Get the parameters of a region.
void pdfGetRegionInfo(PDFViewerHandle viewer, PDFRegionHandle region, int *page, double *x0, double *y0, double *x1, double *y1, COLORREF *color, COLORREF *selectColor, char *label, int maxLabel)
This function returns the parameters of the specified region.

The returned values are the same ones that were passed to pdfAddRegion, except that the coordinates may have changed if the user has resized the region.

The label buffer is provided by the caller, and has room for maxLabel bytes.

int page; double x0, y0, x1, y1; COLORREF color, selectColor; char label[100]; pdfGetRegionInfo(viewer, region, &p, &x0, &y0, &x1, &y1, &color, &selectColor, label, sizeof(label));