Restore DC before EndPage call to state if was just after StartPage. We need this because EndPage clips page with current clipping region.

BUG=71509
TEST=unittest

Review URL: https://chromiumcodereview.appspot.com/10557019

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@143119 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 49 insertions, 38 deletions

diff --git a/printing/emf_win.cc b/printing/emf_win.cc
index 984c8b3..3634cbd 100644
--- a/printing/emf_win.cc
+++ b/printing/emf_win.cc
@@ -109,10 +109,12 @@ bool Emf::SafePlayback(HDC context) const {
     NOTREACHED();
     return false;
   }
+  Emf::EnumerationContext playback_context;
+  playback_context.base_matrix = &base_matrix;
   return EnumEnhMetaFile(context,
                          emf_,
                          &Emf::SafePlaybackProc,
-                         reinterpret_cast<void*>(&base_matrix),
+                         reinterpret_cast<void*>(&playback_context),
                          &GetPageBounds(1).ToRECT()) != 0;
 }
 
@@ -190,32 +192,34 @@ int CALLBACK Emf::SafePlaybackProc(HDC hdc,
                                    const ENHMETARECORD* record,
                                    int objects_count,
                                    LPARAM param) {
-  const XFORM* base_matrix = reinterpret_cast<const XFORM*>(param);
-  EnumerationContext context;
-  context.handle_table = handle_table;
-  context.objects_count = objects_count;
-  context.hdc = hdc;
-  Record record_instance(&context, record);
-  bool success = record_instance.SafePlayback(base_matrix);
+  Emf::EnumerationContext* context =
+      reinterpret_cast<Emf::EnumerationContext*>(param);
+  context->handle_table = handle_table;
+  context->objects_count = objects_count;
+  context->hdc = hdc;
+  Record record_instance(record);
+  bool success = record_instance.SafePlayback(context);
   DCHECK(success);
   return 1;
 }
 
-Emf::Record::Record(const EnumerationContext* context,
-                    const ENHMETARECORD* record)
-    : record_(record),
-      context_(context) {
+Emf::EnumerationContext::EnumerationContext() {
+  memset(this, 0, sizeof(*this));
+}
+
+Emf::Record::Record(const ENHMETARECORD* record)
+    : record_(record) {
   DCHECK(record_);
 }
 
-bool Emf::Record::Play() const {
-  return 0 != PlayEnhMetaFileRecord(context_->hdc,
-                                    context_->handle_table,
+bool Emf::Record::Play(Emf::EnumerationContext* context) const {
+  return 0 != PlayEnhMetaFileRecord(context->hdc,
+                                    context->handle_table,
                                     record_,
-                                    context_->objects_count);
+                                    context->objects_count);
 }
 
-bool Emf::Record::SafePlayback(const XFORM* base_matrix) const {
+bool Emf::Record::SafePlayback(Emf::EnumerationContext* context) const {
   // For EMF field description, see [MS-EMF] Enhanced Metafile Format
   // Specification.
   //
@@ -259,7 +263,8 @@ bool Emf::Record::SafePlayback(const XFORM* base_matrix) const {
   // We also process any custom EMR_GDICOMMENT records which are our
   // placeholders for StartPage and EndPage.
   // Note: I should probably care about view ports and clipping, eventually.
-  bool res;
+  bool res = false;
+  const XFORM* base_matrix = context->base_matrix;
   switch (record()->iType) {
     case EMR_STRETCHDIBITS: {
       const EMRSTRETCHDIBITS * sdib_record =
@@ -271,7 +276,7 @@ bool Emf::Record::SafePlayback(const XFORM* base_matrix) const {
       const BYTE* bits = record_start + sdib_record->offBitsSrc;
       bool play_normally = true;
       res = false;
-      HDC hdc = context_->hdc;
+      HDC hdc = context->hdc;
       scoped_ptr<SkBitmap> bitmap;
       if (bmih->biCompression == BI_JPEG) {
         if (!DIBFormatNativelySupported(hdc, CHECKJPEGFORMAT, bits,
@@ -311,14 +316,14 @@ bool Emf::Record::SafePlayback(const XFORM* base_matrix) const {
                                     sdib_record->dwRop));
         }
       } else {
-        res = Play();
+        res = Play(context);
       }
       break;
     }
     case EMR_SETWORLDTRANSFORM: {
       DCHECK_EQ(record()->nSize, sizeof(DWORD) * 2 + sizeof(XFORM));
       const XFORM* xform = reinterpret_cast<const XFORM*>(record()->dParm);
-      HDC hdc = context_->hdc;
+      HDC hdc = context->hdc;
       if (base_matrix) {
         res = 0 != SetWorldTransform(hdc, base_matrix) &&
                    ModifyWorldTransform(hdc, xform, MWT_LEFTMULTIPLY);
@@ -332,7 +337,7 @@ bool Emf::Record::SafePlayback(const XFORM* base_matrix) const {
                 sizeof(DWORD) * 2 + sizeof(XFORM) + sizeof(DWORD));
       const XFORM* xform = reinterpret_cast<const XFORM*>(record()->dParm);
       const DWORD* option = reinterpret_cast<const DWORD*>(xform + 1);
-      HDC hdc = context_->hdc;
+      HDC hdc = context->hdc;
       switch (*option) {
         case MWT_IDENTITY:
           if (base_matrix) {
@@ -371,15 +376,20 @@ bool Emf::Record::SafePlayback(const XFORM* base_matrix) const {
             reinterpret_cast<const PageBreakRecord*>(comment_record->Data);
         if (page_break_record && page_break_record->IsValid()) {
           if (page_break_record->type == PageBreakRecord::START_PAGE) {
-            res = !!::StartPage(context_->hdc);
+            res = !!::StartPage(context->hdc);
+            DCHECK_EQ(0, context->dc_on_page_start);
+            context->dc_on_page_start = ::SaveDC(context->hdc);
           } else if (page_break_record->type == PageBreakRecord::END_PAGE) {
-            res = !!::EndPage(context_->hdc);
+            DCHECK_NE(0, context->dc_on_page_start);
+            ::RestoreDC(context->hdc, context->dc_on_page_start);
+            context->dc_on_page_start = 0;
+            res = !!::EndPage(context->hdc);
           } else {
             res = false;
             NOTREACHED();
           }
         } else {
-          res = Play();
+          res = Play(context);
         }
       } else {
         res = true;
@@ -387,7 +397,7 @@ bool Emf::Record::SafePlayback(const XFORM* base_matrix) const {
       break;
     }
     default: {
-      res = Play();
+      res = Play(context);
       break;
     }
   }
@@ -427,9 +437,6 @@ bool Emf::FinishPage() {
 }
 
 Emf::Enumerator::Enumerator(const Emf& emf, HDC context, const RECT* rect) {
-  context_.handle_table = NULL;
-  context_.objects_count = 0;
-  context_.hdc = NULL;
   items_.clear();
   if (!EnumEnhMetaFile(context,
                        emf.emf(),
@@ -467,7 +474,7 @@ int CALLBACK Emf::Enumerator::EnhMetaFileProc(HDC hdc,
     DCHECK_EQ(emf.context_.objects_count, objects_count);
     DCHECK_EQ(emf.context_.hdc, hdc);
   }
-  emf.items_.push_back(Record(&emf.context_, record));
+  emf.items_.push_back(Record(record));
   return 1;
 }
 
diff --git a/printing/emf_win.h b/printing/emf_win.h
index 8317627..b593e24 100644
--- a/printing/emf_win.h
+++ b/printing/emf_win.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.
 
@@ -113,9 +113,13 @@ class PRINTING_EXPORT Emf : public Metafile {
 };
 
 struct Emf::EnumerationContext {
+  EnumerationContext();
+
   HANDLETABLE* handle_table;
   int objects_count;
   HDC hdc;
+  const XFORM* base_matrix;
+  int dc_on_page_start;
 };
 
 // One EMF record. It keeps pointers to the EMF buffer held by Emf::emf_.
@@ -123,24 +127,22 @@ struct Emf::EnumerationContext {
 class PRINTING_EXPORT Emf::Record {
  public:
   // Plays the record.
-  bool Play() const;
+  bool Play(EnumerationContext* context) const;
 
   // Plays the record working around quirks with SetLayout,
   // SetWorldTransform and ModifyWorldTransform. See implementation for details.
-  bool SafePlayback(const XFORM* base_matrix) const;
+  bool SafePlayback(EnumerationContext* context) const;
 
   // Access the underlying EMF record.
   const ENHMETARECORD* record() const { return record_; }
 
  protected:
-  Record(const EnumerationContext* context,
-         const ENHMETARECORD* record);
+  explicit Record(const ENHMETARECORD* record);
 
  private:
   friend class Emf;
   friend class Enumerator;
   const ENHMETARECORD* record_;
-  const EnumerationContext* context_;
 };
 
 // Retrieves individual records out of a Emf buffer. The main use is to skip
@@ -163,6 +165,8 @@ class PRINTING_EXPORT Emf::Enumerator {
   const_iterator end() const;
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(EmfPrintingTest, Enumerate);
+
   // Processes one EMF record and saves it in the items_ array.
   static int CALLBACK EnhMetaFileProc(HDC hdc,
                                       HANDLETABLE* handle_table,
diff --git a/printing/emf_win_unittest.cc b/printing/emf_win_unittest.cc
index add23f9..8d07213 100644
--- a/printing/emf_win_unittest.cc
+++ b/printing/emf_win_unittest.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.
 
@@ -116,7 +116,7 @@ TEST_F(EmfPrintingTest, Enumerate) {
     // If you get this assert, you need to lookup iType in wingdi.h. It starts
     // with EMR_HEADER.
     EMR_HEADER;
-    EXPECT_TRUE(itr->SafePlayback(NULL)) <<
+    EXPECT_TRUE(itr->SafePlayback(&emf_enum.context_)) <<
         " index: " << index << " type: " << itr->record()->iType;
   }
   context->PageDone();