This is the one I like (you can zoom in using the mouse):
Or if you want a really simple one
Open in online IDE;Mandelbrot Fractal code, edit by muk on 8/2/06 Screen_Width=800 Screen_Height=600 AppTitle "Mandelbrot Fractal" Graphics Screen_Width,Screen_Height,32,2 SetBuffer BackBuffer() ; ------------------ ; Make palette ; ------------------ ;Px,Py,Tx,Ty,StartRed#,StartGrn#,StartBlu#,EndRed#,EndGrn#,EndBlu#,Dir Procedure_DrawGradientBlock(0,0,255,5,50,0,255,0,0,0,0) Dim col(256) LockBuffer For i=0 To 255 col(i)=ReadPixelFast(i,2)*8 And $FFFFFF ;<- edit: use readpixelfast Next UnlockBuffer .reset ;<- edit: reset zoom maxcolor=255 largeval#=10000 ;<- edit: set largevalue leftside#=-2.0 *largeval# ;<- edit: multiply by largevalue top#=1.2 *largeval# xside#=2.5 *largeval# yside#=-2.5 *largeval# ; ------------ ; Redraw ; ------------ .again Cls ;<- edit: clear screen before redraw xmax#=Screen_Width ymax#=Screen_Height xscale#=xside#/Float(xmax) yscale#=yside#/Float(ymax) For y=0 To ymax-1 LockBuffer For x=0 To xmax-1 cx#=x*xscale#+leftside# cy#=y*yscale#+top# cx#=cx#/Float(largeval) ;<- edit: divide by largevalue cy#=cy#/Float(largeval) zx#=0 zy#=0 colorcounter=0 While zx#*zx#+zy#*zy#<4 And colorcounter<maxcolor tempx#=zx#*zx#-zy#*zy#+cx# zy#=2*zx#*zy#+cy# zx#=tempx# colorcounter=colorcounter+1 Wend WritePixelFast x,y,Col(colorcounter) ;<- edit: use writepixelfast If KeyDown(1) Then End ;<- edit: escape while redrawing Next UnlockBuffer Flip ;<- nb: in fullscreen flip only draws every other line? Text 0,0,"Redrawing, Please Wait..." ;<- edit: text message Next For y=0 To 12 ;<- edit: oops, ok draw over the text message again LockBuffer For x=0 To 200 cx#=x*xscale#+leftside# cy#=y*yscale#+top# cx#=cx#/Float(largeval) ;<- edit: divide by largevalue cy#=cy#/Float(largeval) zx#=0 zy#=0 colorcounter=0 While (zx#*zx#+zy#*zy#<4 And colorcounter<maxcolor) tempx#=zx#*zx#-zy#*zy#+cx# zy#=2*zx#*zy#+cy# zx#=tempx# colorcounter=colorcounter+1 Wend WritePixelFast x,y,Col(colorcounter) Next UnlockBuffer Next ; ---------------------------------------------------- ; Wait for rectangular selection for zoom ; ---------------------------------------------------- mandel=CreateImage(Screen_Width,Screen_Height) ;<- edit: draw full screen CopyRect 0,0,Screen_Width,Screen_Height,0,0,BackBuffer(),ImageBuffer(mandel) SetBuffer BackBuffer() Color 255,255,255 mousepress=False selection=False MouseHit(1) MouseHit(2) Repeat Cls ;<- edit: to clear rect in fullscreen DrawImage mandel,0,0 Color 255,255,255 Plot MouseX(),MouseY() ;<- edit: show mouse position in fullscreen Text 0,0,xside+"-"+yside If Not mousepress If MouseHit(1) sx=MouseX() sy=MouseY() mousepress=True End If If MouseHit(2) ;<- edit: reset on rightclick selection=2 End If If KeyDown(1) Then End ;<- edit: escape Else If MouseDown(1) ex=MouseX() ey=sy+(ex-sx)*3/4 ;<- edit: true screen rect box, instead of MouseY() If sx>ex startx=ex endx=sx Else startx=sx endx=ex End If If sy>ey starty=ey endy=sy Else starty=sy endy=ey End If Rect startx,starty,endx-startx,endy-starty,False Else LockBuffer ;<- edit: prevent redraw if selected pixels all same color startcolor=ReadPixelFast(startx,starty) And $FFFFFF For iy=starty To endy For ix=startx To endx currcolor=ReadPixelFast(ix,iy) And $FFFFFF If currcolor<>startcolor selection=True Exit End If Next Next UnlockBuffer If Not selection Then mousepress=False End If End If Flip Until selection FreeImage mandel newxside#=xside#*Float((endx-startx)/Float(xmax)) newyside#=yside#*Float((endy-starty)/Float(ymax)) newleftside#=leftside#+(xside#*Float(startx/Float(xmax))) newtop#=top#+(yside#*Float(starty/Float(ymax))) leftside#=newleftside top#=newtop xside#=newxside yside#=newyside Cls ;<- edit: to clear in fullscreen Flip If selection=2 Goto reset Else Goto again End If ; ---------------------------- ; Draw Gradient block ; ---------------------------- Function Procedure_DrawGradientBlock(Px,Py,Tx,Ty,StartRed#,StartGreen#,StartBlue#,EndRed#,EndGreen#,EndBlue#,Dir=0) If Dir=0 Direction=Tx Temp_X=Px Temp_Y=Tx Else Direction=Ty Temp_X=Py Temp_Y=Ty EndIf GradientRed#=(EndRed-StartRed)/Direction GradientGreen#=(EndGreen-StartGreen)/Direction GradientBlue#=(EndBlue-StartBlue)/Direction For Grad=Temp_X To Temp_X+Temp_Y Color StartRed,StartGreen,StartBlue If Dir=0 Line Grad,Py,Grad,Py+Ty Else Line Px,Grad,Px+Tx,Grad EndIf StartRed=StartRed+GradientRed StartGreen=StartGreen+GradientGreen StartBlue=StartBlue+GradientBlue Next End Function
Or if you want a really simple one
Graphics 800,600,16,2 SetBuffer BackBuffer() maxcolor=255 leftside#=-2 : top#=1.25 xside#=2.5 : yside#=-2.5 xmax=800 : ymax=680 xscale# = xside# / xmax yscale# = yside# / ymax For y=1 To ymax For x=1 To xmax cx# = x * xscale# + leftside# cy# = y * yscale# + top# zx# = 0 zy# = 0 colorcounter = 0 max = 5 ; 4 While (zx# * zx# + zy# * zy# < max And colorcounter < maxcolor) tempx# = zx# * zx# - zy# * zy# + cx# zy# = 2 * zx# * zy# + cy# zx# = tempx# colorcounter=colorcounter+1 Wend Dot(x,y,colorcounter) Next Flip Next WaitKey End Function Dot(x,y,colorcounter) offset = 0 r = offset + (colorcounter * 8) g = offset + (colorcounter * 4) b = offset + (colorcounter * 1) Color r,g,b Plot x,y End Function