使用ezdxf将尺寸线移动到新图层

Question

I used ezdxf to change the layer name and try to move the entity, but only the dimension line remains on the old layer.

I wrote code to move an entity to a new layer name, but it didn't move.

import ezdxf
import glob
from pathlib import Path
from typing import TYPE_CHECKING, TextIO, Iterable

file_list=glob.glob('./input/*.dxf')
for filename in file_list:
    dwg = ezdxf.readfile(filename,encoding='auto',legacy_mode=False)
    msp = dwg.modelspace()

old_layername1 = 'ABC'
new_layername1 = 'DEF'

try:
    layer = dwg.layers.get(old_layername)
except ValueError:
    print('Layer {} not found.'.format(old_layername))
else:
    layer.dxf.name = new_layername

# move entities in model space to new layer
all_entities_on_old_layer = dwg.modelspace().query('*[layer=="%s"]' % old_layername)
for entity in all_entities_on_old_layer:
    entity.dxf.layer = new_layername  # this assigns the new layer

Only the dimension line remains in the old layer name.

I want to know the solution.

Answer 1

Renaming layers is not implemented in ezdxf. The usage of layers is not bound to the table entries, this means if you rename a layer table entry, all entities of this layer still have the old layer name stored as DXF attribute, remember ezdxf is an interface to DXF file format not a CAD application. In your special case the DIMENSION entity has also a graphical representation as anonymous BLOCK, all entities of this BLOCK may still refer to the old layer name, also some entities of other BLOCKS and paperspace layouts. This is the code to rename a layer and all entities referring to this layer, tested with beta version v0.10:

import ezdxf

def rename_layer(doc, old, new):
    """ 
    Works only for layers with an entry in the layer table, 
    layers can be used without such an entry. 
    """
    if old not in doc.layers:
        raise ValueError('Old layer "{}" does not exist.'.format(old))
    if new in doc.layers:
        raise ValueError('New layer "{}" does already exist.'.format(new))

    def rename_layer_table_entry():
        layer = doc.layers.get(old)
        layer.dxf.name = new
        # this is an internal API call, renaming table entries isn't implemented (yet)
        doc.layers.replace(old, layer)

    def rename_entities_layer_attribute():
        # layer names are case insensitive
        old_lower = old.lower()
        # iterate over all entities of modelspace, paperspace layouts
        # and block definitions
        for e in doc.chain_layouts_and_blocks():
            if e.get_dxf_attrib('layer', '0').lower() == old_lower:
                e.dxf.layer = new


    rename_layer_table_entry()
    rename_entities_layer_attribute()

# TESTING

def add_entities(layout):
    layout.add_text('A', dxfattribs={'layer': 'text'})
    layout.add_line((0, 0), (1, 1), dxfattribs={'layer': 'line'})


doc = ezdxf.new('R2010')
doc.layers.new('text')
doc.layers.new('line')

msp = doc.modelspace()
add_entities(msp)

blk = doc.blocks.new('Test')
add_entities(blk)

rename_layer(doc, 'text', 'text1')
rename_layer(doc, 'line', 'line1')

assert msp[0].dxf.layer == 'text1'
assert msp[1].dxf.layer == 'line1'

assert blk[0].dxf.layer == 'text1'
assert blk[1].dxf.layer == 'line1'

assert 'text1' in doc.layers
assert 'line1' in doc.layers

This function does not care about existing layer filters, which may be broken or frozen layers in viewports and all the things I still don't know. Overall renaming layers is not a good idea and may produce unreadable DXF files.

Update:

Added rename method to Layer , will be released with v0.10b4:

layer = doc.layers.get(old_name)
layer.rename(new_name)

Renames all known layer references, but not for LAYER_INDEX and LAYER_FILTER, both entities are just preserved as a bunch of tags by ezdxf, so be careful - renaming layers with ezdxf may damage DXF files.