Font size guidelines in Matplotlib - Step-by-Step Execution

Concept Flow - Font size guidelines

Start Plot

↓

Set Font Size

↓

Apply Font Size to Title

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Apply Font Size to Axis Labels

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Apply Font Size to Tick Labels

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Render Plot with Fonts

↓

End

The flow shows how font sizes are set step-by-step for different parts of a matplotlib plot before rendering.

Execution Sample

Matplotlib

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [4, 5, 6])
plt.title('My Plot', fontsize=16)
plt.xlabel('X Axis', fontsize=12)
plt.ylabel('Y Axis', fontsize=12)
plt.tick_params(labelsize=10)
plt.show()

This code creates a simple line plot and sets font sizes for the title, axis labels, and tick labels.

Execution Table

Step	Action	Font Size Set	Target Element	Effect
1	Create plot	Default	Plot area	Plot initialized with default font sizes
2	Set title font size	16	Title	Title font size set to 16 points
3	Set x-axis label font size	12	X-axis label	X-axis label font size set to 12 points
4	Set y-axis label font size	12	Y-axis label	Y-axis label font size set to 12 points
5	Set tick label font size	10	Tick labels	Tick labels font size set to 10 points
6	Render plot	Applied	All text elements	Plot displayed with specified font sizes

💡 Plot rendered with all font sizes applied as specified.

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	After Step 5	Final
title_fontsize	Default (varies)	16	16	16	16	16
xlabel_fontsize	Default (varies)	Default	12	12	12	12
ylabel_fontsize	Default (varies)	Default	Default	12	12	12
tick_labelsize	Default (varies)	Default	Default	Default	10	10

Key Moments - 2 Insights

Why do we set font sizes separately for title, labels, and ticks?

Each text element has its own font size property, so setting them separately (see execution_table steps 2-5) allows precise control over appearance.

What happens if we don't set tick label font size explicitly?

Tick labels keep the default size, which may be too small or large compared to other text (see variable_tracker tick_labelsize before step 5).

Visual Quiz - 3 Questions

Look at the execution table, what font size is set for the plot title at step 2?

A 12

B 10

C 16

D Default

💡 Hint

Check the 'Font Size Set' column at step 2 in the execution_table.

At which step are the tick label font sizes set?

A Step 5

B Step 3

C Step 4

D Step 6

💡 Hint

Look for 'Set tick label font size' in the 'Action' column of execution_table.

If we remove the line setting xlabel font size, what happens to xlabel_fontsize in variable_tracker after step 3?

A It becomes 16

B It stays at default

C It becomes 10

D It becomes 12

💡 Hint

Check how xlabel_fontsize changes after step 3 in variable_tracker.

Concept Snapshot

matplotlib font size guidelines:
- Use 'fontsize' parameter to set size for title, xlabel, ylabel.
- Use 'tick_params(labelsize=...)' to set tick label size.
- Set sizes separately for clear control.
- Sizes are in points (pt).
- Apply before plt.show() to see effect.

Full Transcript

This visual execution shows how to set font sizes in matplotlib plots. We start by creating a plot, then set font sizes for the title, x-axis label, y-axis label, and tick labels step-by-step. Each step updates the font size of a specific text element. The variable tracker shows how font size values change after each step. Key moments clarify why separate settings are needed and what happens if some are omitted. The quiz tests understanding of font size assignments at different steps. This helps beginners see exactly how font sizes affect plot text elements.