Chuyển đổi cuốn sách bìa Trong phần này, bạn sử dụng các dịch vụ hình ảnh trong Google App Engine để lật một hình ảnh đăng tải trên trục thẳng đứng của nó. Bạn cũng thừa hưởng một số trong những điều bạn đã học về lưu trữ dữ liệu trong Chương 7. | CHAPTER 8 APP ENGINE SERVICES Figure 8-8. Transformed book cover In this section you used the Images service in Google App Engine to flip an uploaded image on its vertical axis. You also leveraged some of the things you learned about the data store in Chapter 7. Before moving on to the Mail API experiment with the transformation options available from the Images service. You can find a full list of available transformations and their descriptions in Table 8-1. Table 8-1. Image transformations Transformation Description of Transformation Resize Resizes images while maintaining the same aspect ratio Rotate Rotates the image in 90-degree increments Flip Horizontally Flips the image on the horizontal axis Flip Vertically Flips the image on the vertical axis Crop Crops the image using a bounding box I m feeling Lucky Auto-adjusts the image to enhance dark and bright colors to optimal levels 188 CHAPTER 8 APP ENGINE SERVICES Next you re going to use two services to interact with users outside of your application. Mail API The services we ve looked at so far this chapter have all been backgroundprocessing or behind-the-scenes services. It s time to take a look at a few services that let you interact with the world outside of your application. Starting with App Engine s Mail API Google App Engine Mail service supports the JavaMail interface for sending e-mails programmatically from within an application. Your application can send e-mails on behalf of either the application administrator or the currently logged-in user. To see a full list of features reference the JavaMail API by visiting http products javamail javadocs . The App Engine Mail API implements the full JavaMail API excluding the ability to connect to other mail services for sending and receiving e-mail messages. Any SMTP configuration added to the Transport or Session will be ignored. As mentioned the Mail service Java API supports the JavaMail interface. This means that you have the .
