Add private PPAPI interfaces for PDFium accessibility.

pdf/pdfium/pdfium_engine.cc

 // 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.
 
 #include "pdf/pdfium/pdfium_engine.h"
 
 #include <math.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 2285 matching lines @@
   if (index < 0 || static_cast<size_t>(index) > pages_.size() - 1)
     return "{}";
 
   std::unique_ptr<base::Value> node(
       pages_[index]->GetAccessibleContentAsValue(current_rotation_));
   std::string page_json;
   base::JSONWriter::Write(*node, &page_json);
   return page_json;
 }
 
+void PDFiumEngine::EnableAccessibility() {
+  if (!(HasPermission(PERMISSION_COPY) ||
+        HasPermission(PERMISSION_COPY_ACCESSIBLE))) {
+    return;

[Lei Zhang, 2016/05/09 23:58:49]

Would it be helpful to return false to give the accessibility code some feedback
and let it (maybe?) pass the failure to the user to let them know that a give
PDF does not have the right permissions?

[dmazzoni, 2016/05/10 22:09:18]

Good thought.

I moved SetAccessibilityDocInfo up to the top, since that already passes through
the accessibility flags, so we can have that metadata sent either way, then skip
the rest if it's not accessible.

+  }
+
+  PP_PrivateAccessibilityViewportInfo viewport_info;
+  viewport_info.scroll.x = 0;
+  viewport_info.scroll.y = -client_->GetToolbarHeight();
+  viewport_info.offset = page_offset_;
+  viewport_info.zoom = current_zoom_;
+  pp::PDF::SetAccessibilityViewportInfo(GetPluginInstance(), &viewport_info);
+
+  PP_PrivateAccessibilityDocInfo doc_info;
+  doc_info.page_count = pages_.size();
+  doc_info.text_accessible = PP_FromBool(
+      HasPermission(PERMISSION_COPY_ACCESSIBLE));
+  doc_info.text_copyable = PP_FromBool(HasPermission(PERMISSION_COPY));
+  pp::PDF::SetAccessibilityDocInfo(GetPluginInstance(), &doc_info);
+
+  for (uint32_t page_index = 0; page_index < pages_.size(); ++page_index) {

[Lei Zhang, 2016/05/09 23:58:49]

size_t instead of uint32_t?

[dmazzoni, 2016/05/10 22:09:18]

Done.

+    FPDF_TEXTPAGE text_page = pages_[page_index]->GetTextPage();
+    int char_count = FPDFText_CountChars(text_page);
+    PP_PrivateAccessibilityPageInfo page_info;
+    page_info.bounds = pages_[page_index]->rect();
+    page_info.char_count = char_count;
+    pp::PDF::SetAccessibilityPageInfo(
+        GetPluginInstance(), page_index, &page_info);
+
+    int char_index = 0;
+    int text_run_index = 0;
+    while (char_index < char_count) {
+      PP_PrivateAccessibilityTextRunInfo text_run_info;
+      pp::FloatRect bounds;
+      pages_[page_index]->GetTextRunInfo(
+          char_index, &text_run_info.len, &text_run_info.font_size, &bounds);
+      text_run_info.direction = PP_PRIVATEDIRECTION_LTR;
+      text_run_info.bounds = bounds;
+      std::vector<PP_PrivateAccessibilityCharInfo> chars;
+      chars.resize(text_run_info.len);

[Lei Zhang, 2016/05/09 23:58:49]

I think you can combine this with the previous line in C++11 std::vector.

[dmazzoni, 2016/05/10 22:09:18]

Done.

+      for (uint32_t i = 0; i < text_run_info.len; ++i) {
+        chars[i].unicode_character = FPDFText_GetUnicode(text_page, i);
+        chars[i].char_width = pages_[page_index]->GetCharWidth(i);
+      }
+
+      pp::PDF::SetAccessibilityTextRunInfo(GetPluginInstance(),
+                                           page_index,
+                                           text_run_index,
+                                           &text_run_info,
+                                           chars.data());
+      text_run_index++;
+      char_index += text_run_info.len;
+    }
+  }
+}
+
 bool PDFiumEngine::GetPrintScaling() {
   return !!FPDF_VIEWERREF_GetPrintScaling(doc_);
 }
 
 int PDFiumEngine::GetCopiesToPrint() {
   return FPDF_VIEWERREF_GetNumCopies(doc_);
 }
 
 int PDFiumEngine::GetDuplexType() {
   return static_cast<int>(FPDF_VIEWERREF_GetDuplex(doc_));
@@ skipping 1557 matching lines @@
   FPDF_DOCUMENT doc =
       FPDF_LoadMemDocument(pdf_buffer, pdf_buffer_size, nullptr);
   if (!doc)
     return false;
   bool success = FPDF_GetPageSizeByIndex(doc, page_number, width, height) != 0;
   FPDF_CloseDocument(doc);
   return success;
 }
 
 }  // namespace chrome_pdf