pdfClearDeviceNImage
Free memory used by a DeviceN image.
void pdfClearDeviceNImage(PDFHandle pdf)
This function frees the memory used by the last call to
pdfConvertPageToDeviceNImage.
Only one DeviceN rasterization (per PDF handle) is held in memory at a
time. If you call pdfConvertPageToDeviceNImage again, the memory
used by the previous call to pdfConvertPageToDeviceNImage will be
automatically freed.
C:
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);