node_wrangler.py

                    fname = file.name
                    filenamecomponents = split_into__components(fname)
                    matches = set(sname[1]).intersection(set(filenamecomponents))
                    # TODO: ignore basename (if texture is named "fancy_metal_nor", it will be detected as metallic map, not normal map)
                    if matches:
                        sname[2] = fname
                        break

        match_files_to_socket_names()
        # Remove socketnames without found files
        socketnames = [s for s in socketnames if s[2]
                       and path.exists(self.directory+s[2])]
        if not socketnames:
            self.report({'INFO'}, 'No matching images found')
            print('No matching images found')
            return {'CANCELLED'}

        # Don't override path earlier as os.path is used to check the absolute path
        import_path = self.directory
        if self.relative_path:
            if bpy.data.filepath:
                import_path = bpy.path.relpath(self.directory)
            else:
                self.report({'WARNING'}, 'Relative paths cannot be used with unsaved scenes!')
                print('Relative paths cannot be used with unsaved scenes!')

        # Add found images
        print('\nMatched Textures:')
        texture_nodes = []
        disp_texture = None
        normal_node = None
        roughness_node = None
        for i, sname in enumerate(socketnames):
            print(i, sname[0], sname[2])

            # DISPLACEMENT NODES
            if sname[0] == 'Displacement':
                disp_texture = nodes.new(type='ShaderNodeTexImage')
                img = bpy.data.images.load(path.join(import_path, sname[2]))
                disp_texture.image = img
                disp_texture.label = 'Displacement'
                if disp_texture.image:
                    disp_texture.image.colorspace_settings.is_data = True

                # Add displacement offset nodes
                disp_node = nodes.new(type='ShaderNodeDisplacement')
                disp_node.location = active_node.location + Vector((0, -560))
                link = links.new(disp_node.inputs[0], disp_texture.outputs[0])

                # TODO Turn on true displacement in the material
                # Too complicated for now

                # Find output node
                output_node = [n for n in nodes if n.bl_idname == 'ShaderNodeOutputMaterial']
                if output_node:
                    if not output_node[0].inputs[2].is_linked:
                        link = links.new(output_node[0].inputs[2], disp_node.outputs[0])

                continue

            if not active_node.inputs[sname[0]].is_linked:
                # No texture node connected -> add texture node with new image
                texture_node = nodes.new(type='ShaderNodeTexImage')
                img = bpy.data.images.load(path.join(import_path, sname[2]))
                texture_node.image = img

                # NORMAL NODES
                if sname[0] == 'Normal':
                    # Test if new texture node is normal or bump map
                    fname_components = split_into__components(sname[2])
                    match_normal = set(normal_abbr).intersection(set(fname_components))
                    match_bump = set(bump_abbr).intersection(set(fname_components))
                    if match_normal:
                        # If Normal add normal node in between
                        normal_node = nodes.new(type='ShaderNodeNormalMap')
                        link = links.new(normal_node.inputs[1], texture_node.outputs[0])
                    elif match_bump:
                        # If Bump add bump node in between
                        normal_node = nodes.new(type='ShaderNodeBump')
                        link = links.new(normal_node.inputs[2], texture_node.outputs[0])

                    link = links.new(active_node.inputs[sname[0]], normal_node.outputs[0])
                    normal_node_texture = texture_node

                elif sname[0] == 'Roughness':
                    # Test if glossy or roughness map
                    fname_components = split_into__components(sname[2])
                    match_rough = set(rough_abbr).intersection(set(fname_components))
                    match_gloss = set(gloss_abbr).intersection(set(fname_components))

                    if match_rough:
                        # If Roughness nothing to to
                        link = links.new(active_node.inputs[sname[0]], texture_node.outputs[0])

                    elif match_gloss:
                        # If Gloss Map add invert node
                        invert_node = nodes.new(type='ShaderNodeInvert')
                        link = links.new(invert_node.inputs[1], texture_node.outputs[0])

                        link = links.new(active_node.inputs[sname[0]], invert_node.outputs[0])
                        roughness_node = texture_node

                else:
                    # This is a simple connection Texture --> Input slot
                    link = links.new(active_node.inputs[sname[0]], texture_node.outputs[0])

                # Use non-color for all but 'Base Color' Textures
                if not sname[0] in ['Base Color'] and texture_node.image:
                    texture_node.image.colorspace_settings.is_data = True

            else:
                # If already texture connected. add to node list for alignment
                texture_node = active_node.inputs[sname[0]].links[0].from_node

            # This are all connected texture nodes
            texture_nodes.append(texture_node)
            texture_node.label = sname[0]

        if disp_texture:
            texture_nodes.append(disp_texture)

        # Alignment
        for i, texture_node in enumerate(texture_nodes):
            offset = Vector((-550, (i * -280) + 200))
            texture_node.location = active_node.location + offset

        if normal_node:
            # Extra alignment if normal node was added
            normal_node.location = normal_node_texture.location + Vector((300, 0))

        if roughness_node:
            # Alignment of invert node if glossy map
            invert_node.location = roughness_node.location + Vector((300, 0))

        # Add texture input + mapping
        mapping = nodes.new(type='ShaderNodeMapping')
        mapping.location = active_node.location + Vector((-1050, 0))
        if len(texture_nodes) > 1:
            # If more than one texture add reroute node in between
            reroute = nodes.new(type='NodeReroute')
            texture_nodes.append(reroute)
            tex_coords = Vector((texture_nodes[0].location.x, sum(n.location.y for n in texture_nodes)/len(texture_nodes)))
            reroute.location = tex_coords + Vector((-50, -120))
            for texture_node in texture_nodes:
                link = links.new(texture_node.inputs[0], reroute.outputs[0])
            link = links.new(reroute.inputs[0], mapping.outputs[0])
        else:
            link = links.new(texture_nodes[0].inputs[0], mapping.outputs[0])

        # Connect texture_coordiantes to mapping node
        texture_input = nodes.new(type='ShaderNodeTexCoord')
        texture_input.location = mapping.location + Vector((-200, 0))
        link = links.new(mapping.inputs[0], texture_input.outputs[2])

        # Create frame around tex coords and mapping
        frame = nodes.new(type='NodeFrame')
        frame.label = 'Mapping'
        mapping.parent = frame
        texture_input.parent = frame
        frame.update()

        # Create frame around texture nodes
        frame = nodes.new(type='NodeFrame')
        frame.label = 'Textures'
        for tnode in texture_nodes:
            tnode.parent = frame
        frame.update()

        # Just to be sure
        active_node.select = False
        nodes.update()
        links.update()
        force_update(context)
        return {'FINISHED'}


class NWAddReroutes(Operator, NWBase):
    """Add Reroute Nodes and link them to outputs of selected nodes"""
    bl_idname = "node.nw_add_reroutes"
    bl_label = "Add Reroutes"
    bl_description = "Add Reroutes to Outputs"
    bl_options = {'REGISTER', 'UNDO'}

    option: EnumProperty(
        name="option",
        items=[
            ('ALL', 'to all', 'Add to all outputs'),
            ('LOOSE', 'to loose', 'Add only to loose outputs'),
            ('LINKED', 'to linked', 'Add only to linked outputs'),
        ]
    )

    def execute(self, context):
        tree_type = context.space_data.node_tree.type
        option = self.option
        nodes, links = get_nodes_links(context)
        # output valid when option is 'all' or when 'loose' output has no links
        valid = False
        post_select = []  # nodes to be selected after execution
        # create reroutes and recreate links
        for node in [n for n in nodes if n.select]:
            if node.outputs:
                x = node.location.x
                y = node.location.y
                width = node.width
                # unhide 'REROUTE' nodes to avoid issues with location.y
                if node.type == 'REROUTE':
                    node.hide = False
                # When node is hidden - width_hidden not usable.
                # Hack needed to calculate real width
                if node.hide:
                    bpy.ops.node.select_all(action='DESELECT')
                    helper = nodes.new('NodeReroute')
                    helper.select = True
                    node.select = True
                    # resize node and helper to zero. Then check locations to calculate width
                    bpy.ops.transform.resize(value=(0.0, 0.0, 0.0))
                    width = 2.0 * (helper.location.x - node.location.x)
                    # restore node location
                    node.location = x, y
                    # delete helper
                    node.select = False
                    # only helper is selected now
                    bpy.ops.node.delete()
                x = node.location.x + width + 20.0
                if node.type != 'REROUTE':
                    y -= 35.0
                y_offset = -22.0
                loc = x, y
            reroutes_count = 0  # will be used when aligning reroutes added to hidden nodes
            for out_i, output in enumerate(node.outputs):
                pass_used = False  # initial value to be analyzed if 'R_LAYERS'
                # if node != 'R_LAYERS' - "pass_used" not needed, so set it to True
                if node.type != 'R_LAYERS':
                    pass_used = True
                else:  # if 'R_LAYERS' check if output represent used render pass
                    node_scene = node.scene
                    node_layer = node.layer
                    # If output - "Alpha" is analyzed - assume it's used. Not represented in passes.
                    if output.name == 'Alpha':
                        pass_used = True
                    else:
                        # check entries in global 'rl_outputs' variable
                        for rlo in rl_outputs:
                            if output.name in {rlo.output_name, rlo.exr_output_name}:
                                pass_used = getattr(node_scene.view_layers[node_layer], rlo.render_pass)
                                break
                if pass_used:
                    valid = ((option == 'ALL') or
                             (option == 'LOOSE' and not output.links) or
                             (option == 'LINKED' and output.links))
                    # Add reroutes only if valid, but offset location in all cases.
                    if valid:
                        n = nodes.new('NodeReroute')
                        nodes.active = n
                        for link in output.links:
                            links.new(n.outputs[0], link.to_socket)
                        links.new(output, n.inputs[0])
                        n.location = loc
                        post_select.append(n)
                    reroutes_count += 1
                    y += y_offset
                    loc = x, y
            # disselect the node so that after execution of script only newly created nodes are selected
            node.select = False
            # nicer reroutes distribution along y when node.hide
            if node.hide:
                y_translate = reroutes_count * y_offset / 2.0 - y_offset - 35.0
                for reroute in [r for r in nodes if r.select]:
                    reroute.location.y -= y_translate
            for node in post_select:
                node.select = True

        return {'FINISHED'}


class NWLinkActiveToSelected(Operator, NWBase):
    """Link active node to selected nodes basing on various criteria"""
    bl_idname = "node.nw_link_active_to_selected"
    bl_label = "Link Active Node to Selected"
    bl_options = {'REGISTER', 'UNDO'}

    replace: BoolProperty()
    use_node_name: BoolProperty()
    use_outputs_names: BoolProperty()

    @classmethod
    def poll(cls, context):
        valid = False
        if nw_check(context):
            if context.active_node is not None:
                if context.active_node.select:
                    valid = True
        return valid

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        replace = self.replace
        use_node_name = self.use_node_name
        use_outputs_names = self.use_outputs_names
        active = nodes.active
        selected = [node for node in nodes if node.select and node != active]
        outputs = []  # Only usable outputs of active nodes will be stored here.
        for out in active.outputs:
            if active.type != 'R_LAYERS':
                outputs.append(out)
            else:
                # 'R_LAYERS' node type needs special handling.
                # outputs of 'R_LAYERS' are callable even if not seen in UI.
                # Only outputs that represent used passes should be taken into account
                # Check if pass represented by output is used.
                # global 'rl_outputs' list will be used for that
                for rlo in rl_outputs:
                    pass_used = False  # initial value. Will be set to True if pass is used
                    if out.name == 'Alpha':
                        # Alpha output is always present. Doesn't have representation in render pass. Assume it's used.
                        pass_used = True
                    elif out.name in {rlo.output_name, rlo.exr_output_name}:
                        # example 'render_pass' entry: 'use_pass_uv' Check if True in scene render layers
                        pass_used = getattr(active.scene.view_layers[active.layer], rlo.render_pass)
                        break
                if pass_used:
                    outputs.append(out)
        doit = True  # Will be changed to False when links successfully added to previous output.
        for out in outputs:
            if doit:
                for node in selected:
                    dst_name = node.name  # Will be compared with src_name if needed.
                    # When node has label - use it as dst_name
                    if node.label:
                        dst_name = node.label
                    valid = True  # Initial value. Will be changed to False if names don't match.
                    src_name = dst_name  # If names not used - this asignment will keep valid = True.
                    if use_node_name:
                        # Set src_name to source node name or label
                        src_name = active.name
                        if active.label:
                            src_name = active.label
                    elif use_outputs_names:
                        src_name = (out.name, )
                        for rlo in rl_outputs:
                            if out.name in {rlo.output_name, rlo.exr_output_name}:
                                src_name = (rlo.output_name, rlo.exr_output_name)
                    if dst_name not in src_name:
                        valid = False
                    if valid:
                        for input in node.inputs:
                            if input.type == out.type or node.type == 'REROUTE':
                                if replace or not input.is_linked:
                                    links.new(out, input)
                                    if not use_node_name and not use_outputs_names:
                                        doit = False
                                    break

        return {'FINISHED'}


class NWAlignNodes(Operator, NWBase):
    '''Align the selected nodes neatly in a row/column'''
    bl_idname = "node.nw_align_nodes"
    bl_label = "Align Nodes"
    bl_options = {'REGISTER', 'UNDO'}
    margin: IntProperty(name='Margin', default=50, description='The amount of space between nodes')

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        margin = self.margin

        selection = []
        for node in nodes:
            if node.select and node.type != 'FRAME':
                selection.append(node)

        # If no nodes are selected, align all nodes
        active_loc = None
        if not selection:
            selection = nodes
        elif nodes.active in selection:
            active_loc = copy(nodes.active.location)  # make a copy, not a reference

        # Check if nodes should be laid out horizontally or vertically
        x_locs = [n.location.x + (n.dimensions.x / 2) for n in selection]  # use dimension to get center of node, not corner
        y_locs = [n.location.y - (n.dimensions.y / 2) for n in selection]
        x_range = max(x_locs) - min(x_locs)
        y_range = max(y_locs) - min(y_locs)
        mid_x = (max(x_locs) + min(x_locs)) / 2
        mid_y = (max(y_locs) + min(y_locs)) / 2
        horizontal = x_range > y_range

        # Sort selection by location of node mid-point
        if horizontal:
            selection = sorted(selection, key=lambda n: n.location.x + (n.dimensions.x / 2))
        else:
            selection = sorted(selection, key=lambda n: n.location.y - (n.dimensions.y / 2), reverse=True)

        # Alignment
        current_pos = 0
        for node in selection:
            current_margin = margin
            current_margin = current_margin * 0.5 if node.hide else current_margin  # use a smaller margin for hidden nodes

            if horizontal:
                node.location.x = current_pos
                current_pos += current_margin + node.dimensions.x
                node.location.y = mid_y + (node.dimensions.y / 2)
            else:
                node.location.y = current_pos
                current_pos -= (current_margin * 0.3) + node.dimensions.y  # use half-margin for vertical alignment
                node.location.x = mid_x - (node.dimensions.x / 2)

        # If active node is selected, center nodes around it
        if active_loc is not None:
            active_loc_diff = active_loc - nodes.active.location
            for node in selection:
                node.location += active_loc_diff
        else:  # Position nodes centered around where they used to be
            locs = ([n.location.x + (n.dimensions.x / 2) for n in selection]) if horizontal else ([n.location.y - (n.dimensions.y / 2) for n in selection])
            new_mid = (max(locs) + min(locs)) / 2
            for node in selection:
                if horizontal:
                    node.location.x += (mid_x - new_mid)
                else:
                    node.location.y += (mid_y - new_mid)

        return {'FINISHED'}


class NWSelectParentChildren(Operator, NWBase):
    bl_idname = "node.nw_select_parent_child"
    bl_label = "Select Parent or Children"
    bl_options = {'REGISTER', 'UNDO'}

    option: EnumProperty(
        name="option",
        items=(
            ('PARENT', 'Select Parent', 'Select Parent Frame'),
            ('CHILD', 'Select Children', 'Select members of selected frame'),
        )
    )

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        option = self.option
        selected = [node for node in nodes if node.select]
        if option == 'PARENT':
            for sel in selected:
                parent = sel.parent
                if parent:
                    parent.select = True
        else:  # option == 'CHILD'
            for sel in selected:
                children = [node for node in nodes if node.parent == sel]
                for kid in children:
                    kid.select = True

        return {'FINISHED'}


class NWDetachOutputs(Operator, NWBase):
    """Detach outputs of selected node leaving inputs linked"""
    bl_idname = "node.nw_detach_outputs"
    bl_label = "Detach Outputs"
    bl_options = {'REGISTER', 'UNDO'}

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        selected = context.selected_nodes
        bpy.ops.node.duplicate_move_keep_inputs()
        new_nodes = context.selected_nodes
        bpy.ops.node.select_all(action="DESELECT")
        for node in selected:
            node.select = True
        bpy.ops.node.delete_reconnect()
        for new_node in new_nodes:
            new_node.select = True
        bpy.ops.transform.translate('INVOKE_DEFAULT')

        return {'FINISHED'}


class NWLinkToOutputNode(Operator, NWBase):
    """Link to Composite node or Material Output node"""
    bl_idname = "node.nw_link_out"
    bl_label = "Connect to Output"
    bl_options = {'REGISTER', 'UNDO'}

    @classmethod
    def poll(cls, context):
        valid = False
        if nw_check(context):
            if context.active_node is not None:
                for out in context.active_node.outputs:
                    if is_visible_socket(out):
                        valid = True
                        break
        return valid

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        active = nodes.active
        output_node = None
        output_index = None
        tree_type = context.space_data.tree_type
        output_types_shaders = [x[1] for x in shaders_output_nodes_props]
        output_types_compo = ['COMPOSITE']
        output_types_blender_mat = ['OUTPUT']
        output_types_textures = ['OUTPUT']
        output_types = output_types_shaders + output_types_compo + output_types_blender_mat
        for node in nodes:
            if node.type in output_types:
                output_node = node
                break
        if not output_node:
            bpy.ops.node.select_all(action="DESELECT")
            if tree_type == 'ShaderNodeTree':
                output_node = nodes.new('ShaderNodeOutputMaterial')
            elif tree_type == 'CompositorNodeTree':
                output_node = nodes.new('CompositorNodeComposite')
            elif tree_type == 'TextureNodeTree':
                output_node = nodes.new('TextureNodeOutput')
            output_node.location.x = active.location.x + active.dimensions.x + 80
            output_node.location.y = active.location.y
        if (output_node and active.outputs):
            for i, output in enumerate(active.outputs):
                if is_visible_socket(output):
                    output_index = i
                    break
            for i, output in enumerate(active.outputs):
                if output.type == output_node.inputs[0].type and is_visible_socket(output):
                    output_index = i
                    break

            out_input_index = 0
            if tree_type == 'ShaderNodeTree':
                if active.outputs[output_index].name == 'Volume':
                    out_input_index = 1
                elif active.outputs[output_index].type != 'SHADER':  # connect to displacement if not a shader
                    out_input_index = 2
            links.new(active.outputs[output_index], output_node.inputs[out_input_index])

        force_update(context)  # viewport render does not update

        return {'FINISHED'}


class NWMakeLink(Operator, NWBase):
    """Make a link from one socket to another"""
    bl_idname = 'node.nw_make_link'
    bl_label = 'Make Link'
    bl_options = {'REGISTER', 'UNDO'}
    from_socket: IntProperty()
    to_socket: IntProperty()

    def execute(self, context):
        nodes, links = get_nodes_links(context)

        n1 = nodes[context.scene.NWLazySource]
        n2 = nodes[context.scene.NWLazyTarget]

        links.new(n1.outputs[self.from_socket], n2.inputs[self.to_socket])

        force_update(context)

        return {'FINISHED'}


class NWCallInputsMenu(Operator, NWBase):
    """Link from this output"""
    bl_idname = 'node.nw_call_inputs_menu'
    bl_label = 'Make Link'
    bl_options = {'REGISTER', 'UNDO'}
    from_socket: IntProperty()

    def execute(self, context):
        nodes, links = get_nodes_links(context)

        context.scene.NWSourceSocket = self.from_socket

        n1 = nodes[context.scene.NWLazySource]
        n2 = nodes[context.scene.NWLazyTarget]
        if len(n2.inputs) > 1:
            bpy.ops.wm.call_menu("INVOKE_DEFAULT", name=NWConnectionListInputs.bl_idname)
        elif len(n2.inputs) == 1:
            links.new(n1.outputs[self.from_socket], n2.inputs[0])
        return {'FINISHED'}


class NWAddSequence(Operator, NWBase, ImportHelper):
    """Add an Image Sequence"""
    bl_idname = 'node.nw_add_sequence'
    bl_label = 'Import Image Sequence'
    bl_options = {'REGISTER', 'UNDO'}

    directory: StringProperty(
        subtype="DIR_PATH"
    )
    filename: StringProperty(
        subtype="FILE_NAME"
    )
    files: CollectionProperty(
        type=bpy.types.OperatorFileListElement,
        options={'HIDDEN', 'SKIP_SAVE'}
    )

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        directory = self.directory
        filename = self.filename
        files = self.files
        tree = context.space_data.node_tree

        # DEBUG
        # print ("\nDIR:", directory)
        # print ("FN:", filename)
        # print ("Fs:", list(f.name for f in files), '\n')

        if tree.type == 'SHADER':
            node_type = "ShaderNodeTexImage"
        elif tree.type == 'COMPOSITING':
            node_type = "CompositorNodeImage"
        else:
            self.report({'ERROR'}, "Unsupported Node Tree type!")
            return {'CANCELLED'}

        if not files[0].name and not filename:
            self.report({'ERROR'}, "No file chosen")
            return {'CANCELLED'}
        elif files[0].name and (not filename or not path.exists(directory+filename)):
            # User has selected multiple files without an active one, or the active one is non-existant
            filename = files[0].name

        if not path.exists(directory+filename):
            self.report({'ERROR'}, filename+" does not exist!")
            return {'CANCELLED'}

        without_ext = '.'.join(filename.split('.')[:-1])

        # if last digit isn't a number, it's not a sequence
        if not without_ext[-1].isdigit():
            self.report({'ERROR'}, filename+" does not seem to be part of a sequence")
            return {'CANCELLED'}


        extension = filename.split('.')[-1]
        reverse = without_ext[::-1] # reverse string

        count_numbers = 0
        for char in reverse:
            if char.isdigit():
                count_numbers += 1
            else:
                break

        without_num = without_ext[:count_numbers*-1]

        files = sorted(glob(directory + without_num + "[0-9]"*count_numbers + "." + extension))

        num_frames = len(files)

        nodes_list = [node for node in nodes]
        if nodes_list:
            nodes_list.sort(key=lambda k: k.location.x)
            xloc = nodes_list[0].location.x - 220  # place new nodes at far left
            yloc = 0
            for node in nodes:
                node.select = False
                yloc += node_mid_pt(node, 'y')
            yloc = yloc/len(nodes)
        else:
            xloc = 0
            yloc = 0

        name_with_hashes = without_num + "#"*count_numbers + '.' + extension

        bpy.ops.node.add_node('INVOKE_DEFAULT', use_transform=True, type=node_type)
        node = nodes.active
        node.label = name_with_hashes

        img = bpy.data.images.load(directory+(without_ext+'.'+extension))
        img.source = 'SEQUENCE'
        img.name = name_with_hashes
        node.image = img
        image_user = node.image_user if tree.type == 'SHADER' else node
        image_user.frame_offset = int(files[0][len(without_num)+len(directory):-1*(len(extension)+1)]) - 1  # separate the number from the file name of the first  file
        image_user.frame_duration = num_frames

        return {'FINISHED'}


class NWAddMultipleImages(Operator, NWBase, ImportHelper):
    """Add multiple images at once"""
    bl_idname = 'node.nw_add_multiple_images'
    bl_label = 'Open Selected Images'
    bl_options = {'REGISTER', 'UNDO'}
    directory: StringProperty(
        subtype="DIR_PATH"
    )
    files: CollectionProperty(
        type=bpy.types.OperatorFileListElement,
        options={'HIDDEN', 'SKIP_SAVE'}
    )

    def execute(self, context):
        nodes, links = get_nodes_links(context)

        xloc, yloc = context.region.view2d.region_to_view(context.area.width/2, context.area.height/2)

        if context.space_data.node_tree.type == 'SHADER':
            node_type = "ShaderNodeTexImage"
        elif context.space_data.node_tree.type == 'COMPOSITING':
            node_type = "CompositorNodeImage"
        else:
            self.report({'ERROR'}, "Unsupported Node Tree type!")
            return {'CANCELLED'}

        new_nodes = []
        for f in self.files:
            fname = f.name

            node = nodes.new(node_type)
            new_nodes.append(node)
            node.label = fname
            node.hide = True
            node.width_hidden = 100
            node.location.x = xloc
            node.location.y = yloc
            yloc -= 40

            img = bpy.data.images.load(self.directory+fname)
            node.image = img

        # shift new nodes up to center of tree
        list_size = new_nodes[0].location.y - new_nodes[-1].location.y
        for node in nodes:
            if node in new_nodes:
                node.select = True
                node.location.y += (list_size/2)
            else:
                node.select = False
        return {'FINISHED'}


class NWViewerFocus(bpy.types.Operator):
    """Set the viewer tile center to the mouse position"""
    bl_idname = "node.nw_viewer_focus"
    bl_label = "Viewer Focus"

    x: bpy.props.IntProperty()
    y: bpy.props.IntProperty()

    @classmethod
    def poll(cls, context):
        return nw_check(context) and context.space_data.tree_type == 'CompositorNodeTree'

    def execute(self, context):
        return {'FINISHED'}

    def invoke(self, context, event):
        render = context.scene.render
        space = context.space_data
        percent = render.resolution_percentage*0.01

        nodes, links = get_nodes_links(context)
        viewers = [n for n in nodes if n.type == 'VIEWER']

        if viewers:
            mlocx = event.mouse_region_x
            mlocy = event.mouse_region_y
            select_node = bpy.ops.node.select(mouse_x=mlocx, mouse_y=mlocy, extend=False)

            if not 'FINISHED' in select_node:  # only run if we're not clicking on a node
                region_x = context.region.width
                region_y = context.region.height

                region_center_x = context.region.width  / 2
                region_center_y = context.region.height / 2

                bd_x = render.resolution_x * percent * space.backdrop_zoom
                bd_y = render.resolution_y * percent * space.backdrop_zoom

                backdrop_center_x = (bd_x / 2) - space.backdrop_offset[0]
                backdrop_center_y = (bd_y / 2) - space.backdrop_offset[1]

                margin_x = region_center_x - backdrop_center_x
                margin_y = region_center_y - backdrop_center_y

                abs_mouse_x = (mlocx - margin_x) / bd_x
                abs_mouse_y = (mlocy - margin_y) / bd_y

                for node in viewers:
                    node.center_x = abs_mouse_x
                    node.center_y = abs_mouse_y
            else:
                return {'PASS_THROUGH'}

        return self.execute(context)


class NWSaveViewer(bpy.types.Operator, ExportHelper):
    """Save the current viewer node to an image file"""
    bl_idname = "node.nw_save_viewer"
    bl_label = "Save This Image"
    filepath: StringProperty(subtype="FILE_PATH")
    filename_ext: EnumProperty(
            name="Format",
            description="Choose the file format to save to",
            items=(('.bmp', "BMP", ""),
                   ('.rgb', 'IRIS', ""),
                   ('.png', 'PNG', ""),
                   ('.jpg', 'JPEG', ""),
                   ('.jp2', 'JPEG2000', ""),
                   ('.tga', 'TARGA', ""),
                   ('.cin', 'CINEON', ""),
                   ('.dpx', 'DPX', ""),
                   ('.exr', 'OPEN_EXR', ""),
                   ('.hdr', 'HDR', ""),
                   ('.tif', 'TIFF', "")),
            default='.png',
            )

    @classmethod
    def poll(cls, context):
        valid = False
        if nw_check(context):
            if context.space_data.tree_type == 'CompositorNodeTree':
                if "Viewer Node" in [i.name for i in bpy.data.images]:
                    if sum(bpy.data.images["Viewer Node"].size) > 0:  # False if not connected or connected but no image
                        valid = True
        return valid

    def execute(self, context):
        fp = self.filepath
        if fp:
            formats = {
                       '.bmp': 'BMP',
                       '.rgb': 'IRIS',
                       '.png': 'PNG',
                       '.jpg': 'JPEG',
                       '.jpeg': 'JPEG',
                       '.jp2': 'JPEG2000',
                       '.tga': 'TARGA',
                       '.cin': 'CINEON',
                       '.dpx': 'DPX',
                       '.exr': 'OPEN_EXR',
                       '.hdr': 'HDR',
                       '.tiff': 'TIFF',
                       '.tif': 'TIFF'}
            basename, ext = path.splitext(fp)
            old_render_format = context.scene.render.image_settings.file_format
            context.scene.render.image_settings.file_format = formats[self.filename_ext]
            context.area.type = "IMAGE_EDITOR"
            context.area.spaces[0].image = bpy.data.images['Viewer Node']
            context.area.spaces[0].image.save_render(fp)
            context.area.type = "NODE_EDITOR"
            context.scene.render.image_settings.file_format = old_render_format
            return {'FINISHED'}


class NWResetNodes(bpy.types.Operator):
    """Reset Nodes in Selection"""
    bl_idname = "node.nw_reset_nodes"
    bl_label = "Reset Nodes"
    bl_options = {'REGISTER', 'UNDO'}

    @classmethod
    def poll(cls, context):
        space = context.space_data
        return space.type == 'NODE_EDITOR'

    def execute(self, context):
        node_active = context.active_node
        node_selected = context.selected_nodes
        node_ignore = ["FRAME","REROUTE", "GROUP"]

        # Check if one node is selected at least
        if not (len(node_selected) > 0):
            self.report({'ERROR'}, "1 node must be selected at least")
            return {'CANCELLED'}

        active_node_name = node_active.name if node_active.select else None
        valid_nodes = [n for n in node_selected if n.type not in node_ignore]

        # Create output lists
        selected_node_names = [n.name for n in node_selected]
        success_names = []

        # Reset all valid children in a frame
        node_active_is_frame = False
        if len(node_selected) == 1 and node_active.type == "FRAME":
            node_tree = node_active.id_data
            children = [n for n in node_tree.nodes if n.parent == node_active]
            if children:
                valid_nodes = [n for n in children if n.type not in node_ignore]
                selected_node_names = [n.name for n in children if n.type not in node_ignore]
                node_active_is_frame = True

        # Check if valid nodes in selection
        if not (len(valid_nodes) > 0):
            # Check for frames only
            frames_selected = [n for n in node_selected if n.type == "FRAME"]
            if (len(frames_selected) > 1 and len(frames_selected) == len(node_selected)):
                self.report({'ERROR'}, "Please select only 1 frame to reset")
            else:
                self.report({'ERROR'}, "No valid node(s) in selection")
            return {'CANCELLED'}

        # Report nodes that are not valid
        if len(valid_nodes) != len(node_selected) and node_active_is_frame is False:
            valid_node_names = [n.name for n in valid_nodes]
            not_valid_names = list(set(selected_node_names) - set(valid_node_names))
            self.report({'INFO'}, "Ignored {}".format(", ".join(not_valid_names)))

        # Deselect all nodes
        for i in node_selected:
            i.select = False

        # Run through all valid nodes
        for node in valid_nodes:

            parent = node.parent if node.parent else None
            node_loc = [node.location.x, node.location.y]

            node_tree = node.id_data
            props_to_copy = 'bl_idname name location height width'.split(' ')

            reconnections = []
            mappings = chain.from_iterable([node.inputs, node.outputs])
            for i in (i for i in mappings if i.is_linked):
                for L in i.links:
                    reconnections.append([L.from_socket.path_from_id(), L.to_socket.path_from_id()])

            props = {j: getattr(node, j) for j in props_to_copy}

            new_node = node_tree.nodes.new(props['bl_idname'])
            props_to_copy.pop(0)

            for prop in props_to_copy:
                setattr(new_node, prop, props[prop])

            nodes = node_tree.nodes
            nodes.remove(node)
            new_node.name = props['name']

            if parent:
                new_node.parent = parent
                new_node.location = node_loc

            for str_from, str_to in reconnections:
                node_tree.links.new(eval(str_from), eval(str_to))

            new_node.select = False
            success_names.append(new_node.name)

        # Reselect all nodes
        if selected_node_names and node_active_is_frame is False:
            for i in selected_node_names:
                node_tree.nodes[i].select = True

        if active_node_name is not None:
            node_tree.nodes[active_node_name].select = True
            node_tree.nodes.active = node_tree.nodes[active_node_name]

        self.report({'INFO'}, "Successfully reset {}".format(", ".join(success_names)))
        return {'FINISHED'}


#
#  P A N E L
#

def drawlayout(context, layout, mode='non-panel'):
    tree_type = context.space_data.tree_type

    col = layout.column(align=True)
    col.menu(NWMergeNodesMenu.bl_idname)
    col.separator()

    col = layout.column(align=True)
    col.menu(NWSwitchNodeTypeMenu.bl_idname, text="Switch Node Type")
    col.separator()

    if tree_type == 'ShaderNodeTree':
        col = layout.column(align=True)
        col.operator(NWAddTextureSetup.bl_idname, text="Add Texture Setup", icon='NODE_SEL')
        col.operator(NWAddPrincipledSetup.bl_idname, text="Add Principled Setup", icon='NODE_SEL')
        col.separator()

    col = layout.column(align=True)
    col.operator(NWDetachOutputs.bl_idname, icon='UNLINKED')
    col.operator(NWSwapLinks.bl_idname)
    col.menu(NWAddReroutesMenu.bl_idname, text="Add Reroutes", icon='LAYER_USED')
    col.separator()

    col = layout.column(align=True)
    col.menu(NWLinkActiveToSelectedMenu.bl_idname, text="Link Active To Selected", icon='LINKED')
    col.operator(NWLinkToOutputNode.bl_idname, icon='DRIVER')
    col.separator()

    col = layout.column(align=True)
    if mode == 'panel':