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% @(#)createart_.hlq 19.1 (ESO-IPG) 02/25/03 13:24:38
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%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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%.COPYRIGHT (c) 1990 European Southern Observatory
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%.KEYWORDS MIDAS, help files, CREATE/ART_IMAGE
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%.PURPOSE On-line help file for the command: CREATE/ART_IMAGE
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%.VERSION 1.0 07-NOV-1990 : Creation, KB
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%----------------------------------------------------------------
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CREATE/ART_IMAGE 26-FEB-1992 PB
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CREATE/ART_IMAGE frame frame dims [starts,steps] [func_type] [coefs]
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CREATE/ART_IMAGE frame = ref_frame [func_type] [coefs]
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create artificial image
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Create a new artifical image frame.
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Artificial frames, models, fractals.
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CREATE/ART_IMAGE frame [dims] [starts,steps] [func_type] [coefs]\\
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CREATE/ART_IMAGE frame = ref_frame [func_type] [coefs]
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frame = name of new frame
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ref_frame = reference frame, i.e. take all descriptors from that frame
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dims = NAXIS,NPIX(1),...,NPIX(NAXIS); default: 2,512,512
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starts,steps = START(1),...,START(NAXIS),STEP(1),...,STEP(NAXIS)\\
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default: = -1.3 for START(i), = 0.005 for STEP(i)\\
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Start and step may have to be adapted depending on the
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chosen function and coefficients.
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func_type = type of function used to define the content of the created
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MANDEL for creation of Mandelbrot set \\
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JULIA for creation of Julia set\\
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LORENZ for creation of Lorenz attractors \\
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ELFLY for simulation of a chaotic system (electronic fly)\\
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COLWHEEL for creation of a colour wheel\\
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coefs = coefficients for the function which is used to create the
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image, number and meaning depends on the parameter
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MANDEL zx,zy,uplimit default: .31,.04,100\\
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JULIA zx,zy,uplimit default: .31,.04,100\\
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LORENZ x0,y0,z0,h,a,b,n_iter \\
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default: 1,1,1,.01,28,0.1,10000\\
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ELFLY a,b,c,d,e,f,n_iter \\
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default: 2.24,.43,-.65,-2.43,1.,300000
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For MANDEL and JULIA, the coefficients represent zx,zy,uplimit
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where zx and zy are the real and imaginary part of a complex
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number zz, which serves as the initial value for z in the
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the real and imaginary parts of c are the x,y coords
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If after 256 iterations z <= uplimit, the pixel at (x,y) is
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set to 0.0, else pixel <- iteration_no .
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For ELFLY, the coefficients represent a,b,c,d,e,f,no_iter where
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a,b,c,d,e,f are control parameters and no_iter the number of
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loops for evaluation of the formulaes:\\
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xx = sin(a*y) - z*cos(b*x)\\
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yy = z*sin(c*x) - cos(d*y)\\
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x = xx, y = yy, z = zz.\\
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the pixel value at resulting x,y coords (z is discarded) is
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For LORENZ, the coefficients represent x0,y0,z0,h,a,b,no_iter
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where x0,y0,z0 are the inital value for a point in space,
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h,a,b are coefficients and no_iter the number of loops for
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evaluating the formulae:\\
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xx = x + 10.*h*(y-x)\\
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yy = y = h*((-x*z)+a*x-y)\\
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zz = z + h*(x*y-b*z)\\
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x = xx, y = yy, z = zz.\\
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the pixel value at resulting x,y coords (z is discarded) is
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CREATE/ART mandel ? -1.6,-1.3,0.05,0.05 MANDEL
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CREATE/ART julia P4=JULIA
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CREATE/ART lorenz ? -25,-25,0.1,0.1 LO .1,.1,.1,.01,28,2.66,4000
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CREATE/ART elfly ? -2.5,-2.5,0.01,0.01 ELFLY 2.24,.43,-.65,-2.43,1,300000