PDF: Use the z-order when there is a link and widget overlaps.

pdf/pdfium/pdfium_page.cc

 // Copyright (c) 2010 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_page.h"
 
 #include <math.h>
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 245 matching lines @@
 }
 
 PDFiumPage::Area PDFiumPage::GetCharIndex(const pp::Point& point,
                                           int rotation,
                                           int* char_index,
                                           int* form_type,
                                           LinkTarget* target) {
   if (!available_)
     return NONSELECTABLE_AREA;
   pp::Point point2 = point - rect_.point();
-  double new_x, new_y;
+  double new_x;
+  double new_y;
   FPDF_DeviceToPage(GetPage(), 0, 0, rect_.width(), rect_.height(),
         rotation, point2.x(), point2.y(), &new_x, &new_y);
 
   int rv = FPDFText_GetCharIndexAtPos(
       GetTextPage(), new_x, new_y, kTolerance, kTolerance);
   *char_index = rv;
 
+  FPDF_LINK link = FPDFLink_GetLinkAtPoint(GetPage(), new_x, new_y);
   int control =
       FPDPage_HasFormFieldAtPoint(engine_->form(), GetPage(), new_x, new_y);
-  if (control > FPDF_FORMFIELD_UNKNOWN) {
-    *form_type = control;
-    return PDFiumPage::NONSELECTABLE_AREA;
-  }
 
-  FPDF_LINK link = FPDFLink_GetLinkAtPoint(GetPage(), new_x, new_y);
-  if (link) {
+  // If there is a control and link at the same point, figure out their z-order
+  // to determine which is on top.
+  if (link && control > FPDF_FORMFIELD_UNKNOWN) {
+    int control_z_order = FPDFPage_FormFieldZOrderAtPoint(
+        engine_->form(), GetPage(), new_x, new_y);
+    int link_z_order = FPDFLink_GetLinkZOrderAtPoint(GetPage(), new_x, new_y);
+    DCHECK_NE(control_z_order, link_z_order);
+    if (control_z_order > link_z_order) {
+      *form_type = control;
+      return PDFiumPage::NONSELECTABLE_AREA;
+    }
+
     // We don't handle all possible link types of the PDF. For example,
     // launch actions, cross-document links, etc.
     // In that case, GetLinkTarget() will return NONSELECTABLE_AREA
     // and we should proceed with area detection.
     PDFiumPage::Area area = GetLinkTarget(link, target);
     if (area != PDFiumPage::NONSELECTABLE_AREA)
       return area;
+  } else if (link) {
+    // We don't handle all possible link types of the PDF. For example,
+    // launch actions, cross-document links, etc.
+    // See identical block above.
+    PDFiumPage::Area area = GetLinkTarget(link, target);
+    if (area != PDFiumPage::NONSELECTABLE_AREA)
+      return area;
+  } else if (control > FPDF_FORMFIELD_UNKNOWN) {
+    *form_type = control;
+    return PDFiumPage::NONSELECTABLE_AREA;
   }
 
   if (rv < 0)
     return NONSELECTABLE_AREA;
 
   return GetLink(*char_index, target) != -1 ? WEBLINK_AREA : TEXT_AREA;
 }
 
 base::char16 PDFiumPage::GetCharAtIndex(int index) {
   if (!available_)
@@ skipping 208 matching lines @@
   page_->loading_count_--;
 }
 
 PDFiumPage::Link::Link() {
 }
 
 PDFiumPage::Link::~Link() {
 }
 
 }  // namespace chrome_pdf