Use DPI from Print Preview on Windows, handle non square

printing/print_settings.h

Index: printing/print_settings.h
diff --git a/printing/print_settings.h b/printing/print_settings.h
index 1311ddbeb911f30b9ca39335c0b679ec6f711bab..72dbf5eab506d34b64f2a702fc4a4ace783c7817 100644
--- a/printing/print_settings.h
+++ b/printing/print_settings.h
@@ -5,6 +5,7 @@
 #ifndef PRINTING_PRINT_SETTINGS_H_
 #define PRINTING_PRINT_SETTINGS_H_
 
+#include <algorithm>
 #include <string>
 
 #include "base/strings/string16.h"
@@ -99,8 +100,11 @@ class PRINTING_EXPORT PrintSettings {
   }
   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;
+  }
+  int dpi() const { return std::min(dpi_[0], dpi_[1]); }

[rbpotter, 2017/04/01 00:08:02]

What do you think makes sense here? The previous idea was to use the
horizontal dpi always (so dpi_[0]). We could do that, or min, or max of
the two dimensions. Not sure what makes the most sense.

[Lei Zhang, 2017/04/01 01:14:13]

Well, for most printers, it doesn't matter right? I feel like this should be min
or max. Not sure which one makes the printer with different DPIs happier though.

 
   void set_scale_factor(double scale_factor) { scale_factor_ = scale_factor; }
   double scale_factor() const { return scale_factor_; }
@@ -108,6 +112,11 @@ class PRINTING_EXPORT PrintSettings {
   void set_rasterize_pdf(bool rasterize_pdf) { rasterize_pdf_ = rasterize_pdf; }
   bool rasterize_pdf() const { return rasterize_pdf_; }
 
+  void set_dpi(int dpi_horizontal, int dpi_vertical) {
+    dpi_[0] = dpi_horizontal;
+    dpi_[1] = dpi_vertical;
+  }
+
   void set_supports_alpha_blend(bool supports_alpha_blend) {
     supports_alpha_blend_ = supports_alpha_blend;
   }
@@ -157,7 +166,8 @@ class PRINTING_EXPORT PrintSettings {
   void set_duplex_mode(DuplexMode duplex_mode) { duplex_mode_ = duplex_mode; }
   DuplexMode duplex_mode() const { return duplex_mode_; }
 
-  int desired_dpi() const { return desired_dpi_; }
+  int dpi_horizontal() const { return dpi_[0]; }
+  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; }
@@ -183,10 +193,6 @@ class PRINTING_EXPORT PrintSettings {
   // 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_;
 
@@ -225,7 +231,7 @@ class PRINTING_EXPORT PrintSettings {
   PageSetup page_setup_device_units_;
 
   // Printer's device effective dots per inch in both axis.
-  int dpi_;
+  int dpi_[2];
 
   // Scale factor
   double scale_factor_;