docs: Add faq page on changing font size 📚

src/SUMMARY.md

@@ -60,6 +60,7 @@
 - [FAQ](./faq/README.md)
 
   - [Duplicate key events on Windows](./faq/duplicate-key-events-windows.md)
+  - [Changing font size](./faq/change-font-size.md)
   - [`tokio` / `async`](./faq/tokio-async.md)
   - [`tui.rs` history](./faq/tui-rs-history.md)
   - [`ratatui` vs `tui-realm`](./faq/ratatui-vs-tui-realm.md)

src/faq/change-font-size.md

@@ -0,0 +1,52 @@
+# Changing font size
+
+`ratatui` itself doesn't control the terminal's font size. `ratatui` renders content based on the
+size and capabilities of the terminal it's running in. If you want to change the font size, you'll
+need to adjust the settings of your terminal emulator.
+
+![](https://user-images.githubusercontent.com/1813121/269147939-0ed031f2-1977-4e92-b4b4-6c217d02e79b.png)
+
+However, changing this setting in your terminal emulator will only change the font size for you
+while you are developing your `ratatui` based application.
+
+When a user zooms in and out using terminal shortcuts, that will typically change the font size in
+their terminal. You typically will not know what the terminal font size is ahead of time.
+
+However, you can know the current terminal size (i.e. columns and rows). Additionally, when zooming
+in and out `ratatui` applications will see a terminal resize event that will contain the new columns
+and rows. You should ensure your `ratatui` application can handle these changes gracefully.
+
+You can detect changes in the terminal's size by listening for terminal resize events from the
+backend of your choice and you can adjust your application layout as needed.
+
+For example, here's how you might do it in
+[crossterm](https://docs.rs/crossterm/0.27.0/crossterm/event/enum.Event.html#variant.Resize):
+
+```rust
+    match crossterm::terminal::read() {
+        Ok(evt) => {
+            match evt {
+                crossterm::event::Event::Resize(x, y) => {
+                    // handle resize event here
+                },
+                _ => {}
+            }
+        }
+    }
+```
+
+```admonish tip
+Since this can happen on the user end without your control, this means that you'll have to design
+your `ratatui` based terminal user interface application to display content well in a
+number of different terminal sizes.
+```
+
+`ratatui` does support various styles, including bold, italic, underline, and more, and while this
+doesn't change the font size, it does provide you with the capability to emphasize or de-emphasize
+text content in your application.
+
+Additionally you can use [`figlet`](https://docs.rs/figlet-rs/latest/figlet_rs/) or
+[`tui-big-text`](https://github.com/joshka/tui-big-text/) to display text content across multiple
+lines. Here's an example using [`tui-big-text`](https://github.com/joshka/tui-big-text/):
+
+![[tui-big-text](https://github.com/joshka/tui-big-text/)](https://camo.githubusercontent.com/3a738ce21da3ae67660181538ef27473b86bebca73f42944e8012d52f86e500d/68747470733a2f2f7668732e636861726d2e73682f7668732d3364545474724c6b79553534684e61683232504152392e676966)