PT96433A - DEVICE FOR EXHIBITING GRAPHICS IN A COMPUTER TERMINAL SCANNER - Google Patents

Description

71 981 P / 8251 / SIS

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The present invention relates to a computer graphic device for representing graphic images on a terminal screen and in particular to a device for use in a non-graphic terminal.

The terms " chart " and " graphics " are used in this application to indicate images displayed on a screen or part of a screen which is not limited in the shapes or arrangement of lines in the image, these being freely selected by a user. Although it is possible to display graphics on a terminal display, the current devices are expensive in terms of the amount of memory required and, in addition, require a specific graphic terminal having appropriate preprogramming. Screens " not graphics " or "" characters " can only display on one screen characters of a predefined set, each character constituting a predefined array of pixels. For this reason, there are only a limited number of shapes that can be displayed to provide an image, and no freehand image can be displayed by the user. However, such terminals are cheaper than graphics terminals. The present invention results from an attempt to provide graphing capability for a non-graphic terminal.

According to the present invention, there is provided a device for displaying graphics on a computer terminal screen comprising: means for scanning an image to be displayed on a digital information beam of predetermined dimensions; means for subdividing said information beam into a plurality of matrices of identically sized pixels each corresponding in size to a standard character displayed on said screen; means for assigning a different preset default character code to each pixel array in the beam;

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means for defining the screen display of the standard character code assigned to each pixel array, according to the information of the scanned image in the respective array of pixels in the beam; means for displaying the characters defined on the screen in continuous arrangement corresponding to the array of pixels in the beam, so as to display the image.

Preferably, the indefinite character codes comprise the standard ASCII character codes, with character redefinition typically being performed at the terminal. The continuous array is conveniently formed so that there are no gaps between any pixels. The coding for the pixels may typically comprise an information subfever comprising the X and Y coordinates of the pixels and indication of the presence or absence of an image line. It is preferred that in particular the digitized information is analyzed and the points connected by a straight line are defined by the appropriate formula for the X and Y coordinates, no information being stored on the intermediate points of the end points of said straight line. The image to be displayed can typically be scanned using a pressure sensitive device, a light or heat activated device, or other devices such as X-ray devices, pen camera, sound devices, etc.,

A specific example of the present invention will now be described for use in a VT220 device of Digital Equipment Corporation in conjunction with a Micro-VAX II computer using Pascal VAX, running under the VMS operating system and intended for the reproduction of personal signatures. The first step in the process is signature scanning and this can be done using any conventional image scanner. A particular preferred method of signature scanning is to use a digitizer board with a " Sign On " (Alan Liebart Associates). In this case, the signature is written

71 981 P / 8251 / SIS -4-on a plate which is sampled at 80 times per second and which captures and digitizes the data in a window of 2550 by 1300 points. This information can be transferred via an asynchronous RS232 line to the host computer. The data is received in an encrypted ASCII format, which is decodable using a commercially available algorithm and appropriate software, and are recorded as series of three variables, namely X coordinate, Y coordinate and Z value (the Z value defines whether the pen is in contact with the paper, 0 = yes, 1 = no).

Definition of characters The terminal has generally used character shapes, for example A, B,%, etc., stored permanently within ROM made from a combination of dots (often called " pixels ") in an 8x10 matrix horizontal by 10 vertical). There is also an option where user-defined character shapes can be loaded (transferred from the host computer to the terminal) via " escape sequences "). The example below shows how an exclamation point character can be redefined to be an " A " character. This information was obtained from a pocket book of the VT220 terminal provided by the manufacturer.

A dot in an array of characters is shown as a and a space is shown as ". &Quot;.

12345678 aO al a2 a3 a4 a5 bO bl b2 to3

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Each character definition column is discharged as 2 numbers (a and b). The value " a " contains a binary representation of a0-a5 (6 bits). The value " b " contains the representation b0-b3 (4 bits). A value of 64 is added to these binary values and one is subtracted from the final value. Binary representations are obtained by assigning a binary bit if a dot (pixel) is present.

Go / Column Pixels Binary + 64 Sub. 1 Final ASCII Go to. col. 1 01000000 = 40H-1 = 3FH-1. col. 2 01110000 z 70H-1 Z 6FH = &quot; o &quot; Go to. col. 3 01101000 = 8H-1 = 67H = &quot; o &quot; Go to. col. 4 01100100 = 64H-1 = 63H Z "c". col. 5 01100100 = 64H-1 = 63H = "c" Go to. col. 6 01101000 68H-1 = 67H = &quot; g &quot; Go to. col. 7 01110000 70H-1 = 6FH = &quot; o &quot; Go to. col. 8 01000000 = 40H-1 = 3FH = ii <2 11 b. col. 1 ... 01000000 = 40H-1 z 3FH 5K II r and II Vai b, col. 2 01000011 = 43H-1 = 42H = &quot; B &quot; col. 3 - - - * 01000000 z 40H-1 = 3FH = ii <2 11 b. col. 4 - 01000000 = 40H-1 = 3FH = ii r and ii It is b. col. 5 .... 01000000 = 40H-1 = 3FH = n ry ii It is b. col. 6 - 01000000 = 4GH-1 = 3FH = II r and II It is b. col. 7 01000011 = 43H-1 = 42H = &quot; B "Go b. col. 8 ____ 01000000 = 40H-1 z 3FH = ii r and 11

The values are then ready for download. The escape sequence is structured in such a way that the final values are listed so that the eight values &quot; a &quot; go first (col, S first to col 1) and give the eight values &quot; b &quot; (col. 8 first again until col. 1). The format is as follows: DCS Pfn; Pcn5Pe; Pcms; Pw? Pt - ([Name] [8 a.vals] / [8 b.vals] ST Where:

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DCS Pf η 5 Pcn

Ps f Pcms 5 Pw 5 Pt C [Name] [8. a, vai] / [8. The. you will] ST

Start of escape sequence ESC P. Number of source seal.

Delimiter 15. character to be defined in the ASCII character set.

Delimiter;

Specifies where to delete all or just new characters »

Delimiter.

Matrix Cell Size.

Delimiter.

Screen Width;

Delimiter.

Specifies whether the font is full cell or text. Signals the end of parameter characters and initiates a load function.

Source name. 8a. col. 8 to col. 1.

Delimiter between values a. and b ,. 8 a. col. 8 to col. 1.

Delimiter of the ESC \ sequence. The exclamation point character &quot;! &Quot; will now be a &quot; A &quot; but it will be appreciated that similar techniques can be used to redefine any set character or any other shape. The signature tracing program picks up data from the ASCII X, Y, Z coordinates of the data file and converts them to integer values. In certain cases all possible points between two sets of coordinates are calculated. Dots are in the range of 1 to 1300 in the Y direction and 1 to 2550 in the X direction. To display this information you need to define a block of character shapes that, when printed in the correct order, will represent the signature. The program generally uses a block of 48 characters (3 lines of 16) as its graphic window. This could be adjusted to the requirements of the user and

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-7-although there is a limitation on the number of characters the setting is possible.

Each character uses an 8x10 matrix (10 rows, 8 columns). A 16 x 3 character block gives a resolution of 30 dots (pixels) in the Y direction by 128 on the X. Each dot is then plotted according to this resolution, and the character where the particular point is contained is calculated. Once the known current character is needed to calculate the row and column that contain the character. To place a bit in a character cell, you need to check whether the dot (pixel) is in the six top rows or the four bottom rows as they are stored separately. This type of storage is used when different logical operations need to be performed on the pixel data, depending on the line number in the cell. As long as all X, Y points have been plotted in proportion to the display window size, and all dots (pixels) have been placed in character definitions, the signature can then be displayed. Characters are unloaded on the terminal via &quot; escape sequences &quot; and the new character set becomes active. The character block is printed on the screen in the correct order. Other &quot; escape sequences &quot; to position the screen cursor are also used at this point, ft signature will now be displayed on the screen. The character set is then set to the original settings, so that normal characters will be available when the program ends. The device operates in the following sequence -a. Declares and initializes data structures b. Reads the file. The data file containing the X, Y data in ASCII form is opened for read access. The first X coordinate is obtained by reading characters in a sequence up to two points &quot;. &quot;. This sequence will then be converted to an integer, representing that value, for example, data from file 1234: (5 characters) is converted into an integer value of 1234 (Thousand Two Hundred and Thirty-four),

The same operation is performed to obtain the Y and X values

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71 981 P / 8251 / SIS for the first item. This will result in all three values being stored as integer variables, to represent the current X, Y, and 2 values, respectively.

The integer values are then compared with two values, representing the maximum and minimum values X and Y7, hitherto read from the file. Of course, in case of reading the first set of coordinates, these values will become the new limits. The Z value is at this point written in a wide bundle containing all the Z values read from the file. The procedure of filling points between values is then called. If the current point is not the first point of the file and the Z value of previous points was 0 (representing the pen when it is on paper) the dots will be filled. A detailed explanation of this procedure will be given later. The above action is then performed on the entire data file until the end-of-file marker (EOF) is reached. The file is then closed »

The maximum and minimum X and Y values will now be set correctly while the whole file has been compared. W. Fill points between points »A procedure in the device will fill (if necessary) all possible points between two points. The first point will obviously not have prior value to join, so no action will be taken. Similarly no action will be taken if the pen was not in the paper for the previous point. This will be known by examining the Z value of the previous point. If the value is] this will indicate that the pen was not on paper and that a line should not be drawn between the dots. A value of 0 for the previous Z value indicates that the points must be joined.

To find all points in a line between two points, we use the mathematical equation for a straight line (y = mx + + c). The process for this is as follows.

71 981 P / 8251 / 3IS-9- i. Calculate the slope (m) =

(previous X - will be current) / (previous X value - will be X current) ii. Calculate the intercept on the y-axis of the line (c) = (previous Y-value - (slope x previous X value))

Knowing the two values &quot; m &quot; and &quot; c &quot; it is possible to calculate all corresponding Y points by placing all intermediate points in the equation. This operation is also performed to calculate all points X by placing all intermediate Y points in the equation. That is, to serve extreme slopes on both axes. A 45-degree slope will produce identical points for both calculations.

All new calculated values are placed in the large bundle of integers containing the X and Y points. An attempt is made to save beam space where each value that is written in the X and Y whole bundles is checked according to the previous written value . If these are the same, there is no advantage in storing this point, the point is consequently abandoned. This will of course not serve for all coordinate duplications. The Z values for calculated points are not necessary (the pen is known to be on paper), and therefore they are not calculated. Consequently, the Z-beam will have only one entry in an index, where the point has actually been read from the file.

At the end of this procedure the current values X, Y and Z are made the previous values, for comparison with the next set of coordinates. d. Find scale. This traces the signature so that it fits best to the size of the screen window. The maximum and minimum X and Y values obtained when the data file was read are used here. and. Calculate the offset in the screen window. The deviation in the screen window is calculated by taking the X and Y coordinate data of the beams and adjusting them by subtracting the scale factor

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(calculated previously). A value in the range of 1 to 128 will be calculated for X, and a value in the range of 1 to 30 for Y. The line number is then calculated. A Y value of 1 to 10 indicates top-row (line 3), 11 to 20 the middle line (line 2) and 21 to 30 the bottom lin-ha (line 1). The Y-position in your character cell is calculated by subtracting O, 10, or 20 respectively. The character number is calculated using the offset X (1-128) and the line number. The character number will be in the range 1-48. Once this is known, it is possible to determine the position of point X in the particular character cell, using a calculation of module 8. f. Stitch (Pixel) in the character definition. This procedure sets a bit corresponding to the X and Y positions in the required character setting. The Y-point position is used to determine the value, which should be logically submitted to 0U with the existing mask, to establish a bit. Y values from 1 to 4 are stored in a beam and values from 5 to 10 are stored in one beam. That is, because of the way, rcomp character forms are loaded. This is shown in greater detail earlier in this document. Logically submitting values to 0U means that if a point (pixel) was set by a particular value, it does not matter if it is established again by subsequent ones. It is quite possible that a number of large scale points will be represented by the same bit, when the &quot; plot &quot; is quite large. Values are as follows.

Point Y 1 2 3 4 5 6 7 8 9 10

Value to be submitted to 0U 8 4 2 1 32 ló 8 4 2 1

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G. Signature drawn on the screen. When all X, Y data have been processed, it is necessary to trace the signature on the VT220 display. This procedure extends the use of &quot; escape sequences &quot; associated with the VT2207 terminal device and it may be beneficial to study a copy of the manual.

Initially, to the new character set, an identification character 2 is given, and the character set is designated by means of an escape sequence. The program uses the &quot; @ &quot; (space and symbol). The designation is performed by sending the following: ESC (sp @ where sp - space character The font is then unloaded using the escape sequence described in the &quot; Character Definitions &quot; section. The two dot position beams ) represent the characters a and b above Character characters 31 to 79 are set All other characters have no value The newly defined characters have no meaning unless they are printed in the correct order They need to be printed as 3 lines of sixteen characters directly above each other.

Other escape sequences are used to position the screen cursor to ensure that lines are printed one above the other.

Finally, it is necessary to reset the screen character set to its original value, to reset the terminal for future operations.

Claims (7)

71 981 P / 8251 / SIS-12- A device for displaying graphics on a computer terminal screen, comprising: i) means for digitizing an image to be displayed in a digital information beam of predetermined dimensions; ii) means for subdividing said information beam into a plurality of matrices of identically sized pixels each corresponding in dimension to a standard character displayed on said screen; iii) means for indicating a predefined character code for each pixel array in the beam; iv) means for defining the screen display of the indicated standard character code for each pixel array according to the information displayed in the respective pixel; v) means for displaying the characters defined on the screen in the continuous array corresponding to the arrangement of the pixels in the beam in order to display the image. Device according to claim 1, characterized in that the image is scanned using a pressure, light, x-ray, heat, or sound-activated device or pen camera Device according to claim 1 or 2, characterized in that the pre-defined character codes are codes for the standard ASCII characters. Device according to any preceding claim, characterized in that the pixels forming the beam are displayed without any gaps between them, Device according to any preceding claim, characterized in that the code for the pixels comprises an information subfeot comprising x and y coordinates of the pixel and an indication of the presence or absence of an image line. Device according to any preceding claim, characterized in that the redefinition of the characters is performed on the terminal. Device according to any preceding claim, characterized in that the digitized information is analyzed and the points connected by a straight line are defined by the appropriate formula for the X and Y coordinates, the information not being stored around intermediate points of the said points straight line. Lisboa -A.'M 1991 By THE MARCONI CQMPANY LIMITED - 0 OFFICIAL AGENT - "PARTIAL COMBUSTION OF WATER" Partial Combustion of Water is a process in which water is produced in the water / water / water / water / water. 96434 M This process allows a great savings of conventional fuel, more than 50 $, and reduces pollution in equal percentage, because the combustion of water releases water vapor, and also because the oxygen required for combustion is supplied by water.