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tags: egg

s9fes-char-graphics

The Scheme 9 from Empty Space character graphics routines.

(canvas-draw canvas integer-X integer-Y char) ==> unspecific

(canvas-draw-string canvas int-X int-Y string) ==> unspecific

(canvas-dump canvas) ==> vector

(canvas-plot canvas integer-X integer-Y char) ==> unspecific

(canvas-plot-line canvas X Y DX DY char) ==> unspecific

(make-canvas int-X int-Y int-W int-H) ==> canvas

(load-from-library "char-canvas.scm")

This is a set of routines for drawing characters and lines on

a scaled, character-based (a.k.a. "ASCII Art") canvas.

MAKE-CANVAS creates a char canvas with a physical size of

x=INT-X times y=INT-Y characters. The virtual size of the

canvas is INT-W (width) times INT-H (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.

CANVAS-DRAW draws character CHAR at position INTEGER-X/INTEGER-Y.

It uses real coordinates. CANVAS-DRAWSTRING draws a string

instead of a single character. When the X or Y coordinate is

outside of the canvas, C will not be drawn. When STRING extends

beyond the limits of the canvas, it will be clipped.

CANVAS-PLOT draws the character CHAR at the virtual position

INTEGER-X/INTEGER-Y. CANVAS-PLOT-LINE 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-DUMP returns a vector of strings that contain the

characters written to the canvas. The vector indexes are the

Y-coordinates, the string offsets the X-coordinates.

Example

(let ((c (make-canvas 10 5 10 10)))

(canvas-plot-line c 0 9 9 0 #\#)

(canvas-plot-line c 0 0 9 9 #\*)

(canvas-dump c)) ==> #("## **"

" ## ** "

" ** "

" ** ## "

"** ##")

(char-plot list symbol integer1 integer2 boolean) ==> unspecific

CHAR-PLOT 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).

INTEGER1 (height) and INTEGER2 ; (width) specify the physical

dimenions of the char canvas. Its virtual dimensions will be

computed in such a way that all data points can be displayed.

When the BOOLEAN (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.

(Example)

(char-plot '(0 1 2 3 4 5 6 7 8 9) 'foo 7 35 #f) ==> unspecific

; output

----------- foo --> -----------------

; | --|

; | --X- |

; | --X---X- |

; | --X- |

; | --X---X- |

; | --X- |

; |X--X- |

; ----------- foo --> -----------------

(draw-tree object) ==> unspecific

Print a tree structure resembling a Scheme datum. Each cons

cell is represented by [o|o] with lines leading to their car

and cdr parts. Conses with a cdr value of () are represented

by [o|/].

(Example)

(draw-tree '((a) (b . c) (d e))) ==> unspecific

Output

[o|o]---[o|o]---[o|/]

| | |

[o|/] | [o|o]---[o|/]

| | | |

a | d e

|

[o|o]--- c

|

b