Initialize weex using portrait screen size. (#2898)

ios/sdk/WeexSDK/Sources/Bridge/WXCoreBridge.mm

@@ -1538,11 +1538,14 @@ + (void)install
         env->AddOption("scale", "1");
         env->AddOption("pixel_scale", std::to_string([[UIScreen mainScreen] scale]));
 
+        // Here we initialize weex device width and height using portrait by default.
         CGSize screenSize = [UIScreen mainScreen].bounds.size;
-        env->SetDeviceWidth(std::to_string(screenSize.width));
-        env->SetDeviceHeight(std::to_string(screenSize.height));
-        env->AddOption("screen_width_pixels", std::to_string(screenSize.width));
-        env->AddOption("screen_height_pixels", std::to_string(screenSize.height));
+        CGFloat w = MIN(screenSize.width, screenSize.height);
+        CGFloat h = MAX(screenSize.width, screenSize.height);
+        env->SetDeviceWidth(std::to_string(w));
+        env->SetDeviceHeight(std::to_string(h));
+        env->AddOption("screen_width_pixels", std::to_string(w));
+        env->AddOption("screen_height_pixels", std::to_string(h));
 
         weex::base::LogImplement::getLog()->setLogImplement(new WeexCore::LogBridgeIOS());
 
@@ -1552,8 +1555,6 @@ + (void)install
         weex::base::LogImplement::getLog()->setDebugMode(false);
 #endif
 
-
-
         platformBridge = new WeexCore::PlatformBridge();
         platformBridge->set_platform_side(new WeexCore::IOSSide());
         platformBridge->set_core_side(new WeexCore::CoreSideInPlatform());