Chapter 11
When you click the title bar icon with the left mouse button, it provides a standard menu for altering or closing the window called the system menu or control menu. The system menu also appears when you right-click the title bar of a window. Although it’s optional, it is a good idea always to include the title bar icon in any main windows that your program generates. Including the title bar icon provides you with a very convenient way of closing the program when things don’t work during debugging.
The client area is the part of the window where you usually want your program to write text or graphics. You address the client area for this purpose in exactly the same way as the yard that you saw in Figure 7-1 in Chapter 7. The upper-left corner of the client area has the coordinates (0, 0), with x increasing from left to right, and y increasing from top to bottom.
The menu bar is optional in a window but is probably the most common way to control an application. Each menu in the menu bar displays a drop-down list of menu items when you click it. The contents of a menu and the physical appearance of many objects that are displayed in a window, such as the icons on the toolbar that appear above, the cursor, and many others, are defined by a resource file. You will see many more resource files when we get to write some more sophisticated Windows programs.
The toolbar provides a set of icons that usually act as alternatives to the menu options that you use most often. Because they give a pictorial clue to the function provided, they can often make a program easier and faster to use.
I’ll mention a caveat about terminology that you need to be conscious of before I move on. Users tend to think of a window as the thing that appears on the screen with a border around it, and of course it is, but it is only one kind of window; however, in Windows a window is a generic term covering a whole range of entities. In fact almost any entity that is displayed is a window — for example, a dialog box is a window and each button is also a window. I will generally use terminology to refer to objects that describe what they are, buttons, dialogs, and so on, but you need to have tucked in the back of your mind that they are windows, too, because you can do things to them that you can do with a regular window — you can draw on a button for instance.
Windows Programs and the Operating System
When you write a Windows, your program is subservient to the operating system and Windows is in control. Your program must not deal directly with the hardware and all communications with the outside must pass through Windows. When you use a Windows program you are interacting primarily with Windows, which then communicates with the application program on your behalf. Your Windows program is the tail, Windows is the dog, and your program wags only when Windows tells it to.
There are a number of reasons why this is so. First and foremost, because your program is potentially always sharing the computer with other programs that may be executing at the same time, Windows has to have primary control to manage the sharing of machine resources. If one application was allowed to have primary control in a Windows environment this would inevitably make programming more complicated because of the need to provide for the possibility of other programs, and information intended for other applications could be lost. A second reason for Windows being in control is that Windows embodies a standard user interface and needs to be in charge to enforce that standard. You can only display information on the screen using the tools that Windows provides, and then only when authorized.
