Use DPI from Print Preview on Windows, handle non square

printing/print_settings.h

 // 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_PRINT_SETTINGS_H_
 #define PRINTING_PRINT_SETTINGS_H_
 
+#include <algorithm>
 #include <string>
 
 #include "base/strings/string16.h"
 #include "printing/page_range.h"
 #include "printing/page_setup.h"
 #include "printing/print_job_constants.h"
 #include "printing/printing_export.h"
 #include "ui/gfx/geometry/rect.h"
 
 namespace printing {
@@ skipping 73 matching lines @@
                                bool landscape_needs_flip);
   const PageSetup& page_setup_device_units() const {
     return page_setup_device_units_;
   }
 
   void set_device_name(const base::string16& device_name) {
     device_name_ = device_name;
   }
   const base::string16& device_name() const { return device_name_; }
 
-  void set_dpi(int dpi) { dpi_ = dpi; }
-  int dpi() const { return dpi_; }
+  void set_dpi(int dpi) {
+    dpi_[0] = dpi;
+    dpi_[1] = dpi;
+  }
+  void set_dpi(int dpi_horizontal, int dpi_vertical) {

[Lei Zhang, 2017/04/04 00:03:03]

Can we name this something else to avoid overloading set_dpi()?

[rbpotter, 2017/04/04 00:36:34]

Done.

+    dpi_[0] = dpi_horizontal;
+    dpi_[1] = dpi_vertical;
+  }
+  int dpi() const { return std::min(dpi_[0], dpi_[1]); }
 
   void set_scale_factor(double scale_factor) { scale_factor_ = scale_factor; }
   double scale_factor() const { return scale_factor_; }
 
   void set_rasterize_pdf(bool rasterize_pdf) { rasterize_pdf_ = rasterize_pdf; }
   bool rasterize_pdf() const { return rasterize_pdf_; }
 
   void set_supports_alpha_blend(bool supports_alpha_blend) {
     supports_alpha_blend_ = supports_alpha_blend;
   }
@@ skipping 36 matching lines @@
 
   void set_color(ColorModel color) { color_ = color; }
   ColorModel color() const { return color_; }
 
   void set_copies(int copies) { copies_ = copies; }
   int copies() const { return copies_; }
 
   void set_duplex_mode(DuplexMode duplex_mode) { duplex_mode_ = duplex_mode; }
   DuplexMode duplex_mode() const { return duplex_mode_; }
 
+  int dpi_horizontal() const { return dpi_[0]; }

[Lei Zhang, 2017/04/04 00:03:03]

Can we keep these grouped with dpi() above?

[rbpotter, 2017/04/04 00:36:34]

Done.

+  int dpi_vertical() const { return dpi_[1]; }
+
 #if defined(OS_WIN)
   void set_print_text_with_gdi(bool use_gdi) { print_text_with_gdi_ = use_gdi; }
   bool print_text_with_gdi() const { return print_text_with_gdi_; }
 
   void set_printer_type(PrinterType type) { printer_type_ = type; }
   bool printer_is_xps() const { return printer_type_ == PrinterType::TYPE_XPS;}
   bool printer_is_ps2() const {
     return printer_type_ == PrinterType::TYPE_POSTSCRIPT_LEVEL2;
   }
   bool printer_is_ps3() const {
     return printer_type_ == PrinterType::TYPE_POSTSCRIPT_LEVEL3;
   }
 #endif
 
   // Cookie generator. It is used to initialize PrintedDocument with its
   // associated PrintSettings, to be sure that each generated PrintedPage is
   // correctly associated with its corresponding PrintedDocument.
   static int NewCookie();
 
  private:
   // Multi-page printing. Each PageRange describes a from-to page combination.
   // This permits printing selected pages only.
   PageRanges ranges_;
 
-  // Desired visible dots per inch rendering for output. Printing should be
-  // scaled to ScreenDpi/dpix*desired_dpi.
-  int desired_dpi_;
-
   // Indicates if the user only wants to print the current selection.
   bool selection_only_;
 
   // Indicates what kind of margins should be applied to the printable area.
   MarginType margin_type_;
 
   // Strings to be printed as headers and footers if requested by the user.
   base::string16 title_;
   base::string16 url_;
 
@@ skipping 17 matching lines @@
 
   // Printer device name as opened by the OS.
   base::string16 device_name_;
 
   // Media requested by the user.
   RequestedMedia requested_media_;
 
   // Page setup in device units.
   PageSetup page_setup_device_units_;
 
   // Printer's device effective dots per inch in both axis.

[Lei Zhang, 2017/04/04 00:03:03]

Can we add some notes to say the two values can only differ on Windows, and even
then it's rare?

[rbpotter, 2017/04/04 00:36:34]

Done.

-  int dpi_;
+  int dpi_[2];
 
   // Scale factor
   double scale_factor_;
 
   // True if PDF should be printed as a raster PDF
   bool rasterize_pdf_;
 
   // Is the orientation landscape or portrait.
   bool landscape_;
 
   // True if this printer supports AlphaBlend.
   bool supports_alpha_blend_;
 
 #if defined(OS_WIN)
   // True to print text with GDI.
   bool print_text_with_gdi_;
 
   PrinterType printer_type_;
 #endif
 
   // If margin type is custom, this is what was requested.
   PageMargins requested_custom_margins_in_points_;
 };
 
 }  // namespace printing
 
 #endif  // PRINTING_PRINT_SETTINGS_H_