# What Is the `corrector` Parameter in Outfancy Table Rendering?

> Master the corrector parameter in Outfancy table rendering. Learn how this integer fine tunes terminal width for perfect table layouts and avoid overflow. Enhance your data visualization now.

- Repository: [Carlos A. Planchón/outfancy](https://github.com/carlosplanchon/outfancy)
- Tags: api-reference
- Published: 2026-02-26

---

**The `corrector` parameter is a small integer added to the detected terminal width before layout calculations to fine-tune usable horizontal space and prevent table overflow or truncation.**

The `corrector` attribute in the Outfancy library allows developers to adjust how table width is calculated against terminal boundaries. When rendering tables in command-line interfaces, this parameter compensates for invisible padding, scrollbars, or margin whitespace that can cause unwanted line wrapping. Understanding this parameter ensures your tables display correctly across different terminal environments.

## How the `corrector` Parameter Works in [`outfancy/table.py`](https://github.com/carlosplanchon/outfancy/blob/main/outfancy/table.py)

The `corrector` functionality is implemented in the core table rendering logic within the `Table` class.

### Definition and Default Value

In [`outfancy/table.py`](https://github.com/carlosplanchon/outfancy/blob/main/outfancy/table.py), the `corrector` attribute is initialized with a default value of **-2**. According to the source code comments, this attribute serves as "the correction value to be applied to the x axis (margin of whitespaces at right of the screen)". This definition appears at lines 51-53, where the attribute is first introduced in the class constructor.

### Application During Width Calculations

During the rendering process, the terminal width (stored as `screen_x`) is adjusted by adding the `corrector` value. At lines 39-41 in [`outfancy/table.py`](https://github.com/carlosplanchon/outfancy/blob/main/outfancy/table.py), the code applies this correction before performing any width-related computations. The adjusted `screen_x` is then used for separator length checks, column-width assignment, and pagination logic.

## Practical Usage of the `corrector` Parameter

You can modify the `corrector` value using the `set_corrector()` method to accommodate different terminal configurations.

```python
from outfancy import Table

tbl = Table()

# Reduce the effective width by 4 characters (adds extra right-margin)

tbl.set_corrector(-4)

print(tbl.render(data))

```

In this example, the table treats the terminal as four characters narrower than reported. This prevents overflow on terminals that reserve space for scrollbars or other UI elements on the right edge.

## When to Adjust the `corrector` Value

Consider modifying this parameter when you encounter specific display issues:

- **Scrollbar compensation**: Set a more negative value (e.g., `-4` or `-5`) if your terminal displays a vertical scrollbar that consumes character width
- **Padding adjustments**: Increase the value slightly if you need extra whitespace margin on the right side of your tables
- **Terminal reporting inaccuracies**: Use positive values if your terminal emulator under-reports its actual width

## Summary

- The `corrector` parameter adjusts the detected terminal width (`screen_x`) by a specified integer value before table layout calculations
- Defined in [`outfancy/table.py`](https://github.com/carlosplanchon/outfancy/blob/main/outfancy/table.py) at lines 51-53 with a default value of **-2**
- Applied to width calculations at lines 39-41 to prevent overflow or truncation
- Modified programmatically via the `set_corrector()` method to handle terminal-specific padding and scrollbar requirements

## Frequently Asked Questions

### How do I change the `corrector` value in Outfancy?

Use the `set_corrector()` method on your `Table` instance. Pass an integer representing the adjustment you want to apply to the detected terminal width. For example, `tbl.set_corrector(-3)` reduces the usable width by three characters to accommodate right-side UI elements.

### Why does the `corrector` default to -2?

The default value of **-2** provides a conservative safety margin that accommodates most terminal environments. This accounts for common right-side whitespace margins or minor discrepancies in how different terminal emulators report their dimensions, preventing tables from wrapping unexpectedly.

### Can I use a positive `corrector` value?

Yes, positive values increase the usable width beyond what the terminal reports. This is useful when your terminal under-reports its capacity or when you want tables to extend closer to the right edge of the screen. However, positive values risk line wrapping if the actual available space is smaller than reported.

### Where in the source code is the `corrector` applied to terminal width?

The adjustment occurs in [`outfancy/table.py`](https://github.com/carlosplanchon/outfancy/blob/main/outfancy/table.py) at lines 39-41, where `self.corrector` is added to `screen_x` immediately after detecting the terminal size. This modified width value then flows through all subsequent layout calculations including column distribution and separator rendering.