Document the meaning of the 'type' integer of a shading
diff --git a/poppler/GfxState.h b/poppler/GfxState.h
index 57f3725..bfbf53c 100644
--- a/poppler/GfxState.h
+++ b/poppler/GfxState.h
@@ -23,6 +23,7 @@
// Copyright (C) 2011-2014, 2016 Thomas Freitag <Thomas.Freitag@alfa.de>
// Copyright (C) 2013 Lu Wang <coolwanglu@gmail.com>
// Copyright (C) 2015, 2017 Adrian Johnson <ajohnson@redneon.com>
+// Copyright (C) 2017 Oliver Sander <oliver.sander@tu-dresden.de>
//
// To see a description of the changes please see the Changelog file that
// came with your tarball or type make ChangeLog if you are building from git
@@ -867,6 +868,13 @@
GBool init(GfxResources *res, Dict *dict, OutputDev *out, GfxState *state);
+ // 1: Function-based shading
+ // 2: Axial shading
+ // 3: Radial shading
+ // 4: Free-form Gouraud-shaded triangle mesh
+ // 5: Lattice-form Gouraud-shaded triangle mesh
+ // 6: Coons patch mesh
+ // 7: Tensor-product patch mesh
int type;
GBool hasBackground;
GBool hasBBox;