> For the complete documentation index, see [llms.txt](https://docs.staruml.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.staruml.io/master/user-guide/customization.md).

# Customization

## Custom Keymaps

If you want to make custom keymaps, you can create `keymap.json` at the user configuration path:

* `/Users/<user>/Library/Application Support/StarUML` for Mac OS.
* `C:\Users\<user>\AppData\Roaming\StarUML` for Windows.
* `~/.config/StarUML` for Linux.

You can get how to edit the custom keymap file (`keymap.json`) at [Keymaps](/master/developing-extensions/keymaps.md).

Here is an example:

```javascript
{
  "cmdctrl-alt-1": null,
  "cmdctrl-alt-g": "view:show-grid"
}
```

The first entry is to release the `Ctrl+Alt+1` (`Cmd+Option+1` in MacOS) key binding and the second entry is to change key binding of **View > Show Grid** (Command ID is `view:show-grid`) to `Ctrl+Alt+G` (`Cmd+Option+G` in MacOS).

If you want to know all command IDs, enter the following expression at **Console** (Debug > Show DevTools > Console tab).

```javascript
Object.keys(app.commands.commands)
```

## Custom Fonts

If you want to use custom fonts, you can add a font folder in the custom fonts folder:

* `/Users/<user>/Library/Application Support/StarUML/fonts` for Mac OS.
* `C:\Users\<user>\AppData\Roaming\StarUML\fonts` for Windows.
* `~/.config/StarUML/fonts` for Linux.

1. Create a font folder (e.g. `my-font`) at the custom fonts folder.
2. Place a font description file (`font.json`) and the TrueType font files `.ttf` in the font folder.

The font description file looks as below:

```javascript
[
  {
    "name"       : "MyFont",
    "regular"    : "MyFont-Regular.ttf",
    "italic"     : "MyFont-Italic.ttf",
    "bold"       : "MyFont-Bold.ttf",
    "boldItalic" : "MyFont-BoldItalic.ttf"
  }
]
```

StarUML should be restarted to recognize the added custom fonts.

## Custom Diagram Canvas Size

> Increasing the diagram canvas size will cause severe performance degradation. In some low-spec computers, StarUML will be crashed. Then, reduce the size of the diagram canvas.

We strongly recommend to keep the small number of elements in a diagram. If you have many elements, then split the diagram into multiple diagrams with a single point of view. Nevertheless, you need to have wider diagram canvas size, you can set the maximum canvas width and height in the configuration file.

Find `config.json` at the user configuration path. If couldn't find, then create one.

* `/Users/<user>/Library/Application Support/StarUML` for Mac OS.
* `C:\Users\<user>\AppData\Roaming\StarUML` for Windows.
* `~/.config/StarUML` for Linux.

Edit the maximum width and height number (default size is `4000` x `3000`) of the diagram canvas as below:

```javascript
{
  "diagramCanvasWidth": 5000,
  "diagramCanvasHeight": 3500
}
```

StarUML should be restarted to affect the changed diagram canvas size.