blender/release/scripts/startup/bl_operators/node.py

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#
#  This program is free software; you can redistribute it and/or
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#  as published by the Free Software Foundation; either version 2
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#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
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#  along with this program; if not, write to the Free Software Foundation,
#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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# ##### END GPL LICENSE BLOCK #####

# <pep8-80 compliant>

import bpy
from bpy.types import Operator, PropertyGroup
from bpy.props import BoolProperty, CollectionProperty, EnumProperty, IntProperty, StringProperty


class NodeSetting(PropertyGroup):
    value = StringProperty(
            name="Value",
            description="Python expression to be evaluated as the initial node setting",
            default="",
            )

# Base class for node 'Add' operators
class NodeAddOperator():

    type = StringProperty(
            name="Node Type",
            description="Node type",
            )
    use_transform = BoolProperty(
            name="Use Transform",
            description="Start transform operator after inserting the node",
            default=False,
            )
    settings = CollectionProperty(
            name="Settings",
            description="Settings to be applied on the newly created node",
            type=NodeSetting,
            options={'SKIP_SAVE'},
            )

    @staticmethod
    def store_mouse_cursor(context, event):
        space = context.space_data
        v2d = context.region.view2d
        tree = space.edit_tree

        # convert mouse position to the View2D for later node placement
        if context.region.type == 'WINDOW':
            space.cursor_location = v2d.region_to_view(event.mouse_region_x,
                                                   event.mouse_region_y)
        else:
            space.cursor_location = tree.view_center

    def create_node(self, context):
        space = context.space_data
        tree = space.edit_tree

        # select only the new node
        for n in tree.nodes:
            n.select = False

        node = tree.nodes.new(type=self.type)

        for setting in self.settings:
            # XXX catch exceptions here?
            value = eval(setting.value)
                
            try:
                setattr(node, setting.name, value)
            except AttributeError as e:
                self.report({'ERROR_INVALID_INPUT'}, "Node has no attribute "+setting.name)
                print (str(e))
                # Continue despite invalid attribute

        if space.use_hidden_preview:
            node.show_preview = False

        node.select = True
        tree.nodes.active = node
        node.location = space.cursor_location
        return node

    @classmethod
    def poll(cls, context):
        space = context.space_data
        # needs active node editor and a tree to add nodes to
        return (space.type == 'NODE_EDITOR' and space.edit_tree)

    # Default execute simply adds a node
    def execute(self, context):
        self.create_node(context)
        return {'FINISHED'}

    # Default invoke stores the mouse position to place the node correctly
    # and optionally invokes the transform operator
    def invoke(self, context, event):
        self.store_mouse_cursor(context, event)
        result = self.execute(context)

        if self.use_transform and ('FINISHED' in result):
            bpy.ops.transform.translate('INVOKE_DEFAULT')

        return result


# Simple basic operator for adding a node
class NODE_OT_add_node(NodeAddOperator, Operator):
    '''Add a node to the active tree'''
    bl_idname = "node.add_node"
    bl_label = "Add Node"


# Add a node and link it to an existing socket
class NODE_OT_add_and_link_node(NodeAddOperator, Operator):
    '''Add a node to the active tree and link to an existing socket'''
    bl_idname = "node.add_and_link_node"
    bl_label = "Add and Link Node"

    link_socket_index = IntProperty(
            name="Link Socket Index",
            description="Index of the socket to link",
            )

    def execute(self, context):
        space = context.space_data
        ntree = space.edit_tree

        node = self.create_node(context)
        if not node:
            return {'CANCELLED'}

        to_socket = getattr(context, "link_to_socket", None)
        if to_socket:
            ntree.links.new(node.outputs[self.link_socket_index], to_socket)

        from_socket = getattr(context, "link_from_socket", None)
        if from_socket:
            ntree.links.new(from_socket, node.inputs[self.link_socket_index])

        return {'FINISHED'}


def node_classes_iter(base=bpy.types.Node):
    """
    Yields all true node classes by checking for the is_registered_node_type classmethod.
    Node types can use specialized subtypes of bpy.types.Node, which are not usable
    nodes themselves (e.g. CompositorNode).
    """
    if base.is_registered_node_type():
        yield base
    for subclass in base.__subclasses__():
        for node_class in node_classes_iter(subclass):
            yield node_class


def node_class_items_iter(node_class, context):
    identifier = node_class.bl_rna.identifier
    # XXX Checking for explicit group node types is stupid.
    # This should be replaced by a generic system of generating
    # node items via callback.
    # Group node_tree pointer should also use a poll function to filter the library list,
    # but cannot do that without a node instance here. A node callback could just use the internal poll function.
    if identifier in {'ShaderNodeGroup', 'CompositorNodeGroup', 'TextureNodeGroup'}:
        tree_idname = context.space_data.edit_tree.bl_idname
        for group in bpy.data.node_groups:
            if group.bl_idname == tree_idname:
                # XXX empty string should be replaced by description from tree
                yield (group.name, "", {"node_tree": group})
    else:
        yield (node_class.bl_rna.name, node_class.bl_rna.description, {})


def node_items_iter(context):
    snode = context.space_data
    if not snode:
        return
    tree = snode.edit_tree
    if not tree:
        return

    for node_class in node_classes_iter():
        if node_class.poll(tree):
            for item in node_class_items_iter(node_class, context):
                yield (node_class,) + item


# Create an enum list from node class items
def node_type_items_cb(self, context):
    # XXX Python has to keep a ref to those strings, else they may be freed :(
    NODE_OT_add_search._enum_str_store = [(str(index), item[1], item[2])
                                          for index, item in enumerate(node_items_iter(context))]
    return NODE_OT_add_search._enum_str_store


class NODE_OT_add_search(NodeAddOperator, Operator):
    '''Add a node to the active tree'''
    bl_idname = "node.add_search"
    bl_label = "Search and Add Node"
    bl_options = {'REGISTER', 'UNDO'}

    # XXX Python has to keep a ref to the data (strings) generated by enum's callback, else they may be freed :(
    _enum_str_store = []

    # XXX this should be called 'node_type' but the operator search
    # property is hardcoded to 'type' by a hack in bpy_operator_wrap.c ...
    type = EnumProperty(
            name="Node Type",
            description="Node type",
            items=node_type_items_cb,
            )

    def execute(self, context):
        for index, item in enumerate(node_items_iter(context)):
            if str(index) == self.type:
                node = self.create_node(context, item[0].bl_rna.identifier)
                for prop, value in item[3].items():
                    setattr(node, prop, value)
                break
        return {'FINISHED'}

    def invoke(self, context, event):
        self.store_mouse_cursor(context, event)
        # Delayed execution in the search popup
        context.window_manager.invoke_search_popup(self)
        return {'CANCELLED'}


class NODE_OT_collapse_hide_unused_toggle(Operator):
    '''Toggle collapsed nodes and hide unused sockets'''
    bl_idname = "node.collapse_hide_unused_toggle"
    bl_label = "Collapse and Hide Unused Sockets"
    bl_options = {'REGISTER', 'UNDO'}

    @classmethod
    def poll(cls, context):
        space = context.space_data
        # needs active node editor and a tree
        return (space.type == 'NODE_EDITOR' and space.edit_tree)

    def execute(self, context):
        space = context.space_data
        tree = space.edit_tree

        for node in tree.nodes:
            if node.select:
                hide = (not node.hide)

                node.hide = hide
                # Note: connected sockets are ignored internally
                for socket in node.inputs:
                    socket.hide = hide
                for socket in node.outputs:
                    socket.hide = hide

        return {'FINISHED'}


class NODE_OT_tree_path_parent(Operator):
    '''Go to parent node tree'''
    bl_idname = "node.tree_path_parent"
    bl_label = "Parent Node Tree"
    bl_options = {'REGISTER', 'UNDO'}

    @classmethod
    def poll(cls, context):
        space = context.space_data
        # needs active node editor and a tree
        return (space.type == 'NODE_EDITOR' and len(space.path) > 1)

    def execute(self, context):
        space = context.space_data

        space.path.pop()

        return {'FINISHED'}