bskendig@phoenix.Princeton.EDU (Brian Kendig) (12/03/89)
First, the situation:
I'm designing a HyperCard stack (actually, now a SuperCard standalone)
for NASA that will tie together a *lot* of technical documentation
about the Space Station Freedom Manned Base and cross-link it.
HyperCard is perfect for this, as I can freely mix text and diagrams,
and still have it be simple enough for the common man to use. Or even
for IBM-lovers to use, one would hope.
Next, the problem:
I have several documents that must be called up by the program. They
range in size from about 5k to 100k. The program must be able to call
them up at the click of a button and display them in a scrollable
window. If the user clicks on one of the words in the displayed text,
the program must be able to determine what word was clicked on, and
take action depending on that word (e. g. "Figure 2.5" -> show the
figure, 'SSFMB' -> show the acronym's meaning, 'Appendix B' -> show
the appendix).
The solution thus far:
I place each document into its own scrollable text field on its own
card. If the text has more than 32k characters, the field can't take
it, so I have to chop the text up across cards. This confuses users
sometimes, but it is the only solution I have been able to come up
with so far. Taking action as a result of clicked words is no
problem: I have written several scripts that are able to determine
what the user clicked on and why he clicked on it, and will produce
the appropriate result.
Problems with this solution:
First of all, scrollable fields in HyperCard are sluggish. The
program hesitates for a moment when you click a scroll arrow; it is
not obvious that you must hold the mouse button down over the arrow
for a second (clicking on an arrow sometimes fails to scroll the
text). Secondly, the vertical scroll bar is active even when all the
text appears in the field; this again confuses users ("Why won't this
scroll bar work? Must be a bug!") and makes *me* look bad.
The biggest problem and most obvious kludge is that I cannot fit a
large document in one field. Splitting it across cards is not an
elegant solution.
Ideally, I would like to write an XCMD or XFCN that will display a
text file of arbitrary length in a scrollable window - not just a text
field, but a window in its own right, with a vertical scroll bar.
Reading the text off disk instead of hardcoding it in the stack allows
me more flexibility. I think that I shouldn't have any problem
reading the file (correct me if I'm wrong, but can't variable
containers hold data of arbitrary length?). If I could pass the
container with the text in it to an XCMD that would then display it,
my problems would be solved.
First difficulty - how do I coerce TextEdit to show the more than 32k
and still allow for natural scrolling? (This is where the 'Eternal
Question' bit comes into play - I imagine that plenty of people have
asked this before!) If anyone has any code that would do this, or any
suggestions on the matter, believe me, I'm all ears. I know it's
possible - word processors do this kind of thing naturally.
Second difficulty - how can I determine what word was clicked on in
the text window? I achieve this right now with a lot of calculations
in HyperTalk for the text field, but I'm not sure how I'd go about it
in C.
My development system consists of HyperCard 1.2.5, SuperCard 1.0, and
THINK C 4.0. This stack is being designed on a Macintosh SE to run on
a Macintosh IIci, so speed probably won't be an issue...
Any help whatsoever (in the form of ideas or code) would be greatly
appreciated. Also, if you happen to come up with another idea of how
I could go about this whole business of displaying large amounts of
text, please do suggest them!
As soon as this program is in a more stable state and has been
approved by the appropriate legal departments, I'll see about putting
it in Sumex and on comp.binaries.mac. But that may not be until next
Fall.
Thank you for taking the time to consider this.
<< Brian >>
--
| Brian S. Kendig | I feel more like I | bskendig |
| Computer Engineering | did when I got here | @phoenix.Princeton.EDU |
| Princeton University | than I do now. | @PUCC.BITNET |
| Systems Engineering, NASA Space Station Freedom / General Electric WP3 |