Glyphs of generated TTF's are attached to the bottom

[quiple]

When I check the converted file, I can see that all the glyphs are stuck at the bottom, as shown in the screenshot.

And If I convert a BDF file other than this BDF file, it has been confirmed that it looks normal. (ex. GNU Unifont)

Here is header of my BDF file. What could be the problem?

STARTFONT 2.1
FONT -Galmuri11-Regular-R-Regular--16-16-75-75-c-80-iso10646-1
SIZE 16 75 75
FONTBOUNDINGBOX 18 19 -1 -3
STARTPROPERTIES 10
FAMILY_NAME Galmuri11
WEIGHT_NAME Regular
FONT_VERSION Version 2.0.2
COPYRIGHT Copyright (c) 2019-2022 Lee Minseo (itoupluk427@gmail.com)
FOUNDRY Made with Bits'n'Picas by Kreative Software
FONT_ASCENT 14
FONT_DESCENT 2
CAP_HEIGHT 12
POINT_SIZE 12
X_HEIGHT 8
ENDPROPERTIES
CHARS 12947

[quiple]

I think I've figured out the cause. Unifont's bitmap data (left) also has vertical margins, while my BDF's bitmap data (right) excludes vertical margins.

Can't you make BBX's Y-axis data reflect?