TextRegion.ln() not working properly when h is provided

[One-Nose]

When using text regions, calling ln() with a custom h value will cause an unwanted second line break after the first line of the next paragraph.

Minimal code

import fpdf

pdf = fpdf.FPDF()
pdf.set_font("Helvetica", size=16)
pdf.add_page()

pdf.write(text="GOOD\nGOOD")
pdf.ln(16)
pdf.write(text="GOOD\nGOOD")

pdf.ln(16)

with pdf.text_columns() as region:
    region.write(text="BAD\nBAD")
    region.ln(16)
    region.write(text="BAD\nBAD")

pdf.output("output.pdf")

Result PDF looks something like this:

GOOD
GOOD

GOOD
GOOD

BAD
BAD

BAD

BAD

As you can see an uncalled for line break was added before the last line.

Environment

• Operating System: Windows
• Python version: 3.14
• fpdf2 version used: 2.8.7

[Pawansingh3889]

I can reproduce this on Python 3.14 with fpdf2 2.8.7.

The root cause is in (text_region.py line 213-224). When is provided, the method sets on the newline fragment. This inflated font size bleeds into the height calculation of the next line in , causing the double line break.

The main (fpdf.py line 5631) handles this differently by directly adjusting , but can't do that since it builds lines lazily.

A possible fix would be to store the custom as a separate attribute on the fragment (e.g. ) rather than modifying , and then handle it in the line height calculation in . Happy to submit a PR if this approach looks right.