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Adapting a Display Management Process for Windowing

IP.com Disclosure Number: IPCOM000039094D
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Anthias, T: AUTHOR [+2]

Abstract

This article describes how to take an existing display interface with existing applications and adapt it for windowing without modifying the application. The method is described with reference to the IBM Graphic Data Display Manager (GDDM). An application program initiates a session with GDDM and constructs data to be displayed in a GDDM device. GDDM is required to run many such applications on windows of a single physical device without modifying the application program. The solution to the problem is as follows. GDDM is functionally extended as follows: -There will be a new object on a GDDM device, called a window. - At any one time, one, and only one, window will be assigned the special status of candidate window.

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Adapting a Display Management Process for Windowing

This article describes how to take an existing display interface with existing applications and adapt it for windowing without modifying the application. The method is described with reference to the IBM Graphic Data Display Manager (GDDM). An application program initiates a session with GDDM and constructs data to be displayed in a GDDM device. GDDM is required to run many such applications on windows of a single physical device without modifying the application program. The solution to the problem is as follows. GDDM is functionally extended as follows: -There will be a new object on a GDDM device, called a window. - At any one time, one, and only one, window will be assigned the special status of candidate window. - If an application tries to open a GDDM device, and the device has already been opened (usually by another

application), so that there is a candidate window, then

the device will be considered by GDDM to be a 'virtual'

device and GDDM will associate it with the candidate

window. GDDM will subsequently cause the 'virtual'

device to be displayed on the area of the real device

specified by the associated window. - Regardles of whether the GDDM device is the real device or a virtual device, when an application uses GDDM

functions, the functions will behave exactly the same

towards the application. This new GDDM function is used by a special application, called a task manager, which is required to defin...