pdfGetLayerVisibility
Get the visibility state of a layer.
int pdfGetLayerVisibility(PDFViewerHandle viewer, PDFLayerHandle layer)
This function returns the current visibility state of a layer -
non-zero if the layer is visible, zero if it is not visible.
The layer argument is an opaque layer handle, returned by
pdfGetLayer.
C:
PDFLayerHandle layer;
int visible;
layer = getGetLayer(viewer, .....);
visible = pdfGetLayerVisibility(viewer, layer);
/* toggle the layer */
pdfSetLayerVisibility(viewer, layer, !visible);