If its written in python can be found with a little digging.
The key here is in the menu, you are defining which operator to use to execute presets
preset_operator = "script.execute_preset"
If we can find it in bpy.types then it has a python module
>>> bpy.ops.script.execute_preset.idname()
'SCRIPT_OT_execute_preset'
>>> bpy.types.SCRIPT_OT_execute_preset.__module__
'bl_operators.presets'
and there it is in 2.91/scripts/startup/bl_operators/presets.py
class ExecutePreset(Operator):
"""Execute a preset"""
bl_idname = "script.execute_preset"
bl_label = "Execute a Python Preset"
filepath: StringProperty(
subtype='FILE_PATH',
options={'SKIP_SAVE'},
)
menu_idname: StringProperty(
name="Menu ID Name",
description="ID name of the menu this was called from",
options={'SKIP_SAVE'},
)
def execute(self, context):
from os.path import basename, splitext
filepath = self.filepath
# change the menu title to the most recently chosen option
preset_class = getattr(bpy.types, self.menu_idname)
preset_class.bl_label = bpy.path.display_name(basename(filepath))
ext = splitext(filepath)[1].lower()
if ext not in {".py", ".xml"}:
self.report({'ERROR'}, "unknown filetype: %r" % ext)
return {'CANCELLED'}
if hasattr(preset_class, "reset_cb"):
preset_class.reset_cb(context)
if ext == ".py":
try:
bpy.utils.execfile(filepath)
except Exception as ex:
self.report({'ERROR'}, "Failed to execute the preset: " + repr(ex))
elif ext == ".xml":
import rna_xml
rna_xml.xml_file_run(context,
filepath,
preset_class.preset_xml_map)
if hasattr(preset_class, "post_cb"):
preset_class.post_cb(context)
return {'FINISHED'}
re-write another operator, using same properties, to do whatever floats your boat when your preset is loaded, and tell the system to use it instead
preset_operator = "script.execute_preset_float_boat_version"
Ok, since we are no longer using the default operator, we can set the defaults for the operator in the draw preset method of menu class
>>> bpy.types.Menu.draw_preset(
draw_preset(self, _context)
Define these on the subclass:
- preset_operator (string)
- preset_subdir (string)
Optionally:
- preset_add_operator (string)
- preset_extensions (set of strings)
- preset_operator_defaults (dict of keyword args)
Define the callbacks
Looking at the operator code, notice two callback functions are run, one before the preset is loaded reset_cb and one after post_cb. Have added these two classmethods to Menu to print to console when called.
so in full
import bpy
from bpy.types import Operator, Menu
from bl_operators.presets import AddPresetBase
from bpy.props import StringProperty
class ExecutePreset(Operator):
"""Execute a preset"""
bl_idname = "script.execute_preset_float_boat"
bl_label = "Execute a Python Preset"
filepath: StringProperty(
subtype='FILE_PATH',
options={'SKIP_SAVE'},
)
menu_idname: StringProperty(
name="Menu ID Name",
description="ID name of the menu this was called from",
options={'SKIP_SAVE'},
)
def execute(self, context):
from os.path import basename, splitext
filepath = self.filepath
# change the menu title to the most recently chosen option
preset_class = getattr(bpy.types, self.menu_idname)
preset_class.bl_label = bpy.path.display_name(basename(filepath))
ext = splitext(filepath)[1].lower()
if ext not in {".py", ".xml"}:
self.report({'ERROR'}, "unknown filetype: %r" % ext)
return {'CANCELLED'}
if hasattr(preset_class, "reset_cb"):
preset_class.reset_cb(context)
if ext == ".py":
try:
bpy.utils.execfile(filepath)
except Exception as ex:
self.report({'ERROR'}, "Failed to execute the preset: " + repr(ex))
elif ext == ".xml":
import rna_xml
rna_xml.xml_file_run(context,
filepath,
preset_class.preset_xml_map)
if hasattr(preset_class, "post_cb"):
preset_class.post_cb(context)
return {'FINISHED'}
class OBJECT_MT_display_presets(Menu):
bl_label = "Object Display Presets"
preset_subdir = "object/display"
preset_operator = "script.execute_preset_float_boat"
preset_operator_defaults = {
"menu_idname" : 'OBJECT_MT_display_presets'
}
draw = Menu.draw_preset
@classmethod
def reset_cb(self, context):
print("Reset")
@classmethod
def post_cb(self, context):
print("Post Callback")
class AddPresetObjectDisplay(AddPresetBase, Operator):
'''Add a Object Display Preset'''
bl_idname = "camera.object_display_preset_add"
bl_label = "Add Object Display Preset"
preset_menu = "OBJECT_MT_display_presets"
# variable used for all preset values
preset_defines = [
"obj = bpy.context.object"
]
# properties to store in the preset
preset_values = [
"obj.display_type",
"obj.show_bounds",
"obj.display_bounds_type",
"obj.show_name",
"obj.show_axis",
"obj.show_wire",
]
# where to store the preset
preset_subdir = "object/display"
# Display into an existing panel
def panel_func(self, context):
layout = self.layout
row = layout.row(align=True)
row.menu(OBJECT_MT_display_presets.__name__, text=OBJECT_MT_display_presets.bl_label)
row.operator(AddPresetObjectDisplay.bl_idname, text="", icon='ZOOM_IN')
row.operator(AddPresetObjectDisplay.bl_idname, text="", icon='ZOOM_OUT').remove_active = True
classes = (
ExecutePreset,
OBJECT_MT_display_presets,
AddPresetObjectDisplay,
)
def register():
for cls in classes:
bpy.utils.register_class(cls)
bpy.types.OBJECT_PT_display.prepend(panel_func)
def unregister():
for cls in classes:
bpy.utils.unregister_class(cls)
bpy.types.OBJECT_PT_display.remove(panel_func)
if __name__ == "__main__":
register()
