Fix printing with XPS printers on Windows.

printing/print_settings_initializer_win.cc

Index: printing/print_settings_initializer_win.cc
diff --git a/printing/print_settings_initializer_win.cc b/printing/print_settings_initializer_win.cc
index c10562b86c5854284da58a7cc0bae93723ff1857..9c3727e73768daf539cd42e36eeb08fecec4bf71 100644
--- a/printing/print_settings_initializer_win.cc
+++ b/printing/print_settings_initializer_win.cc
@@ -10,6 +10,31 @@
 
 namespace printing {
 
+namespace {
+
+bool IsPrinterXPS(HDC hdc) {
+  int device_type = ::GetDeviceCaps(hdc, TECHNOLOGY);
+  if (device_type != DT_RASPRINTER)
+    return false;
+
+  const int escape = GETTECHNOLOGY;

[scottmg, 2016/10/05 23:21:40]

nit; DWORD since that's what the docs say.

https://msdn.microsoft.com/en-us/library/windows/desktop/dd144931(v=vs.85).aspx
implies you can just call the second one and it'll return 0 though so maybe you
don't need to call it at all?

[Lei Zhang, 2016/10/05 23:37:56]

Done.
I tested with several printers that are known to not support GETTECHNOLOGY and
called ExtEscape with GETTECHNOLOGY anyway.

- Some returned 0
- Some returned 1, and did not appear to write to |buffer|.

It feels like this is getting into undefined territory, so I'll stick with the
QUERYESCSUPPORT check to avoid potentially upsetting some fragile printer
driver.

+  const char* escape_ptr = reinterpret_cast<const char*>(&escape);
+  int ret =
+      ExtEscape(hdc, QUERYESCSUPPORT, sizeof(escape), escape_ptr, 0, nullptr);
+  if (ret <= 0)
+    return false;
+
+  char buffer[256] = {'\0'};
+  ret = ExtEscape(hdc, GETTECHNOLOGY, 0, nullptr, sizeof(buffer), buffer);
+  if (ret <= 0)
+    return false;
+
+  static const char kXPSDriver[] = "http://schemas.microsoft.com/xps/2005/06";
+  return strcmp(buffer, kXPSDriver) == 0;
+}
+
+}  // namespace
+
 // static
 void PrintSettingsInitializerWin::InitPrintSettings(
     HDC hdc,
@@ -17,23 +42,26 @@ void PrintSettingsInitializerWin::InitPrintSettings(
     PrintSettings* print_settings) {
   DCHECK(hdc);
   DCHECK(print_settings);
+
   print_settings->SetOrientation(dev_mode.dmOrientation == DMORIENT_LANDSCAPE);
 
   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
-  // support different dpi settings in X and Y axis.
+  // applications that it's not even needed to care about. Blink doesn't support
+  // different dpi settings in X and Y axis.
   DCHECK_EQ(dpi, GetDeviceCaps(hdc, LOGPIXELSY));
 
   DCHECK_EQ(GetDeviceCaps(hdc, SCALINGFACTORX), 0);
   DCHECK_EQ(GetDeviceCaps(hdc, SCALINGFACTORY), 0);
 
-  // Initialize page_setup_device_units_.
+  // Initialize |page_setup_device_units_|.
   gfx::Size physical_size_device_units(GetDeviceCaps(hdc, PHYSICALWIDTH),
                                        GetDeviceCaps(hdc, PHYSICALHEIGHT));
   gfx::Rect printable_area_device_units(GetDeviceCaps(hdc, PHYSICALOFFSETX),
@@ -52,6 +80,8 @@ void PrintSettingsInitializerWin::InitPrintSettings(
   print_settings->SetPrinterPrintableArea(physical_size_device_units,
                                           printable_area_device_units,
                                           false);
+
+  print_settings->set_printer_is_xps(IsPrinterXPS(hdc));
 }
 
 }  // namespace printing