Display apparatus which can scroll displayed data with regard to cursor position

• US 4,734,689 A
• Filed: 02/24/1986
• Issued: 03/29/1988
• Est. Priority Date: 03/07/1985
• Status: Expired due to Fees

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: Kurakake, Shigeo
• Primary Examiner(s): Curtis, Marshall M.
• Assistant Examiner(s): FATAHI YAR, MAHMOUD
• Application Number:
  US06/833,055
• Time in Patent Office: 764 Days
• Field of Search: 340/726, 340/724, 340/723, 340/709, 340/721
• US Class Current: 345/684
• CPC Class Codes: G06F 3/0485 Scrolling or panning
• CPC Class Codes: G09G 5/343 for systems having a character code-mapped display memory

Abstract

A display apparatus includes a document memory for storing data, a display section for displaying the data stored in a desired storage area of the document memory on a screen, and a scroll controller for designating data to be displayed on the display section and designating a cursor position to be displayed. When a cursor is located outside of a predetermined range on the screen, if a cursor-up or-down movement command is input, the displayed data is scrolled without moving the cursor position. When the cursor is located in the predetermined range on the screen, if the cursor-up or - down movement command is input, the cursor position changes in accordance with the command, and the displayed data is not scrolled. Even when the cursor is located outside of the predetermined range on the screen, if a storage area to be displayed by scrolling is not present in the document memory, or even if the storage area is present, if data to be displayed is not present on the screen, the cursor is displayed just as when located in the predetermined range.

Claims

1. A display apparatus which can scroll displayed data in response to a cursor position command, comprising:

storage means for storing data to be displayed over a plurality of lines;

display means for reading out an amount of stored data from said storage means for display on a screen having a certain line display range with line numbers increasing from top to bottom, and for displaying the readout data as display data within the line display range of the screen, together with a cursor mark which indicates a position where correction of the display data may be made;

input means for inputting cursor movement commands including a down-movement command and an up-movement command for the cursor mark;

cursor position-detecting means for determining if the cursor mark is displayed in a predetermined narrow screen region which is located at approximately the middle of said screen, in response to a cursor movement command entered by said input means;

first data detecting means for determining if said storage means contains data for display at lines exceeding the greatest line of data displayed within the display range of said screen when said cursor position-detecting means determines that the cursor mark is currently positioned in the predetermined narrow screen region and said input means enters a down-movement command;

down movement-controlling means responsive to said first data detecting means for maintaining the cursor mark at the current position, and for scrolling up on said screen the data read out from said storage means and displayed on said screen by one line if said storage means stores data at lines exceeding the greatest line of data currently displayed on said screen, and for maintaining the current display of lines of data fixed on the screen and moving the cursor mark position down by one line if no data is stored in said storage means at lines exceeding those currently displayed;

second data detecting means for determining if said storage means contains data for display at lines less than the least line of data displayed within the display range of said screen when said cursor position-detecting means determines that the cursor mark is currently positioned in the predetermined narrow screen region and said input means enters an up-movement command; and

up movement-controlling means responsive to said second data detecting means for maintaining the cursor mark at the current position and for scrolling down on said screen the data read out from said storage means and displayed on said screen by one line if said storage means stores data at lines less than the least line of data currently displayed on said screen, and for maintaining the current display of lines of data fixed on the screen and moving the cursor mark position up by one line if no data is stored in said storage means at lines less than those currently displayed.

2. The apparatus according to claim 1, wherein said down-movement controlling means comprises means for maintaining the current display of lines of data fixed on the screen and moving the cursor mark position down by one line in response to said down-movement command, if said cursor position-detecting means detects that the cursor mark is positioned outside the predetermined narrow screen region.

3. The apparatus according to claim 1, wherein said up movement-controlling means comprises means for maintaining the current display of lines of data fixed on the screen and moving the cursor mark position up by one line in response to said up movement command, if said cursor position-detecting means detects that the cursor mark is positioned outside the predetermined narrow screen region.

4. The apparatus according to claim 1, wherein the predetermined narrow screen region is located along a horizontal screen line dividing said screen into two equal upper and lower portions.

5. The apparatus according to claim 1, wherein the predetermined narrow screen region is bounded by lines separated from upper and lower ends of said screen at respective predetermined intervals.

6. A method of controlling a display apparatus which reads out display data for display on a screen having a certain line display range, from a memory storing a number of lines of document data, and which apparatus displays the readout data on the display screen, together with a cursor, comprising the steps of:

(a) maintaining the data read out from the memory on the screen and moving the cursor down by one line, when the cursor is positioned above a first predetermined line which is located at approximately the middle of the screen and when a cursor down-movement command is input;

(b) repeating step (a) until the cursor is positioned at the first predetermined line;

(c) maintaining the cursor fixed in position at the first predetermined line and scrolling up on the screen the data read out from the memory by one line, when the cursor is positioned at the first predetermined line, a cursor down-movement command is input, and document data at lines exceeding currently displayed data is present in the memory;

(d) maintaining the currently displayed data fixed on the screen and moving the cursor down by one line, when no document data at lines exceeding the currently displayed data is present in the memory and the cursor down-movement command is input;

(e) maintaining currently displayed data fixed on the screen and moving the cursor up by one line, when the cursor is positioned below a second predetermined line which is located above said first predetermined line and approximately at the middle of the screen, and a cursor up-movement command is input;

(f) repeating step (e) until the cursor is positioned at the second predetermined line;

(g) maintaining the cursor fixed in position at the second predetermined line and scrolling down on the screen the data read out from the memory by one line, when the cursor is positioned at the second predetermined line, a cursor up-movement command is input, and document data at lines less than the currently displayed data is present in the memory; and

(h) maintaining the currently displayed data fixed on the screen and moving the cursor up by one line, when no document data at lines less than the currently displayed data is present in the memory and the cursor up-movement command is input.

7. A method of controlling a display apparatus which reads out display data for display on a screen having a certain line display range including an upper display line and a lower display line, from a memory storing a number of lines of document data, and which apparatus displays the read out data on the screen, together with a cursor, comprising the steps of:

(a) maintaining the data read out from the memory fixed on the screen and moving the cursor down by one line, when data corresponding to an uppermost line of the document data stored in the memory is displayed on the screen and a cursor down-movement command is input;

(b) repeating step (a) until the cursor is positioned at a predetermined line which is located at approximately the middle of the screen;

(c) maintaining the cursor fixed in position at the predetermined line and scrolling up on the screen the data read out from the memory by one line, when the cursor is positioned at the predetermined line and the cursor down-movement command is input;

(d) repeating step (c) until data corresponding to a lowermost line of the document data stored in the memory is displayed on the screen;

(e) maintaining the display data read out from the memory fixed on the screen and moving the cursor down by one line, when the lowermost line data is displayed on the screen and the cursor down-movement command is input;

(f) repeating step (e) until the cursor is positioned at the lower display line of the screen;

(g) maintaining the display data fixed on the screen and moving the cursor up by one line, when the lowermost line data is displayed on the screen and a cursor up-movement command is input;

(h) repeating step (g) until the cursor is positioned at the predetermined line;

(i) maintaining the cursor fixed in position at the predetermined line and scrolling the display data down by one line, when the cursor is positioned at the predetermined line and the cursor up-movement command is input;

(j) repeating step (i) until the uppermost line data in the memory is displayed on the screen;

(k) maintaining the display data fixed on the screen and moving the cursor up by one line when the uppermost line data is displayed on the screen and the cursor up-movement command is input; and

(l) repeating step (k) until the cursor is positioned at the upper display line of the screen.