<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd"> <html><head><meta name="qrichtext" content="1" /><style type="text/css"> p, li { white-space: pre-wrap; } </style></head><body style=" font-family:'monospace'; font-size:9pt; font-weight:400; font-style:normal;"> On dimanche 10 septembre 2017 10:50:42 CEST jose.aliste@gmail.com wrote: > Hi, > the internal c++ API is not intended for use by external applications, only > by frontends. So, if you want a stable API, you should be using either of > the frontends. There is a cpp frontend that should be fare more stable. Jose, I'm aware of the cpp frontend, but unless I miss something, it is mostly about rendering or text search. GDAL needs go far beyond rendering as I explained. Even > > Regards > > > On Sun, Sep 10, 2017 at 10:41 AM, Even Rouault <even.rouault@spatialys.com> > > wrote: > > Hi, > > > > > > > > I'm one of the developper of the GDAL library (http://gdal.org) that > > reads various raster & vector formats, mostly geospatial, including PDF > > and > > its georeferencing extensions (either expressed wtih Adobe Supplement to > > ISO 32000 or with Open Geospatial Consortium Best Practice: > > > > https://portal.opengeospatial.org/files/?artifact_id=40537 ) > > > > > > > > Currently we use the Poppler internal C++ API and regularly must adjust > > for changes in it. Recently we had to do adjustments to accomodate for > > Poppler 0.58 changes. Supporting multiple Poppler versions begin to make > > our code ugly. So I and packagers from Linux distribution are wondering if > > there would be a way to access a more stable C++ API > > > > > > > > Besides rendering as image, we need really low-level access to PDF > > objects, to be able to parse georeferencing objects, retrieve layers, turn > > on/off OCG, or even access streams to decode drawing instructions so as to > > build vector objects > > > > > > > > I've tried to summarize below our current use of Poppler C++ API. I > > probably missed a few calls, but you should get the overall picture: > > > > - Object class: getType(), getTypeName(), getBool(), getInt(), getReal(), > > getString(), getName(), getStream(), getArray() > > > > - Dict class: lookupNF(), lookup(), getLength(), getKey() > > > > - Array class: getLength(), getNF(), get() > > > > - Stream class: getDict(), reset(), getChar(), fillGooString() > > > > - Catalog class: getPage(), getPageRef(), readMetadata() > > > > - GooString: getCString(), getLength() > > > > - Ref class: access to num and gen > > > > - PDFDoc class: isOk(), displayPageSlice(), getCatalog(), > > getOptContentConfig(), getNumPages(), getDocInfo(), getErrorCode(), str > > private member(accessed through a ugly "#define private public" before > > including poppler! we need to access it to be able to delete it with our > > heap since we allocated a stream object provided to PDFDoc() constructor. > > this is to avoid potential problems on Windows with cross-heap issues) > > > > - Page class: isOk(), pageObj private member (accessed through a ugly > > "#define private public" before including poppler!), getMediaBox() > > > > - OCGs class: isOk(), getOCGs() > > > > - GooList class: getLength(), get() > > > > - OptionalContentGroup class: setState() > > > > - SplashBitmap class: getBitmap(), getWidth(), getHeigh(), getDataPtr(), > > getAlphaPtr(), getAlphaRowSize(), getRowSize() > > > > - SplashOutputDev class: we subclass this class and override all/most > > virtual methods to be able to turn on/off rendering of various elements as > > we offer options to render selectively vector, raster and/or text elements > > (so basically just a conditional test to decide whether to return as a > > no-op or call the base implementation) > > > > - BaseStream class: we subclass this class to use GDAL own I/O abstraction > > layer (which beyond regular files can read in .zip files, in-memory files, > > files available through HTTP, etc...). So we implement copy(), > > makeSubStream(), getPos(), getStart(), setPos(), moveStart(), getKind(), > > getFileName(), getChar(), makeSubStream(), lookChar(), reset(), > > unfilteredReset(), close(), hasGetChars(), getChars() > > > > - GlobalParams class: setPrintCommands() > > > > - setErrorCallback() function > > > > > > > > If you want to glance at the code, the most relevant files are: > > > > https://github.com/OSGeo/gdal/blob/trunk/gdal/frmts/pdf/pdfobject.cpp > > > > https://github.com/OSGeo/gdal/blob/trunk/gdal/frmts/pdf/pdfio.cpp > > > > https://github.com/OSGeo/gdal/blob/trunk/gdal/frmts/pdf/pdfdataset.cpp > > > > > > > > I'm not clear if that would be feasible for Poppler to provide a more > > stable API for our use. At least, this makes you aware of external users > > of > > this API. > > > > > > > > Best regards, > > > > > > > > Even > > > > > > > > -- > > > > Spatialys - Geospatial professional services > > > > http://www.spatialys.com > > > > _______________________________________________ > > poppler mailing list > > poppler@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/poppler -- Spatialys - Geospatial professional services http://www.spatialys.com</body></html>