to numerate shapes

[007CPS]

Hello,

I would like to numerate each shape of a selection.
I found a solution by exploring the parameters:

print(selected_shapes())

all_selected_shape = selected_shapes()
print(all_selected_shape[0])
print(all_selected_shape[0].__dict__)

print(all_selected_shape[0]._inkscape_obj)

print(all_selected_shape[0]._transform)

print(type(all_selected_shape[0]._transform.matrix))
print(all_selected_shape[0]._transform.matrix)

print(all_selected_shape[0]._transform.matrix[0])

print(type(all_selected_shape[0]._transform.matrix[0][0]))
print(all_selected_shape[0]._transform.matrix[0][0])

print("positionX:", all_selected_shape[0]._transform.matrix[0][2])
print("positionY:", all_selected_shape[0]._transform.matrix[1][2])

output:

My actual solution is to obtain the coordinates from ._transfrom.
My code is as follows:

   all_selected_shape = selected_shapes()
   n_id = 1
   
   for obj in all_selected_shape:
       obj_x = obj._transform.matrix[0][2]
       obj_y = obj._transform.matrix[1][2]
       
       t = text(f'{n_id}', (obj_x, obj_y), font_size='10pt')
       print(n_id,obj_x,obj_y)
       n_id=n_id+1

In the example of a selected triangle, we have the following coordinates:

the result is shown in the following image:

I guess that the numering is done on the first node.

How can i get correctly the coordinates (in another way than .transform) and on the center of the shape ?

Thanks!

[spakin]

It's possible to iterate over the control points of the underlying inkex object. The center can be computed either manually (by averaging all control points) or by asking the shape's bounding box for its center.

Here's some code to get you started:

for obj in selected_shapes():
    if not isinstance(obj, SimplePathObject):
        continue
    iobj = obj.get_inkex_object()
    for i, ep in enumerate(iobj.get_path().end_points):
        text(str(i + 1), ep, font_size='10pt')
    text('C', iobj.bounding_box().center, font_size='10pt')

[007CPS]

Thanks for your solution. I tried and it works for wide triangle.

but i don't understand why there are several text layers:

Plus, if we take into account thin polygonal shape, it doesn't really work any more

How can we aske for the shape's bounding box?

[spakin]

but i don't understand why there are several text layers:

There aren't; Inkscape is showing you the individual objects within the layer. (That's why the panel is called "Layers and Objects".) You can turn that off—I usually do—by clicking the gear icon at the top of the panel and checking Only show layers.

Plus, if we take into account thin polygonal shape, it doesn't really work any more

What's not working? In your screenshot, C is indeed located at the center of the bounding box containing the thin polygonal shape. For any other definition of "center" you'll need to calculate the point yourself. For example, the following code draws "Ca" at the average endpoint coordinate and, for comparison, "Cb" at the center of the bounding box:

for obj in selected_shapes():
    if not isinstance(obj, SimplePathObject):
        continue
    iobj = obj.get_inkex_object()
    average = inkex.Vector2d(0, 0)
    endpoints = list(iobj.get_path().end_points)
    for i, ep in enumerate(endpoints):
        text(str(i + 1), ep, font_size='10pt')
        average += ep
    average /= len(endpoints)
    text('Ca', average, font_size='10pt')
    text('Cb', iobj.bounding_box().center, font_size='10pt')

Note that "center" is not a uniquely defined geometric property. There are tens of thousands of different centers of triangles according to the Encyclopedia of Triangle Centers. You'll have to think hard about what center you're actually looking for then find/write the Python code to compute it.