Thanks Ferdinand.
with info=c4d.PLUGINFLAG_TOOL_EDITSTATES everything works fine.

I mark your answer as correct.
is it the right way to set the topic as solved?

@ferdinand
Thanks.
I will be away in the next days.
I will try it as soon as possible and inform you about the result.

P.S . when the "info" is set as in your example, the isoline editing checkbox in the viewport configuration is automatically seen by the plugin or I have to configure the basedraw setting in the code?

@ferdinand
Hi,
here's the code ( a simplified version but with the same problem )

import c4d, os, sys, pprint, itertools, math, random, time
from dataclasses import dataclass, field
from typing import List
from itertools import islice
from c4d import plugins, gui
from c4d import utils as u
from c4d import Vector as vc

# Be sure to use a unique ID obtained from www.plugincafe.com
TOOL_PLUGIN_ID = 1045691
GET_KEYS = False
DEBUG = False


class TimeController(object):
    """This object makes sure to sleep as long as necessary to keep a specific
    time-rate."""

    def __init__(self, twait):
        self.twait = twait
        self.lastCall = 0

    def __call__(self):
        t = time.process_time()
        delta = t - self.lastCall
        if delta < self.twait:
            time.sleep(self.twait - delta)
        self.lastCall = time.process_time()


class ToolSelector(c4d.plugins.ToolData):
    def __init__(self):
        self.obj = None
        self.base_select = None
        self.mouseCoordinate = None
        self.direction = None
        self.poly_sel_array = []
        self.pick_data = False
        self.selector_tag = None

    def InitTool(self, doc, data, bt):
        self.mouseCoordinate = None
        self.direction = None
        self.pick_data = False
        self.poly_sel_array = []
        self.selector_tag = None
        self.obj = None

        return True

    def InitObject(self, doc):
        if self.obj:
            self.base_select = self.obj.GetPolygonS()
            doc.SetActiveObject(self.obj, 0)
            doc.SetMode(c4d.Mpolygons)

        c4d.EventAdd()

        return True


    def FreeTool(self, doc, data):
        self.obj = None

    def GetState(self, doc):
        return c4d.CMD_ENABLED

    def Debug(self, msg):
        c4d.CallCommand(13957)  # Konsole loeschen

        return True

    def KeyboardInput(self, doc, data, bd, win, msg):
        key = msg.GetInt32(c4d.BFM_INPUT_CHANNEL)
        cstr = msg.GetString(c4d.BFM_INPUT_ASC)
        mod = msg.GetInt32(c4d.BFM_INPUT_QUALIFIER)


        if key == c4d.KEY_ESC:
            c4d.CallCommand(300001111)

            return True


        elif msg[c4d.BFM_INPUT_ASC] == "\t":
            self.pick_data = True
            c4d.DrawViews(
                    c4d.DRAWFLAGS_ONLY_ACTIVE_VIEW
                    | c4d.DRAWFLAGS_NO_THREAD
                    | c4d.DRAWFLAGS_NO_ANIMATION
                )
            c4d.EventAdd()

            return True

        return False

    def CallViewportSelect(self, viewport_select, bd, doc):
        frame = bd.GetFrame()
        w = frame["cr"] - frame["cl"] + 1
        h = frame["cb"] - frame["ct"] + 1

        viewport_select.Init(
            w,
            h,
            bd,
            [self.obj],
            c4d.Mpolyedgepoint,
            True,
            c4d.VIEWPORTSELECTFLAGS_USE_HN | c4d.VIEWPORTSELECTFLAGS_USE_DEFORMERS | c4d.VIEWPORTSELECTFLAGS_FORCE_USE_DEFORMERS,
        )

    def MouseInput(self, doc, data, bd, win, msg):
        if not self.obj:
            self.obj = doc.GetActiveObject() if doc.GetActiveObject() else None

            if self.obj:
                self.InitObject(doc)
            else:
                return True

        bc = c4d.BaseContainer()
        pick_poly = None

        mouse_x = msg[c4d.BFM_INPUT_X]
        mouse_y = msg[c4d.BFM_INPUT_Y]

        myPoint = c4d.Vector(mouse_x, mouse_y, 0)

        viewport_select = c4d.utils.ViewportSelect()
        self.CallViewportSelect(viewport_select, bd, doc)

        win.MouseDragStart(c4d.KEY_MLEFT, mouse_x, mouse_y, c4d.MOUSEDRAGFLAGS_DONTHIDEMOUSE)

        if msg[c4d.BFM_INPUT_QUALIFIER] != c4d.QSHIFT:
            self.base_select.DeselectAll()
            self.poly_sel_array = []

        controller = TimeController(40 / 1000)

        while True:
            controller()

            result, m_deltax, m_deltay, channels = win.MouseDrag()
            delta = c4d.Vector(m_deltax, m_deltay, 0)
            myPoint = myPoint + delta

            if result == c4d.MOUSEDRAGRESULT_CONTINUE:
                self.dragging = True

                pick_poly = viewport_select.GetNearestPolygon(self.obj, int(myPoint.x), int(myPoint.y))

                if pick_poly["i"] not in self.poly_sel_array:
                    self.poly_sel_array.append(pick_poly["i"])

                doc.AddUndo(c4d.UNDOTYPE_CHANGE_SELECTION, self.obj)
                self.base_select.Select(pick_poly["i"])

                c4d.DrawViews(
                    c4d.DRAWFLAGS_ONLY_ACTIVE_VIEW
                    | c4d.DRAWFLAGS_NO_THREAD
                    | c4d.DRAWFLAGS_NO_ANIMATION
                )

            elif result in (c4d.MOUSEDRAGRESULT_FINISHED, c4d.MOUSEDRAGRESULT_ESCAPE):
                self.dragging = False
                break

        win.MouseDragEnd()

        if pick_poly:
            if pick_poly["i"] not in self.poly_sel_array:
                self.poly_sel_array.append(pick_poly["i"])

        c4d.EventAdd()

        return True

    def Draw(self, doc, data, bd, bh, bt, flags):

        return c4d.DRAWRESULT_OK

    def GetCursorInfo(self, doc, data, bd, x, y, bc):
        if bc.GetId() == c4d.BFM_CURSORINFO_REMOVE:
            self.mouseCoordinate = c4d.Vector(-1)
            return True

        c4d.DrawViews()

        self.mouseCoordinate = c4d.Vector(x, y, 0)

        if self.pick_data:
            mouse_x = x
            mouse_y = y

            viewport_select = c4d.utils.ViewportSelect()

            pick_objects = viewport_select.PickObject(
                bd, doc, int(mouse_x), int(mouse_y), rad=0, flags=c4d.VIEWPORT_PICK_FLAGS_0
            )

            if pick_objects:
                if pick_objects[0] != self.obj:
                    self.poly_sel_array = []

                self.obj = pick_objects[0]

                while not isinstance(self.obj, c4d.PolygonObject):
                    self.obj = ObjectData(self.obj.GetDown())


                self.InitObject(doc)
                self.pick_data = False

            c4d.EventAdd()
            return True

        return True

    def AllocSubDialog(self, bc):

        return SettingsDialog(None)


if __name__ == "__main__":

    plugins.RegisterToolPlugin(
        id=TOOL_PLUGIN_ID,
        str="Tool Selector",
        info=0,
        icon=None,
        help="tool selector",
        dat=ToolSelector(),
    )

and two images to show what I'm trying to reach:

with Mpolygons mode and the move tool active:

and when my tool is active:

what I meant with "expanding" is creating a tool that can remember the selection order of polygons.
and use this selection for custom functions.

thanks again
please tell me if you need more information

@ferdinand sorry to bother you again.
I think I'm not able to exactly describe my request, maybe it's my poor english or bad terminology

I'm trying to create a tool plugin for expanding the selection tool with custom functionality.
And when I switch to it, the isoline editing (still enabled in the basedraw) seems disabled in the viewport.

If I edit a polygon object under HN I'd like to have the same display that I have with the move tool, but I have the same display of the loop cut tool. I don't know if it's possible or where I have to set a specific option (maybe in the draw method ?)

I added this:

print(bd[c4d.BASEDRAW_DATA_SDSEDIT])
print(bd.IsViewOpen(doc))

in the Draw and MouseInput method and the result is always 1 and True

I'm using ViewportSelect GetNearestPolygon to select the polygon under the mouse.

I hope it's everything clear...

thank you

Thank you.
But I realise I used the wrong option.
I was trying to enable the isoline editing while in polygon mode inside my tool.
I know that some tools, like Loop cut for example, are not using isoline display, but I don't know if it's a choice or is it impossible to enable it.
While using my tool, in the viewport settings the option is enabled, but I think it also depends on some unknown features

Sorry for the confusion.
Do you need me to change the post title?

Hi, I'v searched the forum but I didn't find any solution.
I'm developing a tool plugin with python for polygon manipulation.
Is it possible to enable deformed isonline editing in the viewport for the selected object under a HN?

thanks

edit [ferdinand]: changed the title the word in the question

Thanks a lot !!!.
I will try it in the next days.
I'm free for my personal projects only during weekends

I don't know exactly how and why, but I found the solution.
setting the basedraw matrix relative to the object when deformer is selected

It's not a clean solution, but I cannot understand the hierarchy cache problem

the modified method is:

def DrawPolyNormals(self, obj):
        for p, n in zip(self.objPolysCenter, self.objPolysNormal):
            mx = self.mx
            if obj.GetDown():
                if obj.GetDown().GetBit(c4d.BIT_ACTIVE):
                    self.basedraw.SetMatrix_Matrix(None, mx)
                else:
                    self.basedraw.SetMatrix_Matrix(None, c4d.Matrix())
            normalDistance = n * self.normalLength
            q = p
            r = q + normalDistance * c4d.Matrix(v1=~mx.v1, v2=~mx.v2, v3=~mx.v3)
            self.basedraw.DrawLine(q, r, 0)

the object points global position are calculated in self.objPolysCenter:

def polysCenter(self, local=False):
        polys = self.polyPlgList
        pts = self.polyPtsList
        nbPolys = self.polyPlgCount
        center = vc()

        for i, poly in enumerate(self.polyPlgList):
            if poly.c != poly.d:
                center = (pts[poly.a] + pts[poly.b] + pts[poly.c] + pts[poly.d]) / 4
            else:
                center = (pts[poly.a] + pts[poly.b] + pts[poly.c]) / 3
            if not local:
                yield center * self.mx
            else:
                yield center

@zipit
I can wait, no hurry

Just to let you know...the same problem occurs with polygonal object and deformer
everything's correct in world center but as soon as I move the object it seems that the matrix are calculated 2 times.
It seems a cache issue

I'm checking the link provided

cheers

@zipit
Thanks

I corrected the matrix calculation as suggested but the problem persist.
I'll try to check the cache issue thread you linked

for now I upload the plugin...it's very messy I think, but I use it also for testing other things ;):
PLUGIN

I also attach 2 screenshots of the problem

when there is no deformer everything's correct (with base object and polygonal object):

as soon as I put a deformer below the lines shift away:

the same problem occurs when I change the deformer alignment to other planes and fit to parent:

thanks for the support