A better fix for scaling issue.

Instead of using TLS and static function, pass scaling in the skia dictionary.

BUG=125499
TEST=Make sure printing is working.

Review URL: https://chromiumcodereview.appspot.com/10387022

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@136055 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 40 insertions, 110 deletions

diff --git a/chrome/renderer/print_web_view_helper_win.cc b/chrome/renderer/print_web_view_helper_win.cc
index 8f2e3f4..7b1916b 100644
--- a/chrome/renderer/print_web_view_helper_win.cc
+++ b/chrome/renderer/print_web_view_helper_win.cc
@@ -12,7 +12,6 @@
 #include "base/win/scoped_hdc.h"
 #include "base/win/scoped_select_object.h"
 #include "chrome/common/print_messages.h"
-#include "printing/custom_scaling.h"
 #include "printing/metafile.h"
 #include "printing/metafile_impl.h"
 #include "printing/metafile_skia_wrapper.h"
@@ -118,41 +117,11 @@ void PrintWebViewHelper::PrintPageInternal(
   gfx::Size page_size_in_dpi;
   gfx::Rect content_area_in_dpi;
 
-  // If we are printing PDF, it may not fit into metafile using 72dpi.
-  // (Metafile is based on screen resolution here.)
-  // (See http://code.google.com/p/chromium-os/issues/detail?id=16088)
-  // If PDF plugin encounter this issue it will save custom scale in TLS,
-  // so we can apply the same scaling factor here.
-  // If will do so ONLY if default scaling does not work.
-  // TODO(gene): We should revisit this solution for the next versions.
-  // Two possible solutions:
-  // We can create metafile of the right size (or resizable)
-  // https://code.google.com/p/chromium/issues/detail?id=126037
-  // or
-  // We should return scale factor all the way from the plugin:
-  //   webkit::ppapi::PluginInstance::PrintPDFOutput - scale calculated here
-  //   webkit::ppapi::PluginInstance::PrintPageHelper
-  //   webkit::ppapi::PluginInstance::PrintPage
-  //   webkit::ppapi::WebPluginImpl::printPage
-  //   WebKit::WebPluginContainerImpl::printPage
-  //   WebKit::ChromePluginPrintContext::spoolPage - always return 1.0 scale
-  //   WebKit::WebFrameImpl::printPage
-  //   PrintWebViewHelper::RenderPage
-  //   PrintWebViewHelper::PrintPageInternal
-
-  printing::ClearCustomPrintingPageScale();
-
   // Render page for printing.
   metafile.reset(RenderPage(params.params, page_number, frame, false,
                             metafile.get(), &actual_shrink, &page_size_in_dpi,
                             &content_area_in_dpi));
 
-  double custom_scale;
-  if (printing::GetCustomPrintingPageScale(&custom_scale)) {
-    actual_shrink = custom_scale;
-    printing::ClearCustomPrintingPageScale();
-  }
-
   // Close the device context to retrieve the compiled metafile.
   if (!metafile->FinishDocument())
     NOTREACHED();
@@ -286,9 +255,18 @@ Metafile* PrintWebViewHelper::RenderPage(
   if (*actual_shrink <= 0 || webkit_scale_factor <= 0) {
     NOTREACHED() << "Printing page " << page_number << " failed.";
   } else {
-    // Update the dpi adjustment with the "page |actual_shrink|" calculated in
-    // webkit.
-    *actual_shrink /= (webkit_scale_factor * css_scale_factor);
+    // 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 (!printing::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);
+    }
   }
 
   bool result = metafile->FinishPage();
diff --git a/printing/custom_scaling.cc b/printing/custom_scaling.cc
deleted file mode 100644
index dead79c..0000000
--- a/printing/custom_scaling.cc
+++ /dev/null
@@ -1,37 +0,0 @@
-// 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 "printing/custom_scaling.h"
-
-#include "base/threading/thread_local.h"
-
-namespace printing {
-
-static base::ThreadLocalPointer<double> gPrintingPageScale;
-
-bool GetCustomPrintingPageScale(double* scale) {
-  double* ptr = gPrintingPageScale.Get();
-  if (ptr != NULL) {
-    *scale = *ptr;
-  }
-  return ptr != NULL;
-}
-
-void SetCustomPrintingPageScale(double scale) {
-  ClearCustomPrintingPageScale();
-  double* ptr = new double;
-  *ptr = scale;
-  gPrintingPageScale.Set(ptr);
-}
-
-void ClearCustomPrintingPageScale() {
-  double* ptr = gPrintingPageScale.Get();
-  if (ptr != NULL) {
-    delete ptr;
-  }
-  gPrintingPageScale.Set(NULL);
-}
-
-}  // namespace printing
-
diff --git a/printing/custom_scaling.h b/printing/custom_scaling.h
deleted file mode 100644
index 3f46d2e..0000000
--- a/printing/custom_scaling.h
+++ /dev/null
@@ -1,33 +0,0 @@
-// 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.
-
-#ifndef PRINTING_CUSTOM_SCALING_H_
-#define PRINTING_CUSTOM_SCALING_H_
-
-#include "printing/printing_export.h"
-
-namespace printing {
-
-// This set of function allows plugin to set custom printing scale in the
-// thread local storage. It is a hack to pass scale through this, but
-// alternative is to do major refactoring to pass this scale factor all the
-// from plugin through webkit to the upper level.
-// We should definitely revisit this approach in favor of better implementation
-// later. In the mean time, this looks like a simplest way fixing printing
-// issues now.
-
-// Gets custom printing scale from the TLS. Return false if it has not been
-// set.
-PRINTING_EXPORT bool GetCustomPrintingPageScale(double* scale);
-
-// Sets custom printing scale in TLS.
-PRINTING_EXPORT void SetCustomPrintingPageScale(double scale);
-
-// Clears custom printing scale in TLS.
-PRINTING_EXPORT void ClearCustomPrintingPageScale();
-
-}  // namespace printing
-
-#endif  // PRINTING_CUSTOM_SCALING_H_
-
diff --git a/printing/metafile_skia_wrapper.cc b/printing/metafile_skia_wrapper.cc
index ee24a66..d4634ef 100644
--- a/printing/metafile_skia_wrapper.cc
+++ b/printing/metafile_skia_wrapper.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -13,6 +13,7 @@ namespace printing {
 namespace {
 
 const char* kMetafileKey = "CrMetafile";
+const char* kCustomScaleKey = "CrCustomScale";
 
 }  // namespace
 
@@ -38,6 +39,25 @@ Metafile* MetafileSkiaWrapper::GetMetafileFromCanvas(const SkCanvas& canvas) {
   return static_cast<MetafileSkiaWrapper*>(value)->metafile_;
 }
 
+// static
+void MetafileSkiaWrapper::SetCustomScaleOnCanvas(const SkCanvas& canvas,
+                                                 double scale) {
+  SkMetaData& meta = skia::getMetaData(canvas);
+  meta.setScalar(kCustomScaleKey, SkFloatToScalar(scale));
+}
+
+// static
+bool MetafileSkiaWrapper::GetCustomScaleOnCanvas(const SkCanvas& canvas,
+                                                 double* scale) {
+  SkMetaData& meta = skia::getMetaData(canvas);
+  SkScalar value;
+  if (!meta.findScalar(kCustomScaleKey, &value))
+    return false;
+
+  *scale = SkScalarToFloat(value);
+  return true;
+}
+
 MetafileSkiaWrapper::MetafileSkiaWrapper(Metafile* metafile)
     : metafile_(metafile) {
 }
diff --git a/printing/metafile_skia_wrapper.h b/printing/metafile_skia_wrapper.h
index 9010449..42bbc5f 100644
--- a/printing/metafile_skia_wrapper.h
+++ b/printing/metafile_skia_wrapper.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -24,6 +24,10 @@ class PRINTING_EXPORT MetafileSkiaWrapper : public SkRefCnt {
 
   static Metafile* GetMetafileFromCanvas(const SkCanvas& canvas);
 
+  // Methods to set and retrieve custom scale factor for metafile from canvas.
+  static void SetCustomScaleOnCanvas(const SkCanvas& canvas, double scale);
+  static bool GetCustomScaleOnCanvas(const SkCanvas& canvas, double* scale);
+
  private:
   explicit MetafileSkiaWrapper(Metafile* metafile);
 
diff --git a/printing/printing.gyp b/printing/printing.gyp
index c9c9790..7d02e60 100644
--- a/printing/printing.gyp
+++ b/printing/printing.gyp
@@ -32,8 +32,6 @@
         'backend/print_backend_consts.cc',
         'backend/print_backend_consts.h',
         'backend/print_backend_dummy.cc',
-        'custom_scaling.cc',
-        'custom_scaling.h',
         'emf_win.cc',
         'emf_win.h',
         'image.cc',
diff --git a/webkit/plugins/ppapi/ppapi_plugin_instance.cc b/webkit/plugins/ppapi/ppapi_plugin_instance.cc
index 140d7af..9ea522c 100644
--- a/webkit/plugins/ppapi/ppapi_plugin_instance.cc
+++ b/webkit/plugins/ppapi/ppapi_plugin_instance.cc
@@ -38,7 +38,6 @@
 #include "ppapi/shared_impl/var.h"
 #include "ppapi/thunk/enter.h"
 #include "ppapi/thunk/ppb_buffer_api.h"
-#include "printing/custom_scaling.h"
 #include "printing/units.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkRect.h"
@@ -1485,7 +1484,8 @@ bool PluginInstance::PrintPDFOutput(PP_Resource print_output,
 
     if (dynamic_scale < page_scale) {
       page_scale = dynamic_scale;
-      printing::SetCustomPrintingPageScale(page_scale);
+      printing::MetafileSkiaWrapper::SetCustomScaleOnCanvas(*canvas,
+                                                            page_scale);
     }
 
     gfx::ScaleDC(dc, page_scale);