WO2001016863A2

WO2001016863A2 - Method and apparatus for symbol storage and display

Info

Publication number: WO2001016863A2
Application number: PCT/US2000/040774
Authority: WO
Inventors: Robert B. O'dell
Original assignee: Dell Robert B O
Priority date: 1999-08-30
Filing date: 2000-08-30
Publication date: 2001-03-08
Also published as: CN1372681A; JP2003528336A; AU8036400A; WO2001016863A3

Abstract

A method and apparatus is provided for storing and displaying symbols (515). The method includes: retrieving a first bitmap (505), where the first bitmap (505) contains information regarding a first part (506) of the image pattern of the symbol (515) for display of the first part of the image pattern of the symbol; displaying the first part of the image pattern of the symbol in a first symbol space (515); retrieving at least a second bitmap (510), where the second bitmap contains information regarding a second part (511-513) of the image pattern of the symbol for display of the second part of the image pattern of the symbol (515); and displaying the second part of the image pattern of the symbol in the first symbol space (515). The present invention also includes a carrier and an apparatus which include program code signals for performing the method of the present invention.

Description

METHOD AND APPARATUS FOR SYMBOL STORAGE AND DISPLAY

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application Serial Number

60/151,495, filed August 30, 1999, and titled "Computer Monitor Display of Characters,

Etc."

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to computer based storage and display of symbols and, in particular but not exclusively, to computer based storage and display of characters.

2. Description of the Related Art

The English language uses its 26 letter alphabet to construct several hundred thousand words in left to right linear groups of varying lengths and combinations of letters. Each letter or group of letters is associated with a sound. Using these 26 letters any word in the English language can be constructed. Therefore, computer based display of English words only requires storage of the image patterns for the 26 letters of the English alphabet. The image pattern of the letter is the visual pattern that the reader sees and associates with the letter. It is what is written, displayed or printed to represent the character. In other words, it is the shape of the character. Some other languages, such as, for example, Chinese, are very different in their writing systems from languages using alphabetic systems. The most elementary unit in Chinese is said to be not an alphabet symbol but a "character", a symbol which is usually equivalent to an English word. Chinese is not the only language to use such characters. For example, Japanese and Korean also use characters. Japanese and Korean have characters that are derived from Chinese characters. In some cases they are identical to Chinese characters.

As used herein, the term "character" refers to, for example, Chinese, Japanese, and Korean characters. As also used herein, the term "symbol" refers to letters, characters, or any predetermined image pattern, including partial characters (which may also herein be referred to as incomplete characters). A partial character as used herein refers to an image pattern (i.e., shape) that contains less than the entire image pattern of the character.

Also unlike English, where different words can be of different lengths and, therefore, can occupy areas of different sizes, in character based writing systems, such as those mentioned above, all characters occupy an area of predefined size. This area within which a character is displayed, printed or written is herein referred to as the character space. The character space can, of course, be changed in a manner similar to changing the font for English letters.

There are said to be as many as perhaps 50,000 Chinese characters, including ancient and very esoteric ones. In existing systems, display of these characters requires storage of bitmaps for each of these characters, where each bitmap contains all the image pattern information needed to display one corresponding character. In other words, each bitmap contains information regarding the entire image pattern of a corresponding character. The image pattern of a character is the visual pattern that the reader sees and associates with what is written, displayed or printed to represent the character. In other words, it is the shape of the character. Assuming a bitmap size of 24 by 24 bits, then storage of bitmaps for 50,000 characters would require a memory of 3.6 Megabytes. The storage of 10,000 characters would require a memory of 720 Kilobytes. These are both relatively large memory requirements, particularly for portable devices, such as, for example, laptop computers, personal digital assistants, and cellular telephones.

In addition to displaying full characters, a character input device can also display partial characters to help guide the user in inputting the character, and to help narrow down the search for the right character. U.S. Patent No. 5,109,352, which is herein incorporated by reference, discloses an input system for characters that involves the display of partial characters. Similarly, International Publication No. WO 00/41062, published on July 13, 2000 and based on International Application No. PCT/US00/00135 of the inventor of the present invention, filed January 4, 2000, and titled "Text Input System For Ideographic And Nonideographic Languages", (herein referred to as "International Publication No. WO

00/41062"), which is also herein incorporated by reference, also discloses an input system for characters that involves the display of partial characters.

In the input systems of the above mentioned references, display of a partial character involves storage of a bitmap that contains information regarding the display of the entire partial character. Therefore, these systems, in addition to storing bitmaps for complete characters, also store bitmaps for the partial characters that they may display. It is estimated that, for some implementations of these systems, it is necessary to store even more partial characters than complete characters. As a result, there has been a need for a method and an apparatus that reduces the number of bitmaps needed to display such a large number of partial characters in addition to the usual set of complete characters in order to reduce the memory required for storing the needed bitmaps. The present invention meets this need.

SUMMARY OF THE INVENTION

The present invention encompasses a method and apparatus for storage and display of symbols. A presently preferred embodiment of the method of the present invention comprises: retrieving a first bitmap, wherein the first bitmap contains information regarding a first part of the image pattern of the symbol for display of the first part of the image pattern of the symbol; displaying the first part of the image pattern of the symbol in a first symbol space for displaying symbols; retrieving at least a second bitmap, wherein the second bitmap contains information regarding a second part of the image pattern of the symbol lor display of the second part of the image pattern of the symbol; and displaying the second part of the image pattern of the symbol in the first symbol space.

In one presently preferred embodiment, the method of the present invention further comprises: selectively loading information regarding the first part of the image pattern of the symbol in a first portion of an image buffer, wherein the first portion corresponds to the first symbol space; and selectively loading information regarding the second part of the image pattern of the symbol in the first portion of the image buffer.

In another presently preferred embodiment, the method of the present invention further comprises: first reading at least one input signal input by the user to identify the symbol; identifying N bitmaps corresponding to the at least one input signal, where N is an integer greater than or equal to 1 and wherein at least one of the N bitmaps is a combination of the first and second bitmaps, further wherein each of the N bitmaps represents an image pattern; and displaying M image patterns represented by M of the N bitmaps, where M is an integer less than or equal to N. The method further comprises: second reading at least one user input signal input since the first reading step; determining that the user has selected one of M image patterns as the symbol; and displaying the selected one of the M image patterns in a symbol space for selected symbols.

The present invention also includes a carrier and an apparatus which include program code signals for performing the method of the present invention.

The present invention is explained in more detail below with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a general block diagram of one presently preferred embodiment of a device of the invention.

Figure 2 is a flowchart of one presently preferred embodiment of the process of identifying and displaying a character.

Figure 3 illustrates an example of a combination of two bitmaps to display a character, where each of the bitmaps represents a stroke in that character.

Figure 4 illustrates an example of a combination of eleven bitmaps to display a symbol, where each of the eleven bitmaps represents a pixel in that symbol.

Figure 5 illustrates an example of a combination of two bitmaps to display a character, where one of the bitmaps represents an element in that character. Figure 6 illustrates an example of a combination of two bitmaps to display a partial character of the complete character shown in Figure 5.

Figure 7 is a table illustrating the correlation between symbols and their corresponding bitmaps.

Figure 8 is a flowchart for one presently preferred embodiment of the process of sequentially loading bitmaps for display on an active matrix display device.

Figure 9 illustrates an example of a combination of truncated bitmaps to create an untruncated bitmap.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention comprises a method and apparatus for storage and display of symbols (i.e., the image pattern of symbols). The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the preferred embodiment will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Thus, the present invention is not intended to be limited to the embodiment shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Figure 1 is a general block diagram of a presently preferred embodiment of a device of the present invention. Device 100 may be a portable device, such as, for example, a laptop computer, a personal digital assistant, or a cellular telephone. Device 100 may also be a non-portable device such as, for example, a desktop computer. In Figure 1, device 100 includes a controller 105, an input device 110, an output device 115, and a memory 120, all of which are coupled by communication channel 125. Controller 105 may, for example, be a central processing unit (CPU). The input device 110 may, for example, be a keyboard, mouse, joystick, a stylus, a microphone or some other device that may be used to input a signal to device 100. Output device 115 may be a display monitor, a printer, or some other device used to output a signal from device 100. Those skilled in the art would know that the output device 115 or memory 120 may include an image buffer that is used to hold digital representations of an image pattern to be displayed by the output device 115. In a presently preferred embodiment, output device 115 comprises an active matrix display monitor. Communication channel 125 may include one or more busses or transmission channels that couple two or more of the components of device 100 or couple device 100 to some other device.

Although input device 110 and output device 115 are shown as being separate devices, they may be integrated as an input/output (I/O) device. For example, a touch screen display monitor may be used both as an input and an output device.

Memory 120 includes a preset number of bitmaps that either alone or in combination are used to display symbols. Some of these bitmaps do not contain information for the entire image pattern or full display of a symbol. Instead, each of these bitmaps contains information for a portion of the image pattern or display of a symbol. In one embodiment, each bitmap contains information for displaying only one pixel of the image pattern of a symbol in a symbol space. In another embodiment, each bitmap contains information for displaying Z pixels of the image pattern of a symbol in a symbol space, where Z is an integer greater than 1. In one embodiment where each bitmap contains information for display of Z pixels of the image pattern of a symbol, each bitmap includes information for the display of a stroke in a character. In other words, each bitmap includes information regarding the image pattern of a stroke in the character. In another embodiment where each bitmap contains information for display of Z pixels of the image pattern of a symbol, each bitmap includes information for the display of the image pattern of an element in a character. In other words, each bitmap includes information regarding the image pattern of an element in the character.

As used herein a stroke is a component of a character and only rarely itself constitutes a complete character. As also used herein an element is a component of a character, is usually comprised of two or more strokes, and when standing alone and sized differently or constructed differently than in their element state, many elements constitute complete characters. For example, when the character for the word tree is compressed horizontally and displayed in the leftmost portion of the character space (as shown in Figures 5 and 6) it is an element. However, if expanded horizontally (from what is shown in Figures 5 and 6) to occupy the entire character space, then the element becomes the character for the word "tree". In other examples, an element may be compressed vertically or both vertically and horizontally in relation to its corresponding stand alone character. In yet other examples, an element is otherwise constructed differently than its corresponding stand alone character.

As will be appreciated from the description herein, the storage of bitmaps which represent the image pattern of a portion rather than the complete symbol and which can be used in combination to display complete symbols can provide substantial savings in required memory for storing the bitmaps needed for displaying a relatively large number of unique symbols. For example, with a symbol space of 24 by 24 bits, only 576 one-pixel bitmaps are needed to display the image pattern of any symbol. As many one-pixel bitmaps as needed (from the set of 576 bitmaps) are added or combined to create the desired partial character or complete character. On the other hand, a system which stores bitmaps for the image patterns of 10,000 characters requires storage of 10,000 bitmaps. In such a system, an increased capacity to display the image pattern of 50,000 characters would requires storage of 50,000 bitmaps. The smaller number of bitmaps needed in the present invention occupies less space both in random access memory (RAM) and in more permanent storage, such as a hard disk.

Memory 120 may also include a table (such as that shown in Figure 7) that associates each character with the corresponding bitmap or combination of bitmaps needed to display the character. In one embodiment such a table associates each character with a combination of bitmaps, where each of the bitmaps is a one-pixel bitmap, i.e., each bitmap contains information for the display of one pixel of the image pattern of the character in the character space. In other words, each bitmap contains one single pixel representing display of a black pixel on a white background or vice versa, where the single pixel represents a pixel in the image pattern of the character. Thus, each bitmap contains one black pixel and

575 white pixels. No two one-pixel bitmaps have the black pixel in the same location. Also, as suggested above, the role of black and white pixels may be reversed. Thus, for example, there may be one white pixel in each bitmap with the remaining 275 pixels being black. In such a case, there would be a white display on a black background. Although the above discussion refers to white and black pixels, it is equally applicable to any other pair of contrasting colors so long as they are distinguishable when displayed.

In another embodiment, the table associates each character with a combination of bitmaps where at least one bitmap represents the image pattern of a stroke in a character.

In yet another embodiment, the table associates each character with a combination of bitmaps, where at least one bitmap represents the image pattern of an element or group of strokes in a character.

In one embodiment, the table may have a hierarchical structure. In other words, a character may include a corresponding bitmap representing the image pattern of an element, which in turn may include a corresponding bitmap representing the image pattern of a stroke, which in turn may include one or more corresponding one-pixel bitmaps. In such an embodiment, one-pixel bitmaps may be used to construct bitmaps for strokes, which may in turn be used to construct bitmaps for elements, which may in turn be used to construct bitmaps for partial or complete characters.

For each stroke, element, partial character, or complete character, a correspondence between the stroke, element, partial character or complete character and the bitmaps needed to create an image thereof may be determined in one of a number of ways. For example, a character may be displayed on a monitor or written on a grid and thereafter, the one-pixel bitmaps, the one-stroke bitmaps, and/or the one-element bitmaps needed to construct the image pattern of the character may be determined.

In one embodiment, device 100 may include program code for performing the method of the present invention. The program code may be stored in memory 120. In another embodiment, device 100 may have dedicated hardware for performing the method of the present invention. For example, controller 105 may include such dedicated hardware for performing the steps of the method of the present invention.

Device 100 generally stores and processes digital signals. These digital signals may represent data or program code. The digital signals may be persistent, where, for example, the carrier of the digital data signal is a recording media. Such recording media include, but are not limited to, fixed disks, removable disks, magnetic tape, CD-ROM, DVD, solid- state memory cards, and magneto-optical disks. The digital signals may also be transient, such as signals transmitted in a wireless or wired network (including an optical network).

Figure 2 is a flowchart of one presently preferred embodiment for the process of identifying and displaying a character. In step 205, the device reads the input signals input by the user to identify a character for display.

An input signal may, for example, be a stroke identifier. In a presently preferred embodiment, a stroke identifier identifies a stroke group to which a stroke belongs. In such a system, each stroke is assigned to one of a number of stroke groups. Each stroke group includes strokes that are similar to one another. In other words, different strokes used are classified into different groups. Each group is given a code number for identification. The user can, for example, identify a stroke by entering a code number that corresponds to the stroke group to which the stroke belongs. In a presently preferred embodiment, the user identifies a character by identifying the strokes that make up the character in the order in which those strokes are written in a traditional writing sequence to make the character. As is known by those familiar with writing in Chinese characters, there is a traditional order for writing strokes to make a character. U.S. Patent No. 5,109,352 and International Publication No. WO 00/41062 disclose the above mentioned presently preferred embodiment of input signals.

The input signals can also be those used in phonetic input systems or other input systems used in character identification. U.S. Patent No. 5,109,352 also describes some of these alternative input systems. In another embodiment, an input signal may be an audio signal that identifies a stroke group, a partial character, or a complete character. This may be accomplished, for example, by use of voice recognition software that associates audio signals with a stroke group, a partial character or a complete character. For example, the user may simply utter the stroke group number to identify the stroke group. Similarly, for example, the user may utter yes or no to indicate whether a displayed partial or complete character is the desired partial or complete character. Alternatively, the user may utter a number associated with a displayed item to indicate selection of that item.

In step 210, using the input signal(s) read in step 205, the device identifies N bitmaps or combinations of bitmaps corresponding to the input signal(s), where N is an integer greater than or equal to 1. Each of the N bitmaps or combinations of bitmaps represents an image pattern. In one presently preferred embodiment, one or more stroke group identifiers entered by the user are compared against stroke group strings stored in memory for various partial or complete characters. Characters or partial characters whose stroke group strings match the sequence of stroke group number(s) entered by the user are selected. For example, if the user identifies a horizontal stroke, followed by a vertical stroke, followed by a left falling stroke, followed by a right falling stroke as the sequence of strokes used for writing the desired character, then one of the N bitmaps may be the bitmap 505 (shown in Figures 5 and 6). If the next two strokes after the above sequence of strokes are two left falling strokes, then one of the N bitmaps may be the combination of bitmaps 505 and 610 which is represented by bitmap 615. As explained in greater detail below, in the present invention, instead of storing bitmap 615 and displaying the image pattern represented thereby, bitmaps 505 and 610 are stored and the image pattern represented by their combination is displayed when needed.

U.S. Patent No. 5,109,352 and International Publication No. WO 00/41062 disclose the above mentioned presently preferred embodiment of selecting characters or partial characters that match a stroke sequence entered by the user. The above mentioned references also illustrate partial characters. As mentioned above, a partial character, as used herein, is an image pattern that contains less than the entire image pattern corresponding to the complete character. A partial character can range from having only one pixel of the image pattern of the complete character to having the image pattern of the complete character minus one pixel. Moreover, a partial character may be composed of any combination of the following: strokes, groups of strokes, elements or groups of elements. (For example, in Figure 3, each of the image patterns represented by bitmaps 305 and 310 alone is a partial character.) In the system of U.S. Patent No. 5,109,352 and International Publication No. WO 00/41062, there is one corresponding bitmap stored for each character or partial character that the system may display. In the systems of the above mentioned references, to display a character or partial character, the bitmap corresponding to the character or partial character is retrieved and displayed. In the present invention, however, there are some characters or partial characters for which there is no single corresponding bitmap stored in memory. Instead, each of these characters or partial characters has a corresponding combination of bitmaps. In other words, a combination of two or more bitmaps is used to display the partial character or , if desired, the complete character in a single character space. This reduces the total number of bitmaps (containing information regarding partial or complete character image patterns) that are needed to display all the desired partial and complete characters.

In a presently preferred embodiment, information identifying the bitmap or combination of bitmaps for each character or partial character that may be displayed is stored in memory. In one embodiment, for example, there may be a table (such as that shown in Figure 7) of characters or partial characters and their corresponding bitmaps or combinations of bitmaps. This table may be used to determine which bitmap or combination of bitmaps is needed to display a particular character or partial character.

In another embodiment, the sequence of strokes input by the user may be directly associated with a bitmap or combination of bitmaps. In other words, there may be a table with stroke group number strings and their corresponding bitmaps or combinations of bitmaps.

In step 215, M image patterns represented by M of the N bitmaps identified by the device are displayed, where M is an integer that is less than or equal to N. In one presently preferred embodiment, N is equal to 15 and M is equal to 5. The character or partial character display process of the present invention is as follows.

For a character or partial character that has one corresponding bitmap, the corresponding bitmap is retrieved from memory and the image pattern represented thereby is displayed. For a character or partial character that has a corresponding combination of bitmaps, the corresponding bitmaps are retrieved from memory and the image pattern represented by their combination is displayed. In one preferred embodiment, the bitmaps of the combination are combined in memory in a combination bitmap and the image pattern represented by the combination bitmap is displayed. In one presently preferred embodiment, a bit in the combination bitmap represents a part of the image pattern of a character if its corresponding bit in any of the bitmaps used in the combination represents a part of the image pattern of the character. For example, in a binary system, a 1 bit may represent a part of the image pattern of a character whereas a 0 bit does not represent a part of the image pattern of a character. In such a system, a bit A_xy in the combination bitmap, where x and y represent the horizontal and vertical coordinates of a bit A, would have a value of 1 if bit A_xy in any of the bitmaps used in the combination has a value of 1. As will be appreciated by those skilled in the art, in such a case, the combination bitmap can be created by logically OR-ing (i.e., using the Boolean OR operator on) the corresponding bits of all bitmaps that are used to make the combination bitmap.

In one presently preferred embodiment, the image patterns represented by the bitmaps of the combination are sequentially displayed on the output device. Each of the bitmaps of the combination are retrieved from memory and the image pattern represented thereby displayed in the same character space of the monitor.

From the display of step 215, the process illustrated in Figure 2 continues with step 220. In step 220, the device reads input signal(s) from the user that are typically input in response to the display of step 215. As suggested above, the input signal(s) read in step 220 are not always input in response to the display of step 215. For example, the user may have input a signal since step 205 but before step 215. Input signal(s) from the user read at step 220 may include additional stroke identifiers or selection of one of the M image patterns as the complete character to be displayed or as a partial character that represents a portion of the complete character. Methods of selecting one or more items from a group of one or more items are well known by those skilled in the art.

In step 225, the device determines whether the user has selected the image pattern of one of the M bitmaps or the combinations of bitmaps as a complete character. If the user does not select an image pattern as a complete character, in other words if the user has selected an image pattern as representing a portion of the image pattern of a completed character or if the user has not selected any of the M image patterns at all, then the process proceeds to step 230. In step 230, the device uses the input signal(s) read in step 220 as well as input signal(s) previously entered such as those read in step 205 or a previous iteration of step 220 to identify N bitmaps or combinations of bitmaps corresponding to the input signals. Step 230 is like step 210 except for the input signal(s) it uses for the identification it performs. Please note that although N has been used in both steps 215 and 230, the N in step 215 need not be the same as the N in step 230. In other words, steps 215 and 230 may identify a different number of bitmaps or combinations of bitmaps. Also, the number of bitmaps or combinations of bitmaps identified during different iterations of the process illustrated in Figure 2 may be different. After step 230, the process continues at step 215.

In step 225, if it is determined that the user has selected an image pattern as a complete character, then the process proceeds to step 235. In step 235, the device displays the selected image pattern in a character space for selected characters.

Figure 3 illustrates an example of a combination of two bitmaps to display a character, where each of the two bitmaps represents (i.e., contains information or data regarding the image pattern of) a stroke in that character. In Figure 3, bitmaps 305 and 310 are combined to form combination bitmap 315. Combination bitmap 315 represents the image pattern of the Chinese character for the number 10. Each of bitmaps 305 and 310 stores the bitmap needed to display a stroke of the character. Bitmaps 305 and 310 represent the horizontal and vertical strokes, respectively, in the character. Thus, instead of storing a bitmap equivalent to combination bitmap 315 to display the character, bitmaps

305 and 310 are stored in memory. Though at first, this may appear to increase the number of bitmaps needed to display characters, it in fact reduces the number of bitmaps needed to be stored to display characters. This is because bitmaps 305 and 310 may be used to construct combination bitmaps for the display of other characters in addition to the character for the number 10.

As can be seen in Figure 3, combination bitmap 315 is the additive result of combining bitmaps 305 and 310. Combination bitmap 315 can be obtained by logically OR-ing corresponding bits of bitmaps 305 and 310. As noted above, bitmaps 305 and 310 contain information for the individual display of the horizontal and vertical strokes, respectively, of the character. Combination bitmap 315, on the other hand, contains information for the display of both the horizontal and vertical strokes of the character.

Figure 4 illustrates an example of a combination of eleven bitmaps to display a symbol, where each of the eleven bitmaps represents (i.e., contains information or data regarding the image pattern of) a pixel in that symbol. In Figure 4, bitmaps 405, 410, 415, 420, 425, 430, 435, 440, 445, 450, and 455 are combined to create combination bitmap 490 which represents a symbol (more specifically a stroke that resembles the English letter "L"). For ease of reference, this stroke will herein be referred to as the L stroke. As can be seen in Figure 4, each of bitmaps 405-455 represents the image of one pixel in a character space. Thus, instead of storing a bitmap that contains all the pixels of the image pattern of the L stroke, bitmaps 405-455 may be stored in memory and combined to create the combination bitmap 490 which includes all the pixels of the image pattern of the L stroke. As noted above, one-pixel bitmaps (i.e., bitmaps having only one pixel of one color against a background of pixels of another color) can be used to create any symbol or character.

Figure 5 illustrates an example of a combination of two bitmaps to display a character, where one of the bitmaps represents (i.e., contains information or data regarding the image pattern of) an element in that character. In Figure 5, bitmaps 505 and 510 are combined to form combination bitmap 515. Combination bitmap 515 represents the image pattern of the Chinese character for a word that is similar to the English word "cedar". Bitmap 505 stores the bitmap needed to display element 506, which when used as a character, i.e., when occupying an entire character space, is the character for the word "wood" or "tree". Bitmap 510 represents the image pattern of three strokes (strokes 511 to

513) on the right hand side of the character represented by the bitmap 515. Thus, instead of storing a bitmap equivalent to combination bitmap 515 to display the character, bitmaps 505 and 510 are stored in memory. Though at first, this may appear to increase the number of bitmaps needed to display characters, it in fact reduces the number of bitmaps needed to be stored to display partial and complete characters. This is because bitmaps 505 may be used to construct combination bitmaps for the display of many other partial or complete characters, in addition to the character for the word "cedar", in which element 506 is an element.

As can be seen in Figure 5, combination bitmap 515 is the additive result of combining bitmaps 505 and 510. Combination bitmap 515 can be obtained by logically

OR-ing the corresponding bits of bitmaps 505 and 510. As noted above, bitmaps 505 and 510 contain information for the display of the element 506 and the three inclined strokes 511-513, respectively, of the character. Combination bitmap 515, on the other hand, contains information for the display of both the element 506 and the three strokes 51 1-513 of the character.

In another embodiment, each of the strokes in bitmap 510 may be saved in a different bitmap that is combined with the bitmap 505 to create the character shown in bitmap 515. Thus, there may be first, second and third bitmaps for the first stroke 511 , the second stroke 512 and the third stroke 513, respectively, instead of only bitmap 510 for all three strokes 511-513 together. Such an embodiment, may be used to disclose partial characters leading up to the character represented by bitmap 515.

Thus, for example, a first combination that is the combination of bitmap 505 with a bitmap of the first stroke 511 only may be used to display a partial character consisting of the element 506 and the first stroke 511. Thereafter, a bitmap for the second stroke 512 only may be added to the first combination to display a partial character consisting of the element 506 and the first and second strokes 511 and 512. In another embodiment, as illustrated in Figure 6, bitmap 505 may be combined with bitmap 610 to create a combination bitmap 615. As shown in Figure 6, bitmap 610 includes the image patterns for the first stroke 511 and the second stroke 512. As can also be seen in Figure 6, combination bitmap 615 includes the image patterns of the element 506 and the first and second strokes 511 and 512. In like manner, a bitmap containing the image pattern of the third stroke 513 only may be added to the combination bitmap 615 to display the complete character represented by bitmap 515.

Thus, in one embodiment, instead of saving three partial character bitmaps and one full character bitmap the system of the present invention saves a bitmap for the element 506, and three bitmaps, one for each of the strokes 511 to 513. The bitmap for the element 506 may be used to construct one of the many partial or complete characters that include element 506. Similarly, one or more of the bitmaps for the first, second and third strokes 511-513 can be used in one of many partial or complete characters that include one or more of the three strokes. This ability to use the bitmaps for the display of many partial or complete characters allows substantial memory savings over a system that stores individual bitmaps for each of the partial or complete characters. Also in another embodiment, bitmaps, such as bitmap 505 may be compressed using one of several well known compression techniques since a large portion of the bitmap 505 does not contain any portion of the image pattern of the element represented thereby. This can provide substantial savings over an uncompressed bitmap. Well known compression techniques include Run Length Encoding, Huffman Encoding, and Lemple-

Ziv- Welch (LZW) Encoding.

Alternatively, instead of using a 24 by 24 pixel bitmap to store the image pattern of an element, a 12 by 24 pixel bitmap may be used. In other words, in some cases, the 24 by 24 pixels bitmap may be truncated to a 12 by 24 pixels bitmap. For example, a 12 by 24 pixel bitmap would be sufficient for storing the image pattern of element 506 since it only occupies no more than one half of a 24 by 24 pixel bitmap.

Figure 9 illustrates use of truncated bitmaps, i.e., bitmaps that are smaller in size (area) than a character space or composite bitmap. In Figure 9, bitmap 905, a 12 by 24 bits bitmap, includes the image pattern of element 506, while bitmap 910, also a 12 by 24 bits bitmap, includes the image pattern of the three strokes 51 1-513.

As illustrated in Figure 9, bitmaps 905 and 910 may be combined to create a bitmap 515 which includes the image pattern for the character for the word "cedar". Bitmap 515, in this embodiment, is constructed by mapping bitmaps 905 and 910 to the left half and right half of a 24 by 24 bitmap, respectively. The proper location of truncated bitmaps 905 and 910 within a character space or untruncated combination bitmap is stored in memory.

Bitmap 515 is the same size as a 24 by 24 bits character space, whereas each of bitmaps 905 and 910 are smaller than a 24 by 24 bits character space (more specifically, half the size of a 24 by 24 bits character space). In another embodiment, each of bitmaps 905 and 910 may be a different size in relation to a character space. For example, bitmap 905 may be 8 by 24 bits, thus being only one third the size of a 24 by 24 bits character space.

Truncated bitmaps 905 and 910 require less memory space than their untruncated counterparts, namely bitmaps 505 and 510. Therefore, the embodiment illustrated in

Figure 9 requires less memory space to store bitmaps than that illustrated in Figure 5. The embodiment illustrated in Figure 9 requires even less memory space for storage of bitmaps as compared with systems which store bitmaps representative of the image pattern of all the partial and complete characters that they display. As mentioned above, many partial and complete characters share a common element in a particular portion of the character space

(frequently the left hand portion). Thus, a truncated bitmap representing the image of the common element may be used in the display of many partial or complete characters.

Similarly, the one-pixel bitmaps may be compressed or represented in a form that requires less memory than storage of the entire bitmap. For example, each one-pixel bitmap may be assigned a number designating the location of the pixel that represents a portion of the image pattern.

As is known by those familiar with Chinese characters, there are many characters that share basic strokes. Similarly, there are many characters that share common elements. For example, there are a large number of characters that include the element 506. Thus the bitmaps for frequently used elements may be saved in memory and combined to construct combination bitmaps representing a large number of different characters.

In one embodiment of the present invention, a table associates each character with the identification of all the one-pixel bitmaps needed to display the character. The character may be identified by a string of the group numbers for the strokes needed to construct the character. The character may also be identified by a code number where each character is given a unique code number that is independent of the stroke group numbers.

Figure 7 is a table showing correspondence between the three symbols shown in Figures 3-5 and their corresponding combinations of bitmaps. As can be seen in Figure 7, bitmaps 305 and 310 correspond to the symbol 315. Similarly, bitmaps 405 to 455 correspond to the symbol 490. Finally, bitmaps 505 and 510 correspond to the symbol 515. Symbols 315, 490, and 515 represent the Chinese character for the number ten, the L stroke, and the Chinese character for the word "cedar", respectively. The bitmaps 305, 310, 405-455, 505, and 510 are as shown in Figures 3-5.

Please note that the above numbers have been selected to identify the symbols and their corresponding bitmaps for ease of correlation with the examples shown in Figure 3-5. Other means of designating the symbols and bitmaps may be used as well. For example, both partial characters and complete characters may be identified by the stroke group identifiers of the strokes which make up the partial characters or complete characters.

Alternatively, complete characters may be identified by their Unicode numbers. Similarly, the bitmaps may be identified by some other numbers than those used in Figures 3-5. For example, in a system using 24 by 24 pixel bitmaps where each bitmap is a one-pixel bitmap, then the bitmaps may be numbered 1 to 576.

It is to be noted that a combination bitmap need not be created by bitmaps which are all from the same category. Thus, for example, a combination bitmap may be constructed by combining one or more one-pixel bitmaps (such as bitmaps 405-455 in Figure 4), one or more one-stroke pixel bitmaps (such as bitmaps 305 and 310 in Figure 3), and one or more one-element pixel bitmaps (such as bitmap 505).

In Figures 3-5, the one-pixel bitmaps, the one-stroke bitmaps, and the one-element bitmaps are 8 by 8 bits, 16 by 16 bits, and 24 by 24 bits, respectively. These bitmap sizes were selected for easy of illustration. In a preferred embodiment, at least in the untruncated state, the one-pixel bitmaps, the one-stroke bitmaps, and the one-element bitmaps are all of the same size. In a preferred embodiment, all these bitmaps are 24 by 24 pixels or larger.

Figure 8 is a flowchart for the process of sequentially loading bitmaps for display on an active matrix display device. In the preferred embodiment, first, a bitmap with all the pixels therein turned on is loaded into the character space. The process illustrated in Figure

8 begins after a first bitmap (other than the all-on pixel bitmap, which in one presently preferred embodiment of the invention is first loaded into the character space) has been loaded into the character space. In step 805, a first pixel is examined to determine whether it is on or off. In step 810, if the pixel is not lit (i.e., it is off), then the process proceeds to step 815. In step 815, the next pixel is examined. From step 815, the process proceeds to step 810. In step 810, if the pixel is lit (i.e., it is on), then the process proceeds to step 820. In step 820, it is determined if the bitmap to be loaded into the character space calls for the pixel to be off. If the answer to the query in step 820 is NO, then the process continues at step 815. If the answer to the query in step 820 is YES, then the process continues at step 825, where the pixel is turned off. From step 825, the process continues at step 815 until all the pixels in the character space have been examined. The process is repeated for subsequent bitmaps to be loaded into the character space. It is to be noted that the above process allows avoiding turning on a pixel that was previously turned off by a previously loaded bitmap that is used to construct the image pattern (i.e., display) of the desired character. It is also to be noted that the effect of the above process would not change if on and off were interchanged throughout the process. This could be done, for example, where an off pixel represents a portion of the image pattern of a symbol to be displayed whereas an on pixel represents a blank (i.e., background) in the symbol space when displaying a symbol.

While the present invention has been particularly described with respect to the illustrated embodiments, it will be appreciated that various alterations, modifications and adaptations may be made based on the present disclosure, and are intended to be within the scope of the present invention. While the invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the present invention is not limited to the disclosed embodiment but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

Claims

1. A method of displaying a symbol having an image pattern, said method comprising:

retrieving a first bitmap, wherein said first bitmap contains information regarding a first part of the image pattern of the symbol for display of the first part of the image pattern of the symbol;

displaying the first part of the image pattern of the symbol in a first symbol space for displaying symbols;

retrieving at least a second bitmap, wherein said second bitmap contains information regarding a second part of the image pattern of the symbol for display of the second part of the image pattern of the symbol; and

displaying the second part of the image pattern of the symbol in the first symbol space.

2. The method of Claim 1, wherein said first and second parts comprise first and second pixels of the image pattern of the symbol, respectively.

3. The method of Claim 1, wherein said first and second parts comprise first and second pluralities of pixels of the image pattern of the symbol, respectively.

4. The method of Claim 3, wherein the symbol comprises a character and wherein said first and second parts comprise first and second strokes in the character, respectively.

5. The method of Claim 3, wherein the symbol comprises a character and said first part comprises an element in the character.

6. The method of Claim 2, wherein said first and second bitmaps are loaded in the symbol space sequentially.

7. The method of Claim 6, wherein for each pixel in the symbol space, a pixel turned off as a result of loading the first bitmap is left off when loading bits of the second bitmap.

8. The method of Claim 1 further comprising: retrieving at least a third bitmap, wherein said third bitmap contains information regarding a third part of the image pattern of the symbol for display of the third part of the image pattern of the symbol; and displaying the third part of the image pattern of the symbol in the first symbol space.

9. The method of Claim 1 further comprising: selectively loading information regarding the first part of the image pattern of the symbol in a first portion of an image buffer, wherein the first portion corresponds to the first symbol space; and selectively loading information regarding the second part of the image pattern of the symbol in the first portion of the image buffer.

10. The method of Claim 9, wherein the steps of displaying the first part and displaying the second part comprise using the information regarding the first and second parts of the image pattern of the symbol selectively loaded into the first portion of the image buffer.

11. The method of Claim 1 further comprising: first reading at least one input signal input by the user to identify the symbol; first identifying N bitmaps corresponding to the at least one input signal, where N is an integer greater than or equal to 1 and wherein at least one of the N bitmaps is a combination of the first and second bitmaps, further wherein each of the N bitmaps represents an image pattern; and first displaying M image patterns represented by M of the N bitmaps, where M is an integer less than or equal to N.

12. The method of Claim 11 further comprising: second reading at least one user input signal input since the first reading step; determining that the user has selected one of the M image patterns as the symbol; and displaying the selected one of M image patterns in a symbol space for selected symbols.

13. The method of Claim 11 further comprising: third reading at least one user input signal input since the first reading step; determining that the user has indicated that none of the M image patterns is the symbol; second identifying N bitmaps corresponding to the user inputs in the first and second reading steps; and second displaying M image patterns represented by M of the N bitmaps identified in the second identifying step.

14. A carrier of digital data signals comprising: a program code signal for retrieving a first bitmap, wherein said first bitmap contains information regarding a first part of an image pattern of a symbol for display of the first part of the image pattern of the symbol; a program code signal for displaying the first part of the image pattern of the symbol in a first symbol space for displaying the image pattern of the symbol; a program code signal for retrieving at least a second bitmap, wherein said second bitmap contains information for display of a second part of the image pattern of the symbol; and a program code signal for displaying the second part of the image pattern of the symbol in the first symbol space.

15. The carrier of Claim 14, wherein said first and second parts comprise first and second pixels of the image pattern of the symbol, respectively.

16. The carrier of Claim 14, wherein said first and second parts comprise first and second pluralities of pixels of the image pattern of the symbol, respectively.

17. The carrier of Claim 16, wherein the symbol comprises a character and said first and second parts comprise first and second strokes in the character, respectively.

18. The carrier of Claim 16, wherein the symbol comprises a character and said first part comprises an element in the character.

19. The carrier of Claim 15 further comprising instruction code for sequentially loading said first and second bitmaps in the first symbol space.

20. The carrier of Claim 19 further comprising instruction code for leaving off, when loading bits of the second bitmap, each pixel turned off as a result of loading the first bitmap.

21. The carrier of Claim 14 further comprising : program code signal for retrieving at least a third bitmap, wherein said third bitmap contains information regarding a third part of the image pattern of the symbol for display of the third part of the image pattern of the symbol; and program code signal for displaying the third part of the image pattern of the symbol in the first symbol space.

22. The carrier of Claim 14 further comprising: program code signal for selectively loading information regarding the first part of the image pattern of the symbol in a first portion of an image buffer, wherein the first portion corresponds to the first symbol space; and program code signal for selectively loading information regarding the second part of the image pattern of the symbol in the first portion of the image buffer.

23. The carrier of Claim 22, wherein the program code signals for displaying the first part of the image pattern of the symbol and displaying the second part of the image pattern of the symbol comprise program code signals for using the information regarding the first and second parts of the image pattern of the symbol selectively loaded into the first portion of the image buffer.

24. The carrier of Claim 14 further comprising: program code signal for first reading at least one input signal input by the user to identify the symbol; program code signal for first identifying N bitmaps corresponding to the at least one input signal, where N is an integer greater than or equal to 1 and wherein at least one of the N bitmaps is a combination of the first and second bitmaps, further wherein each of the N bitmaps represents an image pattern; and program code signal for first displaying M image patterns represented by M of the

N bitmaps, where M is an integer less than or equal to N.

25. The carrier of Claim 24 further comprising: program code signal for second reading at least one user input signal input since the first reading; program code signal for determining that the user has selected one of the M image patterns as the symbol; and program code signal for displaying the selected one of the M image patterns in a symbol space for selected symbols.

26. The carrier of Claim 24 further comprising: program code signal for third reading at least one user input signal input since the first reading; program code signal for determining that the user has indicated that none of the M image patterns is the symbol; program code signal for second identifying N bitmaps corresponding to the user inputs in the first and second readings; and program code signal for second displaying M image patterns represented by M of the N bitmaps identified in the second identifying.

27. An apparatus comprising: a display device; a controller coupled to said display device via a communication channel; and a memory coupled to said controller and said display device the communication channel, said memory comprising a first bitmap containing information regarding a first part of an image pattern of a symbol for display of the first part of the image pattern of the symbol and a second bitmap containing information regarding a second part of the image pattern of the symbol for display of the second part of the image pattern of the symbol, wherein the first and second parts of the image pattern are displayed in one symbol display space.

28. The apparatus of Claim 27, wherein said controller is a central processing unit.

29. The apparatus of Claim 28, wherein said display device comprises a display monitor.

30. The apparatus of Claim 28, wherein said display device comprises a printer.

31. The apparatus of Claim 27, wherein said first and second parts comprise first and second pixels of the image pattern of the symbol, respectively.

32. The apparatus of Claim 27, wherein said first and second parts comprise first and second pluralities of pixels of the image pattern of the symbol, respectively.

33. The apparatus of Claim 31 , wherein the symbol comprises a character and said first and second parts comprise first and second strokes in the character, respectively.

34. The apparatus of Claim 31 , wherein the symbol comprises a character and said first part comprises an element of the character.

35. The apparatus of Claim 31 , wherein said first and second bitmaps are loaded in the symbol space sequentially.

36. The apparatus of Claim 35, wherein for each pixel in the symbol space, a pixel turned off as a result of loading the first bitmap is left off when loading bits of the second bitmap.

37. The apparatus of Claim 27, wherein one of said memory and said display device comprises an image buffer, further wherein information regarding the first and second parts of the image pattern of the symbol are selectively loaded in a first portion of the image buffer, wherein the first portion corresponds to the first symbol space.

38. The apparatus of Claim 37, wherein the information regarding the first and second parts of the image pattern of the symbol selectively loaded into the first portion of the image buffer is used to display the first and second parts of the image pattern of the symbol in the one symbol display space.

39. The apparatus of Claim 27, wherein the first and second bitmaps are combined into a third combination bitmap that includes information regarding the first and second parts of the image pattern of the symbol for the display of the first and second parts of the image pattern of the symbol, further wherein the third combination bitmap is stored in said memory.

40. The apparatus of Claim 27, wherein one of said controller and memory further comprising: program code signal for reading at least one input signal input by the user to identify the symbol; program code signal for identifying N bitmaps corresponding to the at least one input signal, where N is an integer greater than or equal to 1 and wherein at least one of the N bitmaps is a combination of the first and second bitmaps, further wherein each of said N bitmaps represents an image pattern; and program code signal for displaying M image patterns represented by M of the N bitmaps, where M is an integer less than or equal to N.

41. An apparatus comprising: means for displaying; means for controlling coupled to said means for displaying via a communication channel; and means for storing coupled to said means for controlling and said means for displaying via the communication channel, said means for storing comprising a first bitmap containing information regarding a first part of an image pattern of a symbol for display of the first part of the image pattern of the symbol and a second bitmap containing information regarding a second part of the image pattern of the symbol for display of the second part of the image pattern of the symbol, wherein the first and second parts are displayed in one symbol display space.

42. The apparatus of Claim 41 , wherein said first and second parts comprise first and second pixels of the image pattern of the symbol, respectively.

43. The apparatus of Claim 41 , wherein said first and second parts comprise first and second pluralities of pixels of the image pattern of the symbol, respectively.

44. The apparatus of Claim 43, wherein the symbol comprises a character and said first and second parts comprise first and second strokes in the character, respectively.

45. The apparatus of Claim 43, wherein the symbol comprises a character and said first part comprises an element in the character.

46. The apparatus of Claim 42, wherein said first and second bitmaps are loaded in the symbol space sequentially.

47. The apparatus of Claim 46, wherein for each pixel in the symbol space, a pixel turned off as a result of loading the first bitmap is left off when loading bits of the second bitmap.

48. The apparatus of Claim 41 wherein one of said means for storing and said means for displaying comprises an image buffer, further wherein information regarding the first and second parts of the image pattern of the symbol are selectively loaded in a first portion of the image buffer, wherein the first portion corresponds to the first symbol space.

49. The apparatus of Claim 48, wherein the information regarding the first and second parts of the image pattern of the symbol selectively loaded into the first portion of the image buffer is used to display the first and second parts of the image pattern of the symbol in the one symbol display space.

50. The apparatus of Claim 41 , wherein the first and second bitmaps are combined into a third combination bitmap that includes information regarding the first and second parts of the image pattern for the display of the first and second parts of the image pattern of the symbol, further wherein the third combination bitmap is stored in said means for storing.

51. A method of identifying and displaying a symbol having an image pattern to a user, said method comprising: first reading at least one input signal input by the user to identify the symbol; first identifying N bitmaps corresponding to the at least one input signal, where N is an integer greater than or equal to 1 and each of the N bitmaps may be a combination of one or more bitmaps, further wherein each of said N bitmaps represents an image pattern; and first displaying M image patterns represented by M of the N bitmaps, where M is an integer less than or equal to N.

52. The method of Claim 51 further comprising: second reading at least one user input signal input since the first reading step; determining that the user has selected one of the M image patterns as the symbol; and displaying the selected one of the M image patterns in a symbol space for selected symbols.

53. The method of Claim 51 further comprising: third reading at least one user input signal input since the first reading step; determining that the user has indicated that none of the M image patterns is the symbol; second identifying N bitmaps corresponding to the user inputs in the first and second reading steps; and displaying M image patterns represented by M of the N bitmaps identified in the second identifying step.

54. A method of displaying a symbol having an image pattern, said method comprising: retrieving a first bitmap, wherein said first bitmap includes information regarding a first part of the image pattern of the symbol for display of the first part of the image pattern of the symbol; selectively loading information regarding the first part of the image pattern of the symbol in a first portion of an image buffer, wherein the first portion corresponds to a first symbol space on a display; retrieving at least a second bitmap, wherein said second bitmap contains information regarding a second part of the image pattern of the symbol for display of the second part of the image pattern of the symbol; and selectively loading information regarding the second part of the image pattern of the symbol in the first portion of the image buffer.

55. The method of Claim 1 , wherein the first symbol space has a first symbol space bitmap size, further wherein said first bitmap has a first bitmap size that is smaller than the first symbol bitmap size, and further wherein said second bitmap has a second bitmap size that is smaller than the first symbol bitmap size.

56. The method of Claim 1, wherein the first and second bitmap sizes are equal.

57. The method of Claim 56, wherein the first and second bitmap sizes together add up to the first symbol space bitmap size.

58. The method of Claim 57, wherein each of the first and second bitmap sizes is 12 by 24 bits and further wherein the first symbol space bitmap size is 24 by 24 bits.