PrintPreview: Hide/Show the header footer option based on print frame margins.

chrome/renderer/print_web_view_helper.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 "chrome/renderer/print_web_view_helper.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 834 matching lines @@
   // PDF printer device supports alpha blending.
   print_pages_params_->params.supports_alpha_blend = true;
 
   bool generate_draft_pages = false;
   if (!settings.GetBoolean(printing::kSettingGenerateDraftData,
                            &generate_draft_pages)) {
     NOTREACHED();
   }
   print_preview_context_.set_generate_draft_pages(generate_draft_pages);
 
-  if (CreatePreviewDocument()) {
+  int margins_type = 0;
+  if (!settings.GetInteger(printing::kSettingMarginsType, &margins_type))
+    margins_type = printing::DEFAULT_MARGINS;
+
+  if (CreatePreviewDocument(margins_type)) {
     DidFinishPrinting(OK);
   } else {
     if (notify_browser_of_print_failure_)
       LOG(ERROR) << "CreatePreviewDocument failed";
     DidFinishPrinting(FAIL_PREVIEW);
   }
 }
 
-bool PrintWebViewHelper::CreatePreviewDocument() {
+bool PrintWebViewHelper::CreatePreviewDocument(int margins_type) {
   PrintMsg_Print_Params print_params = print_pages_params_->params;
   const std::vector<int>& pages = print_pages_params_->pages;
   if (!print_preview_context_.CreatePreviewDocument(&print_params, pages,
                                                     ignore_css_margins_,
                                                     fit_to_page_)) {
     return false;
   }
 
   PageSizeMargins default_page_layout;
   ComputePageLayoutInPointsForCss(print_preview_context_.frame(), 0,
                                   print_params, ignore_css_margins_,
                                   fit_to_page_, NULL, &default_page_layout);
+
+  bool preview_is_modifiable = print_preview_context_.IsModifiable();
   if (!old_print_pages_params_.get() ||
       !PageLayoutIsEqual(*old_print_pages_params_, *print_pages_params_)) {
     bool has_page_size_style = PrintingFrameHasPageSizeStyle(
         print_preview_context_.frame(),
         print_preview_context_.total_page_count());
+
+    bool header_footer_applies = true;

[vandebo (ex-Chrome), 2012/03/15 21:47:17]

It seems like this is solely concerned with the presentation of the print
preview and therefore should live entirely in the javascript if possible.   From
our discussion, that means sending the printable are to javascript, which seems
reasonable.

[kmadhusu, 2012/03/17 00:29:12]

Done.

+    if (!preview_is_modifiable || margins_type == printing::NO_MARGINS) {
+      header_footer_applies = false;
+    } else if (margins_type != printing::PRINTABLE_AREA_MARGINS) {
+#if defined(OS_LINUX)
+    header_footer_applies =
+        (default_page_layout.margin_top > 0) ||
+        (default_page_layout.margin_bottom > 0);
+#else
+    int dpi = GetDPI(&print_params);
+    int non_printable_area_top = ConvertUnit(
+        print_pages_params_->params.printable_area.y(),
+            dpi, printing::kPointsPerInch);
+    int non_printable_area_bottom = ConvertUnit(
+        print_pages_params_->params.page_size.height() -
+            print_pages_params_->params.printable_area.y() -
+            print_pages_params_->params.printable_area.height(),
+        dpi, printing::kPointsPerInch);
+    header_footer_applies =
+        (default_page_layout.margin_top > non_printable_area_top) ||
+        (default_page_layout.margin_bottom > non_printable_area_bottom);
+#endif
+    }
     // Margins: Send default page layout to browser process.
     Send(new PrintHostMsg_DidGetDefaultPageLayout(routing_id(),
                                                   default_page_layout,
-                                                  has_page_size_style));
+                                                  has_page_size_style,
+                                                  header_footer_applies));
   }
 
   PrintHostMsg_DidGetPreviewPageCount_Params params;
   params.page_count = print_preview_context_.total_page_count();
-  params.is_modifiable = print_preview_context_.IsModifiable();
+  params.is_modifiable = preview_is_modifiable;
   params.document_cookie = print_pages_params_->params.document_cookie;
   params.preview_request_id = print_pages_params_->params.preview_request_id;
   params.clear_preview_data = print_preview_context_.generate_draft_pages();
   Send(new PrintHostMsg_DidGetPreviewPageCount(routing_id(), params));
   if (CheckForCancel())
     return false;
 
   while (!print_preview_context_.IsFinalPageRendered()) {
     int page_number = print_preview_context_.GetNextPageNumber();
     DCHECK_GE(page_number, 0);
@@ skipping 874 matching lines @@
   DCHECK(IsRendering());
   return prep_frame_view_->GetPrintCanvasSize();
 }
 
 void PrintWebViewHelper::PrintPreviewContext::ClearContext() {
   prep_frame_view_.reset();
   metafile_.reset();
   pages_to_render_.clear();
   error_ = PREVIEW_ERROR_NONE;
 }