Allow users to define default language for print format (#4777)

* Update print_format.json

* Update print.js

* Update print.js

* Update form.js

* Set default lang when print_format lang not found

frappe/printing/doctype/print_format/print_format.json

@@ -441,7 +441,38 @@
    "search_index": 0, 
    "set_only_once": 0, 
    "unique": 0
-  }, 
+  },
+  {
+   "allow_bulk_edit": 0, 
+   "allow_on_submit": 0, 
+   "bold": 0, 
+   "collapsible": 0, 
+   "columns": 0, 
+   "fieldname": "default_print_language", 
+   "fieldtype": "Link", 
+   "hidden": 0, 
+   "ignore_user_permissions": 0, 
+   "ignore_xss_filter": 0, 
+   "in_filter": 0, 
+   "in_global_search": 0, 
+   "in_list_view": 0, 
+   "in_standard_filter": 0, 
+   "label": "Default Print Language", 
+   "length": 0, 
+   "no_copy": 0, 
+   "options": "Language", 
+   "permlevel": 0, 
+   "precision": "", 
+   "print_hide": 0, 
+   "print_hide_if_no_value": 0, 
+   "read_only": 0, 
+   "remember_last_selected_value": 0, 
+   "report_hide": 0, 
+   "reqd": 0, 
+   "search_index": 0, 
+   "set_only_once": 0, 
+   "unique": 0
+  },
   {
    "allow_bulk_edit": 0, 
    "allow_on_submit": 0, 
@@ -733,4 +764,4 @@
  "sort_order": "DESC", 
  "track_changes": 1, 
  "track_seen": 0
-}
+}

frappe/public/js/frappe/form/print.js

@@ -35,6 +35,7 @@ frappe.ui.form.PrintPreview = Class.extend({
 		this.print_sel = this.wrapper
 			.find(".print-preview-select")
 			.on("change", function () {
+				me.set_default_print_language();
 				me.multilingual_preview();
 			});
 
@@ -111,6 +112,16 @@ frappe.ui.form.PrintPreview = Class.extend({
 			.val(this.lang_code);
 		this.preview();
 	},
+	set_default_print_language: function () {
+ 		var print_format = this.get_print_format();
+ 	
+ 		if (print_format.default_print_language) {
+ 			this.lang_code = print_format.default_print_language;
+ 			this.language_sel.val(this.lang_code);
+ 		} else {
+			this.language_sel.val(frappe.boot.lang);	
+		}
+ 	},
 	multilingual_preview: function () {
 		var me = this;
 		if (this.is_old_style()) {

frappe/public/js/legacy/form.js

@@ -178,6 +178,8 @@ _f.Frm.prototype.print_doc = function() {
 	this.print_preview.refresh_print_options().trigger("change");
 	this.page.set_view("print");
 	this.print_preview.set_user_lang();
+	this.print_preview.set_default_print_language();
+	this.print_preview.preview();
 };
 
 _f.Frm.prototype.hide_print = function() {