in KDE 5 how to make a GUI application show/hide with a shortcut similar to Tilda/guake/yakuake

Question

I simply want to setup Emacs GUI to toggle (hide/show) visibility just like we see in guake, tilda or yakuake terminals(it is called drop down in these terminals). for example I am working with Emacs within the GUI and I have a browser window behind it, I want to hide Emacs GUI with a shortcut(e.g F12) and then see my browser (with focus) interact with or any other window, then again press F12 and I will have my Emacs GUI back(I am running KDE 5.13). Also if you know how to do this in XFCE or gnome please share your knowledge.