Print enhancement: add webContents.printerList And a print option to select printer

atom/browser/api/atom_api_web_contents.cc

@@ -41,6 +41,7 @@
 #include "atom/common/options_switches.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_task_runner_handle.h"
+#include "base/values.h"
 #include "brightray/browser/inspectable_web_contents.h"
 #include "brightray/browser/inspectable_web_contents_view.h"
 #include "chrome/browser/printing/print_preview_message_handler.h"
@@ -65,6 +66,7 @@
 #include "content/public/browser/storage_partition.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/context_menu_params.h"
+#include "native_mate/converter.h"
 #include "native_mate/dictionary.h"
 #include "native_mate/object_template_builder.h"
 #include "net/url_request/url_request_context.h"
@@ -83,6 +85,7 @@ namespace {
 struct PrintSettings {
   bool silent;
   bool print_background;
+  base::string16 device_name;
 };
 
 }  // namespace
@@ -120,10 +123,25 @@ struct Converter<PrintSettings> {
       return false;
     dict.Get("silent", &(out->silent));
     dict.Get("printBackground", &(out->print_background));
+    dict.Get("deviceName", &(out->device_name));
     return true;
   }
 };
 
+template<>
+struct Converter<printing::PrinterBasicInfo> {
+    static v8::Local<v8::Value>
+    ToV8(v8::Isolate* isolate, const printing::PrinterBasicInfo& val) {
+      mate::Dictionary dict(isolate, v8::Object::New(isolate));
+      dict.Set("printerName", val.printer_name);
+      dict.Set("printerDescription", val.printer_description);
+      dict.Set("printerStatus", val.printer_status);
+      dict.Set("isDefault", val.is_default);
+      dict.Set("options", val.options);
+      return dict.GetHandle();
+    }
+};
+
 template<>
 struct Converter<WindowOpenDisposition> {
   static v8::Local<v8::Value> ToV8(v8::Isolate* isolate,
@@ -1114,14 +1132,24 @@ bool WebContents::IsAudioMuted() {
 }
 
 void WebContents::Print(mate::Arguments* args) {
-  PrintSettings settings = { false, false };
+  PrintSettings settings = { false, false, base::string16() };
   if (args->Length() == 1 && !args->GetNext(&settings)) {
     args->ThrowError();
     return;
   }
 
   printing::PrintViewManagerBasic::FromWebContents(web_contents())->
-      PrintNow(settings.silent, settings.print_background);
+      PrintNow(settings.silent,
+               settings.print_background, settings.device_name);
+}
+
+
+std::vector<printing::PrinterBasicInfo> WebContents::GetPrinterList(
+    mate::Arguments* args) {
+  std::vector<printing::PrinterBasicInfo> printerList;
+  auto printBackend = printing::PrintBackend::CreateInstance(nullptr);
+  printBackend->EnumeratePrinters(&printerList);
+  return printerList;
 }
 
 void WebContents::PrintToPDF(const base::DictionaryValue& setting,
@@ -1616,6 +1644,7 @@ void WebContents::BuildPrototype(v8::Isolate* isolate,
                  &WebContents::UnregisterServiceWorker)
       .SetMethod("inspectServiceWorker", &WebContents::InspectServiceWorker)
       .SetMethod("print", &WebContents::Print)
+      .SetMethod("printerList", &WebContents::GetPrinterList)
       .SetMethod("_printToPDF", &WebContents::PrintToPDF)
       .SetMethod("addWorkSpace", &WebContents::AddWorkSpace)
       .SetMethod("removeWorkSpace", &WebContents::RemoveWorkSpace)

atom/browser/api/atom_api_web_contents.h

@@ -16,6 +16,7 @@
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/common/favicon_url.h"
 #include "native_mate/handle.h"
+#include "printing/backend/print_backend.h"
 #include "ui/gfx/image/image.h"
 
 namespace blink {
@@ -109,6 +110,7 @@ class WebContents : public mate::TrackableObject<WebContents>,
   void SetAudioMuted(bool muted);
   bool IsAudioMuted();
   void Print(mate::Arguments* args);
+  std::vector<printing::PrinterBasicInfo> GetPrinterList(mate::Arguments* args);
   void SetEmbedder(const WebContents* embedder);
 
   // Print current page as PDF.

chromium_src/chrome/browser/printing/print_job_worker.cc

@@ -24,6 +24,21 @@
 #include "printing/printing_utils.h"
 #include "ui/base/l10n/l10n_util.h"
 
+#include <stddef.h>
+#include <algorithm>
+#include <cmath>
+#include <memory>
+#include <string>
+#include <utility>
+
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/time/time.h"
+#include "printing/page_size_margins.h"
+#include "printing/print_job_constants.h"
+#include "printing/print_settings.h"
+#include "printing/units.h"
+
 using content::BrowserThread;
 
 namespace printing {
@@ -36,6 +51,81 @@ void HoldRefCallback(const scoped_refptr<printing::PrintJobWorkerOwner>& owner,
   callback.Run();
 }
 
+void SetCustomMarginsToJobSettings(const PageSizeMargins& page_size_margins,
+                                   base::DictionaryValue* settings) {
+  std::unique_ptr<base::DictionaryValue> custom_margins(new base::DictionaryValue());
+  custom_margins->SetDouble(kSettingMarginTop, page_size_margins.margin_top);
+  custom_margins->SetDouble(kSettingMarginBottom, page_size_margins.margin_bottom);
+  custom_margins->SetDouble(kSettingMarginLeft, page_size_margins.margin_left);
+  custom_margins->SetDouble(kSettingMarginRight, page_size_margins.margin_right);
+  settings->Set(kSettingMarginsCustom, std::move(custom_margins));
+}
+
+void PrintSettingsToJobSettings(const PrintSettings& settings,
+                                base::DictionaryValue* job_settings) {
+  // header footer
+  job_settings->SetBoolean(kSettingHeaderFooterEnabled,
+                           settings.display_header_footer());
+  job_settings->SetString(kSettingHeaderFooterTitle, settings.title());
+  job_settings->SetString(kSettingHeaderFooterURL, settings.url());
+
+  // bg
+  job_settings->SetBoolean(kSettingShouldPrintBackgrounds,
+                           settings.should_print_backgrounds());
+  job_settings->SetBoolean(kSettingShouldPrintSelectionOnly,
+                           settings.selection_only());
+
+  // margin
+  auto margin_type = settings.margin_type();
+  job_settings->SetInteger(kSettingMarginsType, settings.margin_type());
+  if (margin_type == CUSTOM_MARGINS) {
+    const auto& margins_in_points = settings.requested_custom_margins_in_points();
+
+    PageSizeMargins page_size_margins;
+
+    page_size_margins.margin_top = margins_in_points.top;
+    page_size_margins.margin_bottom = margins_in_points.bottom;
+    page_size_margins.margin_left = margins_in_points.left;
+    page_size_margins.margin_right = margins_in_points.right;
+    SetCustomMarginsToJobSettings(page_size_margins, job_settings);
+  }
+  job_settings->SetInteger(kSettingPreviewPageCount, 1);
+
+  // range
+
+  if (!settings.ranges().empty()) {
+    base::ListValue* page_range_array = new base::ListValue;
+    job_settings->Set(kSettingPageRange, page_range_array);
+    for (size_t i = 0; i < settings.ranges().size(); ++i) {
+      std::unique_ptr<base::DictionaryValue> dict(new base::DictionaryValue);
+      dict->SetInteger(kSettingPageRangeFrom, settings.ranges()[i].from + 1);
+      dict->SetInteger(kSettingPageRangeTo, settings.ranges()[i].to + 1);
+      page_range_array->Append(std::move(dict));
+    }
+  }
+
+  job_settings->SetBoolean(kSettingCollate, settings.collate());
+  job_settings->SetInteger(kSettingCopies, 1);
+  job_settings->SetInteger(kSettingColor, settings.color());
+  job_settings->SetInteger(kSettingDuplexMode, settings.duplex_mode());
+  job_settings->SetBoolean(kSettingLandscape, settings.landscape());
+  job_settings->SetString(kSettingDeviceName, settings.device_name());
+  job_settings->SetInteger("scaleFactor", 100);
+  job_settings->SetBoolean("rasterizePDF", false);
+
+  job_settings->SetInteger("desiredDpi", settings.desired_dpi());
+  job_settings->SetInteger("dpi", settings.dpi());
+
+  job_settings->SetBoolean(kSettingPrintToPDF, false);
+  job_settings->SetBoolean(kSettingCloudPrintDialog, false);
+  job_settings->SetBoolean(kSettingPrintWithPrivet, false);
+  job_settings->SetBoolean(kSettingPrintWithExtension, false);
+
+  job_settings->SetBoolean("showSystemDialog", false);
+  job_settings->SetInteger(kSettingPreviewPageCount, 1);
+}
+
+
 class PrintingContextDelegate : public PrintingContext::Delegate {
  public:
   PrintingContextDelegate(int render_process_id, int render_view_id);
@@ -115,7 +205,8 @@ void PrintJobWorker::GetSettings(
     bool ask_user_for_settings,
     int document_page_count,
     bool has_selection,
-    MarginType margin_type) {
+    MarginType margin_type,
+    const base::string16& device_name) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
   DCHECK_EQ(page_number_, PageNumber::npos());
 
@@ -137,6 +228,13 @@ void PrintJobWorker::GetSettings(
                               base::Unretained(this),
                               document_page_count,
                               has_selection)));
+  } else if (!device_name.empty()) {
+    BrowserThread::PostTask(
+        BrowserThread::UI, FROM_HERE,
+        base::Bind(&HoldRefCallback, make_scoped_refptr(owner_),
+                   base::Bind(&PrintJobWorker::InitWithDeviceName,
+                              base::Unretained(this),
+                              device_name)));
   } else {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
@@ -212,6 +310,14 @@ void PrintJobWorker::UseDefaultSettings() {
   GetSettingsDone(result);
 }
 
+void PrintJobWorker::InitWithDeviceName(const base::string16& device_name) {
+  const auto& settings = printing_context_->settings();
+  std::unique_ptr<base::DictionaryValue> dic(new base::DictionaryValue);
+  PrintSettingsToJobSettings(settings, dic.get());
+  dic->SetString(kSettingDeviceName, device_name);
+  UpdatePrintSettings(std::move(dic));
+}
+
 void PrintJobWorker::StartPrinting(PrintedDocument* new_document) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
   DCHECK_EQ(page_number_, PageNumber::npos());

chromium_src/chrome/browser/printing/print_job_worker.h

@@ -46,7 +46,8 @@ class PrintJobWorker {
       bool ask_user_for_settings,
       int document_page_count,
       bool has_selection,
-      MarginType margin_type);
+      MarginType margin_type,
+      const base::string16& device_name);
 
   // Set the new print settings.
   void SetSettings(std::unique_ptr<base::DictionaryValue> new_settings);
@@ -127,6 +128,9 @@ class PrintJobWorker {
   // systems.
   void UseDefaultSettings();
 
+  // set the printer name
+  void InitWithDeviceName(const base::string16& device_name);
+
   // Printing context delegate.
   std::unique_ptr<PrintingContext::Delegate> printing_context_delegate_;
 

chromium_src/chrome/browser/printing/print_view_manager_base.cc

@@ -64,9 +64,10 @@ PrintViewManagerBase::~PrintViewManagerBase() {
 }
 
 #if !defined(DISABLE_BASIC_PRINTING)
-bool PrintViewManagerBase::PrintNow(bool silent, bool print_background) {
+bool PrintViewManagerBase::PrintNow(bool silent, bool print_background,
+                                    const base::string16& device_name) {
   return PrintNowInternal(new PrintMsg_PrintPages(
-      routing_id(), silent, print_background));
+      routing_id(), silent, print_background, device_name));
 }
 #endif  // !DISABLE_BASIC_PRINTING
 

chromium_src/chrome/browser/printing/print_view_manager_base.h

@@ -39,7 +39,7 @@ class PrintViewManagerBase : public content::NotificationObserver,
   // Prints the current document immediately. Since the rendering is
   // asynchronous, the actual printing will not be completed on the return of
   // this function. Returns false if printing is impossible at the moment.
-  virtual bool PrintNow(bool silent, bool print_background);
+  virtual bool PrintNow(bool silent, bool print_background, const base::string16&);
 #endif  // !DISABLE_BASIC_PRINTING
 
   // PrintedPagesSource implementation.

chromium_src/chrome/browser/printing/printer_query.cc

@@ -82,7 +82,31 @@ void PrinterQuery::GetSettings(
                                is_print_dialog_box_shown_,
                                expected_page_count,
                                has_selection,
-                               margin_type));
+                               margin_type,
+                               base::string16()));
+}
+
+void PrinterQuery::GetSettings(
+    GetSettingsAskParam ask_user_for_settings,
+    int expected_page_count,
+    bool has_selection,
+    MarginType margin_type,
+    const base::string16& device_name,
+    const base::Closure& callback) {
+  DCHECK(RunsTasksOnCurrentThread());
+  DCHECK(!is_print_dialog_box_shown_);
+  StartWorker(callback);
+
+  // Real work is done in PrintJobWorker::GetSettings().
+  is_print_dialog_box_shown_ = ask_user_for_settings == ASK_USER;
+  worker_->PostTask(FROM_HERE,
+                    base::Bind(&PrintJobWorker::GetSettings,
+                               base::Unretained(worker_.get()),
+                               is_print_dialog_box_shown_,
+                               expected_page_count,
+                               has_selection,
+                               margin_type,
+                               device_name));
 }
 
 void PrinterQuery::SetSettings(std::unique_ptr<base::DictionaryValue> new_settings,

chromium_src/chrome/browser/printing/printer_query.h

@@ -50,7 +50,15 @@ class PrinterQuery : public PrintJobWorkerOwner {
       MarginType margin_type,
       const base::Closure& callback);
 
-  // Updates the current settings with |new_settings| dictionary values.
+  void GetSettings(
+      GetSettingsAskParam ask_user_for_settings,
+      int expected_page_count,
+      bool has_selection,
+      MarginType margin_type,
+      const base::string16& device_name,
+      const base::Closure& callback);
+
+    // Updates the current settings with |new_settings| dictionary values.
   void SetSettings(std::unique_ptr<base::DictionaryValue> new_settings,
                    const base::Closure& callback);
 

chromium_src/chrome/browser/printing/printing_message_filter.cc

@@ -123,6 +123,9 @@ bool PrintingMessageFilter::OnMessageReceived(const IPC::Message& message) {
 #endif
     IPC_MESSAGE_HANDLER_DELAY_REPLY(PrintHostMsg_GetDefaultPrintSettings,
                                     OnGetDefaultPrintSettings)
+
+    IPC_MESSAGE_HANDLER_DELAY_REPLY(PrintHostMsg_InitSettingWithDeviceName,
+                                  OnInitSettingWithDeviceName)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(PrintHostMsg_ScriptedPrint, OnScriptedPrint)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(PrintHostMsg_UpdatePrintSettings,
                                     OnUpdatePrintSettings)
@@ -278,6 +281,30 @@ void PrintingMessageFilter::OnGetDefaultPrintSettings(IPC::Message* reply_msg) {
                  reply_msg));
 }
 
+void PrintingMessageFilter::OnInitSettingWithDeviceName(const base::string16& device_name,
+                                                        IPC::Message* reply_msg) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  scoped_refptr<PrinterQuery> printer_query;
+  printer_query = queue_->PopPrinterQuery(0);
+  if (!printer_query.get()) {
+    printer_query =
+        queue_->CreatePrinterQuery(render_process_id_, reply_msg->routing_id());
+  }
+
+  // Loads default settings. This is asynchronous, only the IPC message sender
+  // will hang until the settings are retrieved.
+  printer_query->GetSettings(
+      PrinterQuery::DEFAULTS,
+      0,
+      false,
+      DEFAULT_MARGINS,
+      device_name,
+      base::Bind(&PrintingMessageFilter::OnGetDefaultPrintSettingsReply,
+                 this,
+                 printer_query,
+                 reply_msg));
+}
+
 void PrintingMessageFilter::OnGetDefaultPrintSettingsReply(
     scoped_refptr<PrinterQuery> printer_query,
     IPC::Message* reply_msg) {

chromium_src/chrome/browser/printing/printing_message_filter.h

@@ -85,6 +85,11 @@ class PrintingMessageFilter : public content::BrowserMessageFilter {
 
   // Get the default print setting.
   void OnGetDefaultPrintSettings(IPC::Message* reply_msg);
+
+  // Set deviceName
+  void OnInitSettingWithDeviceName(const base::string16& device_name,
+                                    IPC::Message* reply_msg);
+
   void OnGetDefaultPrintSettingsReply(scoped_refptr<PrinterQuery> printer_query,
                                       IPC::Message* reply_msg);
 

chromium_src/chrome/common/print_messages.cc

@@ -23,7 +23,8 @@ PrintMsg_Print_Params::PrintMsg_Print_Params()
     print_scaling_option(blink::WebPrintScalingOptionSourceSize),
     title(),
     url(),
-    should_print_backgrounds(false) {
+    should_print_backgrounds(false),
+    device_name() {
 }
 
 PrintMsg_Print_Params::~PrintMsg_Print_Params() {}
@@ -45,6 +46,7 @@ void PrintMsg_Print_Params::Reset() {
   title.clear();
   url.clear();
   should_print_backgrounds = false;
+  device_name.clear();
 }
 
 PrintMsg_PrintPages_Params::PrintMsg_PrintPages_Params()

chromium_src/chrome/common/print_messages.h

@@ -52,6 +52,7 @@ struct PrintMsg_Print_Params {
   base::string16 title;
   base::string16 url;
   bool should_print_backgrounds;
+  base::string16 device_name;
 };
 
 struct PrintMsg_PrintPages_Params {
@@ -213,9 +214,10 @@ IPC_STRUCT_END()
 
 // Tells the render view to switch the CSS to print media type, renders every
 // requested pages and switch back the CSS to display media type.
-IPC_MESSAGE_ROUTED2(PrintMsg_PrintPages,
+IPC_MESSAGE_ROUTED3(PrintMsg_PrintPages,
                     bool /* silent print */,
-                    bool /* print page's background */)
+                    bool /* print page's background */,
+                    base::string16 /* device name*/)
 
 // Tells the render view that printing is done so it can clean up.
 IPC_MESSAGE_ROUTED1(PrintMsg_PrintingDone,
@@ -260,6 +262,11 @@ IPC_MESSAGE_ROUTED1(PrintHostMsg_DidPrintPage,
 IPC_SYNC_MESSAGE_ROUTED0_1(PrintHostMsg_GetDefaultPrintSettings,
                            PrintMsg_Print_Params /* default_settings */)
 
+// you can set the printer
+IPC_SYNC_MESSAGE_ROUTED1_1(PrintHostMsg_InitSettingWithDeviceName,
+    base::string16, /* device name */
+    PrintMsg_Print_Params /* default_settings */)
+
 // The renderer wants to update the current print settings with new
 // |job_settings|.
 IPC_SYNC_MESSAGE_ROUTED2_2(PrintHostMsg_UpdatePrintSettings,

chromium_src/chrome/renderer/printing/print_web_view_helper.cc

@@ -661,13 +661,14 @@ void PrintWebViewHelper::OnDestruct() {
 }
 
 #if !defined(DISABLE_BASIC_PRINTING)
-void PrintWebViewHelper::OnPrintPages(bool silent, bool print_background) {
+void PrintWebViewHelper::OnPrintPages(bool silent, bool print_background,
+                                      const base::string16& device_name) {
   if (ipc_nesting_level_> 1)
     return;
 
   blink::WebLocalFrame* frame =
       render_view()->GetMainRenderFrame()->GetWebFrame();
-  Print(frame, blink::WebNode(), silent, print_background);
+  Print(frame, blink::WebNode(), silent, print_background, device_name);
 }
 #endif  // !DISABLE_BASIC_PRINTING
 
@@ -851,7 +852,8 @@ void PrintWebViewHelper::PrintNode(const blink::WebNode& node) {
 void PrintWebViewHelper::Print(blink::WebLocalFrame* frame,
                                const blink::WebNode& node,
                                bool silent,
-                               bool print_background) {
+                               bool print_background,
+                               const base::string16& device_name) {
   // If still not finished with earlier print request simply ignore.
   if (prep_frame_view_)
     return;
@@ -859,7 +861,7 @@ void PrintWebViewHelper::Print(blink::WebLocalFrame* frame,
   FrameReference frame_ref(frame);
 
   int expected_page_count = 0;
-  if (!CalculateNumberOfPages(frame, node, &expected_page_count)) {
+  if (!CalculateNumberOfPages(frame, node, &expected_page_count, device_name)) {
     DidFinishPrinting(FAIL_PRINT_INIT);
     return;  // Failed to init print page settings.
   }
@@ -995,10 +997,16 @@ void PrintWebViewHelper::ComputePageLayoutInPointsForCss(
   CalculatePageLayoutFromPrintParams(params, page_layout_in_points);
 }
 
-bool PrintWebViewHelper::InitPrintSettings(bool fit_to_paper_size) {
+bool PrintWebViewHelper::InitPrintSettings(bool fit_to_paper_size,
+                                           const base::string16& device_name) {
   PrintMsg_PrintPages_Params settings;
-  Send(new PrintHostMsg_GetDefaultPrintSettings(routing_id(),
+  if (device_name.empty()) {
-                                                &settings.params));
+    Send(new PrintHostMsg_GetDefaultPrintSettings(routing_id(),
+                                                  &settings.params));
+  } else {
+    Send(new PrintHostMsg_InitSettingWithDeviceName(routing_id(), device_name,
+                                                    &settings.params));
+  }
   // Check if the printer returned any settings, if the settings is empty, we
   // can safely assume there are no printer drivers configured. So we safely
   // terminate.
@@ -1023,10 +1031,11 @@ bool PrintWebViewHelper::InitPrintSettings(bool fit_to_paper_size) {
 
 bool PrintWebViewHelper::CalculateNumberOfPages(blink::WebLocalFrame* frame,
                                                 const blink::WebNode& node,
-                                                int* number_of_pages) {
+                                                int* number_of_pages,
+                                                const base::string16& device_name) {
   DCHECK(frame);
   bool fit_to_paper_size = !(PrintingNodeOrPdfFrame(frame, node));
-  if (!InitPrintSettings(fit_to_paper_size)) {
+  if (!InitPrintSettings(fit_to_paper_size, device_name)) {
     notify_browser_of_print_failure_ = false;
     Send(new PrintHostMsg_ShowInvalidPrinterSettingsError(routing_id()));
     return false;

chromium_src/chrome/renderer/printing/print_web_view_helper.h

@@ -98,7 +98,7 @@ class PrintWebViewHelper
 
   // Message handlers ---------------------------------------------------------
 #if !defined(DISABLE_BASIC_PRINTING)
-  void OnPrintPages(bool silent, bool print_background);
+  void OnPrintPages(bool silent, bool print_background, const base::string16&);
   void OnPrintingDone(bool success);
 #endif  // !DISABLE_BASIC_PRINTING
   void OnPrintPreview(const base::DictionaryValue& settings);
@@ -137,7 +137,8 @@ class PrintWebViewHelper
   void Print(blink::WebLocalFrame* frame,
              const blink::WebNode& node,
              bool silent = false,
-             bool print_background = false);
+             bool print_background = false,
+             const base::string16& device_name = base::string16());
 
   // Notification when printing is done - signal tear-down/free resources.
   void DidFinishPrinting(PrintingResult result);
@@ -146,12 +147,14 @@ class PrintWebViewHelper
 
   // Initialize print page settings with default settings.
   // Used only for native printing workflow.
-  bool InitPrintSettings(bool fit_to_paper_size);
+  bool InitPrintSettings(bool fit_to_paper_size,
+                         const base::string16& device_name = base::string16());
 
   // Calculate number of pages in source document.
   bool CalculateNumberOfPages(blink::WebLocalFrame* frame,
                               const blink::WebNode& node,
-                              int* number_of_pages);
+                              int* number_of_pages,
+                              const base::string16& device_name = base::string16());
 
   // Update the current print settings with new |passed_job_settings|.
   // |passed_job_settings| dictionary contains print job details such as printer

docs/api/web-contents.md

@@ -859,18 +859,54 @@ Unregisters any ServiceWorker if present and returns a boolean as
 response to `callback` when the JS promise is fulfilled or false
 when the JS promise is rejected.
 
+#### `contents.printerList()`
+
+Get the system printer list, the result is an array of printer description.
+eg:
+````js
+[{ printerName: 'Zebra_LP2844',
+     printerDescription: 'Zebra LP2844',
+     printerStatus: 3,
+     isDefault: 0,
+     options:
+      { copies: '1',
+        'device-uri': 'usb://Zebra/LP2844?location=14200000',
+        finishings: '3',
+        'job-cancel-after': '10800',
+        'job-hold-until': 'no-hold',
+        'job-priority': '50',
+        'job-sheets': 'none,none',
+        'marker-change-time': '0',
+        'number-up': '1',
+        'printer-commands': 'none',
+        'printer-info': 'Zebra LP2844',
+        'printer-is-accepting-jobs': 'true',
+        'printer-is-shared': 'true',
+        'printer-location': '',
+        'printer-make-and-model': 'Zebra EPL2 Label Printer',
+        'printer-state': '3',
+        'printer-state-change-time': '1484872644',
+        'printer-state-reasons': 'offline-report',
+        'printer-type': '36932',
+        'printer-uri-supported': 'ipp://localhost/printers/Zebra_LP2844',
+        system_driverinfo: 'Z' } }]
+````
+
+
 #### `contents.print([options])`
 
 * `options` Object (optional)
   * `silent` Boolean - Don't ask user for print settings. Default is `false`.
   * `printBackground` Boolean - Also prints the background color and image of
     the web page. Default is `false`.
+  * `deviceName` String - Set the printer
 
 Prints window's web page. When `silent` is set to `true`, Electron will pick
-up system's default printer and default settings for printing.
+up printer depending on `deviceName`(when left will pick system's default printer)
+ and default settings for printing.
 
 Calling `window.print()` in web page is equivalent to calling
-`webContents.print({silent: false, printBackground: false})`.
+`webContents.print({silent: false, printBackground: false, deviceName: ''})`.
 
 Use `page-break-before: always; ` CSS style to force to print to a new page.