1.1 Basic elements and data structures

1.1.4 Windows

A window is a viewport that is surrounded by a frame viewport and that is automatically attached to a bitmap, a bitmap output stream, and a mouse input stream. Any Lisp function that takes one of these objects as its argument can take a window as an argument.

The frame viewport holds the window's frame. The frame is a bitmap-like object that provides a functional means of drawing a border, a title, and scroll bars.

The window border consists of two strips: the black strip around the edge of the window is the outer border, and the white strip inside the black strip is the inner border. A window optionally displays a title. If the window's main viewport is smaller than its bitmap, the window can optionally have scroll bars, which are mouse-sensitive objects that allow you to move the viewport in any direction over the surface of the bitmap.

The foreground of a window frame includes the outer border and the title bar (if any), which are usually black. The background of a window frame includes the inner border and the text of the title (if any), which are generally white.

You can picture the relationships among viewports, windows, and bitmaps in the Window Tool Kit as presented in Figure 1.1.

Figure 1.1 Relationships between bitmaps, viewports, and windows

You can attach active regions to bitmaps only.

The Window Tool Kit - 9 SEP 1996

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