This is not about viewport. The viewport is ok. One thing is the viewport size of the screen, width and height, and another is the graphical interface browser (window), that is opened when you run casperjs test.js --engine=slimerjs.
It's ok that the browser opens when I run casperjs test.js --engine=slimerjs, very useful for testing purposes. But when I stopped testing and want to do something bigger I don't want that browser window open 10 times or 100 times.
I've been reading a while and couldn't find any in the documentation, google or here.
If this is possible, throw the command, I will be very grateful for that. Thank you very much.
Yes, it`s possible, you can hidden window with xvfb util. How to do it. Docs