I have PDF files containing a single image. I would like to extract the image to a buffer, uncompressed, inside a C++ application.
Can you advise a (preferably lightweight, preferably free) library to achieve that ?
One of the best-known open source libraries for parsing PDF is Ghostscript. Depending on what you’re going to do with your application, there might be a free edition, but I don’t know the details, so please check their website. Their latest API is documented here.
If you want something easier to use, consider the LEADTOOLS PDF Pro library. (Disclaimer: I am an employee of the vendor of this toolkit). The following C++ code gets the page as bitmap then gets pixel data into a buffer:
BITMAPHANDLE bmp = {0};
L_LoadBitmap(pszPdfFileName, &bmp, sizeof(bmp), 24, ORDER_BGR, nullptr, nullptr);
// Optional: save as BMP or any other file format
L_SaveBitmap(TEXT("d:\\tst1230.bmp"), &bmp, FILE_BMP, 24, 2, nullptr);
// calculate buffer size and allocate it
L_SIZE_T uBytes = BITMAPHEIGHT(&bmp) * bmp.BytesPerLine;
L_UCHAR* pBuffer = new L_UCHAR[uBytes];
// Copy all rows of bitmap into buffer
L_AccessBitmap(&bmp);
L_GetBitmapRow(&bmp, pBuffer, 0, uBytes);
L_ReleaseBitmap(&bmp);
// free the bitmap
L_FreeBitmap(&bmp);
// use pBuffer as needed then free it.
delete pBuffer;
There are also other advanced options if you want more control on how the bitmap is loaded.
If you would like to try it, there’s a free evaluation edition here. The evaluation is fully-functional (but time-limited) and comes with free technical support through email and chat.
