Improve postscript language level detection

printing/print_settings_initializer_win.cc

 // Copyright (c) 2011 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/print_settings_initializer_win.h"
 
 #include <windows.h>
 
 #include "printing/print_settings.h"
 
 namespace printing {
 
 namespace {
 
 bool HasEscapeSupprt(HDC hdc, DWORD escape) {
   const char* ptr = reinterpret_cast<const char*>(&escape);
   return ExtEscape(hdc, QUERYESCSUPPORT, sizeof(escape), ptr, 0, nullptr) > 0;
 }
 
 bool IsTechnology(HDC hdc, const char* technology) {
   if (::GetDeviceCaps(hdc, TECHNOLOGY) != DT_RASPRINTER)
     return false;
 
+  // If postscript, try to query Postscript Identify and then set to
+  // postscript mode before calling any more ExtEscape functions. Otherwise,
+  // PSLEVEL query will not work.
+  if (strcmp(technology, "PostScript") == 0 &&

[Lei Zhang, 2017/02/25 02:49:50]

Doing this within IsTechnology() seems weird, but it looks like we are going to
fix it in https://codereview.chromium.org/2714073002/.

+      HasEscapeSupprt(hdc, POSTSCRIPT_IDENTIFY)) {
+    DWORD mode = PSIDENT_PSCENTRIC;
+    const char* ptr = reinterpret_cast<const char*>(&mode);
+    ExtEscape(hdc, POSTSCRIPT_IDENTIFY, sizeof(DWORD), ptr, 0, nullptr);
+    return true;
+  }
+
   if (!HasEscapeSupprt(hdc, GETTECHNOLOGY))
     return false;
 
   char buf[256];
   memset(buf, 0, sizeof(buf));
   if (ExtEscape(hdc, GETTECHNOLOGY, 0, nullptr, sizeof(buf) - 1, buf) <= 0)
     return false;
   return strcmp(buf, technology) == 0;
 }
 
 bool IsPrinterPostScript(HDC hdc, int* level) {
   static constexpr char kPostScriptDriver[] = "PostScript";
   if (!IsTechnology(hdc, kPostScriptDriver)) {
     return false;
   }
 
-  // Query the PS Level if possible. Many PS printers do not implement this.

[Lei Zhang, 2017/02/25 02:49:50]

Are there printers that only support this in PS mode or something?

+  // Query the PS Level if possible.
   if (HasEscapeSupprt(hdc, GET_PS_FEATURESETTING)) {
     constexpr int param = FEATURESETTING_PSLEVEL;
     const char* param_char_ptr = reinterpret_cast<const char*>(&param);
     int param_out = -1;
     char* param_out_char_ptr = reinterpret_cast<char*>(&param_out);
     if (ExtEscape(hdc, GET_PS_FEATURESETTING, sizeof(param), param_char_ptr,
                   sizeof(param_out), param_out_char_ptr) > 0) {
       if (param_out < 2 || param_out > 3)
         return false;
 
@@ skipping 58 matching lines @@
   // area rect of 0, 0, 0, 0, so it seems some drivers don't set it.
   if (printable_area_device_units.IsEmpty() ||
       !gfx::Rect(physical_size_device_units).Contains(
           printable_area_device_units)) {
     printable_area_device_units = gfx::Rect(physical_size_device_units);
   }
   DCHECK_EQ(print_settings->device_units_per_inch(), dpi);
   print_settings->SetPrinterPrintableArea(physical_size_device_units,
                                           printable_area_device_units,
                                           false);
-  if (IsPrinterXPS(hdc)) {
-    print_settings->set_printer_type(PrintSettings::PrinterType::TYPE_XPS);
-    return;
-  }
+  // Check for postscript first so that we can change the mode with the
+  // first command.
   int level;
   if (IsPrinterPostScript(hdc, &level)) {
     if (level == 2) {
       print_settings->set_printer_type(
           PrintSettings::PrinterType::TYPE_POSTSCRIPT_LEVEL2);
       return;
     }
     DCHECK_EQ(3, level);
     print_settings->set_printer_type(
         PrintSettings::PrinterType::TYPE_POSTSCRIPT_LEVEL3);
     return;
   }
+  if (IsPrinterXPS(hdc)) {
+    print_settings->set_printer_type(PrintSettings::PrinterType::TYPE_XPS);
+    return;
+  }
   print_settings->set_printer_type(PrintSettings::PrinterType::TYPE_NONE);
 }
 
 }  // namespace printing