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|
(ns jvui.widgets
"The widgets, in the calling convention dvui made popular: you call them, and
what they answer is what the person did.
(when (w/button \"Save\") (save!))
(reset! on? (w/checkbox @on? \"Enabled\"))
There is no widget object to hold, no handler to register and nothing to
free — a button that is not called this frame is not on the screen, which is
the property the whole style is for.
Containers are macros so their contents read as a body rather than as a
closure. They are thin: each is `core/box*` with a different set of defaults
from the theme."
(:require [jvui.core :as c]
[jvui.theme :as theme]
[jvui.frames :as frames]
[clojure.string :as str]))
;; -------------------------------------------------------------- containers
(defmacro box
"The general container. See `core/box*` for the options."
[opts & body]
`(c/box* ~opts (fn [~'_id ~'_rect] ~@body)))
(defmacro vbox [opts & body] `(box (assoc ~opts :dir :vertical) ~@body))
(defmacro hbox [opts & body] `(box (assoc ~opts :dir :horizontal) ~@body))
(defn card*
"A surface with a border and a radius: the thing a group of controls sits on."
[opts body]
(c/box* (merge {:dir :vertical
:padding (c/th :padding)
:spacing (c/th :spacing)
:radius (c/th :radius)
:fill (c/th :surface)
:border {:colour (c/th :border) :width (c/th :border-width)}
:expand :horizontal}
opts)
body))
(defmacro card [opts & body] `(card* ~opts (fn [~'_id ~'_rect] ~@body)))
(defn page*
"The root container: the window's background, padded, with its contents kept
to `:max-width` and centred in whatever is left."
[opts body]
(c/box* (merge {:dir :vertical :expand :both :fill (c/th :bg)
:padding (c/th :padding)}
(dissoc opts :max-width))
(fn [_ _]
;; The column expands vertically and is *given* its width, so the
;; gravity has something left over to centre it in.
(c/box* {:dir :vertical
:spacing (c/th :spacing)
:expand :vertical
:gravity [0.5 0.0]
;; EXACTLY this wide, rather than at least: without
;; `:fixed` the column reports what its children asked
;; for, and its own width is then whatever they asked
;; for last time — a page whose width is a function of
;; its own width. Where that does not come to rest it
;; swings between two widths forever, one per frame,
;; and every card on the page swings with it. Fixed
;; here, the width is the window's and the cap's, and
;; the wrapping below it has something that holds
;; still to wrap against.
:fixed true
:min-size [(min (double (or (:max-width opts) 1.0e9))
(max 0.0 (- (double (first (:size (c/ui))))
(* 2 (double (c/th :padding))))))
0.0]}
body))))
(defmacro page [opts & body] `(page* ~opts (fn [~'_id ~'_rect] ~@body)))
;; -------------------------------------------------------------------- text
(defn- break-word
"Cut a word too long for `width` into pieces that fit.
Character-wise and greedy. Only ever reached for a word that would not
fit on a line of its own — an ordinary sentence never comes here."
[w size width]
(loop [rest* w out []]
(if (or (empty? rest*) (<= (first (c/measure rest* size)) width))
(if (seq rest*) (conj out rest*) out)
(let [n (loop [i 1]
(cond (>= i (count rest*)) (count rest*)
(> (first (c/measure (subs rest* 0 i) size)) width) (max 1 (dec i))
:else (recur (inc i))))]
(recur (subs rest* n) (conj out (subs rest* 0 n)))))))
(defn- wrap-lines
"Break `s` into lines that each fit `width`, on spaces.
Greedy and word-wise, and a word that cannot fit on a line of its own
is broken at a character. That second half was left out first time
round on the grounds that a URL cut in half reads worse than one that
overflows — which was wrong, and the sign-in screen showed why: an
OAuth login URL is one unbreakable word, so it made its container
wider than the window and pushed the whole page off both edges. A
broken URL is worse than an unbroken one; a window you cannot read is
worse than both.
Measured through the same `c/measure` the drawing uses, so a line that
is said to fit does fit — a wrap computed against a different metric
than the renderer's is off by a word at the worst moments."
[s size width]
(let [words (mapcat (fn [w]
(if (> (first (c/measure w size)) width)
(break-word w size width)
[w]))
(str/split (str s) #" "))]
(loop [[w & more] words line nil out []]
(cond
(nil? w) (if line (conj out line) out)
(nil? line) (recur more w out)
:else
(let [try* (str line " " w)]
(if (<= (first (c/measure try* size)) width)
(recur more try* out)
(recur more w (conj out line))))))))
(defn label
"A line of text, wrapped to the space it was given. Answers its rectangle.
Wrapping is on when the text does not fit and the box has told us how
much room there is. That is not a style choice: without it one long
sentence makes its container wider than the window, and a page that
centres its content then hangs off BOTH edges — which is exactly what
frq's sign-in screen did the first time it was painted here.
`:wrap false` turns it off for a caller that would rather overflow, and
a width of zero — the first frame, before any box knows its size — is
read as \"not yet\" rather than \"no room\"."
([s] (label s {}))
([s {:keys [size colour expand gravity align wrap]
:or {expand :horizontal gravity [0.0 0.5] align :left wrap true}}]
(let [size (or size (c/th :font-size))
colour (or colour (c/th :text))
[tw0 th0] (c/measure s size)
avail (c/avail-width)
lines (if (and wrap (pos? avail) (> tw0 avail))
(wrap-lines s size avail)
[(str s)])
many? (> (count lines) 1)
widths (mapv #(first (c/measure % size)) lines)
tw (if many? (reduce max 0.0 widths) tw0)
lh (max th0 (c/line-height size))
rect (c/leaf [(double tw) (double (* lh (count lines)))]
expand gravity)
[x y w h] rect]
(dotimes [i (count lines)]
(let [ln (nth lines i)
lw (nth widths i)
tx (case align
:center (+ x (/ (- w lw) 2.0))
:right (+ x (- w lw))
x)]
(c/draw-text! ln tx (+ y (* i lh) (/ (- lh th0) 2.0)) size colour)))
rect)))
(defn title [s & [opts]]
(label s (merge {:size (c/th :font-size-title)} opts)))
(defn dim-label [s & [opts]]
(label s (merge {:colour (c/th :text-dim)} opts)))
;; ------------------------------------------------------------------ button
(defn button
"Answers true on the frame the button is released inside itself.
opts: :kind (:normal or :primary) :expand :gravity :key :min-width"
([s] (button s {}))
([s {:keys [kind expand gravity key min-width]
:or {kind :normal expand :none gravity [0.0 0.5]}}]
(let [size (c/th :font-size)
pad (c/th :padding)
[tw th*] (c/measure s size)
w (max (double (or min-width 0.0)) (+ tw (* 2 pad) (* 2 pad)))
h (max (double (c/th :control-height)) (+ th* pad))
id (c/next-id key)
rect (c/leaf [w h] expand gravity)
{:keys [hover? pressed? clicked? focused?]} (c/interact! id rect)
primary? (= kind :primary)
base (cond primary? (c/th :accent)
:else (c/th :surface-alt))
fill (cond pressed? (if primary?
(theme/mix base [0 0 0 255] 0.25)
(c/th :press))
hover? (if primary?
(theme/mix base [255 255 255 255] 0.12)
(c/th :hover))
:else base)
text-colour (if primary? (c/th :accent-text) (c/th :text))
[rx ry rw rh] rect]
(c/fill! rect fill (c/th :radius)
(if focused? (c/th :focus) (c/th :border))
(if focused? 2.0 (c/th :border-width)))
(c/draw-text! s (+ rx (/ (- rw tw) 2.0)) (+ ry (/ (- rh th*) 2.0))
size text-colour)
clicked?)))
;; ---------------------------------------------------------------- checkbox
(defn checkbox
"Answers the value the checkbox should have after this frame."
([value s] (checkbox value s {}))
([value s {:keys [key expand] :or {expand :horizontal}}]
(let [size (c/th :font-size)
gap 8.0
side 18.0
[tw th*] (c/measure s size)
h (max side (double th*))
id (c/next-id key)
rect (c/leaf [(+ side gap tw) h] expand [0.0 0.5])
{:keys [hover? clicked? focused?]} (c/interact! id rect)
[rx ry _ rh] rect
by (+ ry (/ (- rh side) 2.0))
boxr [rx by side side]
on? (if clicked? (not value) value)]
(c/fill! boxr
(cond on? (c/th :accent)
hover? (c/th :hover)
:else (c/th :surface-alt))
4.0
(if focused? (c/th :focus) (c/th :border))
(if focused? 2.0 (c/th :border-width)))
(when on?
;; the tick, as two strokes rather than a glyph, so it does not depend
;; on the font having one
(let [cx (+ rx 4.0) cy (+ by (/ side 2.0))]
(c/draw-line! cx cy (+ rx 7.5) (+ by side -5.0) (c/th :accent-text) 2.0)
(c/draw-line! (+ rx 7.5) (+ by side -5.0) (+ rx side -4.0) (+ by 5.0)
(c/th :accent-text) 2.0)))
(c/draw-text! s (+ rx side gap) (+ ry (/ (- rh th*) 2.0)) size (c/th :text))
on?)))
;; ------------------------------------------------------------------ slider
(defn slider
"A horizontal slider. Answers the value after this frame.
The drag is tracked through `capture`, so the value keeps following the
pointer after it leaves the track — which is what a person expects when they
drag fast, and what a plain hit-test gets wrong."
([value] (slider value {}))
([value {:keys [min max key expand step]
:or {min 0.0 max 1.0 expand :horizontal}}]
(let [lo (double min) hi (double max)
h (double (c/th :control-height))
id (c/next-id key)
rect (c/leaf [120.0 h] expand [0.0 0.5])
{:keys [hover? pressed? focused?]} (c/interact! id rect)
[rx ry rw rh] rect
knob 16.0
track-h 6.0
travel (clojure.core/max 1.0 (- rw knob))
mx (first (:mouse (c/ui)))
raw (if pressed?
(+ lo (* (- hi lo)
(clojure.core/max 0.0
(clojure.core/min 1.0 (/ (- mx rx (/ knob 2.0)) travel)))))
(double value))
v (clojure.core/max lo (clojure.core/min hi
(if step (* step (Math/round (/ raw (double step)))) raw)))
t (if (= hi lo) 0.0 (/ (- v lo) (- hi lo)))
ty (+ ry (/ (- rh track-h) 2.0))
kx (+ rx (* t travel))]
(c/fill! [rx ty rw track-h] (c/th :surface-alt) (/ track-h 2.0))
(c/fill! [rx ty (+ (* t travel) (/ knob 2.0)) track-h] (c/th :accent)
(/ track-h 2.0))
(c/fill! [kx (+ ry (/ (- rh knob) 2.0)) knob knob]
(if (or hover? pressed?)
(theme/mix (c/th :accent) [255 255 255 255] 0.2)
(c/th :accent))
(/ knob 2.0)
(if focused? (c/th :focus) (c/th :border))
(if focused? 2.0 1.0))
v)))
;; ---------------------------------------------------------------- progress
(defn progress
([fraction] (progress fraction {}))
([fraction {:keys [expand height] :or {expand :horizontal height 8.0}}]
(let [t (max 0.0 (min 1.0 (double fraction)))
rect (c/leaf [120.0 (double height)] expand [0.0 0.5])
[rx ry rw rh] rect]
(c/fill! rect (c/th :surface-alt) (/ rh 2.0))
(when (pos? t) (c/fill! [rx ry (* t rw) rh] (c/th :accent) (/ rh 2.0)))
rect)))
;; ------------------------------------------------------------------- filler
(defn spacer
([] (spacer {}))
([{:keys [size expand] :or {size 0.0 expand :none}}]
(c/leaf [(double size) (double size)] expand [0.0 0.0])))
(defn separator
[]
(let [rect (c/leaf [1.0 (double (c/th :border-width))] :horizontal [0.0 0.5])]
(c/fill! rect (c/th :border))
rect))
;; -------------------------------------------------------------- text entry
(defn- clamp [v lo hi] (max lo (min hi v)))
(defn entry-activated?
"Did the field under `id` see Enter on the frame just walked?
Asked after `text-entry`, which records it. Enter is the one key a text
field must NOT treat as input — the client sends on it — and a widget
that answered only its text gave a caller no way to know."
[id]
(boolean (c/state id :activated false)))
(defn entry-lines
"How many lines the field under `id` was drawn as on the frame just walked.
A field that grows moves everything under it, and a caller laying out a
screen by hand — frq reserves the strip below its message list in points —
has to be told, or the box grows down over the bottom edge of the window."
[id]
(long (c/state id :lines 1)))
(defn- fit-count
"How many characters from `a` fit in `width`, without running past `end`.
At least one: a width narrower than a single character would otherwise
answer zero, and a wrap that consumes nothing never terminates."
[s a end size width]
(loop [k 1]
(cond
(>= (+ a k) end) (- end a)
(> (first (c/measure (subs s a (+ a k)) size)) width) (max 1 (dec k))
:else (recur (inc k)))))
(defn- wrap-hard-line
"Break `s` between `a` and `end` into [lo hi] index pairs that each fit.
Index pairs and not strings, unlike `wrap-lines` above: a caret is an
offset into the whole string, and a line it cannot be located in is a
line the caret cannot be drawn on. The space a line is broken at belongs
to neither side — it is stepped over — which is what makes the pairs a
partition of the text rather than a copy of it."
[s a end size width]
(loop [a a out []]
(if (>= a end)
(conj out [a end])
(let [k (fit-count s a end size width)]
(if (>= (+ a k) end)
(conj out [a end])
(let [sp (str/last-index-of (subs s a (+ a k 1)) " ")]
(if sp
(recur (+ a sp 1) (conj out [a (+ a sp)]))
(recur (+ a k) (conj out [a (+ a k)])))))))))
(defn- wrap-spans
"The whole string as [lo hi] pairs: hard breaks first, then wrapping.
A width of zero or less is \"no room known yet\" — the first frame, before
the box has a size — and answers one span, exactly as an unwrapped field
would. Reading it as no room instead pins every line to one character."
[s size width]
(let [n (count s)]
(if-not (pos? width)
[[0 n]]
(loop [a 0 out []]
(let [nl (str/index-of s "\n" a)
end (or nl n)
out (into out (wrap-hard-line s a end size width))]
(if nl (recur (inc nl) out) out))))))
(defn- span-at
"Which of `spans` the caret is on, as an index into them.
The first that contains it, so a caret sitting exactly on a soft break
shows at the end of the line it was typed on rather than jumping to the
head of the next one — the break has not been typed and the eye did not
move."
[spans caret]
(or (first (keep-indexed (fn [i [_ hi]] (when (<= caret hi) i)) spans))
(max 0 (dec (count spans)))))
(defn text-entry
"An editable string. Answers the text after this frame.
One line by default. `:rows` is how many it is tall to start with and
`:max-rows` how many it may GROW to: a field given room to grow wraps its
text instead of sliding it sideways, and gains a line every time the text
stops fitting, up to that cap — past which it scrolls by lines, keeping
the caret in view. That is the shape a compose box wants; a handle or a
URL field leaves `:max-rows` alone and keeps the old single line.
The caret is an index into the string kept under the widget's id, which is
the one piece of state a text field cannot recompute from its value."
([value] (text-entry value {}))
([value {:keys [key expand placeholder min-width rows max-rows]
:or {expand :horizontal rows 1}}]
(let [size (c/th :font-size)
pad (c/th :padding)
lh (double (c/line-height size))
;; `(or rows 1)` and not only the destructuring default: a backend
;; forwarding a client's props writes the key whether or not the
;; client set it, and an explicit nil never reaches an `:or`.
rows (max 1 (long (or rows 1)))
max-rows (max rows (long (or max-rows rows)))
grows? (> max-rows 1)
id (c/next-id key)
s (str value)
;; What the text is wrapped against, in this order: the width the
;; field actually had last frame, and before there was one, what the
;; box says is free. The first is exact and the second is not — a row
;; has not yet subtracted the Send button sitting after this field —
;; so the estimate is only ever what the opening frame wraps by.
prev (c/rect-of id)
inner0 (- (if (and prev (pos? (nth prev 2)))
(double (nth prev 2))
(c/avail-width))
(* 2 pad))
spans (if grows? (wrap-spans s size inner0) [[0 (count s)]])
;; The height is asked for BEFORE this frame's text is known — the
;; box needs a size to place the widget — so it is the height the
;; string coming in wants. A keystroke that adds a line shows on the
;; next frame, which is the same frame the text itself lands on.
shown (clamp (count spans) rows max-rows)
h (+ (double (c/th :control-height)) (* (dec shown) lh))
rect (c/leaf [(double (or min-width 160.0)) h] expand [0.0 0.5])
{:keys [hover? focused?]} (c/interact! id rect)
[rx ry rw rh] rect
inner (- rw (* 2 pad))
spans (if grows? (wrap-spans s size inner) spans)
caret0 (clamp (c/state id :caret (count s)) 0 (count s))
evs (c/key-events id)
;; Where the caret would land on the line above or below, by the
;; offset it holds INTO its line rather than by how far along the
;; line it looks. Two lines of proportional text never share a
;; column, and a caret that tracked pixels would drift a character
;; either way on every press; one that keeps its offset comes back
;; to where it started when the key is pressed the other way.
line-step (fn [caret by]
(let [i (span-at spans caret)
[lo _] (nth spans i)
j (clamp (+ i by) 0 (dec (count spans)))]
(if (= i j)
caret
(let [[lo' hi'] (nth spans j)]
(min hi' (+ lo' (- caret lo)))))))
[s' caret']
(reduce
(fn [[s caret] e]
(case (:kind e)
:text (let [t (:text e)]
[(str (subs s 0 caret) t (subs s caret))
(+ caret (count t))])
:key-down
(case (:key e)
:backspace (if (pos? caret)
[(str (subs s 0 (dec caret)) (subs s caret))
(dec caret)]
[s caret])
:delete (if (< caret (count s))
[(str (subs s 0 caret) (subs s (inc caret))) caret]
[s caret])
:left [s (max 0 (dec caret))]
:right [s (min (count s) (inc caret))]
:up [s (line-step caret -1)]
:down [s (line-step caret 1)]
;; Line-local, on a field that has lines. Home on the third
;; line of a paragraph means the head of that line — the
;; whole string's start is what Ctrl+Home is elsewhere, and
;; a caret that leapt three lines away on a key pressed to
;; reach the margin is a key nobody presses twice.
:home [s (if grows? (first (nth spans (span-at spans caret))) 0)]
:end [s (if grows?
(second (nth spans (span-at spans caret)))
(count s))]
;; Shift+Enter is the break, and only where there is room for
;; one: plain Enter still belongs to the client, which sends
;; on it. A field one line tall takes neither — a newline it
;; could not show would leave the text saying one thing and
;; the box another.
:return (if (and grows? (:shift? e))
[(str (subs s 0 caret) "\n" (subs s caret))
(inc caret)]
[s caret])
[s caret])
[s caret]))
[s caret0] (or evs []))
caret' (clamp caret' 0 (count s'))
spans' (if grows? (wrap-spans s' size inner) [[0 (count s')]])]
(c/state! id :caret caret')
;; What the NEXT frame will be tall enough for, recorded for a caller
;; that has to leave room for it. A frame late by construction, which is
;; the same beat everything else about this field runs on.
(c/state! id :lines (clamp (count spans') rows max-rows))
;; Enter is not an edit and must not be swallowed as one: a client
;; sends its message on it. Recorded as state rather than returned,
;; because `text-entry` already answers the text and a second return
;; value would change every existing call.
(c/state! id :activated
(boolean (some #(and (= :key-down (:kind %)) (= :return (:key %))
(not (and grows? (:shift? %))))
(or evs []))))
;; A field that just gained or lost a line has to be walked again to be
;; drawn at its new height, and on a loop that paints only when
;; something happened the keystroke it grew on is already spent.
(when (not= (count spans') (count spans)) (c/refresh!))
(c/fill! rect (c/th :surface) (c/th :radius)
(if focused? (c/th :focus) (c/th :border))
(if focused? 2.0 (c/th :border-width)))
(let [[_ th*] (c/measure (if (= s' "") "M" s') size)
i (span-at spans' caret')
;; Which line is at the top, on a field with more text than it can
;; show. Kept between frames so a reader who scrolled away with the
;; arrows stays where they left off, and pulled back whenever the
;; caret has left the window — which is what typing does.
visible (clamp (count spans') rows max-rows)
top (-> (long (c/state id :top 0))
(clamp 0 (max 0 (- (count spans') visible)))
(clamp (- i (dec visible)) i)
(max 0))
;; One line is centred in the control's height, as it always was.
;; Several start from the top inset by that same half-gap, so the
;; first line of a grown box sits where the only line of a short
;; one did and the text does not shuffle as it grows.
ty0 (+ ry (/ (- (double (c/th :control-height)) th*) 2.0))
[clo chi] (nth spans' i)
caret-x (first (c/measure (subs s' clo caret') size))
;; Sideways only where there is nowhere to wrap to. A field of one
;; line narrower than its contents is the ordinary case — a handle,
;; a URL, a password — and without this the text simply runs out
;; past the border and over whatever is beside it.
shift (if grows? 0.0 (max 0.0 (- caret-x inner)))]
(c/state! id :top top)
(c/with-clip [(+ rx pad) ry inner rh]
(fn []
(if (and (= s' "") placeholder (not focused?))
(c/draw-text! placeholder (+ rx pad) ty0 size (c/th :text-dim))
(dotimes [k (min visible (- (count spans') top))]
(let [[lo hi] (nth spans' (+ top k))]
(c/draw-text! (subs s' lo hi) (- (+ rx pad) shift)
(+ ty0 (* k lh)) size (c/th :text)))))))
;; The caret rides the same shift, and inside the same clip: a caret
;; drawn at the untranslated offset sits past the border on a full
;; field, pointing at where the text would have been.
(when focused?
(c/with-clip [(+ rx pad) ry inner rh]
(fn []
(c/fill! [(- (+ rx pad caret-x) shift)
(+ ty0 (* (- i top) lh) 1.0) 1.5 (- th* 2.0)]
(c/th :text))))))
s')))
;; ------------------------------------------------------------------- scroll
(defonce ^:private scroll-areas
;; Offsets kept by NAME, outliving the node that showed them.
;;
;; A widget id is a position in this frame's tree, so two lists that are
;; never on screen together — one channel's messages and another's —
;; share one id and therefore one offset, and switching between them
;; carries the wrong scroll across. `:scroll-key` names the area instead,
;; and the name outlives the node.
(atom {}))
(defn scroll-offset
"How far the area named `k` is scrolled, or nil if it has never shown.
Public because it is the only way to ask a viewport what it did — the
widget answers its rectangle, not its state — and a caller restoring a
position, or a test asking whether a list actually followed its
content, has nowhere else to look."
[k]
(:offset (get @scroll-areas k)))
(defn scroll*
"A clipped viewport that scrolls its contents vertically.
The viewport reports the height it was given, not the height of what is
in it; the difference between the two is what there is to scroll, which
is why `core/box*` keeps both numbers.
opts beyond `core/box*`'s:
:height the viewport's own height
:scroll-key a name for the offset, so it survives the node
:reserve leave this much of the available height behind
:stick-to-bottom follow new content while the reader is at the end
:scroll-to-bottom a number the caller BUMPS to ask for a jump
:on-at-end called with true/false as the reader arrives at or
leaves the end"
[opts body]
(let [{:keys [scroll-key reserve stick-to-bottom scroll-to-bottom on-at-end]} opts
id (c/next-id (:key opts))
area (or scroll-key id)
prev (c/data id)
;; A viewport with no height of its own FILLS what is left rather
;; than ASKING for it. Asking is what it did first — a minimum of
;; the whole column — and then the column had nothing left for
;; the separator and compose bar under it, which went off the
;; bottom of the window.
;;
;; So the height is the one it was GIVEN last frame, and it
;; reports a minimum of nothing. Two hundred is the answer on the
;; first frame only, before it has been given anything.
given (nth (:rect prev) 3 nil)
h (double (cond
(:height opts) (:height opts)
(and given (pos? (double given)))
(max 0.0 (- (double given) (double (or reserve 0.0))))
:else 200.0))
content-h (second (or (:content-min prev) [0.0 0.0]))
view (or (:rect prev) [0.0 0.0 0.0 0.0])
maxoff (max 0.0 (- content-h h))
st (get @scroll-areas area {})
off0 (min maxoff (max 0.0 (or (:offset st) 0.0)))
wheel (or (c/wheel-events view) [])
;; A jump is asked for by CHANGING the number, not by setting it:
;; a caller that wanted to jump twice to the same place would
;; otherwise have nothing to say the second time.
jump? (and scroll-to-bottom
(pos? (double scroll-to-bottom))
(not= scroll-to-bottom (:jumped st)))
;; The wheel is applied FIRST, and a wheel that moved the list
;; breaks the stick for that frame. Deciding to stick before
;; reading it pins the offset at the end every frame and the
;; reader can never scroll up at all — they drag and it snaps
;; back, which reads as the window being broken.
wheeled (reduce (fn [o e] (min maxoff (max 0.0 (- o (* 40.0 (:dy e))))))
off0 wheel)
moved? (not= wheeled off0)
;; Sticking and jumping are the same control pulling opposite
;; ways. Sticking wins over a jump, so a jump to an old message
;; is not snatched back by the next arrival — but a hand on the
;; wheel wins over both.
stick? (and stick-to-bottom (not jump?) (not moved?) (:at-end st true))
off (cond
jump? maxoff
stick? maxoff
:else wheeled)
;; The gutter the bar is drawn in, taken off the content whether or
;; not there is anything to scroll yet. Always, because the
;; alternative is that a list reflows the moment it grows past the
;; window — every line rewrapping under the reader as the message
;; that overflowed arrives. And taken at all because the bar is
;; painted over the viewport's right edge: without it the last
;; characters of every wrapped line sit under the bar, which is
;; where "the sidebar truncates" comes from.
;; The bar's own width and a gap beside it. Reserving the bar alone
;; leaves the wrap boundary exactly at its left edge, so a line ends
;; flush against it — legible, but it reads as text running into the
;; bar, and a glyph whose drawn width runs a hair past its measured
;; one touches it. A gap is what puts the last word beside the bar
;; rather than on it.
gutter (+ (double (c/th :scrollbar)) (double (c/th :spacing)))
r (c/box* (merge {:dir :vertical
:expand :both
:pad-right gutter
;; An explicit :height IS a demand and is
;; reported as one. Without it the viewport
;; fills what is left and asks for nothing —
;; asking is what left the compose bar off the
;; bottom of the window.
:min-size [0.0 (if (:height opts) h 0.0)]
:fixed true
:clip? true
:spacing (c/th :spacing)
:key (:key opts)
:offset [0.0 (- off)]}
(dissoc opts :height :scroll-key :reserve :stick-to-bottom
:scroll-to-bottom :on-at-end))
body)
;; Within a couple of lines of the end counts as at it: a reader
;; who has not moved should not stop being followed because the
;; last message was a pixel taller than the one before.
at-end? (>= off (- maxoff 24.0))
;; Arriving at the end is reported at once; leaving it has to hold
;; for a few frames. A burst of messages grows the content faster
;; than the offset follows, and reporting that honestly would
;; blink "scrolled away" whenever a channel is busy.
away (if at-end? 0 (inc (or (:away st) 0)))
settled (cond at-end? true (>= away 3) false :else nil)
was (:reported st)]
(swap! scroll-areas assoc area
(cond-> (assoc st :offset off :at-end at-end? :away away)
jump? (assoc :jumped scroll-to-bottom)
(some? settled) (assoc :reported settled)))
;; Not on the first report: the opening one arrives before the content
;; has a height, and every list would announce itself as at its end.
(when (and on-at-end (some? settled) (some? was) (not= was settled))
(on-at-end settled))
(when (pos? maxoff)
(let [[vx vy vw vh] (or (:rect (c/data id)) view)
bw (double (c/th :scrollbar))
bh (max 24.0 (* vh (/ vh (max 1.0 content-h))))
by (+ vy (* (/ off maxoff) (- vh bh)))]
(c/fill! [(- (+ vx vw) bw) vy bw vh] (c/th :surface-alt) (/ bw 2.0))
(c/fill! [(- (+ vx vw) bw) by bw bh] (c/th :border) (/ bw 2.0))))
r))
(defmacro scroll [opts & body] `(scroll* ~opts (fn [~'_id ~'_rect] ~@body)))
(defn- picture
"The texture for either kind of source: a live `feed` or a file `src`."
[{:keys [feed src]}]
(cond feed (frames/lookup feed)
src (frames/from-file src)))
(defn image
"A picture: live pixels under `:feed`, or a file at `:src`.
One widget and not two, because everything downstream — the fit, the
bounds, the click — is the same for both. That is libvidya's arrangement
too, and frq writes [:image {:feed k}] for a call tile and
[:image {:src p}] for an attachment.
`:fit` gives it every point of the space it has been handed; otherwise it
asks for its own size, bounded by `:max-width` and `:max-height`. Either
way the picture keeps its shape — a 16:9 camera in a square tile is the
ordinary case, and stretching it is the one thing nobody wants.
A source with no picture yet — a feed before its first frame, a file that
will not decode — draws the empty tile and nothing else. Not a
broken-image glyph: the text beside it already says what it was meant to
be, and a tile that appears only once a frame lands rearranges the wall
under the person every time somebody joins."
([opts] (image opts {}))
([{:keys [feed src] :as source}
{:keys [fit max-width max-height size expand gravity placeholder?]
:or {gravity [0.5 0.5] placeholder? true}}]
(let [t (picture source)
[tw th*] (if t [(:w t) (:h t)] [0 0])
want (cond
size size
(and fit) [320.0 180.0]
(pos? tw)
(let [k (min (if max-width (/ (double max-width) tw) 1.0)
(if max-height (/ (double max-height) th*) 1.0))]
[(* tw k) (* th* k)])
:else [(double (or max-width 160)) (double (or max-height 90))])
rect (c/leaf (mapv double want)
(or expand (if fit :both :none))
gravity)]
(when placeholder? (c/fill! rect (c/th :surface-alt) 6.0))
(when (and t (:tex t)) (c/draw-picture! (:tex t) (:w t) (:h t) rect))
rect)))
(defn title-2
"A second-level heading — smaller than `title`, still bold."
[s]
(label s {:size (* 1.15 (c/th :font-size)) :colour (c/th :text)}))
(defn status
"A line of text with a dot in front of it saying whether the thing is live."
([s] (status s false))
([s live?]
(c/box* {:dir :horizontal :spacing 6 :gravity [0.0 0.5]}
(fn [_ _]
(let [line (c/th :font-size)
d (max 7.0 (min 12.0 (* line 0.55)))
r (c/leaf [(+ d 4.0) line] :none [0.0 0.5])
[x y w h] r]
(c/fill! [(+ x 2.0) (+ y (/ (- h d) 2.0)) d d]
(if live? (c/th :accent) (c/th :text-dim))
(/ d 2.0)))
(label s)))))
(defn spinner
"A turning mark, and a word beside it if there is one.
Turned from the wall clock rather than a frame counter: a loop that
dropped frames would otherwise show a spinner that stutters in a way that
reads as the work having stalled, which is the one thing it is there to
deny."
([] (spinner ""))
([s]
(c/box* {:dir :horizontal :spacing 6 :gravity [0.0 0.5]}
(fn [_ _]
(let [line (c/th :font-size)
r (c/leaf [line line] :none [0.0 0.5])
[x y w h] r
cx (+ x (/ w 2.0)) cy (+ y (/ h 2.0))
rad (* 0.4 (min w h))
t (/ (double (mod (System/currentTimeMillis) 1000)) 1000.0)
a (* t 2.0 Math/PI)]
;; Three ticks around a circle: enough to read as turning, and no
;; arc primitive needed.
(dotimes [i 3]
(let [th* (+ a (* i (/ (* 2.0 Math/PI) 3.0)))]
(c/fill! [(+ cx (* rad (Math/cos th*)) -1.5)
(+ cy (* rad (Math/sin th*)) -1.5) 3.0 3.0]
(c/th :accent) 1.5))))
(when (seq s) (label s))))))
(defn link
"Text that is a place to go. Answers true on the frame it was clicked."
([s] (link s {}))
([s {:keys [key]}]
(let [id (c/next-id key)
rect (label s {:colour (c/th :accent)})]
(:clicked? (c/interact! id rect)))))
(defn emoji
"One emoji, drawn as a character and sized to sit level with the words
either side.
In colour where there is a colour face to draw it from, and as text
where there is not.
The two paths differ in more than the picture: a colour emoji face is a
bitmap with one 128-pixel strike, so it cannot be a fallback font and is
drawn as an image scaled into the line — which means the glyph occupies a
SQUARE of the size asked for, decided here rather than measured. The text
path stays exactly what it was, a label in the UI font, and is what a
machine with no colour face gets."
([s] (emoji s nil))
([s size]
(let [sz (double (or size (c/th :font-size)))]
(if (c/colour-emoji? s)
(let [rect (c/leaf [sz sz] :none [0.5 0.5])]
(c/draw-emoji! s rect)
rect)
(label s {:size sz})))))
(defn avatar
"A round picture for somebody, or their initial on a colour if there is
none.
The fallback is not a placeholder to be replaced later — most people in
most rooms have no picture, so the initial IS the avatar, and its colour
comes from the name so the same person is the same colour everywhere."
([nick] (avatar nick {}))
([nick {:keys [src size] :or {size 24.0}}]
(let [rect (c/leaf [size size] :none [0.5 0.5])
t (when src (frames/from-file src))]
(if (and t (:tex t))
(c/draw-picture! (:tex t) (:w t) (:h t) rect)
(let [name (str nick)
bare (str/replace name #"^[#&@+%~]+" "")
initial (if (seq bare) (str/upper-case (subs bare 0 1)) "?")
[x y w h] rect]
(c/fill! rect (c/name-colour name) (/ size 2.0))
(let [sz (* size 0.5)
[tw th*] (c/measure initial sz)]
(c/draw-text! initial (+ x (/ (- w tw) 2.0)) (+ y (/ (- h th*) 2.0))
sz (c/th :accent-text)))))
rect)))
(defn reaction
"A tally wearing a pill: an emoji, how many people, and whether you are one
of them.
Answers the interaction — `:clicked?`, `:hover?` and the `:rect` it was
given — rather than a bare click.
The same glyph `emoji` draws, and the same two ways of drawing it: a
colour face gives a square picture, and everything else is text. So the
glyph and the tally are measured and drawn apart rather than as one
string — a picture cannot be concatenated onto a number.
A reaction is not a character otherwise either: it answers the pointer
and it is a count. `mine?` is bordered rather than filled differently,
because the pill has to stay readable at the size a line of them ends
up."
([glyph] (reaction glyph {}))
([glyph {:keys [count mine? size key]
:or {count 0 mine? false}}]
(let [sz (double (or size (c/th :font-size)))
colour? (c/colour-emoji? (str glyph))
tally (when (pos? count) (str " " count))
[gw gh] (if colour? [sz sz] (c/measure (str glyph) sz))
[cw ch] (if tally (c/measure tally sz) [0.0 0.0])
tw (+ (double gw) (double cw))
th* (max (double gh) (double ch))
pad 6.0
rect (c/leaf [(+ tw (* 2 pad)) (+ th* 4.0)] :none [0.0 0.5])
id (c/next-id key)
[x y w h] rect]
(c/fill! rect (if mine? (c/th :press) (c/th :surface-alt))
(/ h 2.0)
(when mine? (c/th :accent)) (if mine? 1.0 0.0))
(if colour?
(c/draw-emoji! (str glyph) [(+ x pad) (+ y (/ (- h sz) 2.0)) sz sz])
(c/draw-text! (str glyph) (+ x pad) (+ y (/ (- h (double gh)) 2.0))
sz (c/th :text)))
(when tally
(c/draw-text! tally (+ x pad (double gw)) (+ y (/ (- h (double ch)) 2.0))
sz (c/th :text)))
;; The whole interaction and not just the click: a reaction is the one
;; chip that answers the pointer resting on it as well as pressing it —
;; who put it there is what the pill's number will not say — so the
;; caller needs `:hover?` too, and the rectangle, to know where to hang
;; the card that answers it.
(assoc (c/interact! id rect) :rect rect))))
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