On this page:
12.1 Plotting
plot
plot3d
points
line
error-bars
vector-field
contour
shade
surface
mix
plot-color?
12.2 Miscellaneous Functions
derivative
gradient
make-vec
8.1.900.1

12 Compatibility Module

Alexander Friedman,
Jamie Raymond,
and Neil Toronto

 (require plot/compat) package: plot-compat

This module provides an interface compatible with Plot 5.1.3 and earlier.

Do not use this module in new programs. It is likely to disappear in a near future release.

Do not try to use both plot and plot/compat in the same program. The new features in Plot 5.2 and later require the objects plotted in plot have to be a different data type than the objects plotted in plot/compat. They do not coexist easily, and trying to make them do so will result in errors.

12.1 Plotting

procedure

(plot data    
  [#:width width    
  #:height height    
  #:x-min x-min    
  #:x-max x-max    
  #:y-min y-min    
  #:y-max y-max    
  #:x-label x-label    
  #:y-label y-label    
  #:title title    
  #:fgcolor fgcolor    
  #:bgcolor bgcolor    
  #:lncolor lncolor    
  #:out-file out-file])  (is-a?/c image-snip%)
  data : (-> (is-a?/c 2d-plot-area%) void?)
  width : real? = 400
  height : real? = 400
  x-min : real? = -5
  x-max : real? = 5
  y-min : real? = -5
  y-max : real? = 5
  x-label : string? = "X axis"
  y-label : string? = "Y axis"
  title : string? = ""
  fgcolor : (list/c byte? byte? byte?) = '(0 0 0)
  bgcolor : (list/c byte? byte? byte?) = '(255 255 255)
  lncolor : (list/c byte? byte? byte?) = '(255 0 0)
  out-file : (or/c path-string? output-port? #f) = #f
Plots data in 2D, where data is generated by functions like points or line.

A data value is represented as a procedure that takes a 2d-plot-area% instance and adds plot information to it.

The result is an image-snip% for the plot. If an #:out-file path or port is provided, the plot is also written as a PNG image to the given path or port.

The #:lncolor keyword argument is accepted for backward compatibility, but does nothing.

procedure

(plot3d data    
  [#:width width    
  #:height height    
  #:x-min x-min    
  #:x-max x-max    
  #:y-min y-min    
  #:y-max y-max    
  #:z-min z-min    
  #:z-max z-max    
  #:alt alt    
  #:az az    
  #:x-label x-label    
  #:y-label y-label    
  #:z-label z-label    
  #:title title    
  #:fgcolor fgcolor    
  #:bgcolor bgcolor    
  #:lncolor lncolor    
  #:out-file out-file])  (is-a?/c image-snip%)
  data : (-> (is-a?/c 3d-plot-area%) void?)
  width : real? = 400
  height : real? = 400
  x-min : real? = -5
  x-max : real? = 5
  y-min : real? = -5
  y-max : real? = 5
  z-min : real? = -5
  z-max : real? = 5
  alt : real? = 30
  az : real? = 45
  x-label : string? = "X axis"
  y-label : string? = "Y axis"
  z-label : string? = "Z axis"
  title : string? = ""
  fgcolor : (list/c byte? byte? byte?) = '(0 0 0)
  bgcolor : (list/c byte? byte? byte?) = '(255 255 255)
  lncolor : (list/c byte? byte? byte?) = '(255 0 0)
  out-file : (or/c path-string? output-port? #f) = #f
Plots data in 3D, where data is generated by a function like surface. The arguments alt and az set the viewing altitude (in degrees) and the azimuth (also in degrees), respectively.

A 3D data value is represented as a procedure that takes a 3d-plot-area% instance and adds plot information to it.

The #:lncolor keyword argument is accepted for backward compatibility, but does nothing.

procedure

(points vecs [#:sym sym #:color color])

  (-> (is-a?/c 2d-plot-area%) void?)
  vecs : (listof (vectorof real?))
  sym : (or/c char? string? exact-integer? symbol?) = 'square
  color : plot-color? = 'black
Creates 2D plot data (to be provided to plot) given a list of points specifying locations. The sym argument determines the appearance of the points. It can be a symbol, an ASCII character, or a small integer (between -1 and 127). The following symbols are known: 'pixel, 'dot, 'plus, 'asterisk, 'circle, 'times, 'square, 'triangle, 'oplus, 'odot, 'diamond, '5star, '6star, 'fullsquare, 'bullet, 'full5star, 'circle1, 'circle2, 'circle3, 'circle4, 'circle5, 'circle6, 'circle7, 'circle8, 'leftarrow, 'rightarrow, 'uparrow, 'downarrow.

procedure

(line f    
  [#:samples samples    
  #:width width    
  #:color color    
  #:mode mode    
  #:mapping mapping    
  #:t-min t-min    
  #:t-max t-max])  (-> (is-a?/c 2d-plot-area%) void?)
  f : (-> real? (or/c real? (vector/c real? real?)))
  samples : (and/c exact-integer? (>=/c 2)) = 150
  width : (>=/c 0) = 1
  color : plot-color/c = 'red
  mode : (one-of/c 'standard 'parametric) = 'standard
  mapping : (one-of/c 'cartesian 'polar) = 'cartesian
  t-min : real? = -5
  t-max : real? = 5
Creates 2D plot data to draw a line.

The line is specified in either functional, i.e. y = f(x), or parametric, i.e. x,y = f(t), mode. If the function is parametric, the mode argument must be set to 'parametric. The t-min and t-max arguments set the parameter when in parametric mode.

procedure

(error-bars vecs [#:color color])

  (-> (is-a?/c 2d-plot-area%) void?)
  vecs : (listof (vector/c real? real? real?))
  color : plot-color? = 'black
Creates 2D plot data for error bars given a list of vectors. Each vector specifies the center of the error bar (x,y) as the first two elements and its magnitude as the third.

procedure

(vector-field f 
  [#:samples samples 
  #:width width 
  #:color color 
  #:style style]) 
  (-> (is-a?/c 2d-plot-area%) void?)
  f : (-> (vector/c real? real?) (vector/c real? real?))
  samples : (and/c exact-integer? (>=/c 2)) = 20
  width : exact-positive-integer? = 1
  color : plot-color? = 'red
  style : (one-of/c 'scaled 'normalized 'real) = 'scaled
Creates 2D plot data to draw a vector-field from a vector-valued function.

procedure

(contour f 
  [#:samples samples 
  #:width width 
  #:color color 
  #:levels levels]) 
  (-> (is-a?/c 2d-plot-area%) void?)
  f : (-> real? real? real?)
  samples : exact-nonnegative-integer? = 50
  width : (>=/c 0) = 1
  color : plot-color/c = 'black
  levels : (or/c (and/c exact-integer? (>=/c 2)) (listof real?))
   = 10
Creates 2D plot data to draw contour lines, rendering a 3D function a 2D graph cotours (respectively) to represent the value of the function at that position.

procedure

(shade f [#:samples samples #:levels levels])

  (-> (is-a?/c 2d-plot-area%) void?)
  f : (-> real? real? real?)
  samples : (and/c exact-integer? (>=/c 2)) = 50
  levels : (or/c (and/c exact-integer? (>=/c 2)) (listof real?))
   = 10
Creates 2D plot data to draw like contour, except using shading instead of contour lines.

procedure

(surface f 
  [#:samples samples 
  #:width width 
  #:color color]) 
  (-> (is-a?/c 3d-plot-area%) void?)
  f : (-> real? real? real?)
  samples : (and/c exact-integer? (>=/c 2)) = 50
  width : (>=/c 0) = 1
  color : plot-color/c = 'black
Creates 3D plot data to draw a 3D surface in a 2D box, showing only the top of the surface.

procedure

(mix data ...)  (-> any/c void?)

  data : (-> any/c void?)
Creates a procedure that calls each data on its argument in order. Thus, this function can composes multiple plot datas into a single data.

procedure

(plot-color? v)  boolean?

  v : any/c
Returns #t if v is one of the following symbols, #f otherwise:

'white 'black 'yellow 'green 'aqua 'pink
'wheat 'grey 'blown 'blue 'violet 'cyan
'turquoise 'magenta 'salmon 'red

12.2 Miscellaneous Functions

procedure

(derivative f [h])  (-> real? real?)

  f : (-> real? real?)
  h : real? = 1e-6
Creates a function that evaluates the numeric derivative of f. The given h is the divisor used in the calculation.

procedure

(gradient f [h])

  (-> (vector/c real? real?) (vector/c real? real?))
  f : (-> real? real? real?)
  h : real? = 1e-6
Creates a vector-valued function that computes the numeric gradient of f.

procedure

(make-vec fx fy)

  (-> (vector/c real? real?) (vector/c real? real?))
  fx : (-> real? real? real?)
  fy : (-> real? real? real?)
Creates a vector-valued function from two parts.