Tim,
I have written some computer programs to plot
variable versus time and variable versus position graphs.
I would be delighted to lead or help out in this venture. What
grant details do you have in mind?
The resolution of braille embossers allows conveying a significant
amount of spacial information.
The graphing utility should represent graphical information in
ASCII text files that one may review with refreshable braille or
send directly to a braille embosser.
The graphing utility should drive a generic embosser.
I attacked the problem this way. After titling the braille
graphic, send the appropriate escape sequence to place the embosser
in graphics mode. For Telesensory's versapoint, dots are uniformly
2.5 mm apart. For Telesensory's Everest, dots are uniformly 2.5 mm
or 2.0 mm, depending upon embosser settings. The portion of the
braille page containing a graphic is an R X N array. Each array
element is on (a braille dot) or off (background space). The
braille graphics mode of most printers requires representing this
array with a braille symbol for every 2 column by 3 row block of
elements.. So to make a braille graphic, first round the position
of the variable to the nearest array element position, and then
emboss braille symbols corresponding to blocks of 2 columns by 3
rows of array elements.
The issue of graphic resolution deserves careful attention. A
Braille Blazer in text mode may display 25 lines at 32 characters
per line or 75 rows X 64 columns. Does it have a graphics mode?
If not, stairstepping artifacts truly hinder the usefulness of a
braille graphic. The Everest embosser's high resolution mode
allows displaying roughly 120 rows X 120 columns per 11 by 1.5 inch
braille page. This resolution begins to provide an accurately
drawn graphic. With the low resolution of braille embossed
graphics, we must accept low resolution artifacts such as
stairstepping. A braille embossed graphic is a tool with severe
limitations. Keeping this in mind, embossed graphics can be very
useful. I have found them so at Qualcomm.
Some basic research and extensive beta testing will help the
graphing utility be as effective as possible with the limited
resolution of braille embossers. What are your thoughts on the
matter? Here are my questions in no particular order.
(1) What graphing utility efforts are in progress? What might we
learn from Noel Runion and Chuck Hallenbeck, for example?
(2) How useful is using braille symbols (yrpgba) for yellow, red,
purple, green, blue, and aqua colors at a resolution of 25 rows by
32 columns?
(3) Which braille embossers support a graphics mode and at what
resolution?
(4) How useful are the operations of translation, rotation, and
stretching?
(5) At 2.5 mm and 2.0 mm resolutions, what braille fonts act as
analogs to color? How many braille font "colors" are there?
(6) How feasible is inserting readable braille labels into a
braille graphic?
(7) How useful is enhancing a braille graphic by outlining shaded
regions, for example?
Sincerely,
John
John A. Miller jamiller@qualcomm.com
(619) 658-3876
member, National Federation of the Blind
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