’s font manager:

import dartwork_mpl as dm  # Fonts are now available!

This happens through the _add_fonts() function in the font module:

from pathlib import Path
from matplotlib import font_manager

def _add_fonts():
    font_dir = [Path(__file__).parent / 'asset/font']
    for font in font_manager.findSystemFonts(font_dir):
        font_manager.fontManager.addfont(font)

_add_fonts()  # Called on import

No manual installation or system-level font configuration required.

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fs(n) - Font Size Helper

Adjusts font size relative to the current base size from rcParams.

Signature:

dm.fs(n)

Parameters:

• n (int/float): Points to add to the base font size

Returns:

• float: The adjusted font size

How It Works:

def fs(n):
    return plt.rcParams['font.size'] + n

Example:

import dartwork_mpl as dm
import matplotlib.pyplot as plt

dm.style.use("scientific")  # Base font size is 8.5

fig, ax = plt.subplots()
ax.set_title("Main Title", fontsize=dm.fs(6))      # 14.5pt
ax.set_xlabel("X Label", fontsize=dm.fs(2))        # 10.5pt
ax.set_ylabel("Y Label", fontsize=dm.fs(0))        # 8.5pt (base)
ax.text(0.5, 0.5, "Note", fontsize=dm.fs(-2))      # 6.5pt

Why Use fs()?

Using relative sizes keeps your typography consistent when switching between styles or output formats:

# Instead of hardcoding:
ax.set_title("Title", fontsize=14)  # May not fit your style

# Use relative sizing:
ax.set_title("Title", fontsize=dm.fs(4))  # Always 4pt larger than base

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fw(n) - Font Weight Helper

Adjusts font weight relative to the current base weight from rcParams.

Signature:

dm.fw(n)

Parameters:

• n (int): Weight steps to add (each step = 100)

Returns:

• int: The adjusted font weight

How It Works:

def fw(n):
    return plt.rcParams['font.weight'] + 100 * n

Example:

import dartwork_mpl as dm
import matplotlib.pyplot as plt

dm.style.use("scientific")  # Base weight is 300 (Light)

fig, ax = plt.subplots()
ax.set_title("Bold Title", fontweight=dm.fw(4))    # 700 (Bold)
ax.set_xlabel("Medium Label", fontweight=dm.fw(2)) # 500 (Medium)
ax.set_ylabel("Light Label", fontweight=dm.fw(0))  # 300 (Light, base)
ax.text(0.5, 0.5, "Thin", fontweight=dm.fw(-2))    # 100 (Thin)

Weight Scale Reference:

fw() Call	Result	Weight Name
fw(-2)	100	Thin
fw(-1)	200	ExtraLight
fw(0)	300	Light (base)
fw(1)	400	Regular
fw(2)	500	Medium
fw(3)	600	SemiBold
fw(4)	700	Bold
fw(5)	800	ExtraBold
fw(6)	900	Black

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plot_fonts() - Font Preview Gallery

Generates a visual preview of all available fonts.

Signature:

dm.plot_fonts(font_dir=None, ncols=3, font_size=11)

Parameters:

• font_dir (str, optional): Directory containing .ttf files. Defaults to the bundled fonts.

• ncols (int): Number of columns in the preview grid. Default: 3

• font_size (int): Sample text size in points. Default: 11

Returns:

• matplotlib.figure.Figure: The preview figure

Example:

import dartwork_mpl as dm
import matplotlib.pyplot as plt

# Preview bundled fonts
fig = dm.plot_fonts(ncols=3, font_size=12)
plt.show()

# Preview custom fonts
fig = dm.plot_fonts(font_dir="/path/to/custom/fonts", ncols=2)
plt.savefig("custom_fonts.png", dpi=150)

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Style Configuration

dartwork-mpl styles configure fonts through matplotlib’s rcParams:

Default Font Settings (dmpl style)

# Font family and weight
font.family: roboto
font.weight: 300

# Base font size
font.size: 8.5

# Math text configuration
mathtext.fontset: custom
mathtext.rm: Noto Sans Math
mathtext.it: Noto Sans Math:italic
mathtext.bf: Noto Sans Math:bold
mathtext.cal: Noto Sans Math
mathtext.sf: Noto Sans Math
mathtext.tt: Noto Sans Math

Applying Styles

import dartwork_mpl as dm

# Apply a preset (recommended)
dm.style.use("scientific")
dm.style.use("presentation")

Custom Font Configuration

Override defaults for specific needs:

import matplotlib.pyplot as plt
import dartwork_mpl as dm

dm.style.use("scientific")

# Change font family
plt.rcParams['font.family'] = 'Inter'

# Change base weight
plt.rcParams['font.weight'] = 400  # Regular instead of Light

# Change base size
plt.rcParams['font.size'] = 10

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Tips and Best Practices

Consistent Typography Hierarchy

Use fs() to create a consistent sizing hierarchy:

# Define your hierarchy
TITLE_SIZE = dm.fs(6)
SUBTITLE_SIZE = dm.fs(3)
LABEL_SIZE = dm.fs(0)
ANNOTATION_SIZE = dm.fs(-2)

# Apply consistently
ax.set_title("Main Title", fontsize=TITLE_SIZE)
ax.text(0.5, 0.95, "Subtitle", fontsize=SUBTITLE_SIZE, transform=ax.transAxes)
ax.set_xlabel("X Axis", fontsize=LABEL_SIZE)

Emphasis with Weight

Use weight for emphasis instead of color when possible:

ax.set_title("Important Finding", fontweight=dm.fw(4))  # Bold
ax.set_xlabel("Supporting Label", fontweight=dm.fw(0))  # Light

Condensed Fonts for Tight Spaces

Switch to condensed variants when space is limited:

# For crowded tick labels
ax.tick_params(axis='x', labelsize=dm.fs(-1))
for label in ax.get_xticklabels():
    label.set_fontfamily('Noto Sans Condensed')

Math Text

Use raw strings with LaTeX-style notation:

ax.set_xlabel(r'$\alpha$ (radians)')
ax.set_ylabel(r'$\sin(\alpha)$')
ax.set_title(r'$y = \sum_{i=1}^{n} x_i$')