【转帖】need advice about redrawing
 

need advice about redrawing
need advice about redrawing
hello,
i want my application to show two parallel lines when the user is introducing a new element. i’ve been using your function overlapdraw(), but i thought i prefer using two lines pertaining to database because it seems to me this results in a more “clear” code.
so i’ve tried these 2 approaches:
approach 1)
code:
in cview derived class include file i’ve declared:
oddblineptr pline1;
oddbobjectid idline1;
oddblineptr pline2;
oddbobjectid idline2;
in cview derived class oninitdialog():
oddbblocktablerecordptr pspace;
pspace = pdb->getmodelspaceid().safeopenobject(oddb::kforwrite);
pline1 = oddbline::createobject();
pdbsbesa->addoddbobject(pline1);
idline1= pspace->appendoddbentity(pline1);
pline1->setcolorindex(1);
pline1->setlayer("0");
pline1->setlineweight(oddb::klnwt000);
pline2 = oddbline::createobject();
pdbsbesa->addoddbobject(pline2);
idline2= pspace->appendoddbentity(pline2);
pline2->setcolorindex(1);
pline2->setlayer("0");
pline2->setlineweight(oddb::klnwt000);
and in cview derived class onmousemove():
pline1 = oddbline::cast(idline1.safeopenobject(oddb::kforwrite));
pline1->setstartpoint(pt3dworldstartpointline1);
pline1->setendpoint(pt3dworldendpointline1);
pline2 = oddbline::cast(idline2.safeopenobject(oddb::kforwrite));
pline2->setstartpoint(pt3dworldstartpointline2);
pline2->setendpoint(pt3dworldendpointline2);
redrawwindow();
this way, no line is painted during onmousemove().
approach 2:
code:
in cview derived class include file i’ve declared:
oddbobjectid idline1;
oddbobjectid idline2;

i’ve also created two functions in cview derived class:

//**************************************************
void cviewcad::start2linesdraw()
{
if(!idline1.isnull())
return;
if(!idline2.isnull())
return;
oddbblocktablerecordptr pspace;
pspace = pdb->getmodelspaceid().safeopenobject(oddb::kforwrite);
oddblineptr pline1;
pline1 = oddbline::createobject();
pdb->addoddbobject(pline1);
oddblineptr pline2;
pline2 = oddbline::createobject();
pdb->addoddbobject(pline2);
idline1= pspace->appendoddbentity(pline1);
idline2= pspace->appendoddbentity(pline2);
pline1->setstartpoint(pt3dworldstartpointline1);
pline1->setendpoint(pt3dworldstartpointline1);
pline1->setcolorindex(1);
pline1->setlayer("0");
pline1->setlineweight(oddb::klnwt000);
pline2->setstartpoint(pt3dworldstartpointline2);
pline2->setendpoint(pt3dworldstartpointline2);
pline2->setcolorindex(1);
pline2->setlayer("0");
pline2->setlineweight(oddb::klnwt000);
}
//**************************************************
void cviewdatoscad:: update2linesdraw ()
{
if(idline1.isnull())
return;
if(idline2.isnull())
return;
oddblineptr pline1;
pline1 = oddbline::cast(idline1.safeopenobject(oddb::kforwrite));
pline1->setstartpoint(pt3dworldstartpointline1);
pline1->setendpoint(pt3dworldendpointline1);
pline1->setcolorindex(1);
oddblineptr pline2;
pline2 = oddbline::cast(idline2.safeopenobject(oddb::kforwrite));
pline2->setstartpoint(pt3dworldstartpointline2);
pline2->setendpoint(pt3dworldendpointline2);
pline2->setcolorindex(1); //color rojo
}
//**************************************************
and in cview derived class onmousemove():
start2linesdraw ();
update2linesdraw ();
redrawwindow();
//**************************************************
when i use this code the lines are painted properly “but” the application throws the following error: