yang686526

binary data & custom objects
binary data & custom objects
hello.
i am trying to store some custom binary data inside a dwg/dxf file, nothing to render, just some meta information that it might be readable by my application.
my first approach was to create a custom object, in order to store just a string, so i modified the excustobject. unfortunately my code does not get to be executed, except the constructor and destructor of my custom object, so my custom data is not saved.
then i saw in the documentation that a creating custom object needs to implement some drawing, transforming and other kind of functions, so i guess a custom object is not quite the right way to store some custom info.
does anybody have any advice on this topic ?
thank you.
cosmin
xrecord is the way to go. you may attach xrecord either to extension dictionary of any object, or you may create your own dictionary in named objects dictiobary and put your xrecords there. see e.g. examples\odwriteex\dbfiller.cpp, dbfiller::addcustomobjects()
vladimir
thank you very much for the answer.
i managed to insert and retrieve a string, however i have a problem inserting a binary data, i want to insert a binary chunk, after another string; as i see in the output dwg file only the beginning of the chunk is added, it stops at the byte 228 of the source binary file. the string is added correctly.
is there some limitation in your library ?
i do like this:
odresbufptr prb, temp;
temp = prb = odresbuf::newrb(odresbuf::kdxfxdasciistring);
temp->setstring(customstring);
temp->setnext(odresbuf::newrb(odresbuf::kdxfbinarychunk ));
temp= temp->next();
bindata.reserve(filesize);
while(parsing some file) {
bindata.append(a_byte);
}
temp->setbinarychunk(bindata);
pxrec->setfromrbchain(prb);
xrecord stores size of binary chunks as uint8. if the size of your binary data is more than 255 than you need use a list of multiple resbufs (they can have the same group codes).
sergey slezkin
thank you very much for the information, everything works as you specified.
i have another question related to this topic.
following your suggestions i am creating an extension dictionary for a block and appending my binary data as sequences of resbufs. everything is ok with the resulting file, i can access the data in autocad using vba.
the problem occurs when exporting/importing this block. both wblock and insert remove the extension dictionary completely.
somebody suggested once () to insert the extension dictionary directly to an entity in the block definition. in the terms of dwg direct i insert it into a oddbblocktablerecord instance. are they (the block definition mentioned in that thread and oddbblocktablerecord) equivalent ? i tried inserting a line into a block and using the extension dictionary of that line; autocad filters it as well.
did anybody have the same problem with wblock/insert ?
thank you.
last edited by cosmin; 9th january 2008 at 05:56 amfff">.