project pequeño

Patches and tutorial on how to allow line spacing less than 1 in vte-based terminals

Final result

The year is 2024, the year of the Linux desktop. Linux is so mainstream now that developers care about the user experience by not allowing them to set line spacing to some crazy value like 0.1.

My reaction:

But we all know that you want that Bisqwit-like terminal:

credit

The plan

1. Patch xfce4-terminal. Compile xfce4-terminal. Install xfce4-terminal.
2. Patch vte. Compile vte. Install vte.
3. Modify your favorite monospace font. Install font.

Environment

• Ubuntu 24.04 LTS
• XFCE 4.18
• X11

Clone repos

git clone https://gitlab.xfce.org/apps/xfce4-terminal.git
git clone https://gitlab.gnome.org/GNOME/vte.git
git clone https://github.com/agiUnderground/project-pequeno.git

xfce4-terminal HEAD - 08918c7be45771584c9e4ad6f80253d855cac1b5
vte HEAD - 4bb767c342c099cafffb760cd0e7a255a72e9578

Let's patch xfce4-terminal first

cd xfce4-terminal
git apply ~/project-pequeno/assets/patches/xfce4-terminal-patch.diff

Check the changes: git diff

Commit:

git add .
git commit -m "Allow decimal values for cell spacing."

Here is what we're changing:

GtkWidget*
gtk_spin_button_new_with_range (
  gdouble min,
  gdouble max,
  gdouble step
)

GParamSpec*
g_param_spec_double (
  const gchar* name,
  const gchar* nick,
  const gchar* blurb,
  gdouble minimum,
  gdouble maximum,
  gdouble default_value,
  GParamFlags flags
)

You can check .diff file with the editor and apply changes manually if you want to. For example you can change step value from 0.01 to 0.001 if you want.

Let's compile xfce4-terminal

sudo apt install xfce4-dev-tools build-essential gtk-doc-tools autopoint
sudo apt build-dep xfce4-terminal
./autogen.sh
make -j$(nproc)
sudo make install

Result of the successful build:

Nice.

Right now, changing the cell spacing value to a value less than 1 has no effect. We need to patch VTE.

Let's patch vte

cd ~/vte
git apply ~/project-pequeno/assets/patches/vte-patch.diff

Check the changes:

git diff

Commit:

git add .
git commit -m "Allow decimal values for cell spacing."

Dependencies and compilation:

sudo apt install meson cmake liblz4-dev libgtk-4-dev libsystemd-dev libgirepository1.0-dev valac
meson _build
ninja -C _build
sudo ninja -C _build install

Check out that you have fresh libs installed:

ls -lah /usr/local/lib/x86_64-linux-gnu/libvte*

Make sure that you terminal binary is linked with the new library:
ldd $(which xfce4-terminal) | grep vte

We're literally half way there:

Custom font

We need a custom font to make our new terminal somewhat usable.

First idea was to patch rendering engine(whatever it is in this case).
But text rendering is really really complex topic, so I'm glad we can get what we need with a custom font.

I'll use JetBrains Mono. link

cd Downloads
wget https://download.jetbrains.com/fonts/JetBrainsMono-2.304.zip
unzip JetBrainsMono-2.304.zip -d jetbrains-mono

Very nice tool to inspect the fonts is ftinspect, you can install it with sudo apt install freetype2-demos.
But to modify the font we gonna use FontForge.
sudo apt install fontforge

Start a fontforge and choose a font jetbrains-mono/fonts/ttf/JetBrainsMono-Regular.ttf.

Now we need to squash symbols vertically.

Edit -> Select -> Select All

Element -> Transformations -> Transform

Scale -> Y value 65% (for example)

Check Roud To Int checkbox, to avoid unnecessary errors.

Element -> Font Info

Modify Fontname and Name For Humans.
Choose PS UID from left column, check Use UniqueID checkbox and set UniqueID field to some random number value.
Choose General from left column, set Em Size to 1024.
In Change UniqueID? dialog choose change.

File -> Generate Fonts...
Choose custom name and type TrueType.

Ignore Errors detected dialog and press Generate button.

Install a new font.
In my case is:

sudo cp JetBrainsMono-Regular-Pequeno.ttf /usr/share/fonts/truetype/

Update fonts cache:

fc-cache -vf

Done.

Disclaimer:
I'm pretty sure that there are a lot of errors. Do not use it anywhere in production.
The main goal of this one evening endeavor was just to make it work.
The VTE patch is most likely not fully correct. If you already fixed it, I'm open to PRs.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.