I have an operator that I want to have controlled by adjustable parameters when it is invoked. It uses openCV to load an image and then traces the alpha channel of that image to create polygons. I can get it to mostly work, but I don't see Adjust Last Operation panel. Here's the class definition:

class Import_Image_With_Alpha(bpy.types.Operator):
    """Import an image with an alpha channel and trace the outline"""
    bl_idname = "object.import_and_trace_alpha"
    bl_label = "Import and trace alpha"
    bl_options = {'REGISTER', 'UNDO'}

    filepath: bpy.props.StringProperty(subtype="FILE_PATH")

    expansion_pixels: bpy.props.IntProperty(
        name = "expansion_pixels",
        description = "expand border (px)",
        default = 12
    )
    alpha_threshold: bpy.props.FloatProperty(
        name = "alpha_threshold",
        description = "Alpha threshold",
        default = 1
    )
    epsilon: bpy.props.FloatProperty(
        name = "epsilon",
        description = "accuracy",
        default = 0.001
    )

    def invoke(self, context, event):
        context.window_manager.fileselect_add(self)
        print(self.filepath)
        return {'RUNNING_MODAL'}

    def execute(self, context):
        # trace the alpha channel with openCV
        image_data = trace_alpha(self.filepath, self.expansion_pixels, self.alpha_threshold, self.epsilon)
        # sort out the hierarchy of outlines returned by openCV
        outlines = outer_contours(image_data)
        # load the image and create a shader
        image = bpy.data.images.load(self.filepath)
        material = create_material(image)
        for outline in outlines:
            # create the blender objects
            outerPoly = create_blender_polygon(outline, 1.0)
            apply_material(outerPoly, material)
        return {"FINISHED"}
 

def menu_func(self, context):
    self.layout.operator(Import_Image_With_Alpha.bl_idname)

def register():
    install_modules()
    bpy.utils.register_class(Import_Image_With_Alpha)
    bpy.types.TOPBAR_MT_file_import.append(menu_func)

def unregister():
    bpy.utils.unregister_class(Import_Image_With_Alpha)
    bpy.types.TOPBAR_MT_file_import.remove(menu_func)

if __name__ == "__main__":
    register()

I've defined a few properties, like expansion_pixels and alpha_threshold, but I'm unsure why they don't appear with the Adjust Last Operation panel.

I have an Operator defined as ImportImageOperator which calls another operator TraceAlphaOperator but it does not trigger showing the Adjust Last Operation panel for the latter operator. But if I directly call TraceAlphaOperator then it shows the panel. But why not when it is invoked by another operator?

I tried calling bpy.ops.object.trace_alpha(param) from the ImportImageOperator and testing it with both parameters EXEC_DEFAULT and INVOKE_DEFAULT, but nothing works. Initially I had everything in one operator but that did not seem to work due to the import dialog that was in the way. So I decided to split the operation into those two aforementioned operators. This is the script:

import bpy

class TraceAlphaOperator(bpy.types.Operator):
    bl_idname = "object.trace_alpha"
    bl_label = "Trace alpha"
    bl_options = {'REGISTER', 'UNDO'} # 'INTERNAL'}

    threshold: bpy.props.FloatProperty(
        name="Threshold",
        default=1.0,
    )

    def execute(self, context):
        print("Execute TraceAlphaOperator")
        # do stuff like tracing the alpha
        return {'FINISHED'}

class ImportImageOperator(bpy.types.Operator):
    bl_idname = "object.import_image_and_trace"
    bl_label = "Import image and trace alpha"
    bl_options = {'REGISTER', 'UNDO'}

    def execute(self, context):
        print("Execute ImportImageOperator")
        # do stuff like save loaded image and further processing ...
        result = bpy.ops.object.trace_alpha('INVOKE_DEFAULT')
        return result

    def invoke(self, context, event):
        context.window_manager.fileselect_add(self)
        return {'RUNNING_MODAL'}

def register():
    bpy.utils.register_class(ImportImageOperator)
    bpy.utils.register_class(TraceAlphaOperator)

def unregister():
    bpy.utils.unregister_class(ImportImageOperator)
    bpy.utils.unregister_class(TraceAlphaOperator)

if __name__ == "__main__":
    register()

The only workaround I know is to have two separate buttons for the two operators. First, I click one button to invoke ImportImageOperator to load the image, and then I click another button to invoke TraceAlphaOperator to perform the alpha tracing, which also displays the Adjust Last Operation panel. However, I would prefer pressing only one button to load and trace the alpha. Is this not possible?

I have an operator that I want to have controlled by adjustable parameters when it is invoked. It uses openCV to load an image and then traces the alpha channel of that image to create polygons. I can get it to mostly work, but I don't see my parameters in the 3D viewport lower left widget, whatever that's called. Here's the class definition:

I've defined a few properties, like expansion_pixels and alpha_threshold, I'm unsure why they don't appear as parameters.

I have an operator that I want to have controlled by adjustable parameters when it is invoked. It uses openCV to load an image and then traces the alpha channel of that image to create polygons. I can get it to mostly work, but I don't see Adjust Last Operation panel. Here's the class definition:

I've defined a few properties, like expansion_pixels and alpha_threshold, but I'm unsure why they don't appear with the Adjust Last Operation panel.