Inconsistent blank space below last line on macOS

[jperkin]

Issue Description

I'm trying and failing to get ghostty to match Terminal.app behaviour with respect to the amount of empty space around the usable text area. For me, ghostty ends up with variable and excessive space below the last line which just looks odd. For example here there is almost an entire extra line's worth of whitespace below.

I have enabled window-step-resize = true because while the default of false does allow me to get rid of this space, it is quite annoying and very finicky to do so, and to have to do it for every terminal window. I've tried window-padding-balance = true but that doesn't appear to help at all. I've had this problem for a while and decided to wait until 1.3.0 was released to see if it helped but there's no change.

Here is how Terminal.app looks (albeit with a different font), I just want ghostty to look like this, no wasted space and consistent across all window sizes.

Expected Behavior

With window-step-resize = true I would expect ghostty to behave as if it were false and the user manually made the window the smallest it could be before the next step change.

Actual Behavior

It's even more odd with my current setup:

window-step-resize = true
window-padding-x = 1
window-padding-y = 1
window-padding-balance = true

You can end up with behaviour like this, where a step resize doesn't even add a new line, you just end up with even more space:

ghostty-resize.mov

I wonder if this is related to the difference in behaviour when resizing fonts. Here is Terminal.app increasing the window size and keeping the border consistent on every resize:

terminal-app-fontsize-720.mov

Whereas ghostty keeps the terminal size the same, but the border size varies dramatically (smaller video due to GH 10MB limit):

ghostty-fontsize-480.mov

Reproduction Steps

1. Enable window-step-resize = true.
2. Note excessive and inconsistent amounts of whitespace below the last line.

Ghostty Logs

No response

Ghostty Version

Ghostty 1.3.0

Version
  - version: 1.3.0
  - channel: stable
Build Config
  - Zig version   : 0.15.2
  - build mode    : .ReleaseFast
  - app runtime   : .none
  - font engine   : .coretext
  - renderer      : renderer.generic.Renderer(renderer.Metal)
  - libxev        : kqueue

OS Version Information

macOS Sequoia 15.7.4

(Linux only) Display Server

None

(Linux only) Desktop Environment/Window Manager

No response

Minimal Ghostty Configuration

window-step-resize = true

Additional Relevant Configuration

No response

I acknowledge that:

• I have reviewed the FAQ and confirm that my issue is NOT among them.
• I have searched the Ghostty repository (both open and closed Discussions and Issues) and confirm this is not a duplicate of an existing issue or discussion.
• I have checked the "Preview" tab on all text fields to ensure that everything looks right, and have wrapped all configuration and code in code blocks with a group of three backticks (```) on separate lines.

[amh4r]

Related to this, I noticed a regression when updating from 1.2.3 to 1.3.0. The bottom padding used to hide when the window was full-height, but it no longer does.

Good (1.2.3):
https://github.com/user-attachments/assets/36de8091-ff05-4eae-b308-7d62918f62b8

Bad (1.3.0):
https://github.com/user-attachments/assets/7938fd05-0551-4109-ae6c-ea8701494ee4

Ghostty config

theme = 0x96f

window-padding-balance = true
window-padding-x = 0
window-padding-y = 0
window-step-resize = true

[ryan-saffer]

im getting this as well on mac and its really frustrating!