Use 'Meiryo UI' and 'MS Gothic' to prevent CJK fonts on Windows(JP)

src/css/jp_fonts.css

@@ -0,0 +1,9 @@
+@font-face {
+  font-family: sans-serif;
+  src: local('Meiryo UI');
+}
+
+@font-face {
+  font-family: monospace;
+  src: local('MS Gothic');
+}

src/index.js

@@ -2,6 +2,9 @@
 
 const electron = require('electron');
 const remote = electron.remote;
+const osLocale = require('os-locale');
+const fs = require('fs');
+
 var url = require('url');
 
 var contextMenu = require('./menus/context');
@@ -44,6 +47,33 @@ webView.addEventListener('new-window', function(e) {
   }
 });
 
+webView.addEventListener("dom-ready", function() {
+  // webView.openDevTools();
+
+  // Use 'Meiryo UI' and 'MS Gothic' to prevent CJK fonts on Windows(JP).
+  if (process.platform === 'win32') {
+    var applyCssFile = function(cssFile) {
+      fs.readFile(cssFile, 'utf8', function(err, data) {
+        if (err) {
+          console.log(err);
+          return;
+        }
+        webView.insertCSS(data);
+      });
+    };
+
+    osLocale(function(err, locale) {
+      if (err) {
+        console.log(err);
+        return;
+      }
+      if (locale === 'ja_JP') {
+        applyCssFile(__dirname + '/css/jp_fonts.css');
+      }
+    });
+  }
+});
+
 // Count unread channels.
 var timer = setInterval(function() {
   webView.send('retrieveUnreadCount');

src/package.json

@@ -7,5 +7,8 @@
   "license": "MIT",
   "devDependencies": {
     "electron-connect": "^0.3.3"
+  },
+  "dependencies": {
+    "os-locale": "^1.4.0"
   }
 }