Method and apparatus for presenting information in a display system using transparent windows

摘要

A central processing unit (CPU) is provided and is coupled to a display for displaying graphic and other data in multiple overlapping windows. The CPU is further coupled to one or more input devices which permits a user to selectively position a cursor and input and manipulate data within each of the windows on the display. The windows include defined areas having window features such as text, icons and buttons corresponding to functions to be executed by the CPU. Multiple applications may be executed concurrently by the CPU such that each application is associated with one or more windows. Each display element ("pixel") comprising the display is represented by multiple bits in a computer frame buffer memory coupled to the CPU. An alpha value ( alpha ) is associated with the intensity of each pixel of the display, such that multiple images may be blended in accordance with a predefined formula utilizing the alpha values. By setting the alpha values appropriately, transparency may be accomplished such that data associated with underlying windows may be rendered visible to the user. Effectively, the present invention merges multiple images through alpha "blending" such that several images appear transparently on top of one another. The present invention, through the selective use of alpha blending, permits underlying windows to display data visible to the user through windows which are overlaid above an underlying window.