Expandable list

The following script shows expandable lists:


Here is the source code:

REBOL [
    title: "(treelist)"
    file: %treelist.r
    author: "Marco Antoniazzi derived from Didier CADIEU"
    email: [luce80 AT libero DOT it]
    date: 16-05-2010
    version: 0.0.1
    needs: {Works only on View 1.2.8+}
    comment: { a simple tree-view}
    Purpose: "show how to build a simple tree list"
    Category: [util vid view]
    license: 'BSD
]
max-rows:
cnt: 0
indent: 12
tree-leaf: 0 tree-opened-node: 1 tree-closed-node: -1
tree-data: [[1 0 root][-1 1 numbers][0 2 "one"][0 2 "two"][-1 2 fruits][0 3 "apple"][0 3 "banana"][0 2 "three"][1 1 names][0 2 "a"][0 2 "b"]
[1 1 numbers][0 2 "101"][0 2 "102"][-1 2 "103"][0 3 "103.1"][0 3 "103.2"][0 2 "104"]]
triangle: [pen none fill-pen blue polygon 8x0 8x8 0x8]
bullets: compose/deep/only [
    [draw (append [translate -1 10 rotate -45] triangle) ]
    [draw [pen none fill-pen black circle 6x10 3]]
    [draw (append [translate 2 6] triangle) ]
]
total_visible: func [/current cur /local visible-count closed-level tree-line curr] [
    curr: 0
    visible-count: 0
    closed-level: 1000
    foreach tree-line tree-data [
        set [opened level line-text] tree-line
        if all[(opened = tree-closed-node) (level < closed-level)] [closed-level: level]
        if all[(opened = tree-opened-node) (level <= closed-level)] [closed-level: 1000]
        if level <= closed-level [visible-count: visible-count + 1]
        if /current [
            curr: curr + 1
            if equal? visible-count cur [visible-count: curr break]
        ]
    ]
    ;print [visible-count]
    visible-count
]
tree-layout: [
    origin 8x8 space 0x0
    across pad 0x4
    tree-list: list 150x0 + (1x18 * 0x6) + 0x8 [
        origin 0 space 0 across
        box (indent * 1x0 + 0x18) with [opened: -2]
        tree-line-txt: text 150x18 black 240.240.240 font [colors: [0.0.0 250.0.0] size: 11] with [opened: -1] [switch_fold face]
    ] supply [
        level: line-text: none
        face/opened: total_visible/current count + cnt
        if count > face/opened [face/show?: false exit]
        face/show?: true
        either index = 1 [
            face/offset/x: level * indent
            face/effect: pick bullets opened + 2
        ] [
            face/offset/x: level * indent + indent
            face/text: line-text
        ]
    ] effect reduce ['grid (indent * 1x0) 0x0 220.220.220]
   
    tree-scroller: scroller tree-list/size * 0x1 + 16x0 [
        value: max 0 to-integer value * (max-rows - visible-rows)
        if value <> cnt [cnt: value show tree-list]
    ] return
    btn "Fold all" [fold_all] btn "Unfold all" [unfold_all]
]
resize_scroller: func [sld [object!] tot-rows [integer!] visible-rows [integer!]] [
    either visible-rows >= tot-rows [
        sld/step: 0
        sld/redrag 1
        sld/data: 0.0
        cnt: 0
        ;sld/show?: false
    ][
        sld/step: 1 / (tot-rows - visible-rows)
        sld/redrag (max 1 visible-rows) / tot-rows
        cnt: to-integer sld/data * (tot-rows - visible-rows)
        ;sld/show?: true
    ]
]
switch_fold: func [face /local tree-line][
    tree-line: pick tree-data face/opened
    tree-line/1: negate tree-line/1
    resize_scroller tree-scroller max-rows: total_visible visible-rows
    show [tree-scroller tree-list ]
]
fold_all: func [/local tree-line][
    foreach tree-line tree-data [if tree-line/1 <> 0 [tree-line/1: -1]]
    resize_scroller tree-scroller max-rows: total_visible visible-rows
    show [tree-scroller tree-list ]
]
unfold_all: func [/local tree-line][
    foreach tree-line tree-data [if tree-line/1 <> 0 [tree-line/1: 1]]
    resize_scroller tree-scroller max-rows: total_visible visible-rows
    show [tree-scroller tree-list ]
]
if block? tree-layout [
    tree-layout: layout tree-layout
    visible-rows: to-integer tree-list/size/y - 4 / tree-line-txt/size/y
    resize_scroller tree-scroller max-rows: total_visible visible-rows
]
view center-face tree-layout