Re: Is HPLOT in MAB broken?

["Polymorph" <polymorph@a2central.com.remove-lv7-this>]

  To: BluPhoenyx
BluPhoenyx wrote:
> limtc wrote:
>> Well, if it does not work as what the manual described (for 3.x, 4.x
>> and 5.0!) and does not work like Applesoft (which is the same as what
>> the manual is saying, which PLOT a dot on the x, y location), then it
>> is in fact broken.
> 
> Considering the 8 bit version works as described in the manual then yes,
> the GS version is broken. I don't know if this is actually a bug or a
> design decision. Perhaps it has something to do with the GS version only
> using GS video modes for high resolution graphics.

My guess is, as I mentioned previously, that MAB is probably using the
Toolbox routines to implement HPLOT. I bet if you compile a MAB program
using "HPLOT X, Y: HPLOT TO X, Y" and look at the binary in Ciderpress,
you would see MoveTo(X,Y) & LineTo(X,Y) somewhere in the listing.

The Quickdraw II Toolbox routines have no concept of a HPlot X,Y
routine. To plot a single point, you have to:

MoveTo(X,Y);
LineTo(X,Y);

So I reckon to simplify the compiler, they probably just translate
"HPLOT  X,Y" into a "MoveTo(X,Y)" and "HPLOT TO X,Y" into a
"LineTo(X,Y)" call.

Remember that the documentation of software is quite often done in
parallel by someone other than the main developer(s) which makes it easy
for these mistakes to creep into the documentation. Another possibility
is that they simply used the 8 bit MAB's documentation and updated all
of the GS specific bits and happened to miss this difference.

Anyway, I wouldn't say that MAB's HPLOT is broken (broken to me means
that it doesn't work), I would say "different".  :-)

-- 

Cheers,
Mike

Find my Apple II projects online at:
http://apple2.sytes.net/

"It's my duty; my duty as a complete and utter bastard!" - Rimmer (Red
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