pdfGetNumLayers
Get the number of layers.
int pdfGetNumLayers(PDFViewerHandle viewer)
This function returns the number of layers in the PDF file.
Layers are numbered 0 through n-1 (where n is the value returned by
pdfGetNumLayers).
Note that many PDF files have zero layers, meaning that there is no content that can be selectively turned on or off. (This is different from some other formats which always have at least one layer.)
C:
PDFLayerHandler layer;
char *name;
BOOL visible;
int n, len, i;
n = pdfGetNumLayers(viewer);
for (i = 0; i < n; ++i) {
layer = pdfGetLayer(viewer, i);
name = pdfGetLayerName(viewer, layer, &len);
visible = pdfGetLayerVisibility(viewer, layer);
/* ... add a list entry using name and visible ... */
pdfFreeMemory(name);
}