You can use the windows you create in any of three ways. You can (1) write to the window, (2) scroll information in a memory screen larger than the window itself, or (3) view text information contained in a memory file.
When you write to a window, you are really writing to its memory screen buffer. A window acts as a sub-screen on the user's screen. When a window is displayed on the screen, anything written to it appears in that area of the screen. The output is automatically kept within the margins of the window.
If the window is displayed when you write to it, the information is automatically echoed to the screen. If you write to a window that is not displayed, the information is stored in the buffer. If the window is later displayed, the stored information will appear in the window.
Vermont Views provides a number of functions to write text, boxes, and lines to a window. You can also create text, boxes and lines in a window using the Designer. When the window is displayed on the screen, the objects you created in the Designer will be displayed in the memory screen.
If you create a virtual window with a memory screen that is larger than the work area of the window, the user can scroll through the information in the memory screen buffer. You can write to a virtual window using the same functions that you use to write to basic windows. You can also create virtual windows in the Designer and put text, boxes and lines in the window's memory screen. When the window is displayed, the user can scroll through the information in the memory screen.
Text information can also be stored in a special structure called a memory file. After defining a memory file and filling it with text (by, for example, reading an ASCII file from disk), you can view it through a window. If the text is larger than the window, you can allow the user to scroll the memory file horizontally and vertically within the window. You can also set the system so that only part of a memory file is displayed. A memory file cannot be changed by writing to a window, but it can be updated using memory file functions.
See Chapter 45, "Creating and Viewing Memory Files," for more information on using and updating memory files.
