yang686526

oddbentity, oddbcurve and subclasses

oddbentity, oddbcurve and subclasses
hi all,
i'm writing my own entity drawer, but i have a great problem:
how can i understand the type of oddbentity i found in database?
when i understand the the oddbentity is an oddbcurve ( ), how do i get the right subclass (oddbpolyline, oddbline, ecc).
i hope this is my last problem to understand
thank you
walter
myzhar
==============
ing. walter lucetti
geomind srl
pisa - italy
==============

myzhar
# 22nd may 2006, 09:36 am

founding member join date: jun 2002
location: bulgaria
posts: 377
well,
if you have a oddbline entiity then it should return true to these checks
bool iscurve = pent->iskindof(oddbcurve::desc());
bool isline = pent->iskindof(oddbline::desc());
best regards
chudomir

chudo
# 22nd may 2006, 09:45 am

registered user join date: feb 2006
location: pisa
posts: 69

quote:
originally posted by chudo
well,
if you have a oddbline entiity then it should return true to these checks
bool iscurve = pent->iskindof(oddbcurve::desc());
bool isline = pent->iskindof(oddbline::desc());
i noticed also
isa()
and
isderivedfrom()
functions.
do you think that using
code:
if(pentity->isderivedfrom( oddbcurve::desc() )
{
if( oddbline::desc()==pentity->isa( ) )
{
// operations.........
}
else if( oddbpolyline::desc()==pentity->isa( ) )
{
// operations.........
}
// and so on..................
}
i would obtain a right result?
myzhar
==============
ing. walter lucetti
geomind srl
pisa - italy
==============

myzhar
# 22nd may 2006, 09:50 am

founding member join date: jun 2002
location: bulgaria
posts: 377
oddbline::desc()==pentity->isa( ) is not really wrong, but if you have a custom entitiy which is child of the line then this check will not work.
i have always seen in the documentations and code that iskindof() is recommened to be used.
isa() is useful when you want to get a string representation of the class - for example pent->isa()->name() would return "acdbline" for the line entity.
best regards
chudomir

chudo
# 22nd may 2006, 10:02 am

registered user join date: feb 2006
location: pisa
posts: 69

ok, i agree !!!
thank you very much
walter
myzhar
==============
ing. walter lucetti
geomind srl
pisa - italy
==============

myzhar
# 22nd may 2006, 11:33 am

moderator join date: mar 2002
posts: 2,994
if you need to check if an entity is oddbline isa() is ok.
but if you need to switch depending on entity type and process different entities differently using protocol extensions is much more efficient than dozens of checks isa() for each known enity class.
see odreadex example which dumps entities using protocol extensions.
sergey slezkin

sslezkin
# 23rd may 2006, 01:46 am

softdev join date: jun 2002
location: st'petersburg, russia
posts: 522

also, if you're implementing your own entity drawer, maybe it is better to use the result of worlddraw, viewportdraw, setattributes calls or even use our vectorization support (odvectorizeex sample) instead handling all entities manually...
sincerely yours,
george udov

george udov

none
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well,
if you have a oddbline entiity then it should return true to these checks
bool iscurve = pent->iskindof(oddbcurve::desc());
bool isline = pent->iskindof(oddbline::desc());
best regards
chudomir

quote:
originally posted by chudo
well,
if you have a oddbline entiity then it should return true to these checks
bool iscurve = pent->iskindof(oddbcurve::desc());
bool isline = pent->iskindof(oddbline::desc());
i noticed also
isa()
and
isderivedfrom()
functions.
do you think that using
code:
if(pentity->isderivedfrom( oddbcurve::desc() )
{
if( oddbline::desc()==pentity->isa( ) )
{
// operations.........
}
else if( oddbpolyline::desc()==pentity->isa( ) )
{
// operations.........
}
// and so on..................
}
i would obtain a right result?
myzhar
==============
ing. walter lucetti
geomind srl
pisa - italy
==============
oddbline::desc()==pentity->isa( ) is not really wrong, but if you have a custom entitiy which is child of the line then this check will not work.
i have always seen in the documentations and code that iskindof() is recommened to be used.
isa() is useful when you want to get a string representation of the class - for example pent->isa()->name() would return "acdbline" for the line entity.
best regards
chudomir

ok, i agree !!!
thank you very much
walter
myzhar
==============
ing. walter lucetti
geomind srl
pisa - italy
==============
if you need to check if an entity is oddbline isa() is ok.
but if you need to switch depending on entity type and process different entities differently using protocol extensions is much more efficient than dozens of checks isa() for each known enity class.
see odreadex example which dumps entities using protocol extensions.
sergey slezkin

also, if you're implementing your own entity drawer, maybe it is better to use the result of worlddraw, viewportdraw, setattributes calls or even use our vectorization support (odvectorizeex sample) instead handling all entities manually...
sincerely yours,
george udov