' ****** START INCLUDE Rgba Core ******
DIM r0%, g0%, b0%, a0%, r1%, g1%, b1%, a1%
DIM RbgaAreaBorder# = &h0000FF

SUB SetRgb0(x%,y%)
    DIM c$
    c$ = RIGHT$("000000" + HEX$(POINT(x%,y%)), 6)
    r0% = VAL("0x" + LEFT$(c$,2))
    g0% = VAL("0x" + MID$(c$,3,2))
    b0% = VAL("0x" + RIGHT$(c$,2))
END SUB

SUB SetRgb1(c&,a%b)
    DIM c$
    c$ = RIGHT$("000000" + HEX$(c&), 6)
    r1% = VAL("0x" + LEFT$(c$,2))
    g1% = VAL("0x" + MID$(c$,3,2))
    b1% = VAL("0x" + RIGHT$(c$,2))
    a0% = 255 - a%b
    a1% = a%b
END SUB

SUB RgbaCorePset(x%,y%)
    PSET(x%,y%), _RGB( [{ (r0%*a0%)+(r1%*a1%) }/255], [{ (g0%*a0%)+(g1%*a1%) }/255], [{ (b0%*a0%)+(b1%*a1%) }/255] )
END SUB
'  ****** END INCLUDE Rgba Core ******

Sub RgbaCircle (xc#, yc#, r#, c&, a%b)
    PCOPY 0,-1
    CIRCLE (xc#, yc#), r#, RbgaAreaBorder#
    
    DIM xc%, yc%, r%, x%, y%, x1%, x2%
    xc% = fix(xc#) : yc% = fix(yc#) : r% = fix(r#)
    SetRgb1(c&, a%b)
    for y% = MAX(0,(yc% - r%)) TO MIN(_HEIGHT-1,(yc% + r%))
      x1% = MAX(xc% - r%, 0)
      WHILE POINT(x1%, y%) <> RbgaAreaBorder# and x1% < MIN(_WIDTH - 1, xc%+r%) : x1% = x1% + 1 : WEND
      x2% = MIN(xc% + r%, _WIDTH - 1)
      WHILE POINT(x2%, y%) <> RbgaAreaBorder# and x2% > MAX(0, xc%-r%) : x2% = x2% - 1 : WEND
      IF x1% > xc% THEN x1% = 0
      IF x2% < xc% THEN x2% = _WIDTH - 1

         IF POINT(x1%,y%) = RbgaAreaBorder# OR POINT(x2%,y%) = RbgaAreaBorder# THEN
         FOR x% = x1% TO x2%
             IF POINT(x%,y%) = RbgaAreaBorder# THEN PCOPY(x%, y%) - (x%, y%), -1, 0
             SetRgb0(x%,y%) : RgbaCorePset(x%,y%)
         NEXT x%
         END IF
    next y%    
    
END SUB

SCREEN _NEWIMAGE(400,400, 27)

▶StartIteration: 
    x% = INT(RND*180) + 20
    y% = INT(RND*180) + 20
    r% = INT(RND*17) + 4
    colour& = INT(RND * &hFFFFFE) + 2
    alpha% = INT( RND * 125 )
    RgbaCircle(x%,y%,r%,colour&,alpha%)
    RgbaCircle(400 - x%,y%,r%,colour&,alpha%)
    RgbaCircle(x%,400-y%,r%,colour&,alpha%)
    RgbaCircle(400-x%,400-y%,r%,colour&,alpha%)
    _DELAY 0.01
GOTO ▶StartIteration