[Print Preview]: Added code to support pdf fit to page functionality.

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/auto_reset.h"
 #include "base/command_line.h"
@@ skipping 323 matching lines @@
   return frame_has_custom_page_size_style;
 }
 
 printing::MarginType GetMarginsForPdf(WebFrame* frame, const WebNode& node) {
   if (frame->isPrintScalingDisabledForPlugin(node))
     return printing::NO_MARGINS;
   else
     return printing::PRINTABLE_AREA_MARGINS;
 }
 
+bool FitToPageEnabled(const DictionaryValue& job_settings) {
+  bool fit_to_paper_size = false;
+  if (!job_settings.GetBoolean(printing::kSettingFitToPageEnabled,
+                               &fit_to_paper_size)) {
+    NOTREACHED();
+  }
+  return fit_to_paper_size;
+}
+
 // Get the (x, y) coordinate from where printing of the current text should
 // start depending on the horizontal alignment (LEFT, RIGHT, CENTER) and
 // vertical alignment (TOP, BOTTOM).
 SkPoint GetHeaderFooterPosition(
     float webkit_scale_factor,
     const PageSizeMargins& page_layout,
     printing::HorizontalHeaderFooterPosition horizontal_position,
     printing::VerticalHeaderFooterPosition vertical_position,
     double offset_to_baseline,
     double text_width_in_points) {
@@ skipping 472 matching lines @@
 }
 
 bool PrintWebViewHelper::IsPrintToPdfRequested(
     const DictionaryValue& job_settings) {
   bool print_to_pdf = false;
   if (!job_settings.GetBoolean(printing::kSettingPrintToPDF, &print_to_pdf))
     NOTREACHED();
   return print_to_pdf;
 }
 
+bool PrintWebViewHelper::IsFitToPaperSizeRequested(
+    const DictionaryValue& job_settings, const PrintMsg_Print_Params& params) {
+  if (print_for_preview_ || params.print_to_pdf) {

[Lei Zhang, 2012/04/27 04:32:47]

Do you need to check |print_for_preview_|? Right now, you only call
IsFitToPaperSizeRequested() when |print_for_preview_| is false.

In fact, if you are going to use |print_preview_context_| below, you should
DCHECK(!print_for_preview); and mention this is only used for print preview.

[kmadhusu, 2012/05/01 16:43:15]

Changed the default value of |fit_to_paper_size| to false in
chrome/common/print_messages.cc (Ref: Patch set 11). We override that value
during preview workflow and normal printing workflow.

+    // Do not fit to paper size when the user is printing the preview data or
+    // saving the print contents as pdf.
+    return false;
+  }
+
+  bool source_is_html = IsSourceHTML(print_preview_context_.frame(),
+                                     print_preview_context_.node(),
+                                     job_settings);
+
+  if (!source_is_html) {
+    // Get the print scaling option for the initiator renderer pdf.
+    bool print_scaling_disabled_for_plugin =
+        print_preview_context_.frame()->isPrintScalingDisabledForPlugin(
+            print_preview_context_.node());
+
+    // If this is the first preview request, UI doesn't know about the print
+    // scaling option of the plugin. Therefore, check the print scaling option
+    // and update the print params accordingly.
+    //
+    // If this is not the first preview request, update print params based on
+    // preview job settings.
+    if ((params.is_first_request && print_scaling_disabled_for_plugin) ||
+        !FitToPageEnabled(job_settings)) {

[Lei Zhang, 2012/04/27 04:32:47]

You can check the result of FitToPageEnabled() first, which is relatively cheap,
and return false without calling isPrintScalingDisabledForPlugin() above.

[kmadhusu, 2012/05/01 16:43:15]

Done.

+      return false;
+    }
+  }
+  return true;
+}
+
+bool PrintWebViewHelper::IsSourceHTML(const WebFrame* frame,
+                                      const WebNode& node,
+                                      const DictionaryValue& job_settings) {
+  bool source_is_html = true;
+  if (print_for_preview_) {
+    if (!job_settings.GetBoolean(printing::kSettingPreviewModifiable,
+                                 &source_is_html)) {
+      NOTREACHED();
+    }
+  } else {
+    source_is_html = !PrintingNodeOrPdfFrame(frame, node);
+  }
+  return source_is_html;
+}
+
 void PrintWebViewHelper::OnPrintPreview(const DictionaryValue& settings) {
   DCHECK(is_preview_enabled_);
   print_preview_context_.OnPrintPreview();
 
   if (!UpdatePrintSettings(print_preview_context_.frame(),
                            print_preview_context_.node(), settings)) {
     if (print_preview_context_.last_error() != PREVIEW_ERROR_BAD_SETTING) {
       Send(new PrintHostMsg_PrintPreviewInvalidPrinterSettings(
           routing_id(), print_pages_params_->params.document_cookie));
       notify_browser_of_print_failure_ = false;  // Already sent.
@@ skipping 14 matching lines @@
     preview_params.expected_pages_count =
         print_preview_context_.total_page_count();
     preview_params.modifiable = print_preview_context_.IsModifiable();
     preview_params.preview_request_id =
         print_pages_params_->params.preview_request_id;
 
     Send(new PrintHostMsg_MetafileReadyForPrinting(routing_id(),
                                                    preview_params));
     return;
   }
+
+  // If we are previewing a pdf and the print scaling is disabled, send a
+  // message to browser.
+  if (!print_preview_context_.IsModifiable() &&
+      print_pages_params_->params.is_first_request &&
+      print_preview_context_.frame()->isPrintScalingDisabledForPlugin(
+          print_preview_context_.node())) {
+    Send(new PrintHostMsg_PrintPreviewScalingDisabled(routing_id()));
+  }
+
   // Always clear |old_print_pages_params_| before rendering the pages.
   old_print_pages_params_.reset();
   is_print_ready_metafile_sent_ = false;
 
   // 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)) {
@@ skipping 408 matching lines @@
     const DictionaryValue& passed_job_settings) {
   DCHECK(is_preview_enabled_);
   const DictionaryValue* job_settings = &passed_job_settings;
   DictionaryValue modified_job_settings;
   if (job_settings->empty()) {
     if (!print_for_preview_)
       print_preview_context_.set_error(PREVIEW_ERROR_BAD_SETTING);
     return false;
   }
 
-  bool source_is_html = true;
-  if (print_for_preview_) {
-    if (!job_settings->GetBoolean(printing::kSettingPreviewModifiable,
-                                  &source_is_html)) {
-      NOTREACHED();
-    }
-  } else {
-    source_is_html = !PrintingNodeOrPdfFrame(frame, node);
-  }
-
+  bool source_is_html = IsSourceHTML(frame, node, *job_settings);

[Lei Zhang, 2012/04/27 04:32:47]

It occurred to me that you can pass this to IsFitToPaperSizeRequested() below,
so it won't have to compute it again. If you do that, then you don't have to
split IsSourceHTML() into a separate function.

[kmadhusu, 2012/05/01 16:43:15]

Done.

   if (print_for_preview_ || !source_is_html) {
     modified_job_settings.MergeDictionary(job_settings);
     modified_job_settings.SetBoolean(printing::kSettingHeaderFooterEnabled,
                                      false);
 
-    // - On Windows, we don't add a margin until we turn it into an EMF when
-    //   printing for print preview (We could add it in the plugin).
-    // - On Mac with Skia, we don't add a margin until we send it to the printer
-    //   using the CG PDF class (We could add it in the plugin).
-    // - On Mac with CG, we can add a margin when generating the preview.
-    // - On Linux, we never add a margin (We Could add it in the plugin).
-#if defined(OS_MACOSX) && !defined(USE_SKIA)
-    bool get_margins_from_pdf = !source_is_html && !print_for_preview_;
-#elif defined(OS_WIN) || defined(OS_MACOSX)
-    bool get_margins_from_pdf = !source_is_html && print_for_preview_;
-#else
-    bool get_margins_from_pdf = false;
-#endif
-
     printing::MarginType margin_type = printing::NO_MARGINS;
-    if (get_margins_from_pdf)
-      margin_type = GetMarginsForPdf(frame, node);
     modified_job_settings.SetInteger(printing::kSettingMarginsType,
                                      margin_type);
     job_settings = &modified_job_settings;
   }
 
   // Send the cookie so that UpdatePrintSettings can reuse PrinterQuery when
   // possible.
   int cookie = print_pages_params_.get() ?
       print_pages_params_->params.document_cookie : 0;
   PrintMsg_PrintPages_Params settings;
@@ skipping 33 matching lines @@
                                   &(settings.params.preview_request_id)) ||
         !job_settings->GetBoolean(printing::kIsFirstRequest,
                                   &(settings.params.is_first_request))) {
       NOTREACHED();
       print_preview_context_.set_error(PREVIEW_ERROR_BAD_SETTING);
       return false;
     }
 
     settings.params.print_to_pdf = IsPrintToPdfRequested(*job_settings);
     UpdateFrameMarginsCssInfo(*job_settings);
-
-    // Fit to paper size.
-    settings.params.fit_to_paper_size = source_is_html &&
-                                        !IsPrintToPdfRequested(*job_settings);
+    settings.params.fit_to_paper_size =
+        IsFitToPaperSizeRequested(*job_settings, settings.params);
 
     // Header/Footer: Set |header_footer_info_|.
     if (settings.params.display_header_footer) {
       header_footer_info_.reset(new DictionaryValue());
       header_footer_info_->SetString(printing::kSettingHeaderFooterDate,
                                      settings.params.date);
       header_footer_info_->SetString(printing::kSettingHeaderFooterURL,
                                      settings.params.url);
       header_footer_info_->SetString(printing::kSettingHeaderFooterTitle,
                                      settings.params.title);
@@ skipping 423 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;
 }