Computer graphics processing and selective visual display system – Computer graphics processing – Character generating
Reexamination Certificate
1999-03-19
2002-01-29
Jankus, Almis R. (Department: 2672)
Computer graphics processing and selective visual display system
Computer graphics processing
Character generating
Reexamination Certificate
active
06342890
ABSTRACT:
§ 1. BACKGROUND OF THE INVENTION
§ 1.1 Field of the Invention
The present invention concerns improving access to stored blocks of data, and in particular, concerns improving access to stored blocks of scaled sub-pixel data that includes an offset value. Once accessed, these blocks of scaled sub-pixel data are subjected to subsequent processing to produce more legible text on flat panel video monitors such as liquid crystal display (or LCD) video monitors.
§ 1.2 Related Art
The present invention may be used in the context of flat panel video monitors, such as LCD video monitors. In particular, the present invention may be used as a part of processing to produce more legible text on LCD video monitors. Color display devices have become the principal display devices of choice for most computer users. The display of color on a monitor is normally achieved by operating the display device to emit light (such as a combination of red, green, and blue light for example) which results in one or more colors being perceived by the human eye.
Although color video monitors in general, and LCD video monitors in particular, are known to those skilled in the art, they are introduced below for the reader's convenience. In § 1.2.1 below, cathode ray tube (or CRT) video monitors are first introduced. Then, in § 1.2.2 below, LCD video monitors are introduced.
§ 1.2.1 CRT VIDEO MONITORS
Cathode ray tube (CRT) display devices include phosphor coatings which may be applied as dots in a sequence on the screen of the CRT. A different phosphor coating is normally associated with the generation of different colors, such as red, green, and blue for example. Consequently, repeated sequences of phosphor dots are defined on the screen of the video monitor. When a phosphor dot is excited by a beam of electrons, it will generate its associated color, such as red, green and blue for example.
The term “pixel” is commonly used to refer to one spot in a group of spots, such as rectangular grid of thousands of such spots for example. The spots are selectively activated to form an image on the display device. In most color CRTs, a single triad of red, green and blue phosphor dots cannot be uniquely selected. Consequently, the smallest possible pixel size will depend on the focus, alignment and bandwidth of the electron guns used to excite the phosphor dots. The light emitted from one or more triads of red, green and blue phosphor dots, in various arrangements known for CRT displays, tend to blend together giving, at a distance, the appearance of a single colored light source.
In color displays, the intensity of the light emitted from the additive primary colors (such as red, green, and blue) can be varied to achieve the appearance of almost any desired color pixel. Adding no color, i.e., emitting no light, produces a black pixel. Adding 100 percent of all three colors produces a white pixel.
Having introduced color CRT video monitors, color LCD video monitors are now introduced in § 1.2.2 below.
§ 1.2.2 LCD VIDEO MONITORS
Portable computing devices (also referred to generally as computing appliance or untethered computing appliances) often use liquid crystal displays (LCDs) or other flat panel display devices, instead of CRT displays. This is because flat panel displays tend to be smaller and lighter than CRT displays. In addition, flat panel displays are well suited for battery powered applications since they typically consume less power than comparably sized CRT displays.
Color LCD displays are examples of display devices which distinctly address elements (referred to herein as pixel sub-components or pixel sub-elements) to represent each pixel of an image being displayed. Normally, each pixel element of a color LCD display includes three (3) non-square elements. More specifically, each pixel element includes adjacent red, green and blue (RGB) pixel sub-components. Thus, a set of RGB pixel sub-components together define a single pixel element.
Known LCD displays generally include a series of RGB pixel sub-components which are commonly arranged to form stripes along the display. The RGB stripes normally run the entire length of the display in one direction. The resulting RGB stripes are sometimes referred to as “RGB striping”. Common LCD monitors used for computer applications, which are wider than they are tall, tend to have RGB vertical stripes.
FIG. 1
illustrates a known LCD screen
100
comprising pixels arranged in a plurality of rows (R
1
-R
12
) and columns (C
1
-C
16
). That is, a pixel is defined at each row-column intersection. Each pixel includes a red pixel sub-component, depicted with moderate stippling, a green component, depicted with dense stippling, and a blue component, depicted with sparse stippling.
FIG. 2
illustrates the upper left hand portion of the known display
100
in greater detail. Note how each pixel element, e.g., the (R
1
, C
4
) pixel element, comprises three distinct sub-element or sub-components, a red sub-component
206
, a green sub-component
207
and a blue sub-component
208
. Each known pixel sub-component
206
,
207
,
208
is ⅓, or approximately ⅓, the width of a pixel while being equal, or approximately equal, in height to the height of a pixel. Thus, when combined, the three ⅓ width, full height, pixel sub-components
206
,
207
,
208
define a single pixel element.
As illustrated in
FIG. 1
, one known arrangement of RGB pixel sub-components
206
,
207
,
208
form what appear to be vertical color stripes on the display
100
. Accordingly, the arrangement of ⅓ width color sub-components
206
,
207
,
208
, in the known manner illustrated in
FIGS. 1 and 2
, exhibit what is sometimes called “vertical striping”.
In known systems, the RGB pixel sub-components are generally used as a group to generate a single colored pixel corresponding to a single sample of the image to be represented. More specifically, in known systems, luminous intensity values for all the pixel sub-components of a pixel element are generated from a single sample of the image to be represented. For example, referring to
FIG. 3
, an image is segmented into nine (9) squares by the grid
320
. Each square of the grid defined by the segmented image represents an area of an image which is to be represented by a single pixel element. In
FIG. 3
, a shaded circle is used to represent a single image sample from which luminous intensity values associated with the red, green, and blue pixel sub-components
332
,
333
, and
334
of the associated pixel are generated.
Having introduced the general structure and operation of known LCD displays, known techniques for rendering text on such LCD displays, as well as perceived shortcomings of such known techniques, are introduced in § 1.2.2.1 below.
§ 1.2.2.1 RENDERING TEXT ON LCD DISPLAYS
Apart from pure image or video information, LCD displays are often used for rendering textual information. For example, a personal information manager may be used to render contact information, such as a person's address, telephone number, fax number, and e-mail address for example, on an untethered computing device. Character size and inter-character spacing are important factors when rendering text.
The expression of textual information using font sets is introduced in § 1.2.2.1.1 below. Then, the rendering of textual information using so-called pixel precision and perceived shortcomings of doing so are introduced in § 1.2.2.1.2 below. Finally, the desire to maintain formatting is described in § 1.2.2.1.3 below.
§ 1.2.2.1.1 FONT SETS
Inter-character spacing, both relative and absolute, can significantly impact the perceived quality of text. In addition, inter-character spacing may affect the format (or layout) of a textual file, such as a word processing file for example.
Many modern computer systems use font outline technology, such as scalable fonts for example, to facilitate the rendering and display of text. In such systems various font sets, such as “Times New Roman,” “Onyx,” “Courier New,” etc. for example, may be provided. The
Cunningham G. F.
Jankus Almis R.
Microsoft Corporation
Workman & Nydegger & Seeley
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