Nuke; Python For Artists; Python Panels UI Video Lecture | Create Visual Effects with Nuke - Professional Skills

nuke5 to introduces python panels which
are a lot more powerful than the old
panel code they use the regular nuke
knob objects which means you can use any
knob that you would normally use to
create a gizmo for example they also use
the new callbacks which means you can
create dynamic interfaces and on top of
that you can choose to either use them
as modal windows or as non-modal parts
of your interface and to save and
restore them with your layouts so let's
have a look at the panel we'll be
putting together in this tutorial this
is a slightly enhanced search and
replace panel which I wrote to replace
the old panel code based one that lives
in edit node file name search and
replace so this is using the old panel
code here if you want to have a look at
that old code it's in the nuke scripts
directory in nukes install folder and
it's called search replaced or pyo but
let's have a look at what the Python
panels can do first I have a drop down
list that determines if I want to search
all nodes or just the selected ones then
I've got my search string so and - like
SC 20 for example to search the nodes
for that string and the moment I shift
focus away from the search string I
already get a result so that's the
callbacks here if I then choose to only
search selected nodes the result adjusts
accordingly and if I change selections
in the node graph and hit the Update
button we get an updated result as well
so now I can go ahead and replace that
string with a new one like so I'm
getting errors because I don't have a
scene 21 so I'll just change that back
and we're pretty much ready to go you'll
note that this is a non model panel so
it's a tab like any other tab in nuke
that I can rearrange in the interface
and save with my layouts and now let's
have a look at how does this put
together the first thing you need to do
to create a Python panel is to create a
class that inherits the basic Python
panel that lives in the nuke scripts
package so let's add that bit of code so
here you see I've created a new class
that is called search replace panel it
inherits the nuke scripts dot Python
panel which gives us all the methods
that we need attached to it and in its
constructor we simply execute the nuke
scripts tab Python panels constructor to
give it a title
and an optional ID the ID needs to be a
unique string and is required for
layouts to communicate with your new
panel so if you pop this up as a modal
panel you don't need the ID once you've
got this header information you are
ready to create your knobs let's go
ahead and create the search entry knob
first and I'm gonna attach it to my
class as the variable search just yeah
and it should be a string knob with the
name suggest here make it an uppercase s
and the label search for like so once
we've created a knob
we need to explicitly attach it to the
new panel class and we can do this by
typing self dot add knob this is a
method inherited from the basic Python
panel in the nuke scripts package and
all this needs is the knob we created
above so once we've created knobs and
added them to the panel we're ready to
pop up the panel let's try a modal
dialogue first I'll create an instance
of a new class and use the method show
modal dialog that was inherited as well
so if we run this code we should get a
basic pop-up window with a search string
in there and we get an OK and cancel
button for free so let's go back and do
more of the same
just gonna copy that line to create my
replace string knob so I'll swap search
for replace
and the label should now read replace
with and once again once we've created
the new knob we need to add it to the
panel in the order we want them to show
up so running this now gives us both
string knobs I don't want to bore you
with my typing so I'll just skip ahead
and create all the knobs we need here we
are and let's quickly examine this the
first knob is our enumeration knob which
gives us the choice to examine either
all nodes all the selected nodes so the
third argument here is a list or a tuple
that gives us the items in the drop-down
list then we've got our search string
then we've got a Python script knob once
again just with a name and a label after
that we've got the multi-line evil
string knob which is just a multi-line
knob for text and in this case I don't
want the users to actually enter text I
just want to print to it as an
information panel which is why I'm
deactivating it here so this makes it
impossible for the user to actually
enter stuff into it or manually change
the results that we're printing to it
then we've got a replaced string and
finally we've got another Python script
knob to perform the replace action and
once we've created all those knobs we
adding them one by one in the order they
should show up in the interface so let's
run this bit and pop up the panel again
so here you see the entire panel with
all the knobs they don't do anything yet
but we're pretty much ready to tie this
into the interface the way we want to so
let's go back to the code and instead of
popping it up as a modal panel I now
want to make it live in my pane menu
right here and to do that I'm going to
write a tiny little function to add the
panel to the pane so I'll call that add
panel and all this does is it returns
the add pane command that's attached to
the panel
so once again we create an instance of
the pedal and we'll use the add to pain
method on it this time rather than the
shown modal dialog once we've got this
we can put it into the menu and the menu
we're after is the pain menu so I go a
new code menu pane and then we can go
menu dot add command give it a label for
the menu and give it the callable that
will actually add the panel to the pane
let's run this code and see what happens
so now we should find this panel living
in the pane menu here it is and if we
run this it is now an on modal panel
that we can move around and use just
like any other tab now once you've done
this you need to register your panel
with your layouts otherwise you'll get a
problem if you want to tie this into
your layouts let's try this first so I'm
gonna save this as layout two and now
I'm gonna go back to my layout one and
try layout two again and instead of
getting the panel we get the error that
our specific panel can't be restored
because it's not registered so let's go
back and register it and that's simply
done by calling the nuke scripts
function called register panel and this
is where we use our unique ID from above
so I'm just going to copy that from here
into here and once the layout finds this
panel we'll tell it what to do and that
is just like before adding the panel to
the pain like this callable is doing for
us so we're giving it that here and now
if we run this whole thing and try again
grabbing the panel here saving the
layout and now we should be good to go
swapping between layouts
and our panel is coming along for the
ride