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Types of windows

There are three types of windows in TPWIN, these are:

• Frames: the exterior of a window.
• Panels: the interior of a frame window.
• Controls: windows used for input/output that are placed on a panel window.

Frames

A frame is a window which can be compared with a frame of a painting. A frame window has a visible border, a title bar and an optional menubar, there is nothing inside it. If a frame window is created and shown on the display the interior is empty, i.e. a frame window does not redraw its interior. Below there is picture of a frame with 'rubbish' in it because a frame window does not paint it's interior. 

The frame class is a container for panel windows, it is not possible to put frame windows inside other frame windows.

Panels

A panel window is a window which can only exist inside a frame window. A panel window does redraw itself when it is asked to do that. it is possible for several panel windows to be inside the same frame window. Below there is a picture of a frame window with a single panel window inside it.

The panel window redraws itself when necessary and it can fill the complete client area of the frame window. The client area of a window is the window excluding the border, title and menu bar. Panel windows inside a frame window automatically resize themselves when the frame window is resized. The panel window class has many methods to create controls.

Controls

A panel window can be used for placing control windows on it, controls are useful for output and/or input of information. Some of the available control classes are:

• Button: displays text and can be clicked with the mouse or spacebar.
• Checkbox: a checkmark which the user can select.
• Combobox: a list from which one item can be selected.
• Edit: area in which text may be entered.
• Groupbox: does nothing except draw a rectangle, it is used to visually group controls together.
• Label: displays text.
• Memo: for input of multiple lines of text.
• Radiobutton: a user can select one radiobutton from a group of radiobuttons.
• Scrollbar: to scroll the contents of a window or change a value.

When a control is created the parent window must be a panel window (child windows are on top of their parent windows, when a parent window is made visible the children also appear).

Below there is a picture of a frame window with a panel window and on top of the panel there is a button control.

The panel window class has many methods to create controls.

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