Add FPDFDest_GetLocationInPage API

public/fpdf_doc.h

Index: public/fpdf_doc.h
diff --git a/public/fpdf_doc.h b/public/fpdf_doc.h
index c3be0e05988218274dd68178067e6ee487558f21..d5e99952e5039f23c614451351d2b4407cb4cfbb 100644
--- a/public/fpdf_doc.h
+++ b/public/fpdf_doc.h
@@ -171,6 +171,25 @@ DLLEXPORT unsigned long STDCALL FPDFAction_GetURIPath(FPDF_DOCUMENT document,
 DLLEXPORT unsigned long STDCALL FPDFDest_GetPageIndex(FPDF_DOCUMENT document,
                                                       FPDF_DEST dest);
 
+// Get the (x, y, zoom) location of |dest| in the destination page, if the
+// destination is in [page /XYZ x y zoom] syntax.
+//
+//   dest    - handle to the destination.
+//   hasX    - out parameter; true if the x value is not null

[Lei Zhang, 2016/11/07 22:04:17]

Still a little ambiguous, as "x" can refer to either the x in [page /XYZ x y
zoom], or the x parameter. Maybe rename the parameters to avoid confusion?

I would also mention that the float out parameters are only written to if the
corresponding boolean is set to true.

[dsinclair, 2016/11/08 14:04:46]

Done.

+//   hasY    - out parameter; true if the y value is not null
+//   hasZoom - out parameter; true if the zoom value is not null
+//   x       - out parameter; the x coordinate, in the page coordinate system.
+//   y       - out parameter; the y coordinate, in the page coordinate system.
+//   zoom    - out parameter; the zoom value.
+// Returns TRUE on successfully reading the /XYZ value.
+DLLEXPORT FPDF_BOOL STDCALL FPDFDest_GetLocationInPage(FPDF_DEST dest,
+                                                       FPDF_BOOL* hasX,
+                                                       FPDF_BOOL* hasY,
+                                                       FPDF_BOOL* hasZoom,
+                                                       FS_FLOAT* x,
+                                                       FS_FLOAT* y,
+                                                       FS_FLOAT* zoom);
+
 // Find a link at point (|x|,|y|) on |page|.
 //
 //   page - handle to the document page.