Convert a page to a DeviceN image.
int pdfConvertPageToDeviceNImage(PDFHandle pdf, int page, double dpi)
This function rasterizes a page in DeviceN mode, i.e., with separate color channels for each process color (cyan, magenta, yellow, and black), and for each custom (a.k.a., spot) color.

After calling pdfConvertPageToDeviceNImage:

Finally, call pdfClearDeviceNImage to release the memory used by pdfConvertPageToDeviceNImage.

To enable an overprint preview rasterization, call pdfSetConfig to set the overprintPreview parameter before calling pdfConvertPageToDeviceNImage:

pdfSetConfig("overprintPreview yes");
int nChannels, i; char *channelName; unsigned int channelCMYK; PDFImageHeader hdr; char *bits; int err; err = pdfConvertPageToDeviceNImage(pdf, pageNum, dpi); if (err != pdfOk) { /* handle the error */ ... } nChannels = pdfGetNumDeviceNChannels(pdf); for (i = 0; i < nChannels; ++i) { channelName = pdfGetDeviceNChannelName(pdf, i); channelCMYK = pdfGetDeviceNChannelCMYK(pdf, i); printf("channel %d: %s = %08x\n", channelName, channelCMYK); pdfGetDeviceNBitmap(pdf, i, 1, 0, &hdr, *bits); /* hdr and bits represent a grayscale bitmap -- similar to pdfConvertPageToBitmap2 with pdfImageGray */ /* each channel has an 8-bit bitmap; the bitmaps for all channels will have the same width and height */ ... /* the bitmap memory must be freed when you are finished */ pdfFreeMemory(bits); } /* free the internal storage used by pdfConvertPageToDeviceNImage */ pdfClearDeviceNImage(pdf);