Re: [libredwg] Entities in Paperspace are appearing in Modelspace.

[Dave Coventry]

I'm sort of a little further on on this.

Debugging with GDB, I can list the contents of a dwg element:
(gdb) p dwg.object[29730]
$1 = {size = 85, address = 4890, type = 49, index = 29730, fixedtype =
DWG_TYPE_BLOCK_HEADER, name = 0x7ffff7e4167c "BLOCK_HEADER",
 dxfname = 0x7ffff7e4167c "BLOCK_HEADER", supertype =
DWG_SUPERTYPE_OBJECT, tio = {entity = 0x55555667c330, object =
0x55555667c330}, handle = {
   code = 0 '\000', size = 3 '\003', value = 2587925, is_global = 0
'\000'}, parent = 0x555555558040 <dwg>, klass = 0x0, bitsize = 314,
bitsize_pos = 10,
 hdlpos = 314, was_bitsize_set = 0 '\000', has_strings = 1 '\001',
stringstream_size = 206, handlestream_size = 366, common_size = 37,
 num_unknown_bits = 0, unknown_bits = 0x0}
(gdb)

If I tab the BLOCK_HEADER object, I get these struct objects:

(gdb) p dwg.object[29730].tio.object.tio.BLOCK_HEADER.
__iterator        block_scaling     first_entity      insert_units
 last_entity       num_owned         xref
anonymous         description       flag              inserts
 layout            parent            xref_pname
base_pt           endblk_entity     flag2             is_xref_dep
 loaded_bit        preview           xrefoverlaid
blkisxref         entities          flag3             is_xref_ref
 name              preview_size
block_entity      explodable        hasattrs          is_xref_resolved
 num_inserts       used
(gdb)

So, if I print the num_owned value, it tells me that there are 7 items
in the block.
(gdb) p dwg.object[29730].tio.object.tio.BLOCK_HEADER.num_owned
$4 = 7
(gdb)

So far so good.

One of the struct elements is called "entities". And, if I tab this,
it lists 3 further struct elements:
(gdb) p dwg.object[29730].tio.object.tio.BLOCK_HEADER.entities.
absolute_ref  handleref     obj
(gdb)

Now, if I treat the obj element as an array, it gives me the entities
comprising the block.
(gdb) p dwg.object[29730].tio.object.tio.BLOCK_HEADER.entities.obj[0]
$6 = {size = 169, address = 227700, type = 34, index = 29951,
fixedtype = DWG_TYPE_VIEWPORT, name = 0x7ffff7e414dd "VIEWPORT",
 dxfname = 0x7ffff7e414dd "VIEWPORT", supertype =
DWG_SUPERTYPE_ENTITY, tio = {entity = 0x5555566efd60, object =
0x5555566efd60}, handle = {
   code = 0 '\000', size = 3 '\003', value = 2588152, is_global = 0
'\000'}, parent = 0x555555558040 <dwg>, klass = 0x0, bitsize = 1177,
 bitsize_pos = 10, hdlpos = 1177, was_bitsize_set = 0 '\000',
has_strings = 1 '\001', stringstream_size = 2, handlestream_size =
175, common_size = 71,
 num_unknown_bits = 0, unknown_bits = 0x0}
(gdb)

Great! So the first item in the block (which is a Paperspace entity)
is a VIEWPORT object which I should be able to access from this.

But, it doesn't work that way.
Dwg_Object_Ref *
entities=dwg.object[ent].tio.object->tio.BLOCK_HEADER->entities; ←
this generates errors which say"Member reference base type 'BITCODE_H'
(aka 'struct _dwg_object_ref *') is not a structure or a union."

Any help would be appreciated.

~ Dave


On Tue, Nov 30, 2021 at 3:55 PM Dave Coventry <dgcoventry@gmail.com> wrote:
>
> For some reason, entities which shoud appear in Paperspace BLOCK areas
> are in the ENTITIES area, which means that they are rendered in
> Modelspace.
>
> How do I find the value of the 330 DXF code of an entity?
>
> The drawing has 3 Paperspace tabs in addition to Modelspace.
>
> *Paper_Space1 and *Paper_Space2 both have entries in the BLOCKS
> SECTION and the entities which belong to these spaces appear before
> the ENDBLK in each block portion.
>
> These entities display which Paperspace BLOCK_HEASER they belong to
> using the structure
> dwg.object[index]->tio.entity->ownerhandle->handleref.value;
>
> So far so good.
>
> However, *Paper_Space does not have a BLOCK entry in the BLOCKS
> SECTION and they are simply listed in the ENTITIES SECTION, albeit
> with a 330 DXF Code which references the *Paper_Space BLOCK_HEADER.
> So dwg.object[index]->tio.entity->ownerhandle is zero and
> dwg.object[index]->tio.entity->ownerhandle->handleref.value; is
> inaccessible.
>
> Hence these entities (which includes VIEWPORT entities) appear in
> model space when they should appear in *Paper_Space.
>
> If I examine the drawing converted to DXF, the 330 DXF code correctly
> identifies the BLOCK_HEADER handle of the *Paper_Space block.
>
> How do I extract the 330 code?
>
> Many Thanks,
>
> ~Dave