I'd like to share my 3 useful functions. Enjoy and experiment!

More on my artistic experimental programming: google 'artist F.P. Brixey saatchionline'. NEW: my collection is visible on deviant art.

`// --------------------------------- //`

// Project: circle1

// Start: Sunday, February 03, 2013

// IDE Version: 10.244

// SETCURRENTDIR("Media") // go to media files

GLOBAL scrx%=666, scry%=666 //your custom size.

// For PC use menu;project;options;win32

GETSCREENSIZE scrx, scry

SETSCREEN scrx,scry,0 // Size matters.

CREATESCREEN 1,1,scrx,scry

// the drawing surface.

GLOBAL cnt%

//****************************************************

WHILE TRUE

//press F12 to view long lines of code.

LOCAL alpha=(RND(1999)/1000.0 -1.0)+0.00000003

// additive when >0

// interpolated when <0, ='mix' ='cross-fade'

// ...in my opinion.

LOCAL color%=RGB(128*RND(2)-1,128*RND(2)-1,128*RND(2)-1)

LOCAL smoothedge = 1.5+9*RND(2)

LOCAL thickness=1.5+11*RND(3)

// USESCREEN 1

IF RND(1) >0

drawdisc2(RND(scrx), RND(scry), 4+RND(300), color, alpha, smoothedge) // yes smoothing.

ELSE

drawcircle2_(RND(scrx), RND(scry), 4+RND(300), thickness,color, alpha, smoothedge) // yes smoothing.

ENDIF

//drawdisc1(RND(scrx), RND(scry), 4+RND(300), color, alpha) // no smoothing. // unused.

//USEASBMP // optional

USESCREEN -1

ALPHAMODE -1

DRAWSPRITE 1,0,0

SHOWSCREEN

INC cnt,1

IF cnt >4

cnt=0

SEEDRND (GETTIMERALL()) //shuffle the cards.

ENDIF

//FOR more clarity:

DEBUG alpha ; DEBUG "\n"

// please activate the 'bug' icon

// SLEEP 2012 // additional time

SLEEP 800 +RND(3333)

//SLEEP 787// Merry dream, liner!

WEND

//****************************************************

FUNCTION drawdisc1:cx%,cy%,r%,col%,a //raw shape

// a fast function with no blending.

//would be nearly 4x faster using symetry, working on just 1/4circle.

LOCAL r2% = r*r

USESCREEN 1

//Only plot within the screen to save time:

LOCAL bx1%=cx-r

IF bx1 <0 THEN bx1=0

LOCAL by1%=cy-r

IF by1 <0 THEN by1=0

LOCAL bx2%=cx+r

IF bx2 >scrx THEN bx2=scrx

LOCAL by2%=cy+r

IF by2 >scry THEN by2=scry

ALPHAMODE a // same speed for a=0, a=-1, strangely. Any suggestion for more speed?

FOR x%=bx1 TO bx2

FOR y%=by1 TO by2

IF (x-cx)*(x-cx) +(y-cy)*(y-cy) <= r2 THEN SETPIXEL x,y,col

NEXT

NEXT

ENDFUNCTION

// On the day the atom is a cube I will start believing in the square pixel.

FUNCTION drawdisc2: cx,cy,r,col%,a,smoo //smoothed.

// Basic values are a=-1, smoo=1.

// N.B. a= -1...+1 but a=0 cancels the smoothing.

// (if trouble try a permanent "INC a, 0.00000000000000042")

// Higher smoo values blur the edges. (Do try it at home!)

// Smoothing is symetrical across the circle position:

// blurring goes both inwards and outwards. It is done in a quick

// way as it doesn't calculate SQR(d^2), using directly the r^2

// values for interpolation. Not as nice as a proper bicubic one.

// Just feel free to try your own way to interpolate the alpha

// value for a nicer smoothing/halo.

USESCREEN 1

IF smoo <0 THEN smoo =0

LOCAL halfsmoo =smoo*0.5

LOCAL r2 = (r-halfsmoo)*(r-halfsmoo) //contracted

LOCAL r2_ = (r+halfsmoo)*(r+halfsmoo) //expanded

LOCAL d2

LOCAL w=r2_ -r2

//Only plot within the screen to save time:

LOCAL bx1%=cx-r-halfsmoo

IF bx1 <0 THEN bx1=0

LOCAL by1%=cy-r-halfsmoo

IF by1 <0 THEN by1=0

LOCAL bx2%=cx+r+halfsmoo

IF bx2 >scrx THEN bx2=scrx

LOCAL by2%=cy+r+halfsmoo

IF by2 >scry THEN by2=scry

FOR x%=bx1 TO bx2

FOR y%=by1 TO by2

d2=(x-cx)*(x-cx) +(y-cy)*(y-cy)

IF d2 <= r2

ALPHAMODE a

SETPIXEL x,y,col

ELSEIF d2 >= r2_

// leave it alone.

ELSE

//interpolation:

ALPHAMODE (r2_ -d2)*a/w

SETPIXEL x,y,col

ENDIF

NEXT

NEXT

ENDFUNCTION

// On the day the atom is a cube I will start believing in the square pixel.

FUNCTION drawcircle2_: cx,cy,r,thick,col%,a,smoo //smoothed.

// Same principle as drawdisc2( .

// using the real r value instead of r*r looks nicer but takes longer.

// This interpolation is linear but I believe a 'S' shape would

// be perfect. Also keep in mind that only an alpha interpolation is

// NOT enough; at the same time you should also interpolate the

// color into the next area. (Yes it's a bit bizarre.)

USESCREEN 1

IF smoo <0 THEN smoo =0

LOCAL halfsmoo =smoo*0.5

LOCAL th =thick*0.5

LOCAL ra = (r+halfsmoo+th)

LOCAL ra2 = (r+halfsmoo+th)*(r+halfsmoo+th) //outermost

LOCAL rb2 = (r+th)*(r+th) //

LOCAL rc2 = (r-th)*(r-th) //

LOCAL rd2 = (r-th-halfsmoo)*(r-th-halfsmoo) //innermost

LOCAL rd = (r-th-halfsmoo)

LOCAL d2

LOCAL r2 =r*r

LOCAL w_out =ra-(r+th) +0.000001//r2_ -r2

LOCAL w_in =(r-th)-rd +0.000001

//Only plot within the screen to save time:

LOCAL bx1%=cx-r-halfsmoo-th

IF bx1 <0 THEN bx1=0

LOCAL by1%=cy-r-halfsmoo-th

IF by1 <0 THEN by1=0

LOCAL bx2%=cx+r+halfsmoo+th

IF bx2 >scrx THEN bx2=scrx

LOCAL by2%=cy+r+halfsmoo+th

IF by2 >scry THEN by2=scry

FOR x%=bx1 TO bx2

FOR y%=by1 TO by2

d2=(x-cx)*(x-cx) +(y-cy)*(y-cy) //distance to center

IF d2 <= r2 //internal

IF d2 >= rc2

//plot it plain.

ALPHAMODE a

SETPIXEL x,y,col

ELSEIF d2 <= rd2

// ignore it

ELSE

// interpolate, blend it.

ALPHAMODE (SQR(d2) -rd)*a/w_in

SETPIXEL x,y,col

ENDIF

ELSE //external

IF d2 < rb2

//plot it plain.

ALPHAMODE a

SETPIXEL x,y,col

ELSEIF d2 >= ra2

// ignore it

ELSE

// interpolate, blend it.

ALPHAMODE (ra -SQR(d2))*a/w_out

SETPIXEL x,y,col

ENDIF

ENDIF

NEXT

NEXT

ENDFUNCTION

//__________________________________________________________________________________

// P.S. On the day the atom is a cube I will start believing in the square pixel.