Computer graphics processing and selective visual display system – Computer graphics processing – Character generating
Reexamination Certificate
2000-12-21
2003-12-09
Nguyen, Phu K. (Department: 2672)
Computer graphics processing and selective visual display system
Computer graphics processing
Character generating
Reexamination Certificate
active
06661416
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a character sequence drawing apparatus. More particularly, the present invention relates to a character sequence drawing apparatus that draws a character sequence or executes a process related to character sequence drawing in response to a request from an application program.
2. Description of Related Art
Recently, as font-related techniques have developed, outline fonts that draw characters of any size with high quality or the like have been provided, as well as bitmap fonts. Also, various fonts or typefaces have been provided. Corresponding to the development of such fonts, Digital TVs, personal computers, printers or the like provide functions for drawing characters with various expressions using various fonts.
Conventionally, in personal computers or the like, operating systems (OS) provide application programs (AP) with character sequence drawing functions. When an AP requests a character sequence drawing specifying a character sequence and a font, an OS accesses font data corresponding to the requested font, obtains a glyph image, namely a dot pattern (hereinafter called a font pattern) of each character in the requested character sequence, and draws the font pattern on a screen. It should be noted here that the font data is information necessary for using a font and contains, for example, information indicating shapes of glyphs.
Conventional OSs can obtain a font pattern by accessing font data having a specific data format, or a specific data structure. Accordingly, when a piece of font data is to be used by an OS, the piece of font data needs to have a specific data structure that can be accessed by the OS.
In contrast, a character sequence outputting apparatus that can deal with a plurality of pieces of font data having any data structures has been disclosed (Japanese Laid-Open Patent No. 6-110888), which is intended to increase flexibility in creation of font data.
The character sequence outputting apparatus corresponds to a character sequence drawing function of conventional OS. The character sequence outputting apparatus includes a table that corresponds fonts with pieces of font data and font pattern expansion programs that expand the pieces of font data to create font patterns. Upon receipt of a character output instruction from outside, the character sequence outputting apparatus refers to the table to identify a font pattern expansion program and a piece of font data corresponding to a font specified in the instruction, generates a font pattern from the identified piece of font data using the identified font pattern expansion program, and sends the generated font pattern to a drawing apparatus, allowing the drawing apparatus to draw the font pattern.
Meanwhile, some fonts are proportional fonts in which each character has a different width. In case an AP can recognize, in drawing a character sequence using a proportional font, the width of each character and use the width for character decoration or in controlling the drawing of the background, the characters can be expressed with more variety.
In outline fonts, outline information used for forming a character, such as coordinates of lines constituting the character, needs to be rasterized to create a drawing font pattern. The drawing speed will be increased if the rasterizing can be done by a rasterizer, a hardware unit.
As described above, OSs are required to have functions for using various fonts in response to their characteristics.
The above character sequence outputting apparatus, however, can only generate font patterns from the font data, and does not have enough functions such as obtaining character width or controlling a rasterizer.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a character sequence drawing apparatus that draws a character sequence with font data of any data structure and also executes various processes to make effective use of fonts in accordance with the characteristics of the fonts or the like.
The above object is fulfilled by a character sequence drawing apparatus comprising: a storage unit operable to store a plurality of pieces of font data and a plurality of font processing functions for using the plurality of pieces of font data; a font access information obtaining unit operable to obtain a piece of font access information which includes a group of addresses of font processing functions, from an application program; a request receiving unit operable to receive from the application program a request which is related to drawing of a character sequence; and a font processing function executing unit operable to identify one or more addresses of font processing functions which have been predetermined with correspondence to the received request among the group of addresses of font processing functions included in the piece of font access information, and respond to the received request by executing one or more font processing functions corresponding to the one or more addresses.
With the above construction, when the AP specifies a piece of font access information that includes a plurality of addresses of a plurality of font processing functions including a font pattern obtaining function, the character sequence drawing apparatus executes various processes (e.g., obtaining width of the character sequence) concerning the drawing of the character sequence in response to requests from the AP, using font processing functions whose locations are identified by the addresses. To make effective use of fonts, various font processing functions are used to execute processes related to the fonts by accessing the font data or the like. Since the AP can specify addresses of the font processing functions, the character sequence drawing apparatus can execute various font processing functions in accordance with requests from the AP. With this construction, the character sequence drawing apparatus need not determine a font processing function it should use in accordance with a font requested by the AP.
In the above character sequence drawing apparatus, the plurality of font processing functions may be classified into a plurality of function types, the storage unit may store one or more font processing functions for each of the plurality of function types, the piece of font access information may include one address for each of the plurality of function types, the font access information obtaining unit, for each obtainment of a piece of font access information, assigns a font ID to each obtained piece of font access information, holds the assigned font IDs and pieces of obtained font access information, and sends each font ID to the application program, wherein the font IDs correspond to the pieces of font access information on a one-to-one basis, the request receiving unit receives a font ID together with a request from the application program, and the font processing function executing unit identifies one or more addresses of font processing functions which have been predetermined with correspondence to the received request among a group of addresses of font processing functions included in a piece of font access information corresponding to the obtained font ID, and respond to the received request by executing one or more font processing functions corresponding to the one or more addresses.
With the above construction, when the AP sends a request related to drawing of a character sequence with specification of a font ID, the character sequence drawing apparatus executes one or more font processing functions corresponding to the specified font ID in response to the request. With this construction, the AP can specify a different font ID for each character sequence to allow the character sequence drawing apparatus to draw each character sequence with a different font.
In the above character sequence drawing apparatus, the storage unit may store one or more font pattern obtaining functions which are classified as a function type and each identify a font pattern based on a piece
Izumi Kenji
Muikaichi Masahiro
Tsujimura Satoshi
Matsushita Electric - Industrial Co., Ltd.
Nguyen Phu K.
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