mGui updates

Posted on Tue 24 June 2014 in blog

For anybody whos been following the mGui Maya GUI construction kit posts, I’ve added a few fixes and tweaks to the GitHub project in the last couple of weeks:

mGui.progress

The progress module wraps Maya’s progressBar command for mGui style coding of progress bars.

There are two classes in the module; ProgressBar is the generic version and MainProgressBar always points at Maya’s main progress bar. Both classes have start(), update() and end() methods instead of Maya’s clunky cmds.progressBar(name, e=True, beginProgress=1) and so on. They also both have an iter() method, which will loop over a generator expression and update the progress bar for each yield then pass along the value. This allows simple idioms like: 

from mGui.progress import MainProgressBar  
import os

def list_files(dir):  
    # pretend this is as long, slow function...  
    for item in os.listdir(dir):  
        yield item

pb = MainProgressBar()  
for each_file in pb.iter(list_files()):  
    print each_file.upper()  
    # here's where you do something with the results

So you can update the progress bar without unduly intertwining the GUI update and the program logic.

mGui.menu_loader

The menu_loader module will create menus from a YAML data file. It does a little bit of introspection to figure out how to create the items and attach their handlers to functions. This makes it easy to set up a menu with several items from a single setup routine.

The menu data is a text-based YAML file that looks like this: 

!MMenu  
    key:   UndeadLabs  
    label: Undead Labs  
    items:  
        - !MMenuItem  
            key: About  
            label: About Undead Labs...  
            annotation: "About this UndeadLabs tool setup"  
            command: tools.common.aboutDialog.open

        - !MMenuItem  
            key: RemoteDebugger  
            label:  Remote Debugger  
            annotation: Start / Stop remote python debugger  
            command: tools.common.remoteDebug.remote_debugger_dialog

And loading the menu is as simple as: 

import mGui.menu_loader as loader  
loader.load_menu('path/to/undeadlabs.YAML')

mGui.scriptJobs

The scriptJobs module adapts the event model for use with scriptJobs. A ScriptJobEvent is a derivative of Event which allows you to hook multiple handlers to a single scriptjob (in the same way that the other Event classes allow for multicast delegates): 

from mGui.scriptJobs import *

def print_selected (*args, **kwargs):  
    print cmds.ls(sl=True) or []

sj = ScriptJobEvent("e", "SelectionChanged")  
sj += print_selected

As with all the mGui Event classes, you can add multiple handlers to single event: 

sj += some_other_function()

The module also includes named subclasses to simplify setup. That way you can do things like: 

closing_sj = RecentCommandChanged()  
closing_sj += close_handler

which is a bit nicer and less typo prone if you use an autocompleting IDE.

mGui Maya