2.3 Pict Combiners

► |  | Slideshow: Figure and Presentation Tools

1 | Creating Slide Presentations
2 | Making Pictures
3 | Making Slides
4 | Typesetting Racket Code
5 | Animations
| Bibliography
| Index

▼ | 2 | Making Pictures

2.1 | Pict Datatype
2.2 | Basic Pict Constructors
2.3 | Pict Combiners
2.4 | Pict Drawing Adjusters
2.5 | Bounding Box Adjusters
2.6 | Pict Finders
2.7 | More Pict Constructors
2.8 | Miscellaneous
2.9 | Rendering
2.10 | Conversion to Picts

On this page:

vl-append
vc-append
vr-append
ht-append
htl-append
hc-append
hbl-append
hb-append
lt-superimpose
ltl-superimpose
lc-superimpose
lbl-superimpose
lb-superimpose
ct-superimpose
ctl-superimpose
cc-superimpose
cbl-superimpose
cb-superimpose
rt-superimpose
rtl-superimpose
rc-superimpose
rbl-superimpose
rb-superimpose
pin-over
pin-under
table

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#### 2.3`` Pict Combiners

> procedure (vl-append [d] pict ...) → pict?
> d : real? = 0.0
> pict : pict?
> (vc-append [d] pict ...) → pict?
> d : real? = 0.0
> pict : pict?
> (vr-append [d] pict ...) → pict?
> d : real? = 0.0
> pict : pict?
> (ht-append [d] pict ...) → pict?
> d : real? = 0.0
> pict : pict?
> (htl-append [d] pict ...) → pict?
> d : real? = 0.0
> pict : pict?
> (hc-append [d] pict ...) → pict?
> d : real? = 0.0
> pict : pict?
> (hbl-append [d] pict ...) → pict?
> d : real? = 0.0
> pict : pict?
> (hb-append [d] pict ...) → pict?
> d : real? = 0.0
> pict : pict?

Creates a new pict as a column (for v...-append) or row (for h...-append) of other picts. The optional d argument specifies amount of space to insert between each pair of pictures in making the column or row.

Different procedures align pictures in the orthogonal direction in different ways. For example, vl-append left-aligns all of the pictures.

The descent of the result corresponds to baseline that is lowest in the result among all of the picts’ descent-specified baselines; similarly, the ascent of the result corresponds to the highest ascent-specified baseline. If at least one pict is supplied, then the last element (as reported by pict-last) for the result is (or (pict-last pict) pict) for the using last supplied pict.

Examples:
> (define combiners (list vl-append vc-append vr-append
> ht-append htl-append hc-append
> hbl-append hb-append))
> (define names (list "vl-append" "vc-append" "vr-append"
> "ht-append" "htl-append" "hc-append"
> "hbl-append" "hb-append"))
> (define pict-a (colorize (filled-rectangle 60 30) "tomato"))
> (define pict-b (colorize (disk 45) "cornflower blue"))
> (define picts
> (for/list ([combiner combiners] [name names])
> (list (text name null 15)
> (combiner pict-a pict-b))))
> > (take picts 4)
> '(( ) ( ) ( ) ( ))
> > (drop picts 4)
> '(( ) ( ) ( ) ( ))

> procedure (lt-superimpose pict ...) → pict?
> pict : pict?
> (ltl-superimpose pict ...) → pict?
> pict : pict?
> (lc-superimpose pict ...) → pict?
> pict : pict?
> (lbl-superimpose pict ...) → pict?
> pict : pict?
> (lb-superimpose pict ...) → pict?
> pict : pict?
> (ct-superimpose pict ...) → pict?
> pict : pict?
> (ctl-superimpose pict ...) → pict?
> pict : pict?
> (cc-superimpose pict ...) → pict?
> pict : pict?
> (cbl-superimpose pict ...) → pict?
> pict : pict?
> (cb-superimpose pict ...) → pict?
> pict : pict?
> (rt-superimpose pict ...) → pict?
> pict : pict?
> (rtl-superimpose pict ...) → pict?
> pict : pict?
> (rc-superimpose pict ...) → pict?
> pict : pict?
> (rbl-superimpose pict ...) → pict?
> pict : pict?
> (rb-superimpose pict ...) → pict?
> pict : pict?

Creates a new picture by superimposing a set of pictures. The name prefixes are alignment indicators: horizontal alignment then vertical alignment.

The descent of the result corresponds to baseline that is lowest in the result among all of the picts’ descent-specified baselines; similarly, the ascent of the result corresponds to the highest ascent-specified baseline. The last element (as reported by pict-last) for the result is the lowest, right-most among the last-element picts of the pict arguments, as determined by comparing the last-element bottom-right corners.

Examples:
> (define combiners (list lt-superimpose ltl-superimpose lc-superimpose
> lbl-superimpose lb-superimpose ct-superimpose
> ctl-superimpose cc-superimpose cbl-superimpose
> cb-superimpose rt-superimpose rtl-superimpose
> rc-superimpose rbl-superimpose rb-superimpose))
> (define names (list "lt-superimpose" "ltl-superimpose" "lc-superimpose"
> "lbl-superimpose" "lb-superimpose" "ct-superimpose"
> "ctl-superimpose" "cc-superimpose" "cbl-superimpose"
> "cb-superimpose" "rt-superimpose" "rtl-superimpose"
> "rc-superimpose" "rbl-superimpose" "rb-superimpose"))
> (define pict-a (colorize (filled-rectangle 60 30) "tomato"))
> (define pict-b (colorize (disk 45) "cornflower blue"))
> (define picts
> (for/list ([combiner combiners] [name names])
> (list (text name null 15)
> (combiner pict-a pict-b))))
> > (take picts 3)
> '(( ) ( ) ( ))
> > (take (drop picts 3) 3)
> '(( ) ( ) ( ))
> > (take (drop picts 6) 3)
> '(( ) ( ) ( ))
> > (take (drop picts 9) 3)
> '(( ) ( ) ( ))
> > (take (drop picts 12) 3)
> '(( ) ( ) ( ))

> procedure (pin-over base dx dy pict) → pict?
> base : pict?
> dx : real?
> dy : real?
> pict : pict?
> (pin-over base find-pict find pict) → pict?
> base : pict?
> find-pict : pict-path?
> find : (pict? pict-path? . -> . (values real? real?))
> pict : pict?

Creates a pict with the same bounding box, ascent, and descent as base, but with pict placed on top. The dx and dy arguments specify how far right and down the second pict’s corner is from the first pict’s corner. Alternately, the find-pict and find arguments find a point in base for find-pict; the find procedure should be something like lt-find.

> procedure (pin-under base dx dy pict) → pict?
> base : pict?
> dx : real?
> dy : real?
> pict : pict?
> (pin-under base find-pict find pict) → pict?
> base : pict?
> find-pict : pict?
> find : (pict? pict? . -> . (values real? real?))
> pict : pict?

Like pin-over, but pict is drawn before base in the resulting combination.

> > procedure
> > (table |  | ncols |  |  |  |
> > |  | picts |  |  |  |
> > |  | col-aligns |  |  |  |
> > |  | row-aligns |  |  |  |
> > |  | col-seps |  |  |  |
> > |  | row-seps) |  | → |  | pict?
> ncols : exact-positive-integer?
> picts : (non-empty-listof pict?)
> col-aligns : (list*of (pict? pict? -> pict?))
> row-aligns : (list*of (pict? pict? -> pict?))
> col-seps : (list*of real?)
> row-seps : (list*of real?)

Creates a table given a list of picts. The picts list is a concatenation of the table’s rows (which means that a Racket list call can be formatted to reflect the shape of the output table).

The col-aligns, row-aligns, col-seps, and row-seps arguments are “lists” specifying the row and columns alignments separation between rows and columns. For c columns and r rows, the first two should have c and r superimpose procedures, and the last two should have c-1 and r-1 numbers, respectively. The lists can be “improper” (i.e., ending in a number instead of an empty list), in which case the non-pair cdr is used as the value for all remaining list items that were expected. The col-aligns and row-aligns procedures are used to superimpose all of the cells in a column or row; this superimposition determines the total width or height of the column or row, and also determines the horizontal or vertical placement of each cell in the column or row.

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