Q: I would like to use PDFTron SDK to render a PDF page to a bitmap.
However the resulting image needs to have alpha channel so that I can
blend it with a backdrop bitmap. This means that page background must
be trasparend and not solid white. How do I do this with PDFNet?
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A: As a starting point you may want to take a look at PDFDraw sample
project (http://www.pdftron.com/pdfnet/samplecode.html#PDFDraw).
To render a PDF page with trasparend background (instead of solid
white), use pdfdraw.SetPageTransparent(true). For example:
...
pdfdraw.SetPageTransparent(true);
pdfdraw.Export(page, "my.png");
Please let me know if this helps and if you have any other questions.