GB2056916A - Apparatus for composing text in arabic - Google Patents

Abstract

The invention may be employed in photo-type-setting machines and typewriters to reduce the number of keys needed to cater for starting, middle, end and isolated forms of Arabic letters. The letters are keyed in as commands which are independent of the position of each letter in the words of the text. A control unit makes a number of different character commands correspond with each letter command and is arranged to select one of the character commands associated with each letter command as a function of whether the preceding command is or is not a space command or a semi-joined letter with only an isolated/starting form and an end/middle form. Normal letters can be decomposed into start and middle forms and a terminating part which, added to the middle and start forms yields the end and isolated forms respectively. A letter key 31 commands a start form (element 33) in the reset state N of a relay 37A common to all keys and also sets the relay. When the relay is set, operation of a key 31 commands the middle form (element 34). The last letter keyed in is always stored in a memory 36. Operation of the space key 32 causes the terminating part (plus space) of the stored character to be printed (element 35). <IMAGE>

Description

SPECIFICATION Apparatus for composing text in arabic The present invention refers to the composition of texts in Arabic.

It must be remembered that Arabic writing is a typically calligraphic writing which does not have independent printing characters like Latin writing, but soley printing characters derived from calligraphy, that is to say, including the joining strokes of handwriting, and that the form of the letter itself is modified according as this letter is placed at the start, the middle or the end of a word or else appears in the form of an isolated letter.

The invention will be exaplained with reference to the accompanying drawings, in which:~ Figure 1 shows the different forms of the letters of the Arabic alphabet, Figure 2 shows components into which the different forms of the letter Ba can be split, and Figures 3 and 4 are block diagrams of two embodiments of the invention, shown by way of example.

Thus in Fig. 1 the 28 letters of the alphabet are each shown from right to left (that is to say, in the direction of composition) in the form of a starting, middle, and end letter and in isolated form (49 characters from the Berthold foundry).

It will immediately be observed that 6 letters only have two forms, one form joined to the right and one isolated form; this type of letter which is joined only to the right will be called below "semi-joined letters", as opposed to letters with four forms which will be called "normal letters". For consistency in the description it may be assumed that the semijoined letters display in fact a starting form and an isolated form which are identical and a middle form and an end form which are identical.

The problems which are posed by this type of alphabet are immediately apparent as the alphabet comprises at least 100 different symbols for composing text. Using, for example, a typewriter or a photo-type-setting machine, the number of control keys is very large; therefore the time for key selection is rather long and the risk of errors is high.

The object of the present invention is to provide apparatus for composing text in Arabic in which the command number of letters of the alphabet is reduced preferably to 28; although the letters composed exhibit a distinct form according to whether they are at the start, in the middle or at the end of the word or else appear in isolated form.

For simplicity, reference is made specifically to text in Arabic, but the invention is equally applicable to text for example, in Persion or in Urdu, which displays the same characteristics for composition as Arabic.

According to the present invention, there is provided apparatus for composing text in Arabic, comprising an input device which provides a command sequence, including input commands for normal letters, semijsined letters, spaces, and non-alphabetical symbols, establishing the text to be composed, and a control unit which makes character commands correspond with the input commands, wherein the input device defines letter commands which are independent of the position of each letter in the words of the text, and the control unit makes a plurality of different character commands correspond with each letter command and is so arranged as to select one of the character commands associated with each letter command as a function of whether the preceding input command is or is not a space command or a semijoined letter command.

In the preferred embodiment, the control unit is as set out in claim 2 and preferably the control unit also includes a memory for the current input command adapted to record an item of information associated with the input command immediately succeeding the previous command.

Thus, for example the current input command memory stores at least the identity of the symbol defined by this current command (n), the antecedent memory stores an item of information relative to the previous command (n-1), and the means of translation acts in a selective manner upon receipt of the next input command (n + 1) and responds to the current command (n) in dependence upon the previous command (n-1) as well as upon the next command (n + 1) with a command for::~ a starting character if the previous command (n-1) is a space or a semi-joined letter and the next command (n + 1) is other than a space, a middle character if the previous command (n-1 ) is other than a space or semi-joined letter and the next command (n + 1B is other than a space, an end character if the previous command (n-1 ) is other than a space or a semijoined letter and if the next command (n + 1) is a space, and an isolated character if the previous command (n-1) is a space or a semi-joined letter and if the next command (n + 1) is a space.

In order to simplify the apparatus it may be provided that the current input command memory is connected to the antecedent memory in order to record a starting or isolated character if the previous command is a space or a semi-joined letter, and a middle or end character if the previous command is other than a space or a semijoined letter, and the means of translation selects the first or the second type of character as a function of the next command (n + 1).

In this embodiment of the invention, the composition of the text is delayed by one key stroke with respect to the input command.

This may present certain minor disadvantages but these disadvantages are largely compensated by the gain in time and the convenience of the apparatus.

One of the advantages of the apparatus is that it may be fitted on existing machines without having to modify the operating members. Thus on a typewriter the characrers will not have to be modified; only the control of the characters and the keyboard have to be modified.

It must be observed that certain symbols other than the space or the semi-joined letters may in certain cases, when they are placed before the word, call for a starting letter. One may then provide, if this type of symbol is always preceded by a space, for dealing with it apart in order that the item of information about the previous command remains the space or else for dealing with this type of symbol as a semi-joined letter; similarly a symbol which would command a starting letter and an end letter like the space migh be dealt with like the space. Other modifications may obviously be carried out in this spirit, depending upon the symbol to be dealt with.

However, in order not to overload the description, it will be assumed that the nonalphabetical symbols are letters having identical forms whatever their places and that these symbols or groups of symbols are introduced and terminated by a space.

Another embodiment of the present invention is based upon the following observations.

Fig. 1 represents the decomposition into three elements of the letter "be". It may be observed that: ~the starting form of the letter consists of the element 1; ~the middle form of the letter consists of the element 2; ~the end form of the letter consists of the element 2 and 3 together; ~the isolated form of the letter consists of the elements 1 and 3 together.

It may be observed that such decomposition may be extended to all of the normal letters.

The element 3 of the decomposition, that is to say, the element obtained by subtracting the middle form from the end form, will be called below the termination element. This refers to the technical termination without implying practical significance in Arabic. In certain cases this decomposition leads to a modification of the form of the letters but not one which disturbs the readability of the texts or the appearance of the text.

In this method of putting the invention into effect, the current memory memorizes a termination element character command associated with the command in progress, the means of translation selects at the time of the order in progress a starting character or a middle character according as the previous command is or is not a space or a semi-joined letter and selects the termination element character and a space at the time of the next command if the latter is a space.

It may obviously be provided that each termination element character includes the space element, for example, on a typewriter the two elements are cast into a single character, or else two distinct characters may be provided.

Of course when the current command in progress is a semi-joined letter or a space, the current memory will preferably have to memorize a "space information" so that another space does not bring the termination element appropriate to the letter of the command (n-2); this space information may be simply an erasure of the memorized command.

This embodiment displays the advantage over the first embodiment that the commands are executed immediately. However the operating members of the machine have to be modified and hence it cannot be fitted easily to existing devices.

On the practical plane it will be noted that numerous termination elements are identical for a number of letters which are differentiated from one another only by the diacritical punctuation; hence the common termination element may be employed for different letters at the level of the operating members.

Fig. 3 represents a first embodiment of the invention. The apparatus includes a set of command elements consisting of keys which for convenience will be separated into 4 groups, the reference 1 designating the keys for normal letters, the reference 2 designating the keys for semi-joined letters, the reference 3 designating the space key and the reference 4 designating the keys for non-alphabetical signs.

The keys 1 and 2 are connected to a current memory 5 for the command (n) in progress which supplies items of information to operating members 6 to 11 which in accordance with conditions provided by the memory 14 execute the normal letter in the starting form, isolated form, end form or middle form for the members 6 to 9 respectively or the semijoined letter in the nonjoined form (starting or isolated form) and in the joined form (middle of end form) for the members 10 and 11 respectively. The keys 4 control their own operating members 4A.

The control unit includes besides the memory 5 an antecedent memory 15 which changes state with the authorisation of the memory 5 and in response to the items of information which are supplied to it by a register 14. The information proceeding from the antecedent memory 15 is decoded by a set of AND-gates 16 to 19, these gates being connected to the register 14 which supplies the selection signals to the operating members 6 to 11. The AND-gates 16 to 19 combine the items of information proceeding from the memory 15 and from the letter keys 1 and 2 or the space key 3.

At the start of the text the memory 15 for antecendent is in the normal position (N) and a relay 20A, 20B is in the position indicated.

Striking a first normal letter on the key 1 leads to the memorization of the letter in the memory 5; no operation occurs. This is the current input character (n).

Striking a second normal letter on the key 1 leads to the memorization of the letter of the command (n + 1) in the memory 5 and the supply of the item of information: "other (n + 1) = letter" to the gates 16 and 19.

The antecedent memory 15 being in the normal position, only the gate 19 is opened, this transferring to the register 14 the item of information "starting letter", which selects the operating members 6 which execute the letter of the command (n) from the memory 5 in the starting letter form.

At the same time the memory 5 authorises the antecedent memory 15 to change its state. This change of state is carried out in response to the item of information supplied by the register 14, namely, "order (n) starting letter" (hence other than a space); the contact 20B being in the position indicated, the antecedent memory 15 changes over to the excited state (E).

Striking another normal letter on the key 1, hence a command (n + 2), reproduces the previous operations with the following differences: only the conditions of the gate 16 are satisfied, namely, memory 15 excited and command (n + 2) = letter and the letter of the command (n + 1) is executed by the members 9, that is to say, in middle letter form.

The item of information supplied by the memory 14 to the memory 15 being still command (n + 1) and different from a space, the contact 20B keeps its position and the memory 15 remains in the excited position.

If the command (n + 3) is a space, only the logic of the gate 17 is satisfied: memory 15 excited and command (n + 3) space, hence the letter of the command (n + 2) is excuted by the member 8 in "end letter" form, then the space is executed by the member 12 and the antecedent memory returns to the normal state thanks to the item of information from the memory 14 command (n + 3) = space.

One may easily understand the striking of an isolated letter thanks to the gate 18 combines antecedent memory in normal state and next command is space.

A particular problem is posed by the semijoined letters. That is, these letters in their sequence call for a starting letter even in a word. Hence it is necessary to provide a circuit which, after the execution of this type of letter, brings the antecedent memory 15 back to the normal state. in order to do this the relay 20A is provided, the winding of which is energised by the execution of a semijoined letter and which operates the contact 20B, which has the effect of bringing the memory 15 back to the normal state.

Fig. 4 represents another embodiment of the invention. The control keys are divided into two groups, the letter identification keys 31 and the space key 32.

The operating members 33 and 34 execute the identified letter in the starting form and the middle form respectively whereas the member 35 in response to action upon the space key 32 executes the termination element corresponding with the letter of the preceding order, memorized in the memory 36.

The antecedent memory consists of a relay 37A whose winding acts upon two contacts 37B and 37C; the winding is excited by the item of information proceeding from the member 33: starting letter executed, and is brought back to the normal state only by the information: space in progress or semi-joined letter in progress.

The operation of the device is easy to understand; the first letter command supplied by the key 31 is executed by the member 33 in starting letter form and the memory 36 memorizes the termination element corresponding with this first letter. At the same time the relay 37 is excited and the position of the contacts 37B and 37C is reversed, hence the next letter will be executed, the contact 37C being closed, in middle letter form by the member 34.

if the command in progress is a space commanded by the key 32, the member 35 executes the termination element memorized by the memory 36, which corresponds with the letter of the preceding order as well as a space. At the same time the relay 37 is brought back to the normal state, whereby the next letter will be executed in "starting letter" form. If during the progress of a word the letter command corresponds with a semijoined letter the latter is executed in starting or middle form depending upon the nature of the preceding command and the relay 37 will be brought back to normal in order to ensure the execution of the next letter in "starting letter'' form.

After the execution of a space or a semijoined letter, the memory 36 preferably contains no information; under these conditions action upon the space key 32 leads soley to the execution of a space.

Of course the two embodiments described are only illustrative of the possibilities within the scope of the invention as claimed. The apparatus is preferably realised by means of electronic components but it is of course possible, taking into account its simplicity, to imagine realising it by means of purely me chanical parts. The apparatus can be employed in any machine for composition in Arabic, in particular photo-type-setting machines and typewriters.

The first embodiment, that is to say, the "shifted stroke" apparatus, demands practically no modification of existing machine and enables the arrangement of the characters in the machine to be preserved (type-baskets, plates, discs, tapes, etc.). It is sufficient quite simply, for example, to arrange a selector keyboard on the keyboard proper of the machine and to remove it when required.

On the other hand, the second embodiment, "non-shifted stroke", necessitates a modification of the characters themselves or at a minimum of the end character which must be transformed into a termination element. In fact it will in general be necessary to provide a new machine.

Claims (6)

1. Apparatus for composing text in Arabic, comprising an input device which provides a command sequence, including input commands for normal letters, semi-joined letter, spaces, and non-alphabetical symbols, establishing the text to be composed, and a control unit which makes character commands correspond with the input commands, wherein the input device defines letter commands which are independent of the position of each letter in the words of the text, and the control unit makes a plurality of different character commands correspond with each letter command and is so arranged as to select one of the character commands associated with each letter command as a function of whether the preceding input command is or is not a space command or a semi-joined letter command.

2. Apparatus according to claim 1, in which the control unit includes an antecedent memory adapted to store an item of information which is representative of whether a previous input command is or is not a space command or a semi-joined letter command, and a means of translation adapted to define in response to the input command immediately succeeding this previous command a character command which is dependent upon the said stored item of information.

3. Apparatus according to claim 2, in which the control unit also includes a memory for current input command, adapted to record an item of information associated with the input command immediately succeeding the previous command.

4. Apparatus according to claim 3, in which the current input command memory stores at least the identity of the symbol defined by this current command (n), the antecedent memory stores an item of information relative to the previous command (n-1), and the means of translation acts in a selective manner upon receipt of the next input command (n + 1 ) and responds to the current command (n) in dependence upon the previous command (n-1) as well as upon the next command (n + 1) with a command for::~ a starting character if the previous command (n-1) is a space or a semi-joined letter and the next command (n + 1) is other than a space, a middle character if the previous command (n-1 ) is other than a space or semi-joined letter and the next command (n + 1) is other than a space, an end character if the previous command (n-1 ) is other than a space or a semi-joined letter and if the next command (n + 1) is a space, and an isolated character if the previous command (n-1 ) is a space or a semi-joined letter and if the next command (n + 1) is a space.

5. Apparatus according to claim 4, in which the current input command memory is connected to the antecedent memory in order to record a starting or isolated character if the previous command is a space or a semi-joined letter, and a middle or end character if the previous command is other than a space or a semi-joined letter, and the means or translation selects the first or the second type of character as a function of the next command (n+1).

6. Apparatus according to claim 3, in which the current input command memory memorizes a termination element character command associated with the order in progress, the means of translation selects at the time of the order in progress a starting character or a middle character according as the previous command is or is not a space or a semi-joined letter and selects the terminal element character and a space at the time of the next command if the latter is a space.