Progressive Picts and Slides (original) (raw)

8.15

The ppict/2 module re-exports the contents ofppict/pict, ppict/tag,ppict/align, and ppict/slideshow2.

Added in version 1.1 of package ppict.

Deprecated. Like ppict/2 but re-exports the deprecated module ppict/slideshow instead ofppict/slideshow2.

Changed in version 1.1 of package ppict: Deprecated ppict.

1 Progressive Picts🔗ℹ

A progressive pict or “ppict” is a kind of pictthat has an associated “pict placer,” which generally represents a position and alignment. New picts can be placed on the progressive pict by calling ppict-add, and the placer can be updated by calling ppict-go. The ppict-do form provides a compact notation for sequences of those two operations.

(ppict-do base-expr ppict-do-fragment ...)
(ppict-do* base-expr ppict-do-fragment ...) ppict-do-fragment = #:go placer-expr | #:set pict-expr	#:next	#:alt (ppict-do-fragment ...)	#:do [def-or-expr ...]	elem-expr base-expr : pict? placer-expr : placer? pict-expr : pict? elem-expr : (or/c pict? real? #f)

Builds a pict (and optionally a list of intermediate picts) progressively. The ppict-do form returns only the final pict; any uses of #:next are ignored. The ppict-do* form returns two values: the final pict and a list of all partial picts emitted due to #:next (the final pict is not included).

A #:go fragment changes the current placer. A #:setfragment replaces the current pict state altogether with a new computed pict. A #:next fragment saves a pict including only the contents emitted so far (but whose alignment takes into account picts yet to come). A #:alt fragment saves the current pict state, executes the sub-sequence that follows, saves the result (as if the sub-sequence ended with #:next), then restores the saved pict state before continuing.

A #:do fragment embeds definitions and expressions which are run when the pict state is computed. The definitions are bound in the rest of the fragments in the pict.

The elem-exprs are interpreted by the current placer. A numeric elem-expr usually represents a spacing change, but some placers do not support them. A spacing change only affects added picts up until the next placer is installed; when a new placer is installed, the spacing is reset, usually to 0.

The ppict-do-state form tracks the current state of the pict. It is updated before a #:go or #:set fragment or before a sequence of elem-exprs. It is not updated in the middle of a chain of elem-exprs, however.

Examples:

> base

The use of ppict-do in the definition of base above is equivalent to

Examples:

> circles-down-1
> (inset circles-down-2 20) ; draws outside its bounding box
> (inset (clip circles-down-2) 20)
'( )

The following demonstrates the use of the #:do fragment:

Example:

More examples of ppict-do are scattered throughout this section.

Tracks the current state of a ppict-do or ppict-do*form.

Returns #t if x is a progressive pict,#f otherwise.

Creates a progressive pict with the given base pict pand the placer pl.

Creates a new pict by adding each elem pict on top ofpp according to pp’s placer. The result pict may or may not be a progressive pict, depending on the placer used. The ppict-add function only the final pict; any occurrences of 'next are ignored. The ppict-add*function returns two values: the final pict and a list of all partial picts emitted due to 'next (the final pict is not included).

An elem that is a real number changes the spacing for subsequent additions. A elem that is #f is discarded; it is permitted as a convenience for conditionally including sub-picts. Note that #f is not equivalent to(blank 0), since the latter will cause spacing to be added around it.

Returns #t if x is a placer, #f otherwise.

Returns #t if x is a placer based on a reference point, #f otherwise.

(coord rel-x rel-y [align #:abs-x abs-x #:abs-y abs-y #:sep sep #:compose composer]) → refpoint-placer?
rel-x : real?
rel-y : real?
align : (or/c 'lt 'ct 'rt 'lc 'cc 'rc 'lb 'cb 'rb) = 'cc
abs-x : real? = 0
abs-y : real? = 0
sep : real? = 0
composer : procedure? = computed from align

Returns a placer that places picts according to rel-x andrel-y, which are interpeted as fractions of the width and height of the base progressive pict. That is, 0,0 is the top left corner of the base’s bounding box, and1, 1 is the bottom right. Then abs-x andabs-y offsets are added to get the final reference point.

Additions are aligned according to align, a symbol whose name consists of a horizontal alignment character followed by a vertical alignment character. For example, if align is 'lt, the pict is placed so that its left-top corner is at the reference point; if align is 'rc, the pict is placed so that the center of its bounding box’s right edge coincides with the reference point.

By default, if there are multiple picts to be placed, they are vertically appended, aligned according to the horizontal component ofalign. For example, if align is 'cc, the default composer is vc-append; for 'lt, the default composer is vl-append. The spacing is initially sep.

Examples:

> (ppict-do base #:go (coord 1 0 'rt #:abs-x -5 #:abs-y 10) 50 ; change spacing (text "abc") (text "12345") 0 ; and again (text "ok done"))

Changed in version 1.1 of package ppict: Added #:sep argument.

Returns a placer that places picts according to a position in a virtual grid. The row and col indexes are numbered starting at 1.

Uses of grid can be translated into uses of coord, but the translation depends on the alignment. For example,(grid 2 2 1 1 'lt) is equivalent to (coord 0 0 'lt), but (grid 2 2 1 1 'rt) is equivalent to (coord 1/2 0 'rt).

Examples:

> (define none-for-me-thanks (ppict-do base #:go (grid 2 2 1 1 'lt) (text "You do not like") (colorize (text "green eggs and ham?") "darkgreen")))
> none-for-me-thanks
> (ppict-do none-for-me-thanks #:go (grid 2 2 2 1 'rb) (colorize (text "I do not like them,") "red") (text "Sam-I-am."))

Changed in version 1.1 of package ppict: Added #:sep argument.

Returns a placer that places picts by evenly spreading them diagonally across the base pict in “cascade” style. This placer does not support changing the spacing by including a real number within the pict sequence.

When a list picts is to be placed, their bounding boxes are normalized to the maximum width and height of all picts in the list; each pict is centered in its new bounding box. The picts are then cascaded so there is step-x space between each of the picts’ left edges; there is also step-x space between the base pict’s left edge and the first pict’s left edge. Similarly for step-y and the vertical spacing.

If step-x or step-y is 'auto, the spacing between the centers of the picts to be placed is determined automatically so that the inter-pict spacing is the same as the spacing between the last pict and the base.

Examples:

Returns a placer that places picts by tiling them in a gridcols columns wide and rows rows high.

Example:

Returns a placer that places picts according to a reference point based on an existing pict within the base.

Example:

> (ppict-do base #:go (cascade) (tag-pict (standard-fish 40 20 #:direction 'right #:color "red") 'red-fish) (tag-pict (standard-fish 50 30 #:direction 'left #:color "blue") 'blue-fish) #:go (at-find-pict 'red-fish rc-find 'lc #:abs-x 10) (text "red fish"))

Changed in version 1.1 of package ppict: Added #:sep argument.

(merge-refpoints x-placer y-placer) → refpoint-placer?
x-placer : refpoint-placer?
y-placer : refpoint-placer?

Returns a placer like x-placer except that the y-coordinate of its reference point is computed by y-placer.

Example:

> (ppict-do base #:go (cascade) (tag-pict (standard-fish 40 20 #:direction 'right #:color "red") 'red-fish) (tag-pict (standard-fish 50 30 #:direction 'left #:color "blue") 'blue-fish) #:go (merge-refpoints (coord 1 0 'rc) (at-find-pict 'red-fish)) (text "red fish"))

2 Progressive Slides🔗ℹ

Added in version 1.1 of package ppict.

(pslide slide-option ... ppict-do-fragment ...)
slide-option = #:title title-expr | #:name name-expr	#:aspect aspect-expr	#:layout layout-expr	#:gap-size gap-expr	#:inset inset-expr	#:timeout timeout-expr	#:condense? condense?-expr
title-expr : (or/c string? #f) name-expr : (or/c string? #f) aspect-expr : aspect? layout-expr : (or/c 'auto 'center 'full-center 'top 'tall) gap-expr : real? inset-expr : slide-inset? timeout-expr : (or/c real? #f) condense?-expr : any/c

Produce slide(s) using progressive picts. The slide body is constructed from the ppict-do-fragments usingppict-do with an initial ppict that depends onaspect and layout (and potentially title andgap-size as well).

The slide-options are interpreted the same as for theslide procedure with the exception of #:layout. The result of layout-expr is interpreted as follows:

• 'auto: same as 'center if the slide has a title, otherwise same as 'full-center
• 'center: the initial ppict is sized liketitleless-page
• 'full-center: the initial ppict is sized likefull-page
• 'top, 'tall: interpreted similarly toslide’s treatment

Changed in version 1.2 of package ppict: Added the #:aspect optional argument.

2.1 Progressive Slides Legacy Library🔗ℹ

Changed in version 1.1 of package ppict: Deprecated ppict/slideshow.

(pslide ppict-do-fragment ...)

Deprecated; use ppict/slideshow2 instead.

3 Tagged Picts🔗ℹ

Returns a pict like p that carries a symbolic tag. The tag can be used with find-tag to locate the pict.

Return the symbolic tag carried by p.

Examples:

Locates a sub-pict of p. Returns a pict-path that can be used with functions like lt-find, etc.

Example:

Like find-tag, but returns all pict-paths corresponding to the given tag-path.

Example:

Returns #t if x is a symbol or a non-empty list of symbols, #f otherwise.

For each entry (list x1 y1 x2 y2 tag) inregions, places a blank pict at the region (x1,y1)-(x2, y2) tagged with tag.

For example, use tag-pict-regions with pixel-based regions to identify features within a bitmap-based pict so that they can be the targets of arrows, anchors for balloons, etc.

Added in version 1.1 of package ppict.

4 Alignment🔗ℹ

Equivalent to (or/c 'lt 'ct 'rt 'lc 'cc 'rc 'lb 'cb 'rb).

Equivalent to (or/c 'l 'c 'r).

Equivalent to (or/c 't 'c 'b).

(align->h a) → halign/c a : align/c
(align->v a) → valign/c a : align/c

Extracts the halign/c or valign/c part froma, respectively.

Computes the fraction corresponding to an alignment where the top-left is 0.

Returns the h*-append or v*-append function for the given horizontal or vertical alignment, respectively.

Pins pict over scene centered atxxy aligned as specified in halign andvalign.