Maxima Graphic object
image (im,x0,y0,width,height)
Renders images in 2D.
2D
image (im,x0,y0,width,height)
plots image im in the rectangular
region from vertex (x0,y0)
to (x0+width,y0+height)
on the real
plane. Argument im must be a matrix of real numbers, a matrix of
vectors of length three or a picture object.
If im is a matrix of real numbers or a levels picture
object,
pixel values are interpreted according to graphic option palette
,
which is a vector of length three with components
ranging from -36 to +36; each value is an index for a formula mapping the levels
onto red, green and blue colors, respectively:
0: 0 1: 0.5 2: 1 3: x 4: x^2 5: x^3 6: x^4 7: sqrt(x) 8: sqrt(sqrt(x)) 9: sin(90x) 10: cos(90x) 11: |x-0.5| 12: (2x-1)^2 13: sin(180x) 14: |cos(180x)| 15: sin(360x) 16: cos(360x) 17: |sin(360x)| 18: |cos(360x)| 19: |sin(720x)| 20: |cos(720x)| 21: 3x 22: 3x-1 23: 3x-2 24: |3x-1| 25: |3x-2| 26: (3x-1)/2 27: (3x-2)/2 28: |(3x-1)/2| 29: |(3x-2)/2| 30: x/0.32-0.78125 31: 2*x-0.84 32: 4x;1;-2x+1.84;x/0.08-11.5 33: |2*x - 0.5| 34: 2*x 35: 2*x - 0.5 36: 2*x - 1
negative numbers mean negative colour component.
palette = gray
and palette = color
are short cuts for
palette = [3,3,3]
and palette = [7,5,15]
, respectively.
If im is a matrix of vectors of length three or an rgb picture
object,
they are interpreted as red, green and blue color components.
Examples:
If im is a matrix of real numbers, pixel values are interpreted according
to graphic option palette
.
(%i1) load(draw)$ (%i2) im: apply( 'matrix, makelist(makelist(random(200),i,1,30),i,1,30))$ (%i3) /* palette = color, default */ draw2d(image(im,0,0,30,30))$ (%i4) draw2d(palette = gray, image(im,0,0,30,30))$ (%i5) draw2d(palette = [15,20,-4], colorbox=false, image(im,0,0,30,30))$
If im is a matrix of vectors of length three, they are interpreted as red, green and blue color components.
(%i1) load(draw)$ (%i2) im: apply( 'matrix, makelist( makelist([random(300), random(300), random(300)],i,1,30),i,1,30))$ (%i3) draw2d(image(im,0,0,30,30))$
Package draw
automatically loads package picture
. In this
example, a level picture object is built by hand and then rendered.
(%i1) load(draw)$ (%i2) im: make_level_picture([45,87,2,134,204,16],3,2); (%o2) picture(level, 3, 2, {Array: #(45 87 2 134 204 16)}) (%i3) /* default color palette */ draw2d(image(im,0,0,30,30))$ (%i4) /* gray palette */ draw2d(palette = gray, image(im,0,0,30,30))$
An xpm file is read and then rendered.
URL http://www.telefonica.net/web2/biomates/maxima/gpdraw/image contains more elaborated examples.