When printing a page containing alpha blending on a printer which doesn't support alpha blending, post-process the

metafile to replace the AlphaBlend calls with BitBlts from a software-composited rendering of the page so far.

BUG=7434
TEST=see bug

Review URL: http://codereview.chromium.org/5362002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@71177 0039d316-1c4b-4281-b951-d872f2087c98

10 files changed, 134 insertions, 12 deletions

diff --git a/chrome/browser/renderer_host/render_message_filter.cc b/chrome/browser/renderer_host/render_message_filter.cc
index 73af165..a0696b5 100644
--- a/chrome/browser/renderer_host/render_message_filter.cc
+++ b/chrome/browser/renderer_host/render_message_filter.cc
@@ -162,6 +162,7 @@ void RenderParamsFromPrintSettings(const printing::PrintSettings& settings,
   // Always use an invalid cookie.
   params->document_cookie = 0;
   params->selection_only = settings.selection_only;
+  params->supports_alpha_blend = settings.supports_alpha_blend();
 }
 
 class ClearCacheCompletion : public net::CompletionCallback {
diff --git a/chrome/common/render_messages_params.cc b/chrome/common/render_messages_params.cc
index 7fab193..a05266c 100644
--- a/chrome/common/render_messages_params.cc
+++ b/chrome/common/render_messages_params.cc
@@ -81,7 +81,8 @@ ViewMsg_Print_Params::ViewMsg_Print_Params()
       max_shrink(0),
       desired_dpi(0),
       document_cookie(0),
-      selection_only(false) {
+      selection_only(false),
+      supports_alpha_blend(true) {
 }
 
 ViewMsg_Print_Params::~ViewMsg_Print_Params() {
@@ -96,13 +97,15 @@ bool ViewMsg_Print_Params::Equals(const ViewMsg_Print_Params& rhs) const {
          min_shrink == rhs.min_shrink &&
          max_shrink == rhs.max_shrink &&
          desired_dpi == rhs.desired_dpi &&
-         selection_only == rhs.selection_only;
+         selection_only == rhs.selection_only &&
+         supports_alpha_blend == rhs.supports_alpha_blend;
 }
 
 bool ViewMsg_Print_Params::IsEmpty() const {
   return !document_cookie && !desired_dpi && !max_shrink && !min_shrink &&
          !dpi && printable_size.IsEmpty() && !selection_only &&
-         page_size.IsEmpty() && !margin_top && !margin_left;
+         page_size.IsEmpty() && !margin_top && !margin_left &&
+         !supports_alpha_blend;
 }
 
 ViewMsg_PrintPage_Params::ViewMsg_PrintPage_Params()
@@ -952,6 +955,7 @@ void ParamTraits<ViewMsg_Print_Params>::Write(Message* m, const param_type& p) {
   WriteParam(m, p.desired_dpi);
   WriteParam(m, p.document_cookie);
   WriteParam(m, p.selection_only);
+  WriteParam(m, p.supports_alpha_blend);
 }
 
 bool ParamTraits<ViewMsg_Print_Params>::Read(const Message* m,
@@ -966,7 +970,8 @@ bool ParamTraits<ViewMsg_Print_Params>::Read(const Message* m,
       ReadParam(m, iter, &p->max_shrink) &&
       ReadParam(m, iter, &p->desired_dpi) &&
       ReadParam(m, iter, &p->document_cookie) &&
-      ReadParam(m, iter, &p->selection_only);
+      ReadParam(m, iter, &p->selection_only) &&
+      ReadParam(m, iter, &p->supports_alpha_blend);
 }
 
 void ParamTraits<ViewMsg_Print_Params>::Log(const param_type& p,
diff --git a/chrome/common/render_messages_params.h b/chrome/common/render_messages_params.h
index 97817d2..0523fdf 100644
--- a/chrome/common/render_messages_params.h
+++ b/chrome/common/render_messages_params.h
@@ -520,6 +520,9 @@ struct ViewMsg_Print_Params {
   // Should only print currently selected text.
   bool selection_only;
 
+  // Does the printer support alpha blending?
+  bool supports_alpha_blend;
+
   // Warning: do not compare document_cookie.
   bool Equals(const ViewMsg_Print_Params& rhs) const;
 
@@ -552,7 +555,7 @@ struct ViewMsg_PrintPages_Params {
   std::vector<int> pages;
 };
 
-//Parameters to describe a rendered document.
+// Parameters to describe a rendered document.
 struct ViewHostMsg_DidPreviewDocument_Params {
   ViewHostMsg_DidPreviewDocument_Params();
   ~ViewHostMsg_DidPreviewDocument_Params();
diff --git a/chrome/renderer/print_web_view_helper_win.cc b/chrome/renderer/print_web_view_helper_win.cc
index bd1e595..22c6e00 100644
--- a/chrome/renderer/print_web_view_helper_win.cc
+++ b/chrome/renderer/print_web_view_helper_win.cc
@@ -8,11 +8,13 @@
 #include "chrome/common/render_messages.h"
 #include "chrome/common/render_messages_params.h"
 #include "chrome/renderer/render_view.h"
+#include "gfx/gdi_util.h"
 #include "gfx/size.h"
 #include "grit/generated_resources.h"
 #include "printing/native_metafile.h"
 #include "printing/units.h"
 #include "skia/ext/vector_canvas.h"
+#include "skia/ext/vector_platform_device.h"
 #include "third_party/WebKit/WebKit/chromium/public/WebFrame.h"
 
 using printing::ConvertUnitDouble;
@@ -20,6 +22,46 @@ using printing::kPointsPerInch;
 using WebKit::WebFrame;
 using WebKit::WebString;
 
+int CALLBACK EnhMetaFileProc(HDC dc,
+                             HANDLETABLE* handle_table,
+                             const ENHMETARECORD *record,
+                             int num_objects,
+                             LPARAM data) {
+  HDC* bitmap_dc = reinterpret_cast<HDC*>(data);
+  // Play this command to the bitmap DC.
+  PlayEnhMetaFileRecord(*bitmap_dc, handle_table, record, num_objects);
+  if (record->iType == EMR_ALPHABLEND) {
+    const EMRALPHABLEND* emr_alpha_blend =
+        reinterpret_cast<const EMRALPHABLEND*>(record);
+    XFORM bitmap_dc_transform, metafile_dc_transform;
+    XFORM identity = { 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f };
+    // Temporarily set the world transforms of both DC's to identity.
+    GetWorldTransform(dc, &metafile_dc_transform);
+    SetWorldTransform(dc, &identity);
+    GetWorldTransform(*bitmap_dc, &bitmap_dc_transform);
+    SetWorldTransform(*bitmap_dc, &identity);
+    const RECTL& rect = emr_alpha_blend->rclBounds;
+    // Since the printer does not support alpha blend, copy the alpha blended
+    // region from our (software-rendered) bitmap DC to the metafile DC.
+    BitBlt(dc,
+           rect.left,
+           rect.top,
+           rect.right - rect.left + 1,
+           rect.bottom - rect.top + 1,
+           *bitmap_dc,
+           rect.left,
+           rect.top,
+           SRCCOPY);
+    // Restore the world transforms of both DC's.
+    SetWorldTransform(dc, &metafile_dc_transform);
+    SetWorldTransform(*bitmap_dc, &bitmap_dc_transform);
+  } else {
+    // Play this command to the metafile DC.
+    PlayEnhMetaFileRecord(dc, handle_table, record, num_objects);
+  }
+  return 1;  // Continue enumeration
+}
+
 void PrintWebViewHelper::PrintPage(const ViewMsg_PrintPage_Params& params,
                                    const gfx::Size& canvas_size,
                                    WebFrame* frame) {
@@ -64,8 +106,8 @@ void PrintWebViewHelper::PrintPage(const ViewMsg_PrintPage_Params& params,
 
   // Mix of Skia and GDI based.
   skia::PlatformCanvas canvas(size_x, size_y, true);
-  canvas.drawARGB(255, 255, 255, 255, SkPorterDuff::kSrc_Mode);
-  float webkit_shrink = frame->PrintPage(params.page_number, &canvas);
+  canvas.drawARGB(255, 255, 255, 255, SkXfermode::kSrc_Mode);
+  float webkit_shrink = frame->printPage(params.page_number, &canvas);
   if (shrink <= 0 || webkit_shrink <= 0) {
     NOTREACHED() << "Printing page " << params.page_number << " failed.";
   } else {
@@ -105,9 +147,59 @@ void PrintWebViewHelper::PrintPage(const ViewMsg_PrintPage_Params& params,
   if (!metafile.CloseDc()) {
     NOTREACHED() << "metafile failed";
   }
+  printing::NativeMetafile* mf = &metafile;
+  printing::NativeMetafile metafile2;
+
+  skia::VectorPlatformDevice* platform_device =
+    static_cast<skia::VectorPlatformDevice*>(canvas.getDevice());
+  if (platform_device->alpha_blend_used() &&
+      !params.params.supports_alpha_blend) {
+    // Page used alpha blend, but printer doesn't support it.  Rewrite the
+    // metafile and flatten out the transparency.
+    HDC bitmap_dc = CreateCompatibleDC(GetDC(NULL));
+    if (!bitmap_dc) {
+      NOTREACHED() << "Bitmap DC creation failed";
+    }
+    SetGraphicsMode(bitmap_dc, GM_ADVANCED);
+    void* bits = NULL;
+    BITMAPINFO hdr;
+    gfx::CreateBitmapHeader(size_x, size_y, &hdr.bmiHeader);
+    HBITMAP hbitmap = CreateDIBSection(
+        bitmap_dc, &hdr, DIB_RGB_COLORS, &bits, NULL, 0);
+    if (!hbitmap) {
+      NOTREACHED() << "Raster bitmap creation for printing failed";
+    }
+
+    HGDIOBJ old_bitmap = SelectObject(bitmap_dc, hbitmap);
+    RECT rect = {0, 0, size_x, size_y };
+    HBRUSH whiteBrush = static_cast<HBRUSH>(GetStockObject(WHITE_BRUSH));
+    FillRect(bitmap_dc, &rect, whiteBrush);
+
+    metafile2.CreateDc(NULL, NULL);
+    HDC hdc = metafile2.hdc();
+    DCHECK(hdc);
+    skia::PlatformDevice::InitializeDC(hdc);
+
+    RECT metafile_bounds = metafile.GetBounds().ToRECT();
+    // Process the old metafile, placing all non-AlphaBlend calls into the
+    // new metafile, and copying the results of all the AlphaBlend calls
+    // from the bitmap DC.
+    EnumEnhMetaFile(hdc,
+                    metafile.emf(),
+                    EnhMetaFileProc,
+                    &bitmap_dc,
+                    &metafile_bounds);
+
+    SelectObject(bitmap_dc, old_bitmap);
+
+    if (!metafile2.CloseDc()) {
+      NOTREACHED() << "metafile failed";
+    }
+    mf = &metafile2;
+  }
 
   // Get the size of the compiled metafile.
-  uint32 buf_size = metafile.GetDataSize();
+  uint32 buf_size = mf->GetDataSize();
   DCHECK_GT(buf_size, 128u);
   ViewHostMsg_DidPrintPage_Params page_params;
   page_params.data_size = 0;
@@ -144,7 +236,7 @@ void PrintWebViewHelper::PrintPage(const ViewMsg_PrintPage_Params& params,
     // Allocate a shared memory buffer to hold the generated metafile data.
     if (shared_buf.CreateAndMapAnonymous(buf_size)) {
       // Copy the bits into shared memory.
-      if (metafile.GetData(shared_buf.memory(), buf_size)) {
+      if (mf->GetData(shared_buf.memory(), buf_size)) {
         page_params.metafile_data_handle = shared_buf.handle();
         page_params.data_size = buf_size;
       } else {
@@ -157,7 +249,7 @@ void PrintWebViewHelper::PrintPage(const ViewMsg_PrintPage_Params& params,
   } else {
     NOTREACHED() << "Buffer too large: " << buf_size;
   }
-  metafile.CloseEmf();
+  mf->CloseEmf();
   if (Send(new ViewHostMsg_DuplicateSection(
       routing_id(),
       page_params.metafile_data_handle,
diff --git a/printing/emf_win.cc b/printing/emf_win.cc
index 9629bb2..5de962b 100644
--- a/printing/emf_win.cc
+++ b/printing/emf_win.cc
@@ -396,6 +396,8 @@ bool Emf::Record::SafePlayback(const XFORM* base_matrix) const {
         } else {
           res = Play();
         }
+      } else {
+        res = true;
       }
       break;
     }
diff --git a/printing/print_settings.cc b/printing/print_settings.cc
index cf8c50a..3f0f842 100644
--- a/printing/print_settings.cc
+++ b/printing/print_settings.cc
@@ -19,7 +19,8 @@ PrintSettings::PrintSettings()
       selection_only(false),
       use_overlays(true),
       dpi_(0),
-      landscape_(false) {
+      landscape_(false),
+      supports_alpha_blend_(true) {
 }
 
 PrintSettings::~PrintSettings() {
@@ -36,6 +37,7 @@ void PrintSettings::Clear() {
   page_setup_device_units_.Clear();
   dpi_ = 0;
   landscape_ = false;
+  supports_alpha_blend_ = true;
 }
 
 void PrintSettings::SetPrinterPrintableArea(
diff --git a/printing/print_settings.h b/printing/print_settings.h
index bc9cbaf..298fcd2 100644
--- a/printing/print_settings.h
+++ b/printing/print_settings.h
@@ -42,6 +42,10 @@ class PrintSettings {
   const std::wstring& device_name() const { return device_name_; }
   void set_dpi(int dpi) { dpi_ = dpi; }
   int dpi() const { return dpi_; }
+  void set_supports_alpha_blend(bool supports_alpha_blend) {
+    supports_alpha_blend_ = supports_alpha_blend;
+  }
+  bool supports_alpha_blend() const { return supports_alpha_blend_; }
   const PageSetup& page_setup_device_units() const {
     return page_setup_device_units_;
   }
@@ -108,6 +112,9 @@ class PrintSettings {
 
   // Is the orientation landscape or portrait.
   bool landscape_;
+
+  // True if this printer supports AlphaBlend.
+  bool supports_alpha_blend_;
 };
 
 }  // namespace printing
diff --git a/printing/print_settings_initializer_win.cc b/printing/print_settings_initializer_win.cc
index f840f4d..065a8db 100644
--- a/printing/print_settings_initializer_win.cc
+++ b/printing/print_settings_initializer_win.cc
@@ -29,6 +29,9 @@ void PrintSettingsInitializerWin::InitPrintSettings(
 
   int dpi = GetDeviceCaps(hdc, LOGPIXELSX);
   print_settings->set_dpi(dpi);
+  const int kAlphaCaps = SB_CONST_ALPHA | SB_PIXEL_ALPHA;
+  print_settings->set_supports_alpha_blend(
+    (GetDeviceCaps(hdc, SHADEBLENDCAPS) & kAlphaCaps) == kAlphaCaps);
   // No printer device is known to advertise different dpi in X and Y axis; even
   // the fax device using the 200x100 dpi setting. It's ought to break so many
   // applications that it's not even needed to care about. WebKit doesn't
diff --git a/skia/ext/vector_platform_device_win.cc b/skia/ext/vector_platform_device_win.cc
index 31ac722..6ec4e39 100644
--- a/skia/ext/vector_platform_device_win.cc
+++ b/skia/ext/vector_platform_device_win.cc
@@ -104,7 +104,8 @@ VectorPlatformDevice::VectorPlatformDevice(HDC dc, const SkBitmap& bitmap)
     : PlatformDevice(bitmap),
       hdc_(dc),
       previous_brush_(NULL),
-      previous_pen_(NULL) {
+      previous_pen_(NULL),
+      alpha_blend_used_(false) {
   transform_.reset();
 }
 
@@ -698,6 +699,8 @@ void VectorPlatformDevice::InternalDrawBitmap(const SkBitmap& bitmap,
     result = SetStretchBltMode(dc, previous_mode);
     SkASSERT(result);
 
+    alpha_blend_used_ = true;
+
     ::SelectObject(bitmap_dc, static_cast<HBITMAP>(old_bitmap));
     DeleteObject(hbitmap);
     DeleteDC(bitmap_dc);
diff --git a/skia/ext/vector_platform_device_win.h b/skia/ext/vector_platform_device_win.h
index 2a5057e..3050a90 100644
--- a/skia/ext/vector_platform_device_win.h
+++ b/skia/ext/vector_platform_device_win.h
@@ -81,6 +81,7 @@ class VectorPlatformDevice : public PlatformDevice {
   virtual bool IsVectorial() { return true; }
 
   void LoadClipRegion();
+  bool alpha_blend_used() const { return alpha_blend_used_; }
 
  private:
   // Applies the SkPaint's painting properties in the current GDI context, if
@@ -129,6 +130,9 @@ class VectorPlatformDevice : public PlatformDevice {
   // Previously selected pen before the current drawing.
   HGDIOBJ previous_pen_;
 
+  // True if AlphaBlend() was called during this print.
+  bool alpha_blend_used_;
+
   // Copy & assign are not supported.
   VectorPlatformDevice(const VectorPlatformDevice&);
   const VectorPlatformDevice& operator=(const VectorPlatformDevice&);