kui_core/metrics.rs
1//! The sizes the stock widgets are built from, as one struct beside the
2//! palette (backlog T2, the axis ADR 0019 scoped itself out of).
3//!
4//! `BUTTON_TEXT` 15, `MENU_WIDTH` 200, every `pad_xy(14.0, 8.0)` and
5//! `radius(6.0)` in `widgets.rs` were hard-coded the way the colours were
6//! before the theme, and for the same reason: nobody had asked. The
7//! argument for a [`Metrics`] is ADR 0019's one axis over — the stock
8//! widgets and an app's own controls should agree on a radius and a
9//! padding without either copying a number out of the other — and the
10//! two questions the backlog entry said to settle first are settled here:
11//!
12//! - **A metric does not scale by itself.** Every field is logical px (or
13//! a text size in logical px), applied *before* `env.scale`, which is
14//! the renderer's and multiplies everything the frame draws. Density is
15//! the app's choice, the way the palette is: [`Metrics::compact`] is a
16//! tighter set, [`Metrics::scaled`] is every length multiplied for a
17//! density slider, and `Core::set_metrics` is the door. The day an OS
18//! text-size setting is plumbed into `env.system`, `scaled` is the
19//! arithmetic and a `MetricsSource` beside [`crate::theme::ThemeSource`]
20//! is the shape; nothing here pre-empts it.
21//! - **The default is the contract; a set metric is the app's.** The
22//! corpus runs with [`Metrics::default`], which is byte for byte the
23//! constants the widgets had, so no scene moved and the report pins the
24//! stock geometry as it always did. An app that sets its own changes
25//! what *its* frames draw, exactly as `set_theme` does, and a
26//! conformance scene never sets one — which is what keeps "the stock
27//! button is 15-px text in 14×8 padding" a sentence about kui and not
28//! about an app.
29//!
30//! Roles, like the palette's: `control_pad_x` is *a button's horizontal
31//! padding*, not "spacing unit 3", and a view that wants a number between
32//! two has arithmetic.
33
34/// The titlebar's height on Windows and everywhere else: the caption
35/// height the OS draws, so the one metric that is the platform's rather
36/// than a density's. Named here so [`Metrics::comfortable`] picks the
37/// running one and the schema row (`MetricRole::platform`) carries both,
38/// which is what keeps a generated table from saying which machine wrote
39/// it (backlog W13).
40pub const TITLEBAR_H_WINDOWS: f32 = 32.0;
41pub const TITLEBAR_H_ELSEWHERE: f32 = 34.0;
42
43/// The sizes the stock widgets are built from. Plain data and [`Copy`]: a
44/// view reads it off `ui.metrics()` and may keep or change its own copy,
45/// and `Core::set_metrics` makes one the frame's.
46#[derive(Clone, Copy, Debug, PartialEq)]
47pub struct Metrics {
48 // -- text ----------------------------------------------------------
49 /// A stock control's label: the button's text size.
50 pub control_text: f32,
51 /// The chrome's text: a menu row, a menu-bar title, the titlebar's
52 /// title.
53 pub chrome_text: f32,
54 /// A tooltip's text.
55 pub hint_text: f32,
56
57 // -- corners -------------------------------------------------------
58 /// The corner of every stock surface: a button, a field, a menu, a
59 /// tooltip.
60 pub radius: f32,
61 /// The corner of a row inside one: a menu row, a menu-bar title.
62 pub radius_inner: f32,
63
64 // -- padding, x then y -----------------------------------------------
65 /// A button's.
66 pub control_pad_x: f32,
67 pub control_pad_y: f32,
68 /// A text field's.
69 pub field_pad_x: f32,
70 pub field_pad_y: f32,
71 /// A tooltip's.
72 pub hint_pad_x: f32,
73 pub hint_pad_y: f32,
74 /// A menu row's; a menu-bar title's is two px shorter, so the bar's
75 /// height and not the title's padding decides the strip.
76 pub menu_pad_x: f32,
77 pub menu_pad_y: f32,
78
79 // -- extents -------------------------------------------------------
80 /// A menu panel's width.
81 pub menu_width: f32,
82 /// The drawn menu bar's height.
83 pub menu_bar_h: f32,
84 /// The titlebar's height where the strip is the app's alone: the
85 /// platform's caption height (32 on Windows, 34 elsewhere), which
86 /// [`Metrics::compact`] leaves alone. Where the OS keeps controls of
87 /// its own over the strip — the macOS traffic lights under custom
88 /// chrome — the strip is as tall as the OS's titlebar, which the
89 /// driver measures into `env.window.native_controls`, and this row
90 /// is not read (`widgets::titlebar_height`).
91 pub titlebar_h: f32,
92}
93
94impl Default for Metrics {
95 /// What the widgets have always drawn: the constants `widgets.rs`
96 /// carried, restated once.
97 fn default() -> Self {
98 Self::comfortable()
99 }
100}
101
102impl Metrics {
103 /// The stock set — [`Default`], named.
104 pub const fn comfortable() -> Self {
105 Metrics {
106 control_text: 15.0,
107 chrome_text: 13.0,
108 hint_text: 12.0,
109 radius: 6.0,
110 radius_inner: 4.0,
111 control_pad_x: 14.0,
112 control_pad_y: 8.0,
113 field_pad_x: 10.0,
114 field_pad_y: 8.0,
115 hint_pad_x: 10.0,
116 hint_pad_y: 6.0,
117 menu_pad_x: 8.0,
118 menu_pad_y: 5.0,
119 menu_width: 200.0,
120 menu_bar_h: 26.0,
121 titlebar_h: if cfg!(target_os = "windows") {
122 TITLEBAR_H_WINDOWS
123 } else {
124 TITLEBAR_H_ELSEWHERE
125 },
126 }
127 }
128
129 /// A tighter set for a dense tool — a mux, an inspector, a table of
130 /// controls: smaller text, shallower padding, sharper corners. The
131 /// titlebar keeps the platform's height, since that is the OS's
132 /// number and not a density.
133 pub const fn compact() -> Self {
134 Metrics {
135 control_text: 13.0,
136 chrome_text: 12.0,
137 hint_text: 11.0,
138 radius: 4.0,
139 radius_inner: 3.0,
140 control_pad_x: 10.0,
141 control_pad_y: 5.0,
142 field_pad_x: 8.0,
143 field_pad_y: 5.0,
144 hint_pad_x: 8.0,
145 hint_pad_y: 4.0,
146 menu_pad_x: 8.0,
147 menu_pad_y: 3.0,
148 menu_width: 180.0,
149 menu_bar_h: 22.0,
150 ..Self::comfortable()
151 }
152 }
153
154 /// Every density multiplied by `factor` — a density slider, or an OS
155 /// text-size setting the day one is plumbed. Logical px in, logical
156 /// px out: `env.scale` is applied after this by the renderer and is
157 /// never folded in here. A row the schema marks the platform's
158 /// (`titlebar_h`: the OS's caption height, which the traffic lights
159 /// are drawn against) is left alone, as [`Metrics::compact`] leaves
160 /// it — a 1.5 slider drew a 51 px strip beside 34 px buttons
161 /// (backlog AR35).
162 pub fn scaled(self, factor: f32) -> Self {
163 let mut m = self;
164 for row in crate::schema::METRIC_ROLES {
165 if row.platform.is_some() {
166 continue;
167 }
168 (row.set)(&mut m, (row.get)(&self) * factor);
169 }
170 m
171 }
172}