Window stalking

[zeruel13]

Another simplish concept here, I've created a UI window, and spawned another (preset display) window from that. I'd like to have the spawn always locate itself at a set relative position to the main window, and wondered if there's any such undocumented (or documented and I'm blind) moveCommand that'll event when a window is repositioned.

Have checked scriptJob events with no joy, and would prefer to avoid having something that checks at intervals

[warpcat]

using the "window" command, you can query the "top left corner", -tlc of a window. This will return an array in pixel space. You can also query the width and height. By adding the -tlc values with the width and height, you can find any edge location in pixel space of your main window. When you create your NEW window, just assign its "-tlc" to be whatever new location you'd like. I use this method to have a main window span smaller windows that position themselves around the main window. Now if you want to automatically UPDATE the position of the slave windows after the main window moves... well... I don't know how to do that yet...

[gnip]

Greets...

You can create this 'live" connection between parent/child windows by using scriptJobs. Yes, there is no built in scriptJob event that triggers when a window is moved, but you can get similar behavior with the scriptJob's "user-defined conditions." You create your own condition with the "condition" MEL command (see docs). Then, you use this condition in a scriptJob with the -conditionTrue flag (see docs).

You can read about the details of these commands in the docs, but the basic approach is to create a MEL proc that watches the position of the parent window and returns true when the parent window has moved (see below for pseudocode). Then, you can hook this condition into a scriptJob and then when this condition is true, the scriptJob will trigger the proc you give it to reposition the child window... Now, I don't know all the under-the-hood details of how Maya runs conditions, but I believe user-defined conditions get called every time Maya is idle. So, the MEL proc you write to use as a condition should be pretty lightweight since it will be called a lot.

Here's the basic approach...

create a proc to use as a user-defined condition...
global proc int hasParentWinMoved()
* query window for current position
* is current window possition different from the previous position stored in your global variable?
* store result of comparison
* store current window position in a global variable to use for next iteration thru condition
* return result of comparison

create the user-defined condition...
condition -script "hasParentWinMoved" myParentMoveCondition

Create the scriptJob...
scriptJob -conditionTrue "myParentMoveCondition" "snapChildToParentWindow" (with snapChildToParentWindow being your proc that moves the child window next to the parent windw)

I haven't touched this in a few months, so I may have some details mixed up... But, I do remember using this type of approach to get a child window to snap to the side of a parent window whenever the parent window moved. I don't remember it being lightning fast... but it worked. If you do this approach, you'll proably also want to use the scriptJob's -parent flag so that the scriptJob gets deleted when the parent window gets closed. That way you don't have tons of rogue scriptJobs hanging around slowing things down....

Good luck!

[warpcat]

Hey, that's a great trick, but for the life of me, I can't make it work. I don't get any errors, it simply dosn't function. IF you want to take the time, here's the code below, lemmie know if I'm missing something obvious:

// build our window:
global proc buildWIN()
{
global int $winPos[];
window WIN;
columnLayout;
button;
showWindow;
int $lct[] = window -q -tlc WIN;
$winPos[0] = $lct[0];
$winPos[1] = $lct[1];
}

// proc that returns whether or not the window has moved:
global proc int winMoved()
{
global int $winPos[];
int $tlc[] = window -q -tlc WIN;
if ($tlc[0] != $winPos[0] || $tlc[1] != $winPos[1])
{
$winPos[0] = $tlc[0];
$winPos[1] = $tlc[1];
return 1;
}
else
return 0;
}

// build the user defined condition:
condition -s "winMoved" conditionWindowMoved;

// build the little proc that's executed when the windows moved:
global proc printMoved()
{
print "Window Moved!!!n";
}

// finally, build the scriptJob that ties it all together:
scriptJob -ct "conditionWindowMoved" printMoved;

So, when I run this, I get no erros... but my printMoved proc never is executed. Any thoughts? Again, thanks for the tip.

[gnip]

Ok, I couldn't get that to work either. I must be remembering wrong. My apologies. But, I believe I now remember what I did...

Forget the whole user-defined condition thing. Nice trick to have for later, but doesn't work for this. I believe that this wasn't running because every user-defined condition must (?) be dependent on some other system condition (condition -dependency). You can take a look at the list of availble conditions (scriptJob -listConditions) but nothing there will help us catch UI events. The only promosing condition is "busy", but this hung Maya for me when I tried to use it. Your mileage may vary. So...

Here's something simpler and I believe what I had working a few months ago. I just did a simple test and it works fine for me. Just create an "-idleEvent" scriptJob...

scriptJob -parent "WIN" -idleEvent "winMoved";
// the -parent flag is so that the scriptJob gets killed when WIN goes away.

...that gets run continously in the background. In the winMoved" code you posted, just add a print statement right before "return 1" so you can see when the window moves.

This worked for me. However, be forewarned that this means that this script runs continuously in the background. It makes Maya peg the CPU usage while this idle scriptJob is running. It doesn't make Maya's performance necessarily degrade, though, because the second you start doing stuff (camera orbiting, etc.), MEL stops calling the idle scriptJob, since Maya no longer sees itself as idle. So, not clean by any stretch of the imagination, but it does work.

Feature request for all you Alias employees on the list... How 'bout a scriptJob event that is called when a window is moved? Or maybe, how a more generic event that is called when any UI event happens (window drag, button click, focus change, field edit, etc.). And, somehow provide the control's name and event type to the assigned scriptJob.

But, I digress... (longingly dreaming of something like Python's wxPython UI creation in Maya... Ahhh... event handling...)

[warpcat]

Hey, thanks for the update. I'll check that out....
Yeh, I'm learning Python in my spare time.... ah.... I'm in love..... I agree, such a shame more advanced functionality can't be built into mel.... (or simply bypassed like you can do in XSI)

[macaronikazoo]

hey warpcat, whatcha learning python for? just wondering, coz i'd be pretty keen to learn it as well, but i just can't really think what i'd use it for...

i kinda need to have a reason to learn something before commiting the brain power to it.

[goggle]

Yeah, I'm curious too. I've heard good things aboutPython as a language but I tend not to learn new languages until I have a task that I can't accomplish any other way.

-James

[joojaa]

Python is kindof handy... I usualy use it instead of perl for some trivial scripimg tasks such as automating photoshop...

[warpcat]

Why am I learning Python? That's a good question. A couple reasons, not necessarily listed in order of importance:

Break free of my reliance of mel: I think I know a thing or two about mel. But my scripting language is now wholy limited to the Maya enviroment. This kind of scares me in a sense. Let's pretend that in the forseeable future I need to take a job at some other company that dosen't use Maya. Not a major posibility, but still, it's there. If I know Python, which is OS independent, and can embed itself into such software as XSI, I suddenly make myself much more marketable.

Doing system tasks: I often find myself doing many system tasks, such as moving files, renaming files, resizing images, converting images, making directories, etc. Currently, I have to do all this through mel's system command. While not a big issue for me, if someone ELSE wants to use my scripts, they have to have Maya installed, and not everyone on the planet has Maya I've come to learn. By using Python, I can have a much more elegant implementation of the task, and not have to cary around the burden of a huge 3D app just to execute a simple rename script.

Get better at mel! Surprisingly enough, by learning Python, I'm getting new ideas with mel. Not that I can really convey those ideas here, but since Python can do so more MORE than mel... and do it so much EASIER, it makes me think of new ways to implement mel to emulate those changes.

Because Python is so easy to use! It was a big decision for me to pick up another scripting language, and I did a lot of research into which one; Python, Perl, Visual Basic (which I've heard rumored mel is actually based on). After talking with users, looking at books, and attending a course or two, I decided on Python. It's lauguage is VERY intuitive, it's data types are SO much more flexable than mel.... it's like in the past you had this little swiss army knife to do your work, and now you have a whole craftsman tool set. It's a very elegant language, and if you know mel, you can EASILY pick up Python.

Python CAN be integrated into Maya of course. You can open a socket connection, and fire comands directly into Maya. If you know what you're doing, you can have Python do all the fancy work, and then "convert" that to a mel happy syntax, and shoot it into Maya. Do I do this? No.... but it "could" be done.

Finally, I've found a fantastic book that I'm learning from. "Python Programming for the Absolute Beginner", (sorry for the long link, tinyrul ain't loading right now) Here it is on Amazon: http://www.amazon.com/exec/obidos/tg/detai...nce&s=books

I think that just about explains it

[gnip]

...thought I'd chime in again ('cause I'm learning to love Python!)...

Its a great language to learn because of all the things Warpcat said...

And, it's a great "glue" scripting language. It is one way to glue different parts of a production pipeline together to help make things run smoother. To start with, you can think of it as a replacement for batch files/shell scripts, but Python is so much more than that...

Most importantly (to me), it is a full featured object oriented scripting language... with all the priviledges and benefits of OO.

And, it comes standard with a boatload of extremely useful libraries like tons of string processing routines, .zip file processing, glob file matching, XLM file parsing, url/web/html manipulation, file system operations, socket programming, date/time mathematics, regular expressions, wrappers around the WIN32 API and the list goes on. You can also get additional modules to do even more... OpenGL wrapper, wxPython (allows you to create cross-platform GUI's), pyGame (a wrapper around the SDL graphics library that gives you very easy access to 2D graphics, sprites, fonts, audio, CD-ROM, joystick, mouse, audio, mixer, video)... you get the idea...

Plus, you can have all of this cross-platform greatness for free. Here's a great place to get a great interpreter and IDE rolled into one (for linux, solaris or Windows)...

http://www.activestate.com/Products/ActivePython/

Ok, I'm done now...

[macaronikazoo]

wow man, sounds cool. yesterday was a bit of a slow day for me, so I downloaded the latest python and started pluggin away. and you're right, it is pretty easy to pick up. I managed to get a little text file parser up and running in a couple of hours.

and yeah, the data types, talk about cool... dictionaries, and mixed data type arrays, DAMN! very cool. the only thing i don't like so far, is that you have to explicitly re-type data types. ie, if you have this in mel:

string $a = "I want ";
int $b = 5;
string $c = " bananas!";
print( $a + $b + $c );

then thats no problem, but in python it seems you have to go:
a = "I want "
b = 5
c = " bananas!"
print( a + str( + c )

which is slightly painful.

now, just a quick question to those who know it better than I... how do you go about developing your code? because the way i did it yesterday was

-write my code in textpad
-load IDLE
-type: import testScript
-type: testScript.parse()
-quit IDLE cause there are errors
-make changes in textpad
-repeat above steps...

which was really quite painful. there doesn't seem to be any way to "reload" a script. so how do others work? pretty simple question i know, but i couldn't find any documentation on workflow... although i havne't looked in any forums yet.

anyone know of any good forums?

[macaronikazoo]

wow, cool jooja. so how do you contorl photoshop with python? like how do you "get into it"? maya has its commandPorts, but how do you get inside photoshop. sounds way cool

[joojaa]

Ole automation... The photoshop scripting host comes with some rudimentaly examples for perl (wich is more widely used than python)... it pretty much teaches you how to do it in python too. But no big magic here. You can use any ole browser to do this, prefeerebly a python one. Read about python and ole automation.

[warpcat]

heh, you did the print wrong. There IS a better way:

print a, b, c

that's it Actually, I'm a Python nubie, so I'm amazed I can even answer that.

However, for your other question, Python has that solved too. When you open IDLE, go file-> new window. This will open a new module window where you can type all your code. All you have to then is go to the "Run" menu and choose "check module" or "run module". You'll have to save it (and it will prompt you), but then, you can code in that window, hit F5 whenever you like to chekc the code, and the result will appear in the main IDLE ui. And of course, you can have as many of these module windows open as you'd like.

As for forums, I don't know of any, but neither have I looked yet. The book I'm using is pretty darn good for answers....

[warpcat]

I'm JUST getting up to speed on OOP myself,... and MAN, it makes me do wishfull thinking about mel...
When I first saw a list of all the libraries (like you listed), it was really exciting. To write a script using pyGame that makes use of my Joystick input... that's just cool...
Finally, you can also get python from the official web site as well:
www.python.org
Is there any difference from Activatestate?

[gnip]

Yeah, working with Python makes me long for lots of things in MEL. The reason MEL is so powerful is because it sits on top of one heck of a 3D package. As a scripting language, though, there's a lot more that could be there (I can't tell you how many different data types I've tried to cram into a string array... lists, maps, trees, tables, etc.). I've heard rumors that MotionBuilder is going to be using Python for its built in scripting language. It be nice to hook some other scripting language into Maya . But, because Maya's UI is build in MEL, to change that would probably be a monumental effort for Alias... Well, we can dream...

I don't know if there is a difference between ActiveState and the official release. I'm guessing the core interpreter is the same. ActiveState's distribution has a nice IDE... I can't speak for what is at www.python.org. Haven't tried it...

[warpcat]

Yeh, one of the ONLY reasons I've ever though of switching to XSI is the fact it has no "default" scripting language, and you can use Python (or Perl, VB, HTML, etc...) if you choose.... ack, so nice! But what you brought up is a good point, it is how mel is hooked into Maya (or vice versa really) that gives it validity. On it's own...? flee, run away!....
I downloaded Python from the web link I listed, it came with everything you need.... which always made me wonder why Activestate repackaged it... Apples and oranges, it's free either way....

[macaronikazoo]

heh, you did the print wrong. There IS a better way:

no, my way works just fine... the method you used it also fine, but the commas automatically add spaces between the variables, which is sometimes not what you want...

When you open IDLE, go file-> new window
is there another way tho? i'd prefer to do write the scripts in my text editor of choice... just coz i'm comfortable and fast working in it. oh well, thanks for the heads up on that anyway.

[macaronikazoo]

i guess that doesn't nessecarily mean that alias won't hook in other scripting languages to control maya... maybe. heres to hoping eh?