# Previewing

`texlab` supports compiling LaTeX using a custom request (`textDocument/build`)
and by building a document after saving if configured to do so.
To enable building on save, simply set `texlab.build.onSave` to true.
Previewing can be configured in a variety of ways:

1. If you are using `latexmk`, you can create a `.latexmkrc` file and call your viewer accordingly.
   Afterwards, you can add the `-pv` flag to your `texlab.build.args`.

2. If you want the PDF viewer to stay synchronized with the cursor position in your editor,
   you can instruct `texlab` to execute a forward search after every build (`texlab.build.forwardSearchAfter`).
   To do so, you need to enable [SyncTeX](http://www.tug.org/TUGboat/tb29-3/tb93laurens.pdf)
   and update the `texlab.forwardSearch` configuration.
   If you want to use this feature, we do _not_ recommend the `-pvc` flag
   because `texlab` does not get notified by `latexmk` when a document gets built.
   Instead, you can use `texlab.build.onSave`.

In the following sections, we will give forward search configurations for several popular viewers.
If your viewer is not listed here, you can send us a pull request or create an issue.

The inverse search configuration depends on the editor.
In this section, we will give instructions for [Visual Studio Code](https://code.visualstudio.com/).
However, these settings can easily be adapted to other editors.
Some plugins can help with setting up inverse search:

- `Neovim`: [`f3fora/nvim-texlabconfig`](https://github.com/f3fora/nvim-texlabconfig)
- `Emacs`: [`ROCKTAKEY/lsp-latex`](https://github.com/ROCKTAKEY/lsp-latex#inverse-search)

---

## SumatraPDF

We highly recommend [SumatraPDF](https://www.sumatrapdfreader.org) on Windows
because Adobe Reader locks the opened PDF file and will therefore prevent further builds.

### Forward Search

Add the following lines to your editor config:

```json
{
  "texlab.forwardSearch.executable": "C:/Users/{User}/AppData/Local/SumatraPDF/SumatraPDF.exe",
  "texlab.forwardSearch.args": [
    "-reuse-instance",
    "%p",
    "-forward-search",
    "%f",
    "%l"
  ]
}
```

### Inverse Search

Add the following line to your SumatraPDF settings file (Menu -> Settings -> Advanced Options):

```ini
InverseSearchCmdLine = "C:\Users\{User}\AppData\Local\Programs\Microsoft VS Code\Code.exe" -g "%f":%l
```

> **Note**: Please make sure to replace `{User}` with your Windows username.

You can execute the search by pressing `Alt+DoubleClick` in the PDF document.

---

## Evince

The SyncTeX feature of [Evince](https://wiki.gnome.org/Apps/Evince) requires communication via D-Bus.
In order to use it from the command line, install the [evince-synctex](https://github.com/latex-lsp/evince-synctex) script.

### Forward Search

Add the following lines to your editor config:

```json
{
  "texlab.forwardSearch.executable": "evince-synctex",
  "texlab.forwardSearch.args": ["-f", "%l", "%p", "\"code -g %f:%l\""]
}
```

### Inverse Search

The inverse search feature is already configured if you use `evince-synctex`.
You can execute the search by pressing `Ctrl+Click` in the PDF document.

---

## Okular

### Forward Search

Add the following lines to your editor config:

```json
{
  "texlab.forwardSearch.executable": "okular",
  "texlab.forwardSearch.args": ["--unique", "file:%p#src:%l%f"]
}
```

### Inverse Search

Change the editor of Okular (Settings -> Configure Okular... -> Editor) to "Custom Text Editor" and set the following command:

```bash
code -g "%f":%l
```

You can execute the search by pressing `Shift+Click` in the PDF document.

---

## Zathura

### Forward Search

Add the following lines to your editor config:

```json
{
  "texlab.forwardSearch.executable": "zathura",
  "texlab.forwardSearch.args": ["--synctex-forward", "%l:1:%f", "%p"]
}
```

### Inverse Search

Add the following lines to your `~/.config/zathura/zathurarc` file:

```bash
set synctex true
set synctex-editor-command "code -g %{input}:%{line}"
```

You can execute the search by pressing `Ctrl+Click` in the PDF document.

---

## qpdfview

### Forward Search

Add the following lines to your editor config:

```json
{
  "texlab.forwardSearch.executable": "qpdfview",
  "texlab.forwardSearch.args": ["--unique", "%p#src:%f:%l:1"]
}
```

### Inverse Search

Change the source editor setting (Edit -> Settings... -> Behavior -> Source editor) to:

```bash
code -g "%1":%2
```

and select a mouse button modifier (Edit -> Settings... -> Behavior -> Modifiers -> Mouse button modifiers -> Open in Source Editor)
of choice.
You can execute the search by pressing `Modifier+Click` in the PDF document.

---

## Skim

We recommend [Skim](https://skim-app.sourceforge.io/) on macOS since it is the only native viewer that supports SyncTeX.

Additionally, enable the "Reload automatically" setting in the Skim preferences (Skim -> Preferences -> Sync -> Check for file changes).

### Forward Search

Add the following lines to your editor config:

```json
{
  "texlab.forwardSearch.executable": "/Applications/Skim.app/Contents/SharedSupport/displayline",
  "texlab.forwardSearch.args": ["%l", "%p", "%f"]
}
```

If you want Skim to stay in the background after
executing the forward search, you can add the `-g` option
to `texlab.forwardSearch.args`.

### Inverse Search

Select the Visual Studio Code preset in the Skim preferences (Skim -> Preferences -> Sync -> PDF-TeX Sync support).
You can execute the search by pressing `Shift+⌘+Click` in the PDF document.

---