Print preview page selection should not require a rerendering of draft pages.

chrome/renderer/print_web_view_helper_mac.mm

 // Copyright (c) 2011 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"
 
 #import <AppKit/AppKit.h>
 
 #include "base/logging.h"
 #include "base/mac/scoped_nsautorelease_pool.h"
@@ skipping 48 matching lines @@
   Send(new PrintHostMsg_DidPrintPage(routing_id(), page_params));
 }
 
 void PrintWebViewHelper::RenderPreviewPage(int page_number) {
   float scale_factor = print_preview_context_.frame()->getPrintPageShrink(0);
   PrintMsg_Print_Params printParams = print_preview_context_.print_params();
   gfx::Rect content_area(printParams.margin_left, printParams.margin_top,
                          printParams.printable_size.width(),
                          printParams.printable_size.height());
 
+  scoped_ptr<printing::Metafile> draft_metafile;
   printing::Metafile* initial_render_metafile =
       print_preview_context_.metafile();
-  scoped_ptr<printing::PreviewMetafile> draft_metafile;
-#if !defined(USE_SKIA)
-  if (print_preview_context_.IsModifiable()) {
-    draft_metafile.reset(new printing::PreviewMetafile);
+
+#if defined(USE_SKIA)
+  bool need_draft_metafile = print_preview_context_.IsModifiable() &&
+                             is_print_ready_metafile_sent_;
+#else
+  bool need_draft_metafile = print_preview_context_.IsModifiable() &&
+                             print_preview_context_.generate_draft_pages();
+  // NOTE: If the rendering page need to be in draft metafile and print ready
+  // metafile, we should always render to the draft metafile first and then
+  // copy that into the print ready metafile because CG does not allow us to do
+  // it in the other order.
+#endif
+
+  if (need_draft_metafile) {
+    draft_metafile.reset(new printing::PreviewMetafile());
     if (!draft_metafile->Init()) {
       DidFinishPrinting(FAIL_PREVIEW);
       return;
     }
     initial_render_metafile = draft_metafile.get();
   }
-#endif
 
   base::TimeTicks begin_time = base::TimeTicks::Now();
   RenderPage(printParams.page_size, content_area, scale_factor, page_number,
              print_preview_context_.frame(), initial_render_metafile);
   print_preview_context_.RenderedPreviewPage(
       base::TimeTicks::Now() - begin_time);
 
-  if (print_preview_context_.IsModifiable()) {
+  if (draft_metafile.get()) {
+    draft_metafile->FinishDocument();
+#if !defined(USE_SKIA)
+    if (!is_print_ready_metafile_sent_) {
+      // With CG, we rendered into a new metafile so we could get it as a draft
+      // document.  Now we need to add it to print ready document.  But the
+      // document has already been scaled and adjusted for margins, so do a 1:1
+      // drawing.
+      printing::Metafile* print_ready_metafile =
+          print_preview_context_.metafile();
+      bool success = print_ready_metafile->StartPage(
+          printParams.page_size, gfx::Rect(printParams.page_size), 1.0);
+      DCHECK(success);
+      // StartPage unconditionally flips the content over, flip it back since it
+      // was already flipped in |draft_metafile|.
+      CGContextTranslateCTM(print_ready_metafile->context(), 0,
+                            printParams.page_size.height());
+      CGContextScaleCTM(print_ready_metafile->context(), 1.0, -1.0);
+      draft_metafile->RenderPage(1,
+                                 print_ready_metafile->context(),
+                                 draft_metafile->GetPageBounds(1).ToCGRect(),
+                                 false /* shrink_to_fit */,
+                                 false /* stretch_to_fit */,
+                                 true /* center_horizontally */,
+                                 true /* center_vertically */);
+      print_ready_metafile->FinishPage();
+    }
+#endif
+  } else {
 #if defined(USE_SKIA)
-    DCHECK(!draft_metafile.get());
-    draft_metafile.reset(
-        print_preview_context_.metafile()->GetMetafileForCurrentPage());
-#else
-    draft_metafile->FinishDocument();
-
-    // With CG, we rendered into a new metafile so we could get it as a draft
-    // document.  Now we need to add it to complete document.  But the document
-    // has already been scaled and adjusted for margins, so do a 1:1 drawing.
-    printing::Metafile* complete_metafile = print_preview_context_.metafile();
-    bool success = complete_metafile->StartPage(
-        printParams.page_size, gfx::Rect(printParams.page_size), 1.0);
-    DCHECK(success);
-    // StartPage unconditionally flips the content over, flip it back since it
-    // was already flipped in |draft_metafile|.
-    CGContextTranslateCTM(complete_metafile->context(), 0,
-                          printParams.page_size.height());
-    CGContextScaleCTM(complete_metafile->context(), 1.0, -1.0);
-
-    draft_metafile->RenderPage(1,
-                               complete_metafile->context(),
-                               draft_metafile->GetPageBounds(1).ToCGRect(),
-                               false /* shrink_to_fit */,
-                               false /* stretch_to_fit */,
-                               true  /* center_horizontally */,
-                               true  /* center_vertically */);
-    complete_metafile->FinishPage();
+    if (print_preview_context_.IsModifiable() &&
+        print_preview_context_.generate_draft_pages()) {
+      DCHECK(!draft_metafile.get());
+      draft_metafile.reset(
+          print_preview_context_.metafile()->GetMetafileForCurrentPage());
+    }
 #endif
   }
-
   PreviewPageRendered(page_number, draft_metafile.get());
 }
 
 void PrintWebViewHelper::RenderPage(
     const gfx::Size& page_size, const gfx::Rect& content_area,
     const float& scale_factor, int page_number, WebFrame* frame,
     printing::Metafile* metafile) {
 
   {
 #if defined(USE_SKIA)
     SkDevice* device = metafile->StartPageForVectorCanvas(
         page_size, content_area, scale_factor);
     if (!device)
       return;
 
     SkRefPtr<skia::VectorCanvas> canvas = new skia::VectorCanvas(device);
     canvas->unref();  // SkRefPtr and new both took a reference.
     WebKit::WebCanvas* canvasPtr = canvas.get();
     printing::MetafileSkiaWrapper::SetMetafileOnCanvas(canvasPtr, metafile);
+    printing::MetafileSkiaWrapper::SetDraftMode(canvasPtr,
+                                                is_print_ready_metafile_sent_);
 #else
     bool success = metafile->StartPage(page_size, content_area, scale_factor);
     DCHECK(success);
     // printPage can create autoreleased references to |context|. PDF contexts
     // don't write all their data until they are destroyed, so we need to make
     // certain that there are no lingering references.
     base::mac::ScopedNSAutoreleasePool pool;
     CGContextRef cgContext = metafile->context();
     CGContextRef canvasPtr = cgContext;
 #endif
     frame->printPage(page_number, canvasPtr);
   }
 
   // Done printing. Close the device context to retrieve the compiled metafile.
   metafile->FinishPage();
 }