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Old 7th December 2009, 00:36   #21  |  Link
Gavino
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GScript version 1.1 now available

This is an update to fix a few problems. A minor extension regarding comments is also included.

Bugs fixed:
- On some systems, a crash would occur when GScript attempted to report any kind of error (eg syntax error or Assert failure).
- In a 'while' loop, the conditional test was evaluated before any implicit assignment to 'last' on the final statement of the block, potentially causing the wrong value of 'last' to be used in the condition.
- When incrementing a 'for' loop variable at the end of the loop body, any user assignments to the variable in the body were ignored.

New extension:
- Within GScript, comments are allowed before a '{'.
This applies not only in the GScript constructs (if, etc), but also to standard uses of '{' in function declarations and try/catch. Arguably, it is a bug that Avisynth itself does not permit this (see this thread).

Get the latest version from the first post in this thread.
For a limited period, also available here:
http://www.sendspace.com/file/9cfhfp

Last edited by Gavino; 7th December 2009 at 00:38.
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Old 19th December 2009, 14:48   #22  |  Link
StainlessS
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This is my new bestest plugin, thanx Gavino,

Thought you might like to know I've posted a little script:-

http://forum.doom9.org/showthread.ph...74#post1354574

Using GScript, uses a recursive function, tried it up to about 140 levels
of recursion without probs, assume that it is a dynamic heap type stack
rather than a real one in Avisynth.

Anyways, LOVE THIS, everyone shoud get this for XMAS.

PS, where can I get one of these fabled Paper cutting laser machines?
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Old 19th December 2009, 17:48   #23  |  Link
Gavino
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Thanks, StainlessS. Interesting example.

Although it doesn't actually seem to be a problem, you could eliminate the recursive call to GScript itself by defining the entire function within GScript, ie
Code:
GScript("""
Function __FPS_23_to_24__(clip Last)
{
  ...
}
""")
Of course, the function itself would still be recursive.
I wondered if that recursion could be easily removed by using a 'while' loop, but I think your algorithm is easier to express recursively, as you have done.
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Old 19th December 2009, 20:31   #24  |  Link
StainlessS
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@ Gavino,

I shall edit the GScipt(""" stuff to outside the function, thought it was purely compile time.

After getting it working recursively, I did spend about 10 mins converting using while loop, but
thought, 'sod it, why bother'. It can be more difficult than recursive, the iterative Euclid() thing
runs quite a lot quicker than rercursive, and in Knuth, (maybe Fundamental Algorithms) he
does a fairly longer iterative version that is quite a bit faster than that. If it could be converted
to iterative, it would not be too difficult a job to make it run without GScript (Eval), but would
not want to even try doing it that way without something that already worked.

I have not really done any coding [other than my new filter Exblend() as posted on doom Dec 2nd],
for about 14 years. Did quite a bit of graphics type stuff, quick drawing of lines, circles, ellipse,
torus etc, using something called DDA. Cannot for the life of me remember what its called [DDA],
nor anything about how it works. Was thinking that maybe I could use it [DDA] in doing a direct
conversion from 23.976 to 25 FPS (instead of a 24FPS interim conversion).
Could you please take a quick look at the below comments from a function I wrote about 16 or 17
years ago, I cant make head nor tail of it and dont even know what to look for on the net,
looked DDA up on Wikipedia, got something completely unrelated.

See Below:-


Code:
void wrcircle0(int xc,int yc,int r,int pen)
{
/*                  circle
  Single pixel render version (ie wrpixel()).
  Draw a lovely round circle on a 1:1 aspect ratio device using a DDA.
  Uses equation of circle:-
    x*x + y*y <= r*r  
      where pixel is exactly on circumference of circle when the
      equation balances exactly.
  We wish for rounding to the nearest pixel using the distance from the
  origin to the circumference ie
    sqrt(x*x + y*y) <= r + 0.5
    The above in effect calculates the distance from the centre of the
  origin to the centre of the target pixel (ie the coords themselves are
  NOT rounded, simply the distance from centre to centre) and it is the
  radius that is rounded rather than the x,y coords.
  We need the pixel that provides the greatest distance from the 
      origin while maintaining the above relationship.
  We want to re-write in the form of the first equation so
    x*x + y*y <= (r + 1/2)*(r + 1/2)
  Expanding the right hand side we get
    x*x + y*y <= r*r + r + 1/4
  As (x*x + y*y) never produces a fractional result, we can drop the 1/4
  from the equation without affect.
  Rewriting:-     
    x*x + y*y - r*r - r <= 0
      where ((r*r) - r) is constant and (x*x) and (y*y) vary
      and can be calculated easily without multiplication as we step
      through the x,y coordinates.
  Where 
    n           -1    0   1   2   3   4 
    (n*n)         -1    0   1   4   9   16  
    (n*n)-((n-1)*(n-1))     -1    1   3   5   7   
    diffstep            2   2   2   2

  The difference (n*n) - ((n-1)*(n-1)) cancels to:-
    2n - 1 and varies by diffstep (2) when stepping through x,y coords.
  The threshhold at x,y of (0,r) is calculated as
    (0*0) + (r*r) - (r*r) - r which cancels to  (-r).
    We step coords clockwise from  top centre (0,r) to (r,0). We check
  first that x+1,y is ok to print and if so we move RIGHT (From our
  rotation and the perfect aspect ratio, the pixel to the right of current
  is ALWAYS further away and always furthest possible if plottable), if
  this fails then we KNOW we have to check 1 DOWN and RIGHT of current as
  this is always next possible longest radius, if plottable we move DOWN
  and RIGHT, otherwise we KNOW that 1 down from current is always closer
  than current so we do not need to check whether its plottable and so we
  move DOWN.
    The above method ensures that plotted points are no more than 1
  pixel from the previous one (counting diagonal as one) and so leaves
  no gaps in the circle.
    To save complications, when plotting 4 quadrants we plot in 2
  parts, the initial top and bottom middle pixels are plotted first
  and it then loops to find the next coords, plots two of those and waits
  until the next loop to do the same coords in the other quadrants.
  This removes the necessity to plot the top, bot, left, and right centre
  pixels as special cases (Otherwise plots same pixels twice).
    Have tested from radius 1 to 1500 and NO pixels overlap any other
  plotted pixels therefore not affecting XOR type operations.
    DONT CHANGE algorithm without good cause.
  Further, To calculate the upper coord of the vertical cord where x==r
  we use:-
    y*y <= (r*r) + r + 1/4 - (x*x)
  As (x == r) and 1/4 will not take any significance we rewrite as:-
    y*y <= r  OR y = (int)sqrt(r);  (Fract part discarded)
  This algorythm does produce the occasional extra pixel at 45 degrees
  which results in a pointy bit instead of a smooth diagonal, however,
  as there are only about 5 instances with a radius less than 10,000 and
  only 4 less than 1000 radius (ie 1, 8, 49, 288). We we could eradicate
  this but do not due to the overhead of detection for such a small
  improvement. [ if((thresh <= 0)&&((x+1)!=y)) step right ELSE step left].
  NOTE, At radius == 1, the aforesaid pointy bit is desired.
*/
long  thresh; /* Needs long (ranges about  +- 2r ) */
long  xd;   /* Needs long (ranges about -1 to 2(r+1) - 1) */
long  yd;   /* Needs long (ranges about -1 to 2r - 1) */
int x,y,terminate,tem;
const   long diffstep = 2L;       /* long to avoid size extension */
  if  (
    (r<=0)        ||
    ((yc-r) > clip[3])  ||
    ((yc+r) < clip[1])  ||
    ((xc-r) > clip[2])  ||
    ((xc+r) < clip[0])
    )return;
  /* Clip thresh, (-ve if fully within clipping area ) */
  if((terminate=clip[1]-yc)<(tem=yc-clip[3]))
    terminate = tem;
  x=0;y=r;    /*  Preset plot at (0,r) and init thresh for (1,r)  */
  yd  = (2L*r - 1L);            /* yd(r) */
  xd  = (2L*0 - 1L + 2L);         /* xd from 0 to 1 */
  thresh  = (-r);             /* thresh(0,r) */
  thresh += xd;             /* thresh(1,r) */
  while((y > 0)&&(y >= terminate))
    {
    wrpixel(xc + x ,yc - y,pen,NULL); /* quad 1 (And starting plot) */
    wrpixel(xc - x ,yc + y,pen,NULL); /* quad 3 (And starting plot) */
    if(thresh <= 0)   /* Can we do (x+1,y), 1 to RIGHT of current */    
      {           /* Yes, step x Right */
      xd  +=  diffstep;   /* xd from x+1 to x+2 */
      thresh  +=  xd;     /* thresh(x+2,y) */
      ++x;          /* This is longest poss radius, DONE */
      }
    else
      {           /* No, stepping y Down */
      thresh  -=  yd;     /* thresh(x+1,y-1) */
      yd  -=  diffstep;   /* yd from y to y-1 */
      if(thresh <= 0)/* Can we do (x+1,y-1), 1 dwn, 1 RGT of current */
        {         /* Yes, stepping both DOWN and RIGHT */
        xd  +=  diffstep; /* xd from x + 1 to x + 2 */
        thresh  +=  xd;   /* thresh(x+2,y-1) */
        ++x;
        }
      --y;              /* Dont forget to DOWN step y */
      }
    wrpixel(xc - x ,yc - y,pen,NULL); /* quad 2 (And closing plot) */
    wrpixel(xc + x ,yc + y,pen,NULL); /* quad 4 (And closing plot) */
    }
}
Any of that mean anything to you? Beats the hell out of me what it is.

PS, Seem to remember that the DDA thing tends to use
XD, YD and Diffstep, whether in line drawing or any other use.
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Old 19th December 2009, 21:17   #25  |  Link
Gavino
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Quote:
Originally Posted by StainlessS View Post
I shall edit the GScipt(""" stuff to outside the function, thought it was purely compile time.
It is (like all recursion and function calls in Avisynth), but inside the function, GScript gets re-evaluated on each recursive call, so it potentially affects script loading time (and stack usage during this phase) - perhaps not noticeably.

I'm preparing for a trip at the moment, so I don't have time to study your circle algorithm right now. Is it related to Bresenham's circle algorithm? I don't see the connection with frame-rate conversion though.
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Old 19th December 2009, 23:11   #26  |  Link
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Bresenham's circle algorithm,

That seems to ring a bell and probably is similar in some
respects (probably even based on), however, the circle
algo I posted was unlike any other currently used on any
platform. At one time there were competing graphical
models floating about and most platforms settled on the
same model. Things like not plotting the last pixel of a line.
The included circle routine plots absolutely lovely round
circles even at small sizes but does not fit in the accepted
model. A similar sized circle done with this compared to
one drawn in windows looks well different. I think part of it
is that my circle judges the origin to be in the centre of
the pixel, whereas the accepted model (rounding to
x,y coordinates) effectively puts the origin in the
bottom left corner (depending upon coordinate system
used). [At least thats what seems to be coming back to me].

EDIT:- Got the above circle center thing completely back to
front.

Anyways, I think there was summick called Bresenhams
line algorithm, and I think that, that is the thing I was
looking for. It uses a DDA, (whatever that means) to draw
eg diagonal lines, stepping regularly on one axis and every
now and again, taking a step on the alternate axis. As you
say, it may be of no use at all in this instance, but i
could not remember how it worked. Will look at your link,
try and figure out the DDA thing, might just have to use
floating point instead, inserting a sysnthesized frame every
23.4140625 input frames.

Thankyou for taking the time to point out Bresenham, he
is exactly the guy I was looking for, I think. Please enjoy
your holiday and dont bother with the circle thing, you given
me every thing I need to find what I am looking for.

Ta very much

Byesey bye


Quote:
Originally Posted by Gavino View Post
don't see the connection with frame-rate conversion though.
EDIT:- Yeah, your right, complete wild goose chase, thanx for your time.

Last edited by StainlessS; 21st December 2009 at 05:00.
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Old 25th March 2010, 11:53   #27  |  Link
Gavino
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Stephen - thanks for your suggestions. I will need to think about them before giving a full answer.

In the meantime:
- a crude way to force exit from a loop is to set the loop counter to its final value;
- you might want to look at the array features in AVSLib.
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Old 1st April 2010, 16:46   #28  |  Link
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I'm still thinking about it.
Neither feature is completely trivial, but on the other hand they're not totally infeasible either.

My current thinking is that arrays would require further support from the core to be worth having, eg ability to use them as function arguments. So the break/continue feature seems a more likely GScript candidate.

I think this could be done, but before expending more effort, I'd like to know how much of a demand there is for this. Note that the effects of break/continue can in principle already be achieved using if/else and appropriate boolean flags in your (G)script.
What do you think, good users?
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Old 17th October 2010, 15:15   #29  |  Link
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Yes...hope there would be more plugin and make avisynth work like OOP, which is much easier to understand. Thanks a lot Gavino, you are a hero.
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Old 20th February 2011, 01:49   #30  |  Link
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Does someone has intention to embed GScript to Avisynth? I think it will be very useful.
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Old 21st October 2014, 04:34   #31  |  Link
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calling a variable using string + incremented value

Hi
Hope this is the right place to post this question

Hi

let's say I have a number of subtitles
c0="Hello World"
c1="Hello and GoodBye"
c2="Love is all you need"
c3="avisynth rocks"
c4="Gscript is awesome"


and I want to call these subtitles (variables) in a loop, where the value of k represents a different clip or image being processed in the loop and I want to add each subtitle

I can use this syntax to use subtitle c0

k=k.subtitle(c0, 8,460)

but how do I use this if I want to use the values of c0, c1, etc

I have been trying something like this

caption= "c" + string(i)
k=k.subtitle(caption,8,460)

this give me text strings "c0", "c1", "c2", . . .
but I want to get the "value" of c0, c1, c2, etc

I tried using

caption= eval("c" + string(i))

but I get "Script Error - invalid arguments to function "Subtitle""


TIA
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Old 21st October 2014, 05:08   #32  |  Link
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I forgot to use subtitle(string(Caption))

so this code works

Code:
caption = Eval("c"+String(i))
k=k.subtitle(string(Caption), 8, 460)
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Old 21st October 2014, 09:02   #33  |  Link
Gavino
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Hi, wiseant.

You shouldn't need to use string(), as caption is already a string.
This works fine for me:

c1 = "Hello"
i = 1
caption = Eval("c"+string(i))
BlankClip().Subtitle(caption)
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Old 21st October 2014, 20:35   #34  |  Link
wiseant
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Hi Gavino

Yes,

caption = Eval("c"+string(i))

that does work - when I tried it yesterday I received the error message - probably because I had more images than captions
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Old 21st November 2014, 01:53   #35  |  Link
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Why is this thread so, so, so, under posted.
The only reason I can think of is that GScript is so perfect, that nobody can find anything to complain about.

Come-on TheFluff, you like to have a good complain about things, complain about this so we can retaliate and get its post count up.
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Old 25th November 2014, 21:29   #36  |  Link
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{:-)]
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Old 17th March 2016, 18:20   #37  |  Link
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Is there a 64bit version of GScript or do I have to move to AVS+ for that? If the latter, does it support ScriptClip or other means of accessing current_frame?
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Old 25th May 2019, 20:44   #38  |  Link
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Why do avisynth devs not include this in avisynth? Original syntax is nightmare especially unhighlighted eval("""""")
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Old 25th May 2019, 21:00   #39  |  Link
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Gscript is integrated into AVS+ already, and for classic AVS it looks like development has ended...

Quote:
GScript (a plugin for AviSynth that provides new control-flow constructs such as loops) has been incorporated natively into AviSynth+. Syntax is mostly unchanged, with two notable differences:
In AviSynth+ there is no need to wrap your GScript code in a string. The language extensions are native to AviSynth+ and can be used transparently.
The "return" statement has been changed to not only exit the GScript code block, but behaves like a normal AviSynth return statement: it causes the termination of the active script block (user function), or if not in a function, the entire script.
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Old 25th May 2019, 21:17   #40  |  Link
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Gscript is integrated into AVS+ already,
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