factor/basis/ui/gadgets/paragraphs/paragraphs.factor

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Factor

! Copyright (C) 2005, 2009 Slava Pestov
! See http://factorcode.org/license.txt for BSD license.
USING: accessors kernel math math.order sequences wrap wrap.words
arrays fry ui.gadgets ui.gadgets.labels ui.gadgets.packs.private
ui.render ui.baseline-alignment ;
IN: ui.gadgets.paragraphs
MIXIN: word-break
! A word break gadget
TUPLE: word-break-gadget < label ;
: <word-break-gadget> ( text -- gadget )
word-break-gadget new-label ;
M: word-break-gadget draw-gadget* drop ;
INSTANCE: word-break-gadget word-break
! A gadget that arranges its children in a word-wrap style.
TUPLE: paragraph < gadget margin ;
: <paragraph> ( margin -- gadget )
paragraph new
horizontal >>orientation
swap >>margin ;
<PRIVATE
: gadget>word ( gadget -- word )
[ ] [ pref-dim first ] [ word-break? ] tri <word> ;
TUPLE: line words height ;
: <line> ( words -- line )
dup [ key>> ] map dup pref-dims measure-height line boa ;
: wrap-paragraph ( paragraph -- wrapped-paragraph )
[ children>> [ gadget>word ] map ] [ margin>> ] bi
dup wrap-words [ <line> ] map ;
: line-width ( wrapped-line -- n )
[ break?>> ] trim-tail-slice [ width>> ] sigma ;
: max-line-width ( wrapped-paragraph -- x )
[ words>> line-width ] [ max ] map-reduce ;
: sum-line-heights ( wrapped-paragraph -- y )
[ height>> ] sigma ;
M: paragraph pref-dim*
wrap-paragraph [ max-line-width ] [ sum-line-heights ] bi 2array ;
: line-y-coordinates ( wrapped-paragraph -- ys )
0 [ height>> + ] accumulate nip ;
: word-x-coordinates ( wrapped-line -- xs )
0 [ width>> + ] accumulate nip ;
: layout-word ( word x y -- )
[ key>> ] 2dip 2array >>loc prefer ;
: layout-line ( wrapped-line y -- )
[
words>>
[ ]
[ word-x-coordinates ]
[ [ key>> ] map align-baselines ] tri
] dip '[ _ + layout-word ] 3each ;
M: paragraph layout*
wrap-paragraph dup line-y-coordinates
[ layout-line ] 2each ;
M: paragraph baseline
wrap-paragraph [ f ] [
first words>>
[ key>> ] map
dup [ pref-dim ] map
measure-metrics drop
] if-empty ;
M: paragraph cap-height pack-cap-height ;
PRIVATE>