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Create a Custom ViewerHandler



I would like to create my own custom viewerhandler that needs to get the renderering information (geometry of polylines, polygons, shells and text) and render it to my own Renderer. How do I access this information form GroupDocs.Viewer? Parsing the HTML file would be very slow to process unfortunatelly.

Thank you



I am afraid that GroupDocs.Viewer doesn’t support custom viewer handler that could meet your scenario. However, please share with us your requirement in more details that how would you like to get the information of polylines, polygons, shells, and text, etc. Furthermore, please tell us the file format of the document from which you want to extract this information.



What I need is to be able to render CAD and PDF design files to my own rendering 3D Canvas so that I can later manipulate them or even extend them on a GUI application. Manipulation would include selection, extrusion addition of more objects using snapping etc that I already support.

From your side I only need the vectorized geometry but instead of outputing this to an html file I need this to a callback API call.

For example I need an API call that will notify me to draw a polyline providing coordinates and a color. All possible vectorization scenarios would be:

2. Polygon (closed polyline)
3. Shell or Mesh

This means that elements like text have to be vectorized and provided as a set of accurate polylines with a reference of course to the original object.

I think you are very close to provide this as an API and it is a must do feature.

Thank you



Thanks for providing the details. I am afraid that, at the moment, your mentioned scenario is not in the scope of GroupDocs.Viewer as the API focuses on accepting files and producing image/HTML/PDF output that can be viewed in the front end applications. However, our sister company, Aspose, provides the APIs that you may find useful when manipulating the PDF and CAD documents. We would recommend you to please have a look at the following APIs:


Really sad to hear that this is not in your plans. There exist other companies (like Open Design Alliance) that make millions by offering this functionality, I would definetely suggest to support this.




We really appreciate your valuable suggestion and shall look into it.