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Description  |
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FIELD OF THE INVENTION
This invention relates to a field of phototypesetting or printing wherein
alphanumeric or other characters are displayed on a screen or other light
sensitive surface to form images.
BACKGROUND OF THE INVENTION
In phototypesetting, a light sensitive surface is illuminated in the shape
of an image such as an alphanumeric or other character. The light
sensitive surface may be the face of a CRT or may be a light sensitive
sheet imaged by a laser beam or other suitable means. Such
phototypesetting systems and printing systems are as shown in U.S. Pat.
Nos. 4,199,815 and 4,231,096, employing a CRT and a laser beam
respectively. Where characters are imaged in varying sizes, the size of
the character is limited by the size of the CRT screen or the range of the
light sensitive sheet over which a beam such as a laser may be directed,
or generally, in the case where these or other imaging means are used, the
physical area over which the imaging means is constrained physically. In
such cases, the size of the character capable of being displayed is
limited by the size of the imaging area. Where larger sized characters are
to be imaged, then the size, cost and complexity of the system must be
increased accordingly to accommodate those larger sized characters.
SUMMARY OF THE INVENTION
According to the principals of this invention, characters or other shapes
to be projected on a limited image area such as a CRT face or the imaging
area covered by an imaging beam or other similar device are compared in
size to the size of the imaging area.
The system in which the inventive principles are used, contains an encoded
character which is encoded at a master size for display at a variable size
which may be larger or smaller than the master encoded size and larger and
small than the display. However, it should be understood that this
invention can be used with a character which is encoded at a single size
for display at that single size and where a change in the screen
resolution, for example, may cause the characters, when projected to be
larger or smaller than the relative encoded size. The characters are
encoded with a character physical baseline. As is usually done, the
character physical baseline is referenced to or aligned with a display
physical baseline location and which typically corresponds to the baseline
of a text appearing on an imaging surface. As is usually the case in
printing and typesetting, the character physical baseline is projected on
the imaging surface to coincide with the text physical baseline. The
display may be thought of as an imaging window through which a writing
means causes the encoded character to be displayed at its desired display
size and relative to a display physical baseline location which serves as
a reference for locating the encoded character physical baseline. Because
it is more efficient to have a limited size display window and to move an
imaging surface past the display window introducing fresh areas for
projection of the displayed character on the imaging surface, the display
physical baseline is referenced to its projected image location on the
imaging surface, as is known in the art. The display, according to the
preferred embodiment, is a CRT with an imaging surface movable past the
face of the CRT in the direction of a first dimension. However, the
display may also be a laser beam having a limited displacement or angular
range in a first dimension and which displays the character and projects
the character onto an imaging surface in a manner similar to the CRT beam,
but without the intermediate imaging surface of the CRT beam.
According to the principles of the invention, a character when displayed is
referenced to a display location by referencing the character physical
baseline to a display physical baseline. In the case of a laser beam, it
would be a location measured by the angular deflection of the laser beam.
In the case of a CRT, it would be a location on the face of the CRT
imaging surface. Where the encoded character at its display size is
indicated as being larger than the display so it is impossible to image
the whole character within the display window, then it would be necessary
to either move the character in the direction of the dimension it extended
beyond the borders of the display, thereby to move the character back into
the display window. This relative movement of character to display window
may be accomplished by moving the character physical baseline so its
location on the display physical baseline causes the aforesaid relative
movement or by moving the display physical baseline and the character
physical baseline referenced to it thereby bringing the character back
into the display window when it is again located in correspondence with
the display physical baseline. The character may be then displayed within
the borders of the display window and then imaged on the movable surface.
Additionally, characters having the said display physical baseline may be
grouped and displayed and imaged as a group prior to and subsequent to the
display and imaging of groups preceding and subsequent in the said order.
When the display writing means is at the limit of its display range or
window, and the movement of the display physical baseline relative to the
character physical baseline is no longer useful to bring a character
within the full dimension of the display, then the imaging surface can be
moved relative thereto and the display means can be reset to reimage
characters in successive groupings. This will be necessary where the image
locations of the display physical baselines associated with the characters
when projected on the imaging surface or outside the range of the display
means.
Further, according to the principles of the invention, where a character
encoded in the master size is to be displayed at a size larger than the
screen the character may be sectioned into encoded separate sections.
Logical baselines may be inserted in those encoded separate sections and
then those logical baselines reference to a display physical baseline and
location and to an image locate corresponding to the display physical
baseline for the encoded logic sections. In this case, the logical
baselines are referenced to the encoded character physical baseline and to
a respective display physical baseline. The respective display physical
baseline for the logical baselines are referenced to their corresponding
projected location on an imaging surface. The encoded separate sections
then are projected on the imaging surface, by the display at locations
spaced from the projected image location of the character physical
baseline, and related to the encoded spacing between the logical baselines
and the encoded character physical baseline so that the characters are
accurately reproduced.
Additionally, encoded characters can be grouped by the location of their
respective display physical baselines on the imaging surface and ordered
according to their respective locations and then displayed and imaged in
groups according to that order.
In imaging master characters typically, the physical baseline or text
baseline of the characters on the imaging area is defined and then the
physical extent of the characters from the baseline is compared to the
extremes of the imaging area border. Where the size of all characters is
such that when located on the physical baseline all the characters fit
within the image area, then no adjustment is necessary. Additionally,
where the characters are relatively small such that more than one or a
series of text lines can fit on the screen, then such text lines may be
imaged in one pass requiring no adjustment of the imaging surface relative
to the screen.
Where a range of character sizes are reproduced from a master size stored
character or from a single stored size, a size will be reached where the
imaged character will be so large that it cannot be accommodated on the
screen.
As the cost and complexity of the screen and associated circuitry is
increased with an increasing imaging surface size, a direct benefit is
realized by limiting the size of the surface and reproducing characters
larger than the predetermined image surface dimensions, according to the
principles of the invention disclosed herein. Where the characters located
on an imaging surface's physical baseline, corresponding, for example, to
the text baseline, extend beyond the limits of the predetermined size of
the image surface, then the surface's physical baseline may be shifted,
thereby shifting or displacing the character on the image surface
therewith to accommodate the whole character in one imaging pass. This may
be accomplished, for example, in the case of a capital "A" by relatively
displacing the display physical baseline on the image surface downwardly.
If an imaging beam is used such as a laser or a CRT, and part of the
character was outside the imaging area of the beam or the CRT, then
accordingly the imaging surface would be moved to locate the physical
baseline location on the imaging surface within the range of the imaging
beam. If the character, for example, had a descender extending beyond the
bottom of the screen, the character physical baseline can be moved thereby
altering the juxtaposition of the character to the display physical
baseline and moving the character within the display.
If a character, projected on a CRT screen, or by a beam on an image
surface, is larger than the available screen or surface area, then
according to the principles of the invention, the character is segmented
and imaged in at least two passes depending upon the size of the
character. Where a character is naturally separated by a gap such as the
case of an accent, the character may be segmented between the accent and
the character, with the accent imaged separately from the character. In
the similar case of a lowercase character divided in two parts, such as a
"j" or an "i", the character may be conveniently segmented at the gap
between the dot portion and the lower body portion. Where a one-piece
character is so large it cannot be accommodated on the available surface,
then it may be segmented at any convenient location. For lowercase
characters such as "o" or "e" without descenders below the text baseline
or ascenders extending beyond the lowercase upper border, such as for "h",
the character may be conveniently cut in the middle. Where the character
has descenders, it may be conveniently cut at the location where it would
ordinarily rest on the text baseline. For ascenders, such as "h" or "b",
the character may be cut where it extends beyond the lowercase border.
Other characters may be cut by referencing the physical baseline on the
surface to the text baseline and segmenting the character where it
intersects with the border of the screen. For example, if brackets ([ ])
referenced to the physical baseline (text baseline) extended beyond the
borders of the screen, the system could segment the brackets at its
intersections with the screen border.
In accordance with established typesetting practice and printing, a
character is referenced to an EM square and its size defined by the EM
square size. The principles of the invention are described with reference
to the EM square as the character is defined on a grid within the EM
square and on an EM square baseline. However, it should clearly be
understood the invention is not limited to the case of a character defined
within an EM square and could be applied to characters defined by other
references. In the case of the preferred embodiment, the defined EM square
grid is 24 units along the vertical dimension of the EM square, from top
to bottom, with regard to the accepted orientation of characters. The
physical baseline is located 18 units from the EM square top. The area for
descenders is located between 18 units from the top and 22 units from the
top, with an extension area for long descenders located at the bottom two
units of the 24 unit EM square (or from 22 units from the top to the
bottom 24 units of the EM square). The area for lower case letters being
the middle area, is located from 8 units from the top to 14 units from the
top, with the bottom of the middle area coinciding with the baseline, and
the top of the middle area coinciding with the lowercase border. An
uppercase area is provided in the EM square, extending 14 units and
starting 4 units from the top and extending to the baseline at the 18 unit
point. An extension area for ascenders is located with the bottom of such
extension area coinciding with the uppercase border 4 units from the top
of the EM square, the top being the 0 unit. Where characters are so large
that they require segmenting in two or more pieces, then convenient
segmenting locations may be chosen accordingly.
Each of the characters may be referenced to a location in a stored look-up
table which may carry the character identification such as the character
number, and its position in its EM square relative to the dimensions
therein and as, for example, described above. The look-up table may be
used to determine whether the character at its desired size will fit on
the surface relative to the physical or text baseline, whether to shift
the baseline or to segment the character and the locations within the EM
square position relative to the character, for segmenting the character.
Accordingly, it is an object of this invention to provide a method and
system for utilizing the full projection area of an imaging surface to
project characters of a size extending beyond the borders of the surface.
It is a further object of this invention to provide a system and method for
segmenting characters as necessary to project the characters on the screen
in separate parts.
It is a further object of this invention to provide a system and method for
identifying one or more such segmenting positions in the character
relative to imaged character size.
These and other objects will become apparent in the following detailed
description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an EM square, divided into 24 units, whose size defines the
size of the character set within the EM square.
FIG. 2 shows a number of characters of difference sizes referenced to a
display of 18 milimeters.
FIG. 3 shows characters at a larger size than the display of FIG. 2 and
with the characters exceeding the display in a first dimension.
FIG. 4 shows how the "A" of FIG. 3 and in particular, the character
physical baseline of the A in FIG. 3 can be shifted on the display
corresponding to the extent a part of the A exceeds the display boundry,
FIG. 4a shows how the physical baseline of a oversize character such as a
J, can be shifted to the extent it exceeds the display boundry, to locate
the character fully on the screen.
FIG. 5 shows how a character larger than the display may be segmented by
inserting a logical baseline in the character.
FIGS. 6-7 show how other characters may be segmented as is done in
accordance with FIG. 5.
FIGS. 8, and 8a and 8b show how characters may be segmented, logical
baselines inserted and characters having the same logical baseline
displacement from the character physical baseline imaged in the same pass
or as a group, prior to the imaging of other groups of characters having
the same respective logical baseline displacement from the character
physical baseline.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows an EM square used in typesetting and printing to define or
provide a reference for a character. This concept does not form part of
the invention but is used as part of the explanation of the inventive
principles herein. The EM square as used in the preferred embodiment
contains a grid and is shown as having 24 units from Top to Bottom. The EM
square character physical baseline is located 18 units from the top and 6
units from the bottom. The Em square character physical baseline is the
conventional location for referencing the character. Some characters, for
example, lowercase "j" and "g", contain descenders which project below the
baseline into the Area for Descenders shown as located from 18 units to 22
units from the EM square top in FIG. 1. An Extension Area for Long
Descenders is also provided in the bottom two units of the EM square. The
Area for Lowercase letters is shown extending from 8 units from the Top to
the baseline. A Lowercase Border, located 8 units from the Top separates
the Area for Lowercases from the Area for Uppercases. For some characters,
such as lowercase "h" and lowercase "b", and lowercase "t", part of the
characters will extend above the Lowercase Border into the Area for
Uppercases. Other characters which may extend above the Lowercase Border
are lowercase "1", lowercase "d" and lowercase "f". An Extension Area for
Accents is provided from the Top of the EM square, (0 unit level), to 4
units from the Top. This area is typically used to locate accents relative
to the character. As conventional in typesetting and printing, the
characters defined within the EM square are encoded in digital data. That
data is then used to modulate a display and to set the characters on a
text baseline relative to each other and with reference to the location of
each character within its individual EM square. As shown in the
aforementioned patents, an encoded normalized character set on a 24 unit
grid may be projected onto a screen at different sizes. In such a case,
the 24 EM square grid units may be expanded to a much higher resolution
such as, for example, 432 vertical by 432 horizontal units.
As stated above, the EM square is not part of the inventive principles, but
it does offer a convenient reference for locating a character relative to
its character physical baseline encoded in the encoded character data and
for identifying one or more logical baselines in the character when the
character is segmented.
For the purpose of explanation, the imaging means is assumed to be a CRT
screen or display which forms an image. The image is then projected on an
image surface. The display physical baseline is then used as a reference
location for the CRT imaging means. In a similar manner and as known in
the art, any other imaging means used, such as a light source projecting
an image directly on a surface, will be referenced directly to the
physical baseline on the surface. In the case of the CRT or any other
imaging means forming an intermediate image, the display physical baseline
on the intermediate imaging means would be referenced relative to the
baseline on the final imaging means, as is known in the art.
Referring to FIG. 2, an example of a CRT screen is shown having a total
vertical dimension of 18 mm. For the purpose of explanation, the 24 unit
EM square shown in FIG. 1, may be thought of as projected to on the 18 mm.
screen, so that the 18 mm. vertical direction corresponds to the 24 units
of the EM square. A character encoded in the 24 unit grid would then fill
the screen when the EM square defining the character is approximately 51
points or 18 mm. in height (51 points=18 mm. divided by 0.351 mm. per
point). As is understood, the character itself defined within the EM
square typically would be less then 18 mm. As can be seen from FIG. 2,
whereas in the preferred embodiment, the physical baseline in the encoded
EM square corresponds to the location of the physical baseline on the
screen, and where none of the characters exceed the imaging surface's
vertical dimension from the baseline to its Top 5 and none of the
characters have descenders which extend beyond the Bottom 6 of the
surface, all of the characters may be accommodated on the screen and no
shift of the physical baseline on the screen or segmenting is necessary.
The characters projected on the screen may be increased in size by
specifying a displayed EM square size larger than 51 points such that only
the lowercase letters are less than the surface size and can be
accommodated with the surface boundaries. For example, in FIG. 3, the
lowercase "c" is shown on the physical baseline within the Top 5 and
Bottom 6 of the screen, while the capital "A" extends over the Top 5 at
locations 7 and 9 and the descender portion of the "j" extends over the
Bottom boundary 6 at location 8.
When projecting the oversize "j" on the screen, the physical baseline on
the screen may be displaced vertically in the direction of arrow 12,
sufficiently to bring the bottom portion of the "j" within the Bottom 6 of
the screen. Similarly, the physical baseline of the A may be displaced
downwardly in direction of arrow 10 to bring the top portion of the "A"
within the Top 5 of the screen. Displacement of the physical baseline
either in the direction of arrow 10 or 12 will bring the character into
full view on the screen until the size becomes larger than the available
screen size. Where the screen size is 18 mm., the maximum size character
that can be accommodated is 18 mm.
The maximum imaged size of the character may be shown for example by FIG. 4
wherein the "A" is projected to the maximum size of the screen and with
the physical baseline for the "A" being referenced at the Bottom 6 of the
screen. In FIG. 4a is shown the "j" wherein the physical baseline is
displaced upwardly so the full size of the "j" including the dot portion
may be displayed on the screen.
Where an intermediate imaging surface is used in conjunction with a final
imaging surface, such as a CRT screen with a film, the screen physical
baseline and the imaging surface must be moved relative to each other to
maintain the screen baseline with the imaging surface baseline in
alignment.
Referring now to FIGS. 5-14, it may be seen how a character may be
segmented where the size of the imaged character on the screen is larger
than the screen. In the case of a characters such as that shown in the EM
square of FIG. 5, having a natural gap, as between the accent and the
character, the character may be separated at the gap by projecting a new
logical baseline for the accent and then referencing that logical baseline
to the screen as shown in FIG. 5a. The imaging surface then would be
shifted relative to the accent to locate the physical baseline of the text
on the imaging surface in correspondence to the accent and at the proper
location relative to the logical baseline of the accent. When imaged, the
logical baseline on the screen may be located on the screen and relative
to the physical baseline on the surface in any suitable relationship.
Where the remaining portion of the character such as the "A" shown in FIG.
5 is large enough to be accommodated on the screen, then its screen
physical baseline may be located as necessary to accommodate the character
at its designated size as shown in FIG. 5b. The character may be imaged in
two passes, first imaging the accent and then relatively shifting the
imaging surface and imaging the remainder of the character.
As shown above, characters larger than the total vertical dimension of the
screen, given in the preferred embodiment as 18 mm., could be accommodated
by segmenting the characters and imaging the characters in parts, and as
shown in FIGS. 5, 5a and 5b by relatively shifting the baseline on the
imaging surface to locate it in correspondence to the character and
baseline on the screen. A character need not be segmented unless its
displayed size is larger than the maximum size of the screen. For example,
if the maximum size of the screen, is 18 mm., as shown, then any character
larger than 18 mm. would be segmented. When segmented, a logical baseline
is added to the character. In addition to the physical baseline, the
logical baseline may be viewed as a reference location on the character
for locating the segmented character parts at their proper locations
relative to the baseline on the screen and imaging surface.
Further examples of segmenting the character may be seen in FIGS. 6, 6a and
6b wherein the character is shown defined within the EM square and
extending from the Area for Descenders (18 to 22 units) into the Extension
Area for Accents (0 to 4 units). A character such as the uppercase "B",
when displayed at a size larger than the available screen size may be
imaged in two or more steps, depending upon the point size and with the
imaging surface shifted to bring the image surface physical baseline into
alignment with the logical baseline relative to the screen. In the case
shown in FIG. 6a where the upper portion of the "B" is displayed, the text
image baseline on the image surface is displaced from the logical
base-line a distance equal to the remaining part of the character opposite
the segmenting line S2. As can be understood, the image surface physical
baseline corresponding to the text baseline would be located at some point
below the screen as shown by, for example, the dash line. In a first pass,
the part of the "B" above the segment line S2 would be imaged. In a
subsequent pass, as shown in FIG. 6b, the bottom portion of the character
"B" extending from the segment line S2 would be imaged.
Where a character has descenders as shown by the lowercase "g" shown with
an EM square in FIG. 7, the character may be segmented where the character
intersects with the physical baseline, shown by S1, and then imaged
relative to the physical baseline or text baseline on the screen in a
similar manner as that explained above. In this case, the logical baseline
would correspond to the physical baseline. In a first pass, the part of
the character above the segment line S1 is imaged relative to the text
baseline on the imaging surface as shown in FIG. 7a. In a subsequent pass,
the relative position of the imaging surface may be adjusted upwardly to
locate the image surface physical baseline in correspondence to the
logical baseline, so the character is imaged opposite the appropriate
location on the imaging surface, as shown in FIG. 7b.
FIGS. 8, 8a, 8b and 8c illustrate how the imaging means such as the CRT
screen may be displaced, relative to the imaging surface to form
successive portions of the characters in successive passes. The relative
vertical dimension of a CRT is shown therein. To illustrate the principles
of the invention, a series of characters are shown imaged in the same
series of sequential scans. It should be understood that each character
can be separately imaged and completed prior to the imaging of any other
character and that the CRT screen may be placed in any location relative
to the imaging surface. Further, the physical baseline on the CRT screen
may take different locations relative to the text baseline. However, as it
will be understood by those skilled in the art, the portion of the
character selected for imaging, will be related to the location of the CRT
screen and the physical baseline on the CRT screen will be located
relative to the text baseline. Also as will be understood by those skilled
in the art, either the CRT screen may be displaced and the imaging surface
held stationary or the imaging surface may be displaced and the CRT screen
or other imaging means held stationary. In the preferred embodiment, the
CRT screen is held stationary and the imaging surface is moved relative
thereto.
As shown in FIG. 8, the CRT is oriented with its physical baseline
corresponding to the Text Baseline. With the given dimensions of the CRT
screen available for imaging as shown in FIG. 8, it can be seen that
lowercase "o", uppercase "A", and uppercase "U", can be fully imaged in
one pass. The accent above the upper case "A", the small lowercase "j" and
the larger lowercase "j" and the "[" will require a succession of passes.
However, it should be understood that with the CRT screen and its physical
baseline oriented differently with regard to the Text Baseline, and with
regard to each individual character, for example, it would be possible to
image in one pass lowercase "o", and the smaller lowercase "j". However,
that process would require more separate increments of the imaging surface
relative to the CRT or imaging means. In the example shown, the characters
in FIG. 8 are imaged in three passes, it being understood that the number
of passes may be varied as well as the orientation of the characters on
the CRT physical baseline and the segmenting for the characters according
to the principles of the invention.
As shown in the preferred embodiment, the accent and the upper portion of
the "[" is imaged on a first pass as shown in FIG. 8a. The imaging surface
is then moved relative to the CRT screen, a distance equal to the vertical
dimension of the imaging surface and in pass number two, the lowercase
"o", the dot on the larger lowercase "j", the capital "A", the captial "U"
and the middle portion of the "[" are imaged. In a third pass, the imaging
surface is moved half the vertical distance of the CRT screen and the
remaining portion of the larger lowercase "j" is imaged and the full
portion of the lowercase "j" is imaged.
As can be seen, the lowercase "o" may be imaged on the CRT face with using
less than the full vertical dimension of the CRT imaging means. The
uppercase "A" and the uppercase "U" are of a size that requires the full
vertical dimension of the CRT screen.
Further, as may be seen with the given orientation of the CRT screen
baseline relative to the text baseline, it is necessary to segment the "A"
accent and the larger lowercase "j" at their respective gaps imaging the
accent first in the first pass and the dot of the larger lowercase "j" in
the second pass. Then, the remaining portion of the "A" accent opposite
the gap may be imaged on the second pass while the remaining portion of
the larger lowercase "j" on the other side of the gap may be imaged on the
third pass.
The "[" is shown imaged in three passes. Since the "[" has no natural gaps
upon which it may be segmented, the "[" is shown segmented at the text
baseline location and at a second location separated from the first
segmenting point by the vertical dimension of the imaging means.
As the small lowercase "j" fits within the CRT beam, it may be imaged in
one pass, namely the third pass upon incrementing the imaging means
relative to the imaging surface one-half the distance of the vertical
dimension of the imaging means.
As previously explained, characters are defined within an EM square. The EM
square is related to the point size of the characters, the point size
being the size of the M square. For example, where a point is the
equivalent to 0.351 mm., the 18 mm. would be an EM square of 51 points.
However, as is known in typesetting and printing, a character defined
within an EM is smaller than the given EM square. For example, where the
EM square is defined in a 24 unit grid and where the 24 unit grid is
assumed to be equal to a 51 point EM square or 18 mm., then a character of
18 units within a 24 unit grid of the 51 point EM square would correspond
to 13 point mm. on the screen. Disregarding the EM square size and
concentrating on the size of the character, unrelated to the EM square,
that same size character can be projected upon the full 18 mm. of the
screen. At the 18 mm. projection and referencing that character to 18
units of the 24 unit EM square, the character would correspond to an EM
square size of approximately 68 points.
Where the character size is greater than 68 points with reference to a 24
unit EM square, then those characters which do not exceed 14 vertical
units can be typeset in one pass. These may be ascendeer characters
without descenders and descender characters without ascenders and lower
and uppercase characters. Suitable shifting of the physical baseline in
accordance with the text baseline and 68 point imaging surface can be
successfully used to avoid segmenting of most characters. Those characters
occupying more than 14 points in the 24 unit EM square such as lowercase
"j" having an ascender and "A" are segmented at specially designated
segmenting cut lines. The position of the cut lines are selected at
locations that will be least visible in the typeset output material. Good
locations for cutting characters are at natural gaps and at the upper and
lowercase borders (see FIG. 1). For example, characters such as lower case
"j", "a" and "o" can be segmented at the lower case borders and the middle
of the gap separating two parts of the characters. Other characters having
descenders will be segmented where that descender crosses the physical
baseline or the text baseline. Other characters located on the baseline
can be segmented at the middle of the character. Above 68 point or 18 mm.,
characters are imaged in as many passed as necessary to display the full
character shape.
When the characters require segmenting, the segmenting locations can be
located in the data store for each character. For example, where the
characters are stored in a dot matrix memory, the rows and columns within
the matrix can be read either up to a segmenting line or started from a
segmenting line depending upon the section of the character to be
displayed. Where outline encoding is used, as in the preferred embodiment,
the segment locations can be referenced as to the encoding points on the
coordinate system.
When the area for accents is inside the screen, then the character is
imaged in one pass.
Where the uppercase area is outside the screen, the character is imaged in
successive passes.
Where the uppercase area is inside the screen, and the lowercase is outside
the screen, the character is imaged in successive passes.
Where the uppercase area is inside the screen and the lowercase area is
inside the screen, the uppercase area is imaged in a first pass with the
lowercase area.
Where the uppercase area is inside the screen and the area for descenders
is outside the screen, the uppercase area is imaged in the first pass.
Where the uppercase area is inside the screen and the lowercase area is
inside the screen and the area for descenders is inside the screen, the
uppercase area is imaged in a first pass together with the lowercase area
and the area for descenders.
Where the superior (uberrangenden) uppercase area is inside the screen, the
uppercase area is partially imaged.
Where the lowercase area is outside the screen, the character is imaged in
successive passes.
Where the lowercase area is inside the screen, the lowercase area is
imaged.
Where the lowercase area is inside the screen and the area for descenders
is outside the screen the character is imaged in successive passes.
Where the superior lowercase is inside the screen the lowercase area is
partially imaged.
Where the area for descenders is outside the screen, the character is
imaged in successive passes.
Where the area for descenders is inside the screen, the area for descenders
is imaged.
The invention may be implemented in two steps. A first step requires that
characters be analyzed for the best location of the segment lines. This
has been described above with regard to accented characters, characters
have ascenders and characters having descenders. The second step requires
a determination of the physical baseline on the CRT screen relative to the
text baseline or in the case of other imagiing devices such as light
sources, the location of the physical baseline of the imaging means
relative to the borders of the available imaging area. As stated above,
and as this invention is described, using the example of a CRT screen, the
second step requires a decision for the location of the physical baseline
on the screen.
According to the preferred embodiment where more than one line of
characters may be imaged on the screen without movement of the screen
relative to the imaging surface, then the character baseline need not be
shifted nor segmenting be accomplished except for those characters located
on baselines near the borders of the screen and where the characters on
those text baselines have portions extending outside the available screen
area. For those cases, the respective text baselines may be imaged after
incrementing or displacement of the screen relative to the image surface,
and with | | |
