Below code sample shows the procedure to modify the “transparency” of the layer using ObjectARX. Below code makes the transparency of layer 0 as 60%. It is required to call regen to make the “transparency” changes reflects on the screen.
void transparency()
{
AcDbDatabase *pDb =
acdbHostApplicationServices()->workingDatabase();
AcDbLayerTable *pLayerTblSrc = NULL;
AcDbLayerTableRecord *pLayerTblRcdSrc;
AcDbObjectId layerId;
Acad::ErrorStatus es =
pDb->getLayerTable(pLayerTblSrc,AcDb::kForRead);
if(es != Acad::eOk)
return;
pLayerTblSrc->getAt(_T("0"), pLayerTblRcdSrc,AcDb::kForRead);
pLayerTblSrc->close();
AcCmTransparency trans = pLayerTblRcdSrc->transparency();
Adesk::UInt8 value = trans.alpha();
int percentage = (int)(((255 – value) * 100) / 255);
acutPrintf(_T("Layer 0 transparency is %d"), percentage);
pLayerTblRcdSrc->upgradeOpen();
//60%
Adesk::UInt8 alpha = (255 * (100 – 60) / 100);
AcCmTransparency newTrans(alpha);
pLayerTblRcdSrc->setLineWeight(pLayerTblRcdSrc->lineWeight());
pLayerTblRcdSrc->setTransparency(newTrans);
pLayerTblRcdSrc->close();
acDocManager->sendStringToExecute(acDocManager->curDocument(),
_T("_Regen "));
}
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