Printing on Windows via PDF

chrome/renderer/printing/print_web_view_helper_pdf_win.cc

+// Copyright 2014 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/printing/print_web_view_helper.h"
+
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/process/process_handle.h"
+#include "chrome/common/print_messages.h"
+#include "content/public/renderer/render_thread.h"
+#include "printing/metafile.h"
+#include "printing/metafile_impl.h"
+#include "printing/metafile_skia_wrapper.h"
+#include "printing/page_size_margins.h"
+#include "printing/units.h"
+#include "skia/ext/platform_device.h"
+#include "skia/ext/vector_canvas.h"
+#include "third_party/WebKit/public/web/WebLocalFrame.h"
+
+
+namespace printing {
+
+using blink::WebFrame;
+
+bool PrintWebViewHelper::RenderPreviewPage(
+    int page_number,
+    const PrintMsg_Print_Params& print_params) {
+  PrintMsg_PrintPage_Params page_params;
+  page_params.params = print_params;
+  page_params.page_number = page_number;
+  scoped_ptr<Metafile> draft_metafile;
+  Metafile* initial_render_metafile = print_preview_context_.metafile();
+  if (print_preview_context_.IsModifiable() && is_print_ready_metafile_sent_) {
+    draft_metafile.reset(new PreviewMetafile);
+    initial_render_metafile = draft_metafile.get();
+  }
+
+  base::TimeTicks begin_time = base::TimeTicks::Now();
+  double actual_shrink =
+      static_cast<float>(print_params.desired_dpi / print_params.dpi);
+  PrintPageInternal(page_params,
+                    print_preview_context_.GetPrintCanvasSize(),
+                    print_preview_context_.prepared_frame(),
+                    initial_render_metafile,
+                    true,
+                    &actual_shrink,
+                    NULL,
+                    NULL);
+  print_preview_context_.RenderedPreviewPage(
+      base::TimeTicks::Now() - begin_time);
+  if (draft_metafile.get()) {
+    draft_metafile->FinishDocument();
+  } else if (print_preview_context_.IsModifiable() &&
+             print_preview_context_.generate_draft_pages()) {
+    DCHECK(!draft_metafile.get());
+    draft_metafile.reset(
+        print_preview_context_.metafile()->GetMetafileForCurrentPage());
+  }
+  return PreviewPageRendered(page_number, draft_metafile.get());
+}
+
+bool PrintWebViewHelper::PrintPagesNative(blink::WebFrame* frame,
+                                          int page_count,
+                                          const gfx::Size& canvas_size) {
+  NativeMetafile metafile;
+  if (!metafile.Init())
+    return false;
+
+  const PrintMsg_PrintPages_Params& params = *print_pages_params_;
+  std::vector<int> printed_pages;
+  std::vector<double> shrink;
+  std::vector<gfx::Size> page_size_in_dpi;
+  std::vector<gfx::Rect> content_area_in_dpi;
+  double dpi_shrink =
+      static_cast<float>(params.params.desired_dpi / params.params.dpi);
+
+  if (params.pages.empty()) {
+    for (int i = 0; i < page_count; ++i) {
+      printed_pages.push_back(i);
+    }
+  } else {
+    // TODO(vitalybuka): redesign to make more code cross platform.
+    for (size_t i = 0; i < params.pages.size(); ++i) {
+      if (params.pages[i] >= 0 && params.pages[i] < page_count) {
+        printed_pages.push_back(params.pages[i]);
+      }
+    }
+  }
+  if (printed_pages.empty())
+    return false;
+
+  for (size_t i = 0; i < printed_pages.size(); ++i) {
+    shrink.push_back(dpi_shrink);
+    page_size_in_dpi.push_back(gfx::Size());
+    content_area_in_dpi.push_back(gfx::Rect());
+  }
+
+  PrintMsg_PrintPage_Params page_params;
+  page_params.params = params.params;
+  for (size_t i = 0; i < printed_pages.size(); ++i) {
+    page_params.page_number = printed_pages[i];
+    PrintPageInternal(page_params,
+                      canvas_size,
+                      frame,
+                      &metafile,
+                      false,
+                      &shrink[i],
+                      &page_size_in_dpi[i],
+                      &content_area_in_dpi[i]);
+  }
+
+  // blink::printEnd() for PDF should be called before metafile is closed.
+  FinishFramePrinting();
+
+  metafile.FinishDocument();
+
+  // Get the size of the resulting metafile.
+  uint32 buf_size = metafile.GetDataSize();
+  DCHECK_GT(buf_size, 0u);
+
+  PrintHostMsg_DidPrintPage_Params printed_page_params;
+  printed_page_params.data_size = 0;
+  printed_page_params.document_cookie = params.params.document_cookie;
+  printed_page_params.page_size = params.params.page_size;
+  printed_page_params.content_area = params.params.printable_area;
+
+  {
+    base::SharedMemory shared_buf;
+    // Allocate a shared memory buffer to hold the generated metafile data.
+    if (!shared_buf.CreateAndMapAnonymous(buf_size)) {
+      NOTREACHED() << "Buffer allocation failed";
+      return false;
+    }
+
+    // Copy the bits into shared memory.
+    if (!metafile.GetData(shared_buf.memory(), buf_size)) {
+      NOTREACHED() << "GetData() failed";
+      shared_buf.Unmap();
+      return false;
+    }
+    shared_buf.GiveToProcess(base::GetCurrentProcessHandle(),
+                             &printed_page_params.metafile_data_handle);
+    shared_buf.Unmap();
+
+    printed_page_params.data_size = buf_size;
+    Send(new PrintHostMsg_DuplicateSection(
+        routing_id(),
+        printed_page_params.metafile_data_handle,
+        &printed_page_params.metafile_data_handle));
+  }
+
+  for (size_t i = 0; i < printed_pages.size(); ++i) {
+    printed_page_params.page_number = printed_pages[i];
+    printed_page_params.actual_shrink = shrink[i];
+    printed_page_params.page_size = page_size_in_dpi[i];
+    printed_page_params.content_area = content_area_in_dpi[i];
+    Send(new PrintHostMsg_DidPrintPage(routing_id(), printed_page_params));
+    printed_page_params.metafile_data_handle = INVALID_HANDLE_VALUE;
+  }
+  return true;
+}
+
+void PrintWebViewHelper::PrintPageInternal(
+    const PrintMsg_PrintPage_Params& params,
+    const gfx::Size& canvas_size,
+    WebFrame* frame,
+    Metafile* metafile,
+    bool is_preview,
+    double* actual_shrink,
+    gfx::Size* page_size_in_dpi,
+    gfx::Rect* content_area_in_dpi) {
+  PageSizeMargins page_layout_in_points;
+  double css_scale_factor = 1.0f;
+  ComputePageLayoutInPointsForCss(frame, params.page_number, params.params,
+                                  ignore_css_margins_, &css_scale_factor,
+                                  &page_layout_in_points);
+  gfx::Size page_size;
+  gfx::Rect content_area;
+  GetPageSizeAndContentAreaFromPageLayout(page_layout_in_points, &page_size,
+                                          &content_area);
+  int dpi = static_cast<int>(params.params.dpi);
+  // Calculate the actual page size and content area in dpi.
+  if (page_size_in_dpi) {
+    *page_size_in_dpi =
+        gfx::Size(static_cast<int>(ConvertUnitDouble(
+                      page_size.width(), kPointsPerInch, dpi)),
+                  static_cast<int>(ConvertUnitDouble(
+                      page_size.height(), kPointsPerInch, dpi)));
+  }
+
+  if (content_area_in_dpi) {
+    *content_area_in_dpi =
+        gfx::Rect(static_cast<int>(
+                      ConvertUnitDouble(content_area.x(), kPointsPerInch, dpi)),
+                  static_cast<int>(
+                      ConvertUnitDouble(content_area.y(), kPointsPerInch, dpi)),
+                  static_cast<int>(ConvertUnitDouble(
+                      content_area.width(), kPointsPerInch, dpi)),
+                  static_cast<int>(ConvertUnitDouble(
+                      content_area.height(), kPointsPerInch, dpi)));
+  }
+
+  if (!is_preview) {
+    page_size =
+        gfx::Size(static_cast<int>(page_layout_in_points.content_width *
+                                   params.params.max_shrink),
+                  static_cast<int>(page_layout_in_points.content_height *
+                                   params.params.max_shrink));
+  }
+
+  gfx::Rect canvas_area =
+      params.params.display_header_footer ? gfx::Rect(page_size) : content_area;
+
+  float webkit_page_shrink_factor =
+      frame->getPrintPageShrink(params.page_number);
+  float scale_factor = css_scale_factor * webkit_page_shrink_factor;
+
+  SkBaseDevice* device = metafile->StartPageForVectorCanvas(page_size,
+                                                            canvas_area,
+                                                            scale_factor);
+  if (!device)
+    return;
+
+  // The printPage method take a reference to the canvas we pass down, so it
+  // can't be a stack object.
+  skia::RefPtr<skia::VectorCanvas> canvas =
+      skia::AdoptRef(new skia::VectorCanvas(device));
+  MetafileSkiaWrapper::SetMetafileOnCanvas(*canvas, metafile);
+  skia::SetIsDraftMode(*canvas, is_print_ready_metafile_sent_);
+
+  if (params.params.display_header_footer) {
+    // |page_number| is 0-based, so 1 is added.
+    PrintHeaderAndFooter(canvas.get(), params.page_number + 1,
+      print_preview_context_.total_page_count(),
+      scale_factor,
+      page_layout_in_points, *header_footer_info_,
+      params.params);
+  }
+
+  float webkit_scale_factor = RenderPageContent(frame,
+                                                params.page_number,
+                                                canvas_area,
+                                                content_area,
+                                                scale_factor,
+                                                canvas.get());
+
+  if (*actual_shrink <= 0 || webkit_scale_factor <= 0) {
+    NOTREACHED() << "Printing page " << params.page_number << " failed.";
+  } else {
+    // While rendering certain plugins (PDF) to metafile, we might need to
+    // set custom scale factor. Update |actual_shrink| with custom scale
+    // if it is set on canvas.
+    // TODO(gene): We should revisit this solution for the next versions.
+    // Consider creating metafile of the right size (or resizable)
+    // https://code.google.com/p/chromium/issues/detail?id=126037
+    if (!MetafileSkiaWrapper::GetCustomScaleOnCanvas(
+            *canvas, actual_shrink)) {
+      // Update the dpi adjustment with the "page |actual_shrink|" calculated in
+      // webkit.
+      *actual_shrink /= (webkit_scale_factor * css_scale_factor);
+    }
+  }
+
+  // Done printing. Close the device context to retrieve the compiled metafile.
+  if (!metafile->FinishPage())
+    NOTREACHED() << "metafile failed";
+}
+
+bool PrintWebViewHelper::CopyMetafileDataToSharedMem(
+    Metafile* metafile, base::SharedMemoryHandle* shared_mem_handle) {
+  uint32 buf_size = metafile->GetDataSize();
+  base::SharedMemory shared_buf;
+  // Allocate a shared memory buffer to hold the generated metafile data.
+  if (!shared_buf.CreateAndMapAnonymous(buf_size)) {
+    NOTREACHED() << "Buffer allocation failed";
+    return false;
+  }
+
+  // Copy the bits into shared memory.
+  if (!metafile->GetData(shared_buf.memory(), buf_size)) {
+    NOTREACHED() << "GetData() failed";
+    shared_buf.Unmap();
+    return false;
+  }
+  shared_buf.GiveToProcess(base::GetCurrentProcessHandle(), shared_mem_handle);
+  shared_buf.Unmap();
+
+  Send(new PrintHostMsg_DuplicateSection(routing_id(), *shared_mem_handle,
+                                         shared_mem_handle));
+  return true;
+}
+
+}  // namespace printing