Export a function from the PDF plugin to get the dimensions of a PDF page.

pdf/pdf_engine.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PDF_PDF_ENGINE_H_
 #define PDF_PDF_ENGINE_H_
 
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
@@ skipping 277 matching lines @@
     bool stretch_to_bounds;
     bool keep_aspect_ratio;
     bool center_in_bounds;
     bool autorotate;
   };
 
   PDFEngineExports() {}
   virtual ~PDFEngineExports() {}
   static PDFEngineExports* Create();
 #if defined(OS_WIN)
-  // See the definition of RenderPDFPageToDC in pdf.cc for details.
+  // |pdf_buffer| is the buffer that contains the entire PDF document to be
+  //     rendered.
+  // |buffer_size| is the size of |pdf_buffer| in bytes.
+  // |page_number| is the 0-based index of the page to be rendered.
+  // |dc| is the device context to render into.

[Dan Beam, 2014/07/09 23:18:24]

remove from here down:

+  // |dpi_x| and |dpi_y| are the x and y resolutions respectively. If either
+  //     value is -1, the dpi from the DC will be used.
+  // |bounds_origin_x|, |bounds_origin_y|, |bounds_width| and |bounds_height|
+  //     specify a bounds rectangle within the DC in which to render the PDF
+  //     page.
+  // |fit_to_bounds| specifies whether the output should be shrunk to fit the
+  //     supplied bounds if the page size is larger than the bounds in any
+  //     dimension. If this is false, parts of the PDF page that lie outside
+  //     the bounds will be clipped.
+  // |stretch_to_bounds| specifies whether the output should be stretched to fit
+  //     the supplied bounds if the page size is smaller than the bounds in any
+  //     dimension.
+  // If both |fit_to_bounds| and |stretch_to_bounds| are true, then
+  //     |fit_to_bounds| is honored first.
+  // |keep_aspect_ratio| If any scaling is to be done is true, this flag
+  //     specifies whether the original aspect ratio of the page should be
+  //     preserved while scaling.
+  // |center_in_bounds| specifies whether the final image (after any scaling is
+  //     done) should be centered within the given bounds.
+  // |autorotate| specifies whether the final image should be rotated to match
+  //     the output bound.

[Dan Beam, 2014/07/09 23:18:23]

^ to here

+  // Returns false if the document or the page number are not valid.
   virtual bool RenderPDFPageToDC(const void* pdf_buffer,
                                  int buffer_size,
                                  int page_number,
                                  const RenderingSettings& settings,
                                  HDC dc) = 0;
 #endif  // OS_WIN

[Dan Beam, 2014/07/09 23:18:24]

nit: \n

-  // See the definition of RenderPDFPageToBitmap in pdf.cc for details.
+  // Renders PDF page into 4-byte per pixel BGRA color bitmap.
+  // |pdf_buffer| is the buffer that contains the entire PDF document to be
+  //     rendered.
+  // |pdf_buffer_size| is the size of |pdf_buffer| in bytes.
+  // |page_number| is the 0-based index of the page to be rendered.
+  // |bitmap_buffer| is the output buffer for bitmap.
+  // |bitmap_width| is the width of the output bitmap.

[Dan Beam, 2014/07/09 23:18:24]

I don't see |bitmap_width|, |bitmap_height|, |dpi|, or |autorotate| in
RenderPDFPageToBitmap(...)

+  // |bitmap_height| is the height of the output bitmap.
+  // |dpi| is the resolutions.
+  // |autorotate| specifies whether the final image should be rotated to match
+  //     the output bound.
+  // Returns false if the document or the page number are not valid.
   virtual bool RenderPDFPageToBitmap(const void* pdf_buffer,
                                      int pdf_buffer_size,
                                      int page_number,
                                      const RenderingSettings& settings,
                                      void* bitmap_buffer) = 0;

[Dan Beam, 2014/07/09 23:18:23]

nit: \n

+  // |page_count| and |max_page_width| are optional and can be NULL.
+  // Returns false if the document is not valid.
   virtual bool GetPDFDocInfo(const void* pdf_buffer,
                              int buffer_size,
                              int* page_count,
                              double* max_page_width) = 0;
+
+  // Gets the dimensions of a specific page in a document.
+  // |pdf_buffer| is the buffer that contains the entire PDF document to be
+  //     rendered.
+  // |pdf_buffer_size| is the size of |pdf_buffer| in bytes.
+  // |page_number| is the page number that the function will get the dimensions
+  //     of.
+  // |width| is the output for the width of the page in points.
+  // |height| is the output for the height of the page in points.
+  // Returns false if the document or the page number are not valid.
+  virtual bool GetPDFPageSizeByIndex(const void* pdf_buffer,
+                                     int pdf_buffer_size, int page_number,
+                                     double* width, double* height) = 0;
 };
 
 }  // namespace chrome_pdf
 
 #endif  // PDF_PDF_ENGINE_H_