EP0381892A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Computer display windowing systems
Assignee: International Business Machines Corp
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Filing: 1989-11-30
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Granted: —
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Expires: 2009-11-30
Abstract
Abstract A computer system having a display adapter, a refresh buffer and an interactive display terminal with a screen display on which is formed a plurality of at least partially overlapping windows, a depth buffer is added to the display adapter for providing clipping assistance to the software-based window manager in the CPU. The window manager is programmed to monitor the current depth position of each of the plurality of windows. In response to an input request for a rearrangement of the windows, the window manager assigns a new depth value to the subject matter associated with each affected window and requests that each application retransmit at least the affected subject matter. The depth buffer includes an array which stores the depth values of the subject matter associated with each of the windows being currently displayed on the screen. In response to the rearrangement request, depth buffer receives the new depth values for the subject matter associated with each affected window from the window manager and compares the current depth values. If the comparator determines that the new subject matter has a depth value associated with the same window or a window closer to the viewer, the depth buffer notifies the refresh buffer to store the newly transmitted subject matter from each of the applications being run on the CPU. In an alternative embodiment, two buffers are used to store the depth information associated with the subject matter in a window, i.e. a W-buffer to store the depth of each window relative to a reference point and a Z-buffer to store the depth of the subject matter within a window.
Inventors
- 👤 Larry Keith Loucks
- 👤 Richard Ormond Simpson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 12:29
CPC Classifications
G; G09; G09G; G09G5/00; G09G5/14; G06; G06T; G06T1/00; G06F; G06F3/00; G06F3/01; G06F3/048; G06F3/0481
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
225 words
A computer system having a refresh buffer; an interactive display terminal with a screen display on which is formed a plurality of at least partially overlapping windows, each window displaying subject matter different from that displayed on the remainder of the screen; means for requesting a rearrangement of the depth of the plurality of windows relative to a reference position from a current arrangement to a new arrangement; manager means for determining the depth of the subject matter associated with each of the windows, wherein said manager means, in response to the input request, determines the new depth of the affected subject matter in each of the plurality of windows in the new arrangement and transmits the new depth values for the affected subject matter in each affected window; and depth buffer means for storing the depth values of the subject matter associated with each of the windows displayed on the screen, wherein said depth buffer means includes means for comparing the depth value for the newly transmitted subject matter to the depth value for the displayed subject matter in response to the input request and, if the new subject matter has a depth value associated with the same window or a window closer to the viewer, the comparator means instructs the refresh buffer to store the newly transmitted subject matter for refreshing the screen.
Claim 2
Dependent Claim
225 words
A computer system having a refresh buffer; an interactive display terminal with a screen display on which is formed a plurality of at least partially overlapping windows, each window displaying subject matter different from that displayed on the remainder of the screen; means for requesting a rearrangement of the depth of the plurality of windows relative to a reference position from a current arrangement to a new arrangement; manager means for determining the depth of the subject matter associated with each of the windows, wherein said manager means, in response to the input request, determines the new depth of the affected subject matter in each of the plurality of windows in the new arrangement and transmits the new depth values for the affected subject matter in each affected window; and depth buffer means for storing the depth values of the subject matter associated with each of the windows displayed on the screen, wherein said depth buffer means includes means for comparing the depth value for the newly transmitted subject matter to the depth value for the displayed subject matter in response to the input request and, if the new subject matter has a depth value associated with the same window or a window closer to the viewer, the comparator means instructs the refresh buffer to store the newly transmitted subject matter for refreshing the screen.
Claim 3
Dependent Claim
33 words
A computer system as claimed in claim 1, wherein said comparator means notifies the depth buffer means to store the depth values for the newly transmitted subject matter stored in the refresh buffer.
Claim 4
Dependent Claim
56 words
A computer system as claimed in claim 1 or claim 2, wherein if the new subject matter has a depth value associated with a window farther from the viewer, said comparator means inhibits the refresh buffer storing the newly transmitted subject matter and the screen is refreshed with the subject matter currently in the refresh buffer.
Claim 5
Dependent Claim
91 words
A computer system as claimed in claims 1, 2 or 3, wherein the subject matter associated with each of the windows is stored in the refresh buffer as a set of pixel values having specific pixel addresses; and said manager means assigns a depth value to each pixel value in each pixel set associated with each window currently on the screen, and, in response to the input request, assigns new depth values to the set of pixel values which are affected by the input request, and transmits the new depth values.
Claim 6
Dependent Claim
47 words
A computer system as claimed in any preceding claim, wherein the depth value for the subject matter comprises a concatenation of the window depth value for the window for the subject matter and the depth value of the subject matter within the window for the subject matter.
Claim 7
Dependent Claim
167 words
A computer system as claimed in claim 1, wherein the depth value for the subject matter associated with a window formed on the screen comprises a window identification and a pixel depth value representative of the depth of the subject matter within the window for the subject matter; said buffer means stores the current window identifications for the plurality of overlapping windows; said comparator means includes a window depth table which stores the current depth value associated with each window identification; said manager means, in response to the request from said input means, outputs a new depth position for each window identification listed in the window depth table and the new window identifications and pixel depth values to said comparator means; and the comparator means reads from said window depth table the depth value of the window identification currently in the buffer means and the depth value for the new window identification and compares the respective depth values for the windows obtained from said window depth table.
Claim 8
Dependent Claim
44 words
A computer system as claimed in claim 6, wherein each depth value comprises a concatenation of the window identification and the pixel depth value within the window; and said comparator compares the concatenated value currently in said buffer means with the new concatenated value.
Claim 9
Dependent Claim
248 words
A computer system as claimed in claim 1, wherein the depth value for the subject matter within a window comprises a window identification and a pixel depth value representative of the depth of the subject matter within the window for the subject matter; said buffer means stores the current window identifications and associated pixel depth values for the plurality of overlapping windows; said manager means, in response to the request from said input means, outputs the new window identifications and associated pixel depth values for the plurality of overlapping windows to said comparator means; said comparator means comprises first comparator means for comparing the new window identification with the current window identification wherein, if the current window and new window identifications are equal, the first comparator outputs a first enable signal; second comparator means for comparing the current pixel depth value associated with each current window identification with the new pixel depth value associated with the new window identification wherein, if the new pixel value is less than or equal to the current pixel depth value, the second comparator outputs a second enable signal; and logic means coupled to the outputs of said first and second comparators, for outputing an update signal to said refresh buffer and said buffer means in response to the receipt of first and second enable signals from said comparators, wherein the refresh buffer accepts the new pixel values and the buffer means accepts the new window identification in response to the update signal.
Claim 10
Dependent Claim
257 words
A computer system as claimed in claim 1, wherein the depth value associated with the subject matter of each window comprises a window identification and a pixel depth value representative of the depth of the subject matter within the window for the subject matter; said buffer means comprises first buffer means for storing the current window identification for the subject matter being displayed on each of the overlapping windows; and second buffer means for storing the current pixel depth value of the subject matter being displayed on each of the overlapping screens; said manager means, in response to the request from said input means, outputs the new window identification and pixel depth value to said comparator means and a new depth position for each window identification to the window identification table, said comparator means comprises first comparator means coupled to the first buffer means for comparing the new window identification with the current window identification wherein, if the current and new window identifications are the same, the first comparator outputs an enable signal to the second comparator; and second comparator means coupled to said second buffer means for comparing the current pixel value with the new pixel value upon receiving an enable signal from said first comparator, wherein, if the new pixel value is less than or equal to the current pixel depth value, said second comparator outputs update signals to the first and second buffer means whereupon said first buffer means stores the new window identification and said second buffer means stores the new depth value.
Claim 11
Dependent Claim
150 words
A computer system as claimed in claim 1, wherein the depth value associated with the subject matter within a window on a screen comprises a window identification; said buffer means stores the current window identification for the subject matter being displayed in each of the overlapping windows; said manager means, in response to the request of the input means, outputs a new window identification; said comparator means compares the window identification of the newly transmitted subject matter to the window identification of the currently displayed subject matter and, if the new window identification identifies the same window or a window closer to the viewer, the comparator outputs enable signals to the refresh buffer and buffer means; and in response to the enable signals, the refresh buffer stores the new subject matter for refreshing the screen display with the new subject matter and the buffer means stores the new window identification.
Claim 12
Dependent Claim
242 words
A computer system capable of running a plurality of applications having a display adapter with a refresh buffer; an interactive display terminal with a screen display on which is formed a plurality of at least partially overlapping windows, each window displaying subject matter different from that displayed on the remainder of the screen; means for requesting a rearrangement of the depth positions of the plurality of windows relative to a reference position from a current arrangement to a new arrangement; manager means for determining the depth position of each of the plurality of windows and assigning a depth value to the subject matter associated with each of the windows, wherein said manager means, in response to the input request, determines the new depth positions of the plurality of windows, assigns a new depth value to the subject matter associated with each affected window and outputs such depth values; and buffer means for storing the depth values of the subject matter associated with each of the windows being displayed on the screen, wherein said buffer means includes means for comparing the depth value for the newly transmitted subject matter to the depth value for the displayed subject matter in response to the input request and, if the new subject matter has a depth value associated with the same window or a window closer to the viewer, the comparator instructs the refresh buffer to store the newly transmitted subject matter for refreshing the screen.
Claim 13
Dependent Claim
242 words
A computer system capable of running a plurality of applications having a display adapter with a refresh buffer; an interactive display terminal with a screen display on which is formed a plurality of at least partially overlapping windows, each window displaying subject matter different from that displayed on the remainder of the screen; means for requesting a rearrangement of the depth positions of the plurality of windows relative to a reference position from a current arrangement to a new arrangement; manager means for determining the depth position of each of the plurality of windows and assigning a depth value to the subject matter associated with each of the windows, wherein said manager means, in response to the input request, determines the new depth positions of the plurality of windows, assigns a new depth value to the subject matter associated with each affected window and outputs such depth values; and buffer means for storing the depth values of the subject matter associated with each of the windows being displayed on the screen, wherein said buffer means includes means for comparing the depth value for the newly transmitted subject matter to the depth value for the displayed subject matter in response to the input request and, if the new subject matter has a depth value associated with the same window or a window closer to the viewer, the comparator instructs the refresh buffer to store the newly transmitted subject matter for refreshing the screen.
Claim 14
Dependent Claim
47 words
A computer system as claimed in claim 11, wherein said buffer means is a RAM array located in the display adapter; and said manager means instructs each application which is affected by the window rearrangementto retransmit the subject matter associated with application directly to the display adapter.
Claim 15
Dependent Claim
107 words
A graphics adaptor card for use with a computer system producing a display including a plurality of at least partially overlapping windows, said card comprising a refresh buffer adapted to store pixel data representative of pixels of said display, a buffer means adapted to store data indicative of which of said windows controls which of said pixels and comparator means responsive said data stored in said buffer means to inhibit updating of said refresh buffer with pixel data received by said card if said received pixel data is not associated with said window controlling said pixel whereby clipping of said windows is carried out by said card.
Claim 16
Dependent Claim
107 words
A graphics adaptor card for use with a computer system producing a display including a plurality of at least partially overlapping windows, said card comprising a refresh buffer adapted to store pixel data representative of pixels of said display, a buffer means adapted to store data indicative of which of said windows controls which of said pixels and comparator means responsive said data stored in said buffer means to inhibit updating of said refresh buffer with pixel data received by said card if said received pixel data is not associated with said window controlling said pixel whereby clipping of said windows is carried out by said card.
References Cited (Backward Citations)
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