I would like to change the window icon of an already existing application on Lubuntu. By window icon, I mean the one that appears in the window title bar, and in lxpanel. By existing application, I mean one that is already running. I don't want to edit the source code of the application itself. I'm running Lubuntu 17.10 with LXDE, Openbox 3.6.1, and xdg-desktop-icon 1.1.0 rc3.
Usually, it seems that icons for applications are described by name, and then looked up in a database managed by xdg-desktop-icon and xdg-icon-resource. The process by which icons are looked up is specified in the FreeDesktop.org specification, and there's some handy scripts to get the icon filepath here.
There are a few tools which may do what I want. The first is xseticon. Unfortunately, it's unmaintained. I don't see a pre-compiled version anywhere and I'm not eager to spend time figuring out a build environment for dubious old code.
xdotool search --name Geany set_window --icon-name help-contents wmctrl -r Geany -I help-contents
Am I using xdotool and wmctrl properly? As I play with obxprop, it seems like WM_ICON_NAME is equivalent to the window title rather than the icon name. I don't see a way to do this with OpenBox configuration files. Is there another tool to do this?