specify pdf viewer for compilation via LSP

[islercn]

to use SumatraPDF as the PDF previewer, i have to create and modify %USERPROFILE%/.latexmkrc

if i can choose the pdf viewer via LSP, like the option "texlab.forwardSearch.executable" for forward search?

after testing, the option "texlab.forwardSearch.executable" is only for forward search, not to view the pdf file after compilation

[clason]

See https://github.com/latex-lsp/texlab/blob/master/docs/previewing.md

[islercn]

See https://github.com/latex-lsp/texlab/blob/master/docs/previewing.md

it is not so portable, perhaps it ok that the .latexmkrc file can be allowed to be placed in the program directory, but it is not valid

so allowing users to specify pdf viewer via LSP is also a good choice

[pfoerster]

it is not so portable, perhaps it ok that the .latexmkrc file can be allowed to be placed in the program directory, but it is not valid

At the moment, texlab does not control the PDF viewer. Instead, the build system (e. g. latexmk) is currently responsible for launching the PDF viewer. Thus, the latexmkrc needs to be found by latexmk and not texlab. texlab does not parse (or better execute) this file. I would avoid hard-coding every possible viewer into texlab as there is quite some maintenance effort involved. I don' think it should be portable because every user uses some different kind of PDF viewer.

[clason]

But you already configure the viewer for forward search, don't you? Wouldn't it be possible to add a callback after (successful) compilation to trigger a forward search?

(Or leave it user definable so they can do whatever they want?)

[pfoerster]

But you already configure the viewer for forward search, don't you?

Yeah, that would be possible. I think I misread the issue a little bit. I thought that we should include the configuration from the documentation inside texlab so the user just specifies texlab.build.viewer: "sumatra" for example. I think adding a texlab.build.viewer.executable setting seems reasonable.

Wouldn't it be possible to add a callback after (successful) compilation to trigger a forward search?

Not exactly. To perform a forward search we need a line number, which is something texlab does not know. In past versions, we tried to guess the value but this approach was pretty much tailored to VSCode and not useful in the general case, which is why I moved it to the extension only. I think this feature is valuable but it needs to implemented correctly.

[pfoerster]

Concerning the forward search after building, there is microsoft/language-server-protocol#718, which would make it possible to implement this feature.

[pfoerster]

texlab 3.2.0 does not rely on a latexmkrc file anymore. Instead, you can use texlab.build.forwardSearchAfter: true to keep the viewer synchronized with the cursor position. The cursor position is guessed by texlab by taking a look at the last edit and completion/hover positions. Note that this may not always be 100% accurate, but for most cases it should suffice. Please take a look at https://github.com/latex-lsp/texlab/blob/master/docs/previewing.md for more information.