Define behaviors of FPDF_RenderPageBitmap_Retail and FPDF_FFLDraw.

public/fpdf_progressive.h

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef PUBLIC_FPDF_PROGRESSIVE_H_
 #define PUBLIC_FPDF_PROGRESSIVE_H_
 
 #include "fpdfview.h"
@@ skipping 48 matching lines @@
 //          bitmap coordinate.
 //          start_y     -   Top pixel position of the display area in the bitmap
 //          coordinate.
 //          size_x      -   Horizontal size (in pixels) for displaying the page.
 //          size_y      -   Vertical size (in pixels) for displaying the page.
 //          rotate      -   Page orientation: 0 (normal), 1 (rotated 90 degrees
 //          clockwise),
 //                              2 (rotated 180 degrees), 3 (rotated 90 degrees
 //                              counter-clockwise).
 //          flags       -   0 for normal display, or combination of flags
-//          defined above.
+//                          defined in fpdfview.h. With FPDF_ANNOT flag, it
+//                          renders all annotations that does not require
+//                          user-interaction, which are all annotations except
+//                          widget and popup annotations.
 //          pause       -   The IFSDK_PAUSE interface.A callback mechanism
 //          allowing the page rendering process
 // Return value:
 //          Rendering Status. See flags for progressive process status for the
 //          details.
 //
 DLLEXPORT int STDCALL FPDF_RenderPageBitmap_Start(FPDF_BITMAP bitmap,
                                                   FPDF_PAGE page,
                                                   int start_x,
                                                   int start_y,
@@ skipping 27 matching lines @@
 //          function.
 // Return value:
 //          NULL
 DLLEXPORT void STDCALL FPDF_RenderPage_Close(FPDF_PAGE page);
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif  // PUBLIC_FPDF_PROGRESSIVE_H_