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

[Dave Coventry]

Damn!

I feel a bit silly.

The entities object is an array.
dwg.object[ent].tio.object->tio.BLOCK_HEADER->entities[0]->obj[0];


On Thu, Dec 2, 2021 at 11:53 AM Dave Coventry <dgcoventry@gmail.com> wrote:
>
> 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