s9fes-char-graphics

The Scheme 9 from Empty Space character graphics routines.

Char Canvas

This is a set of routines for drawing characters and lines on a scaled, character-based (a.k.a. "ASCII Art") canvas.

Assumes one character per column. Do not use wide characters.

Usage

(import (s9fes char-canvas))

make-canvas

[procedure] (make-canvas COLUMNS ROWS [WIDTH [HEIGHT]]) => canvas

Creates a character canvas with a physical size of COLUMNS X ROWS characters. The virtual size of the canvas is WIDTH X HEIGHT "pixels".

"Real coordinates" relate to the physical size of the canvas. "Virtual coordinates" are translated to real coordinates by scaling. Both types of coordinates are specified in X/Y notation.

The origin 0/0 is at the lower left corner of the canvas. The new canvas will be filled with blanks initially.

[procedure] (canvas? OBJ) => boolean
[procedure] (canvas-columns CANVAS) => fixnum
[procedure] (canvas-rows CANVAS) => fixnum
[procedure] (canvas-width CANVAS) => integer
[procedure] (canvas-height CANVAS) => integer

canvas-physical

[procedure] (canvas-physical CANVAS X Y) -> X Y

Returns the physical coordinates for the supplied virtual X Y.

canvas-virtual

[procedure] (canvas-virtual CANVAS X Y) -> X Y

Returns virtual coordinates for the supplied physical X Y.

Note canvas-virtual <=> canvas-physical is not guaranteed. So this routine is of little use.

canvas-dump

[procedure] (canvas-dump CANVAS) => (list-of string)

Returns a list of strings that contain the characters written to the canvas. The list elements are the rows, the strings the columns.

canvas-print

[procedure] (canvas-print CANVAS)

Prints the CANVAS, one row per line.

canvas->string

[procedure] (canvas-string CANVAS) => string

Prints the CANVAS to a string.

canvas-clear

[procedure] (canvas-clear CANVAS)

canvas-draw

[procedure] (canvas-draw CANVAS X Y [CHAR])

Draws character CHAR at position X/Y. It uses real coordinates. When the X or Y coordinate is outside of the canvas, C will not be drawn.

current-plotter-char

[procedure] (current-plotter-char [CHAR]) => char

Default char for drawing.

canvas-draw-string

[procedure] (canvas-draw-string CANVAS X Y STRING)

Draws a STRING at position X/Y. It uses real coordinates. When STRING extends beyond the limits of the canvas, it will be clipped.

canvas-plot

[procedure] (canvas-plot CANVAS X Y [CHAR])

Draws the character CHAR at the virtual position X/Y.

Draws a line from the virtual position X/Y to DX/DY using the character CHAR. All arguments must be integers. Lines originating or extending outside of the canvas will be clipped.

canvas-plot-string

[procedure] (canvas-plot-string CANVAS X Y STRING)

Draws a STRING at virtual position X/Y. When STRING extends beyond the limits of the canvas, it will be clipped.

canvas-plot-line

[procedure] (canvas-plot-line CANVAS X Y DX DY [CHAR])

canvas-plot-lines

[procedure] (canvas-plot-lines CANVAS LINES [CONFIG])

LINES: (list-of integer) ; list of line segment x y.
CONFIG: (or false char (list-of (or false char))) ; drawing pattern, n elements, #f for skip or a char to draw; default is (current-plotter-char).

Char Canvas Shape Oval

Usage

(import (s9fes char-canvas shape oval))

Shared Arguments & Types:

octant-plotter: (canvas fixnum fixnum fixnum fixnum -> boolean) ; returns continue?
octant-visitor: (canvas fixnum fixnum -> boolean) ; returns continue?

generate-circle-octant

[procedure] (generate-circle-octant CANVAS RADIUS VISITOR)

Generates the coordinates for the first octant of a circle of RADIUS. It uses real coordinates. The VISITOR is called for each generated point. Should the VISITOR return #f the generator halts early.

RADIUS: fixnum ; radius
VISITOR: octant-visitor

circle-octant-point

[procedure] (circle-octant-point OCTANT X0 Y0 X Y) => fixnum fixnum

Returns coordinates for octant 0 point X Y in the specified OCTANT, centered at X0 Y0.

OCTANT: fixnum ; octant, 0..7, coordinates to calculate
X0 Y0: fixnum fixnum ; center
X Y: fixnum fixnum ; offset

circle-octant-visitor

[procedure] (circle-octant-visitor X0 Y0 PLOTTER) => octant-visitor

X0 Y0: fixnum fixnum ; center
PLOTTER: octant-plotter

circle-octant-plotter

[procedure] (circle-octant-plotter [CONFIG]) => octant-plotter

Returns a canvas-drawing procedure for the specified octant drawing pattern CONFIG.

CONFIG: (or false char (list-of (or false char))) ; octant drawing pattern, 8 elements, octant 0 to octant 8, #f for skip or a char to draw; default is (current-plotter-char).

generate-virtual-circle-octant

[procedure] (generate-virtual-circle-octant CANVAS RADIUS VISITOR [AVERAGE?])

Same as generate-circle-octant but w/ virtual coordinates (see above).

RADIUS: integer ; radius
VISITOR: octant-visitor

virtual-circle-octant-visitor

[procedure] (virtual-circle-octant-visitor X0 Y0 PLOTTER) => octant-visitor

Same as circle-octant-visitor but w/ virtual coordinates (see above).

X0 Y0: integer integer ; center
PLOTTER: octant-plotter

Char Canvas Shape Cross

Shared Arguments & Types:

shape-plotter: (canvas #!optional fixnum fixnum -> void)

Usage

(import (s9fes char-canvas shape cross))

cross-+-plotter

[procedure] (cross-+-plotter WD [HT [CONFIG]]) => shape-plotter

WD: integer
HT: integer ; default WD
CONFIG: (or false char (list-of (or false char))) ; drawing pattern, 2 elements, #f for skip or a char to draw; default is (current-plotter-char).

cross-x-plotter

[procedure] (cross-x-plotter WD [HT [CONFIG]]) => shape-plotter

WD: integer
HT: integer ; default WD
CONFIG: (or false char (list-of (or false char))) ; drawing pattern, 2 elements, #f for skip or a char to draw; default is (current-plotter-char).

(let ((cv (make-canvas 10 5 10 10)))
  (cross-x-plotter cv 10)
  (canvas-print cv) )
=>
##      **
  ##  **
    **
  **  ##
**      ##

Char Plot

Usage

(import (s9fes char-plot))

char-plot

[procedure] (char-plot LIST SYMBOL HEIGHT WDITH [COMPR?])

Creates a character canvas (see make-canvas), marks the data points in LIST with #\X and draws a line through the points with #\-. SYMBOL will be used to label the X axis (on which the data points will be distributed).

HEIGHT and WDITH specify the physical dimensions of the char canvas. Its virtual dimensions will be computed in such a way that all data points can be displayed.

When the COMPR? (compression) argument is set to #t, then the X axis will start at the magnitude of the least data point instead of zero, so that the entire width of the canvas is available for distributing the supplied data points. The default is #t.

(char-plot '(0 1 2 3 4 5 6 7 8 9) 'foo 7 35 #f)</procedure>
=>
----------- foo --> -----------------
|                              -X   |
|                          --X-     |
|                   --X--X-         |
|                -X-                |
|         -X---X-                   |
|     --X-                          |
|X--X-                              |
----------- foo --> -----------------

Draw Tree

Usage

(import (s9fes draw-tree))

draw-tree

[procedure] (draw-tree ROOT [MAX-WIDTH])

Draws a character graphic representation of the tree LIST on (current-output-port).

ROOT: pair ; tree root node.
MAX-WIDTH: fixnum ; maximum printed node width, in characters. default is 7.

(draw-tree '((a) (b . c) (d e)))
=>
[o|o]---[o|o]---[o|/]
  |       |       |
[o|/]     |     [o|o]---[o|/]
  |       |       |       |
  a       |       d       e
          |
        [o|o]---  c
          |
          b

If you want to check out the source code repository of this egg and you are not familiar with Subversion, see this page.

Version history

1.4.2: .
1.4.1: .
1.4.0: Add current-plotter-char, shape oval & shape cross.
1.3.2: Fix octant stream.
1.3.1: Fix canvas? type.
1.3.0: Add generate-circle-octant & friends.
1.2.0: Add canvas-plot-string.
1.1.0: Add canvas-print, canvas-physical, canvas-virtual.
1.0.1: .
1.0.0: Initial release.

License

Public Domain