HP 3000 Manuals HP 3000 Manuals
Overview Panels allows you to create up to 65534 panels and to have 254 panels visible on the screen (subject to your machine having enough memory). Panels takes care of maintaining the areas of the screen that are overlaid by another window automatically. It is intended for programmers who require high performance screen handling facilities. The basic concept provided by Panels is that of a panel. This can be considered as a virtual screen that can be written to just like a real screen. However, a panel can be larger or smaller than the real screen. The contents of a panel are viewed through a window. It is the window associated with a panel that is actually displayed on the real screen. The window can be smaller than the actual size of the panel, in which case only part of the panel's contents will be visible. The part of the panel which is visible through the window can be varied by the programmer. Any number of windows can be displayed on the screen at once, overlapping each other if necessary. The window associated with a particular panel can either be visible on the screen (enabled) or it can be invisible (disabled). Even if the panel is disabled, it can still be written to, but its contents will not be visible on the screen until the panel is enabled again. The position and size of a window on the screen can be altered at any time. Any part of a panel can be written to or read from by a program. Also, any rectangular region of a panel can be scrolled in any direction. Frequently Used Terms ADIS The run-time module that executes extended ACCEPT/DISPLAY statements. The ADIS module can be told to DISPLAY data in a panel rather than directly on the screen and to ACCEPT data from a panel. Attribute buffer The attributes defined in the Working-Storage Section of your program which are then included in a panel. Clipping Reducing the window size if the specified size is larger than can be created. For example, if the value of the start column is such that a window of the specified size would be off the right-hand edge of the screen, the width of the window will automatically be reduced to fit the screen. Disabled A particular window is not visible on the screen. Enabled A particular window is visible on the screen. Panel A virtual screen that can be written to just like a real screen, but which can be larger or smaller than the real screen. Before a panel can be used, it must be created by supplying the height and width of the panel together with the dimensions and position of the visible portion on the screen and which part of the panel is actually visible. Parameter Block The means of communication between a program and Panels. The Parameter Block is made up of fields that you initialize to execute a particular function within Panels. All fields relevant to a function must be initialized before calling Panels. Rectangle A rectangular portion of a panel, which can be scrolled independently. Text-buffer Text defined in the Working-Storage Section of your program which is then included in a panel. Window The visible portion of a panel.