调整手柄

概览

link

Web

tanrei-handle

clock_loader_40

SwiftUI

TanreiHandle

radio_button_unchecked

Jetpack Compose

TanreiHandle

radio_button_unchecked

Flutter

TanreiHandle

radio_button_unchecked

React Native

Handle

radio_button_unchecked

生成自 docs/status/status.json, specs/handle.spec.json

改变高度的手柄、改变宽度的手柄，以及在角上同时改变两者的手柄

调整手柄位于某个可以由人改变大小之物的边或角上：面板的上边、文本字段的下角、窗格或预览的边。被拖动时，它报告移动了多远；用键盘移动时，它报告请求的是哪一步；不拖动而按下时，它也报告这一点。它自己从不改变任何东西的大小。大小由它所在之物保存，一步是多少也由那一方决定，并把大小交还给手柄，让辅助技术能够读出。

在 Web 上它是 <tanrei-handle>。其他平台尚未实现。

用法

link

<div class="notes">
  <textarea aria-label="笔记"></textarea>
  <!-- 放在下边：它改变高度。value 属于所有者，单位也是所有者的。 -->
  <tanrei-handle label="调整笔记大小" value="4" min="2" max="12" value-text="4 行"></tanrei-handle>
</div>

<script type="module">
  import '@tanrei/web/components/handle';
  const handle = document.querySelector('.notes tanrei-handle');
  const notes = document.querySelector('.notes textarea');
  const lineHeight = 24;
  let start = 0;
  const show = (lines) => {
    lines = Math.min(12, Math.max(2, Math.round(lines)));
    notes.rows = lines;
    handle.value = lines;
    handle.valueText = `${lines} 行`;
  };
  handle.addEventListener('resizestart', () => (start = notes.rows));
  // 距按下点的距离（像素）：block 向下为正。
  handle.addEventListener('resize', (e) => show(start + e.detail.block / lineHeight));
  // 这里一步是一行；Home 和 End 请求最小和最大。
  handle.addEventListener('step', (e) => {
    const { direction, amount } = e.detail;
    show(amount === 'limit' ? (direction < 0 ? 2 : 12) : notes.rows + direction * (amount === 'large' ? 3 : 1));
  });
  // 不拖动而按下：在你知道的两个大小之间切换，这样任何大小都不需要拖动。
  handle.addEventListener('activate', () => show(notes.rows < 12 ? 12 : 2));
</script>

import { Handle } from '@tanrei/react';

<Handle
  label="调整笔记大小"
  value={rows}
  min={2}
  max={12}
  valueText={`${rows} 行`}
  onResizeStart={() => setStart(rows)}
  onResize={(e) => setRows(clamp(start + e.detail.block / 24))}
  onStep={(e) => setRows(stepped(rows, e.detail))}
  onActivate={() => setRows(rows < 12 ? 12 : 2)}
/>

规格

link

使用之前看不见：把指针移上去，或用 Tab 移到它

构成

部件	说明
1 container	The box the line is drawn in: a pill across the line for one axis, a square at its corner for two. It carries hover, focus and press, and draws nothing at rest.
2 line	The drawn mark: a capsule with round ends across the axis it resizes (a horizontal capsule for a handle that changes a height), or a quarter of a circle with round ends that bows toward its corner for a handle that changes both. A drawn line, never a glyph of the icon set.
3 target	The hit area: at least the minimum target, centred on the line, reaching past the box the handle stands on where it must. It is not drawn.
4 focus-ring · 可选	Gap-then-ring indicator around the container, shown for keyboard focus.

属性

属性	类型	默认值	说明
axis	vertical | horizontal | both	"vertical"	Which size the handle changes. vertical: a height — the line lies across it, horizontal (a sheet's top, a field's bottom edge). horizontal: a width — the line stands upright (a pane's or a frame's end edge). both: a height and a width at once — the line is an arc at a corner (a field's or a frame's bottom-end corner).
corner	bottom-end | bottom-start | top-end | top-start	"bottom-end"	The corner an arc bows toward while axis is both, in logical terms: end is the right in a left-to-right layout and the left in a right-to-left one. Ignored for one axis.
size	small | medium	"medium"	medium for a sheet, a pane or a frame; small for the corner of a text field, where a large mark would cover the text. The hit area meets the minimum target at both sizes. A design system may add values.
value	number	null	The size the handle stands for, as its owner counts it (lines, pixels, a percentage), told to assistive technology. Null exposes the handle as a button with no value: a handle that switches between sizes its owner knows (a sheet's two heights) rather than one that sets a size.
min	number	0	The least value, told to assistive technology with value. Ignored while value is null.
max	number	100	The greatest value, told to assistive technology with value. Ignored while value is null.
valueText	string	""	The value in the product's words ("6 lines", "390 by 844"), read in place of the number. Empty reads the number.
expanded	boolean	null	While value is null: whether what the handle switches is at its larger size, told to assistive technology as the button's expanded state. Null tells no such state.
label	string	""	The accessible name, in the product's words, saying what it resizes ("Resize message", "Resize preview"). Never drawn. Required: a handle without a name is still drawn and reported in debug builds.
disabled	boolean	false	Draws the handle as unavailable; it takes no input and no focus.
revealed	boolean	false	Draws the line at rest. False (the default) keeps the handle out of sight until it is used: it appears while a fine pointer is over it, while it has keyboard focus and while a press or a drag holds it, and it is always drawn where the primary pointer cannot hover (a touch screen). Set it where the handle must be seen to be found (a sheet's grip, which tells that the sheet can be pulled), or while a pointer is over what the handle stands on.

事件

事件	说明
resizeStart	A drag began: a press on the target moved past the platform's touch slop. Carries pointerType (mouse, touch or pen).
resize	The drag moved; emitted in every frame it moves. Carries inline and block, the distance from the press in pixels: inline positive toward the end edge (to the right in a left-to-right layout, to the left in a right-to-left one), block positive downward.
resizeEnd	The drag ended, once: the press was released, or cancelled by the platform. Carries inline and block as resize does, and cancelled (true when the platform cancelled the press).
step	A key or an assistive-technology adjustment asked for a change. Carries axis (inline or block), direction (1 downward or toward the end edge, −1 upward or toward the start edge) and amount (one, large, or limit — limit with direction −1 for Home and 1 for End, the owner's least and greatest size).
activate	The handle was pressed and released without a drag, or Enter or Space was pressed while it had keyboard focus. Its owner switches between sizes it knows.

状态

行为

以 EARS 形式写成的需求。每个平台的实现都按这些 ID 逐条测试。需求原文取自规格文件，原样以英文呈现。

ID	需求
HDL-1	WHILE axis is vertical or horizontal THE handle SHALL draw its line as a capsule with round ends, comp.handle.line.length.medium long and comp.handle.line.thickness.medium thick for size medium (and so on for each size), lying across the axis it resizes — horizontal WHILE axis is vertical, upright WHILE axis is horizontal — centred in its container, in the line color of its state (comp.handle.standard.line.color at rest).
HDL-2	WHILE axis is both THE handle SHALL draw its line as a quarter of a circle with round ends, comp.handle.arc.radius.medium in radius and comp.handle.line.thickness.medium thick for size medium (and so on), bowed toward its corner: its centre lies comp.handle.arc.radius.medium plus comp.handle.inset in from both edges of that corner, so that the middle of the stroke comes within comp.handle.inset of each edge and the arc shares its centre with a corner of that radius; it SHALL be drawn in the line color of its state.
HDL-3	THE handle SHALL lay out its container — WHILE axis is vertical, comp.handle.container.length.medium wide and comp.handle.container.breadth.medium high for size medium (and so on); WHILE axis is horizontal, the same turned a quarter turn; WHILE axis is both, a square of comp.handle.container.breadth.medium on each side at its corner — with comp.handle.container.shape corners, filled with the container color of its state (comp.handle.standard.container.color at rest, which is clear in the default system), and SHALL take no other room: it is placed by the component it stands on, or by the product, and draws no elevation.
HDL-4	WHILE a fine pointer is over the handle, or a press or a drag holds it, THE handle SHALL draw its line comp.handle.line.active-thickness.medium thick for size medium (and so on) and, WHILE axis is vertical or horizontal, comp.handle.line.active-length.medium long (and so on), growing about its centre, and its arc at the same radius, and SHALL draw line, container and opacity from the component tokens of the highest-precedence active state, with precedence pressed over focused over hovered; focus gained by pointer or touch SHALL NOT select the focused state. WHEN it changes between these forms THE handle SHALL move its length and thickness, and its colors, over comp.handle.motion.state-duration with comp.handle.motion.state-easing, and SHALL make the change at once where motion is reduced.
HDL-5	THE handle SHALL give its target at least sys.target.touch on each side for touch input and sys.target.pointer for fine pointers, centred on its container, reaching past the box it stands on where it must, without changing its drawn size or its owner's layout; a platform that cannot tell the input type SHALL use sys.target.touch. WHILE a fine pointer is over the target THE handle SHALL show the platform's resize cursor for its axis: a vertical double arrow WHILE axis is vertical, a horizontal one WHILE it is horizontal, and WHILE it is both the diagonal one that runs through its corner (from top-left to bottom-right for a bottom-end corner in a left-to-right layout), where the platform has one.
HDL-6	WHEN a press that began on the target moves farther than the platform's touch slop THE handle SHALL emit resizeStart once with the press's pointer type, then resize with the distance from the press in every frame the press moves, and resizeEnd once WHEN the press is released or the platform cancels it; it SHALL follow the press without a motion of its own, SHALL keep receiving the press wherever it moves — past the window's edge, and over an embedded document, which takes no input while the drag lasts — SHALL NOT select text, scroll the page, move a caret or take focus because of the press or the drag (focus stays in what the person was working in: a field keeps its caret while its handle is dragged), and SHALL change no size itself: its owner sizes what it stands on from the distances (a sheet, a field, a frame).
HDL-7	WHEN a press on the target is released without having moved farther than the touch slop, or Enter or Space is pressed while the handle has keyboard focus, THE handle SHALL emit activate once and no resize; its owner switches between sizes it knows (a sheet's two heights, a field's own height and the height its text needs, a frame's whole width and the width it had), so that no size it offers depends on a drag (WCAG 2.5.7).
HDL-8	THE handle SHALL be one focus stop, and SHALL be exposed WHILE value is not null as a focusable separator — the platform's adjustable trait where it has no separator — named by label, with value as its value, min and max as its least and greatest, valueText as its value text where it is not empty, and an orientation that is its line's (horizontal WHILE axis is vertical or both, vertical WHILE axis is horizontal); and WHILE value is null as a button named by label, with the expanded state WHILE expanded is not null. Its line and container SHALL be hidden from assistive technology. WHILE label is empty THE handle SHALL still render and work, and in debug builds report that it has no accessible name.
HDL-9	WHILE the handle has keyboard focus and value is not null THE handle SHALL emit step for the arrow keys of its axis — Up Arrow and Down Arrow WHILE axis is vertical, Left Arrow and Right Arrow WHILE it is horizontal, all four WHILE it is both — with the axis they move along and the direction they point (Down 1, Up −1; the arrow toward the end edge 1, the other −1), amount large WHILE Shift is held and amount one otherwise; Page Down and Page Up SHALL emit the same as Shift with Down Arrow and Up Arrow WHILE axis is vertical or both, and as Shift with the arrows toward the end and the start edge WHILE it is horizontal; Home SHALL emit step with amount limit and direction −1 and End with amount limit and direction 1, along its axis (the block axis WHILE axis is both), following the window splitter pattern, where Home gives what it stands on its least size and End its greatest. The handle SHALL change nothing itself, and SHALL let every other key reach its owner.
HDL-10	WHEN assistive technology increments or decrements the handle (a vertical swipe on an adjustable element, the platform's increment and decrement actions) WHILE value is not null THE handle SHALL emit step with amount one, direction 1 for an increment and −1 for a decrement, along the block axis WHILE axis is vertical or both and the inline axis WHILE it is horizontal; its owner, which knows whether its size grows downward or upward, changes value accordingly.
HDL-11	WHEN the handle is pressed by pointer, touch, Enter or Space THE handle SHALL show the pressed state without delay and SHALL keep it visible for at least sys.motion.duration.press-hold, even when the press ends sooner, and for as long as a drag lasts.
HDL-12	WHILE pressed THE handle SHALL answer as sys.behavior.pressed-feedback names: overlay applies the pressed tokens to the whole container at once; ripple grows the pressed state layer from the point of contact (from the center for keyboard activation); dim applies the pressed opacity to the whole control and draws no state layer; none draws no answer to the press. Under ripple and dim only the container color stays with the state under the press; line, opacity and shape still come from the pressed tokens. Under none every part stays with the state under the press. The ripple grows over comp.handle.motion.feedback-duration with comp.handle.motion.state-easing, fades over comp.handle.motion.state-duration with comp.handle.motion.state-easing once the press has ended and press-hold has passed, and appears whole where motion is reduced.
HDL-13	THE handle SHALL ease its container corners by sys.shape.corner-smoothing (0 is a quarter circle, 0.6 the iOS continuous corner; a platform with only the OS curve draws it for any amount above 0) and show its keyboard focus as sys.behavior.focus-style names (ring or glow); a platform that cannot draw a choice SHALL fall back to the first value and state that in its README.
HDL-14	WHEN the handle receives keyboard focus THE handle SHALL show the focus ring around its container, sys.focus.offset outside it, without animation; focus gained by pointer or touch SHALL NOT show it.
HDL-15	WHILE disabled is true THE handle SHALL draw its line and container from its disabled tokens, SHALL NOT be focusable, SHALL take no press, emit no event and show no resize cursor, and SHALL expose the disabled state to assistive technology.
HDL-16	WHERE the platform draws with a person's own forced colors (the web's forced-colors mode, and a platform's equivalent where it has one) THE handle SHALL draw its line in the platform's button-text color, in the platform's highlight color while a fine pointer is over it or a press holds it, and in the platform's disabled-text color WHILE disabled is true, and its focus indicator in the platform's highlight color; it SHALL draw no container fill.
HDL-17	WHERE the layout direction is right-to-left THE handle SHALL place an arc's end corners at the left (a bottom-end arc bows toward the bottom-left), mirror the diagonal resize cursor with it, and take the arrow toward the end edge as Left Arrow (HDL-9) and the inline distance of resize as positive toward the left (HDL-6); a capsule SHALL be drawn as in a left-to-right layout.
HDL-18	THE handle SHALL take its layout direction from where it is used — the direction of the nearest ancestor that sets one, and the platform's own where none does — and SHALL have no direction setting of its own; WHEN that direction changes while the handle is shown THE handle SHALL draw itself for the new direction at once, without a motion of its own.
HDL-19	WHILE the text size is enlarged THE handle SHALL keep its line, its container and its target at the sizes of its size: it is a mark on an edge, enlarged with the page and not with the text.
HDL-20	WHEN size names a value that the active design system does not have, or axis or corner a value the component does not define, THE handle SHALL render with the default value (medium, vertical, bottom-end), and in debug builds report the unknown value.
HDL-21	THE handle SHALL have no words of its own and SHALL read none of the product's words: label and valueText are about the one thing this handle resizes, and are the instance's alone.
HDL-22	WHEN value, min, max, valueText or expanded changes THE handle SHALL expose the new value at once and SHALL NOT announce it by itself: a separator's value is read by assistive technology as it changes, as a slider's is.
HDL-23	WHILE revealed is false and the primary pointer can hover THE handle SHALL draw neither its line nor its container at rest, and SHALL draw them as its state says WHILE a fine pointer is over its target, WHILE it has keyboard focus and WHILE a press or a drag holds it; WHEN it comes into sight or goes out of it THE handle SHALL fade its line and container over comp.handle.motion.state-duration with comp.handle.motion.state-easing, at once where motion is reduced, and SHALL go out of sight only once the press-hold of HDL-11 has passed.
HDL-24	WHILE the handle is out of sight THE handle SHALL keep everything else it is — one stop in the focus order, its target, its resize cursor (HDL-5), its accessible name, role and value (HDL-8), its drag, its keys and its activation — so that a keyboard finds it by Tab and is shown it with its focus ring at once (WCAG 2.4.7, and 2.4.11: what has focus is in sight), a fine pointer is shown it by the resize cursor and the line as it comes over the target, and no size depends on finding it by a drag (WCAG 2.5.7, HDL-7).
HDL-25	WHERE the primary pointer cannot hover (a touch screen), and WHILE revealed is true, THE handle SHALL draw its line at rest: a mark that shows only under a hovering pointer would never be found by a finger, and a press on its unseen target would take a touch meant for what lies under it.
HDL-26	WHERE the platform has ARIA attributes (the web), WHEN the product sets an aria- attribute on the host, by the attribute or by the ARIA property that reflects it, THE handle SHALL move it to the data-aria- attribute of the same name, so that the host is no second node with its name, description or state, and SHALL expose it on the element that carries its role (HDL-8) — its separator WHILE value is not null, its button otherwise — an id reference by the elements it names in the host's tree or a tree around it, a description after its own — except those the handle owns (aria-disabled, aria-expanded), which it SHALL move and not expose. WHILE label is not empty it is the handle's name, over a name given so; WHILE label is empty, a name given so is the handle's name and SHALL NOT be reported as having none in debug builds. WHEN the product removes the aria- attribute or its data-aria- twin, or sets the ARIA property that reflects it (ariaLabel, ariaDescribedByElements…) to null, THE handle SHALL take it off that element. WHEN the product sets an aria- attribute the handle owns THE handle SHALL report it in debug builds.

各平台名称对照

对等并不意味着 API 完全相同。同一份契约，由各平台以自己的惯用方式表达。

规格	Web	SwiftUI	Jetpack Compose	Flutter	React Native
组件	tanrei-handle	TanreiHandle	TanreiHandle	TanreiHandle	Handle
axis · 属性	axis	axis	axis	axis	axis
corner · 属性	corner	corner	corner	corner	corner
size · 属性	size	size	size	size	size
value · 属性	value	value	value	value	value
min · 属性	min	range.lowerBound	valueRange.start	min	min
max · 属性	max	range.upperBound	valueRange.endInclusive	max	max
valueText · 属性	valueText	valueText	valueText	valueText	valueText
expanded · 属性	expanded	isExpanded	expanded	expanded	expanded
label · 属性	label	label	label	label	label
disabled · 属性	disabled	disabled	enabled	enabled	disabled
revealed · 属性	revealed	revealed	revealed	revealed	revealed
resizeStart · 事件	resizestart	onResizeStart	onResizeStart	onResizeStart	onResizeStart
resize · 事件	resize	onResize	onResize	onResize	onResize
resizeEnd · 事件	resizeend	onResizeEnd	onResizeEnd	onResizeEnd	onResizeEnd
step · 事件	step	onStep	onStep	onStep	onStep
activate · 事件	activate	onActivate	onActivate	onActivate	onActivate
备注	<tanrei-handle axis corner size value min max value-text expanded label disabled revealed>. The shadow root holds one focusable element: role="separator" with aria-valuenow/aria-valuemin/aria-valuemax/aria-valuetext and aria-orientation while value is set, a <button> with aria-expanded while it is not. The capsule is a box with round ends, the arc an SVG circle drawn a quarter of the way round by its dash; both are aria-hidden. Out of sight (HDL-23) is opacity: 0 on the box and the line, under @media (hover: hover) only (HDL-25). The drag uses Pointer Events with setPointerCapture and touch-action: none on the target, and a pointer press refuses its mousedown, so that it takes no focus and selects nothing; an owner that holds an iframe sets pointer-events: none on it between resizestart and resizeend (HDL-6). Events are CustomEvents that bubble out of the shadow root: resizestart { pointerType }, resize { inline, block }, resizeend { inline, block, cancelled }, step { axis, direction, amount }, activate (no detail).	A DragGesture(minimumDistance:) with the platform's slop; accessibilityAdjustableAction for HDL-10 while value is set, the button trait while it is not. The resize cursor is NSCursor on macOS and the pointer style on iPadOS. Out of sight (HDL-23) only where a pointer hovers (macOS, iPadOS with a pointer); on a touch screen the line is always drawn (HDL-25).	enabled is the inverse of disabled. Modifier.pointerInput with detectDragGestures; semantics progressBarRangeInfo and setProgress while value is set, Role.Button while it is not; pointerHoverIcon for the cursor on desktop. Out of sight (HDL-23) only where a pointer hovers (a desktop window, a mouse); on a touch screen the line is always drawn (HDL-25).	enabled is the inverse of disabled. A GestureDetector with pan callbacks; Semantics(slider: true, value:, increasedValue:, onIncrease:) while value is set, button: true while it is not; MouseRegion(cursor:) for the resize cursor. Out of sight (HDL-23) only where a pointer hovers (a desktop or web target with a mouse); on a touch screen the line is always drawn (HDL-25).	A PanResponder (or Gesture Handler where the product has it); accessibilityRole="adjustable" with accessibilityActions increment and decrement while value is set, button while it is not. A touch screen has no hover, so the line is always drawn there (HDL-25); where a pointer hovers (react-native-web, Windows, macOS) it is out of sight as HDL-23 says.

令牌

令牌	引用	解析值（浅色）
--tanrei-comp-handle-arc-radius-medium	—	16px
--tanrei-comp-handle-arc-radius-small	—	8px
--tanrei-comp-handle-container-breadth-medium	—	24px
--tanrei-comp-handle-container-breadth-small	—	16px
--tanrei-comp-handle-container-length-medium	—	48px
--tanrei-comp-handle-container-length-small	—	20px
--tanrei-comp-handle-container-shape	sys.shape.corner.full	9999px
--tanrei-comp-handle-disabled-opacity	—	1
--tanrei-comp-handle-focused-opacity	—	1
--tanrei-comp-handle-hovered-opacity	—	1
--tanrei-comp-handle-inset	sys.space.space50	4px
--tanrei-comp-handle-line-active-length-medium	—	40px
--tanrei-comp-handle-line-active-length-small	—	16px
--tanrei-comp-handle-line-active-thickness-medium	—	6px
--tanrei-comp-handle-line-active-thickness-small	—	4px
--tanrei-comp-handle-line-length-medium	—	32px
--tanrei-comp-handle-line-length-small	—	12px
--tanrei-comp-handle-line-thickness-medium	—	4px
--tanrei-comp-handle-line-thickness-small	—	3px
--tanrei-comp-handle-motion-feedback-duration	sys.motion.role.feedback	450ms
--tanrei-comp-handle-motion-state-duration	sys.motion.role.state.compact	200ms
--tanrei-comp-handle-motion-state-easing	sys.motion.easing.state	cubic-bezier(0.2, 0, 0, 1)
--tanrei-comp-handle-pressed-opacity	—	1
--tanrei-comp-handle-standard-container-color	—	#000000 · 0%
--tanrei-comp-handle-standard-disabled-container-color	—	#000000 · 0%
--tanrei-comp-handle-standard-disabled-line-color	—	#1b1b1b · 38%
--tanrei-comp-handle-standard-disabled-state-layer-color	—	#1b1b1b · 38%
--tanrei-comp-handle-standard-focused-container-color	—	#848484 · 10%
--tanrei-comp-handle-standard-focused-line-color	—	#848484
--tanrei-comp-handle-standard-focused-state-layer-color	—	#848484
--tanrei-comp-handle-standard-hovered-container-color	—	#848484 · 8%
--tanrei-comp-handle-standard-hovered-line-color	—	#4b4b4b
--tanrei-comp-handle-standard-hovered-state-layer-color	—	#848484
--tanrei-comp-handle-standard-line-color	sys.color.outline	#848484
--tanrei-comp-handle-standard-pressed-container-color	—	#848484 · 10%
--tanrei-comp-handle-standard-pressed-line-color	—	#4b4b4b
--tanrei-comp-handle-standard-pressed-state-layer-color	—	#848484
--tanrei-comp-handle-standard-state-layer-color	comp.handle.standard.line.color	#848484

测试样例

作为基准的渲染结果。所有平台都以相同的 ID 为每个样例截取快照，以便相互比较。

size: small (3)

small

size: small value: 4 label: Resize message revealed: true

small-horizontal

axis: horizontal size: small value: 4 label: Resize message revealed: true

small-both

axis: both size: small value: 4 label: Resize message revealed: true

size: medium (10)

default

label: Resize sheet

revealed

label: Resize sheet revealed: true

horizontal

axis: horizontal value: 50 label: Resize preview revealed: true

both-bottom-end

axis: both value: 6 min: 3 max: 12 valueText: 6 lines label: Resize message revealed: true

both-bottom-start

axis: both corner: bottom-start value: 6 label: Resize message revealed: true

both-top-end

axis: both corner: top-end value: 6 label: Resize message revealed: true

both-top-start

axis: both corner: top-start value: 6 label: Resize message revealed: true

button-expanded

expanded: true label: Sheet height revealed: true

disabled

value: 50 label: Resize preview disabled: true revealed: true

rtl-both

axis: both value: 6 label: Resize message revealed: true direction: rtl

生成自 specs/handle.spec.json, tokens/comp/handle.tokens.json, design/tokens/

指南

link

何时使用

link

在应当让人把某样东西调成想要的大小的地方使用：写长回答的字段、地图上的面板、侧边面板、以另一宽度查看页面的预览。

你需要	使用
把列表中的项移到另一个位置	列表的重新排序手柄，用圆点绘制。线改变大小，点改变位置。
在几个固定大小之间选择，中间没有其他大小	分段按钮，或切换大小的按钮。
从下边升起的面板	底部面板，它绘制自己的拖动手柄。

形态

link

axis	绘制为	位于
vertical（默认）	一段水平短线	下边或上边：改变高度。
horizontal	一段竖直短线	起始边或结束边：改变宽度。
both	一段朝 corner 鼓起的四分之一圆弧	角：同时改变高度和宽度。

corner 用逻辑方向书写：end 在从左到右的布局中是右边，在从右到左的布局中是左边，因此 bottom-end 的圆弧会自行跟随页面的方向。

size	用于
medium（默认）	面板、窗格、框。
small	文本字段的角，较大的标记会遮住文字的地方。

两种尺寸都保持最小目标。命中区域在需要时会伸出它所在之物之外，而不改变绘制的样子。

它告诉你什么，你做什么

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事件	何时	你做什么
resizestart	拖动开始：按下后移动超过了触摸容差。	记住开始时的大小。关闭所调整之物中任何 iframe 的 pointer-events。
resize	拖动移动的每一帧。inline 和 block 是距按下点的距离（像素）：inline 朝结束边为正，block 向下为正。	设置大小：开始的大小加上距离，用你自己的单位，在你的范围之内。
resizeend	拖动结束，只一次。平台取消时 cancelled 为 true。	保留大小，或者在被取消时恢复。重新打开 iframe。
step	某个按键请求了变化：axis、direction（1 或 −1）和 amount（one、large，Home 和 End 为 limit）。	决定一步是多少——一行、1 或 10 像素、5%——并按它改变大小。
activate	不拖动而按下并松开，或按 Enter 或 Space。	在你知道的两个大小之间切换：文字所需的高度和最小高度，全宽和之前的宽度。

每次改变之后，把新的大小作为 value 交给手柄（还有 min、max，以及数字说不清时的 valueText）。辅助技术读出的就是它。没有 value 的手柄是一个按钮：只在你知道的大小之间切换的手柄用这种形态，并给它 expanded。

使用之前看不见

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调整手柄很安静：静止时什么也不绘制，让人看到的是它所在之物，而不是工具。鼠标移到它上面、键盘焦点到达它、以及按下和拖动期间，它才显现。移到它上面时，指针也变成调整大小的光标。在没有悬停的触摸屏上，它总是被绘制。

在必须被看到才能被发现的地方设置 revealed：面板的握把就是这样，它告诉人面板可以拉动。如果希望在指针位于手柄所在之物上时显示手柄（字段在被指向时显示它角上的手柄），也在那段时间设置它。

放置

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手柄只占它自己的框，把它放到边或角上的是你。把线放在边的中间。把圆弧放在角上，并让那个角的半径等于 arc.radius 加 inset，这样圆弧和角共用一个圆心。

推荐

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• 给每个手柄一个说明它调整什么的 label：“调整笔记大小”“调整预览大小”。
• 每次改变后把大小作为 value 交还，并在 valueText 中用你的单位书写。
• 用一个不需要拖动的大小来响应 activate。
• 保持调整后的大小，直到人再次改变它。

避免

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• 不要用手柄把东西移到另一个位置。
• 不要把东西缩小到其内容无法使用的大小，也不要把页面放宽到需要横向滚动的宽度。
• 不要把手柄放在人正在阅读的文字上；它是边上的标记。

无障碍

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角色

separator (focusable, with a value) while value is set; button while value is null

标注

Named by label, which says what it resizes, in the product's words; required. A handle with a value is a focusable separator with its value, least and greatest value and value text; a handle without one is a button, with the expanded state where its owner gives one. The line is hidden.

最小目标

即使外观尺寸更小，点击区域也满足最小目标尺寸。 minimum 32px · pointer 44px · spacing 8px · touch 48px

键盘操作

按键	动作
Tab	Moves focus to the handle; it is one stop, also while it is out of sight, and comes into sight with its focus ring.
Arrow keys of its axis	Ask the owner for one step along the axis (step, amount one). Shift asks for a large step.
Page Up / Page Down	Ask for a large step along the block axis (the inline axis for a handle that changes a width).
Home / End	Ask for the owner's least and greatest size (step, amount limit), as a window splitter does.
Enter / Space	Activates the handle (activate): the owner switches between the sizes it knows.

备注

• Window splitter pattern (WAI-ARIA Authoring Practices): a focusable separator with aria-valuenow, aria-valuemin and aria-valuemax, arrow keys of its orientation, Enter to collapse and restore, Home and End to the least and greatest size. The handle emits the request and its owner keeps the value, so a sheet, a field and a frame each say what a step is.
• Dragging movements (WCAG 2.5.7): every owner gives a size reachable without a drag through activate (HDL-7) — a field's height its text needs, a sheet's other height, a frame's whole width.
• A handle changes a size, never a place. A reorder handle (the list's six dots, a button that opens a move menu) is another control with other keys; the two are told apart by shape: a line is a size, dots are a place.
• Out of sight until used (HDL-23 to HDL-25). Focus visible (WCAG 2.4.7) and focus not obscured (2.4.11) ask that a keyboard user sees what has focus: the handle comes into sight with its focus ring the moment Tab reaches it. A fine pointer is told it is there by the resize cursor and the line as it comes over it. Nothing is hidden from assistive technology, and the size it offers never depends on finding it by a drag (2.5.7). A touch screen has no hover, so there it is always drawn; an owner that needs it seen at rest everywhere sets revealed (a sheet's grip).

生成自 specs/handle.spec.json, tokens/sys/measure.tokens.json

组件负责的部分

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• 有 value 时，它是一个可聚焦的分隔符——ARIA Authoring Practices 中的窗口分隔条——由 label 命名，带有值、范围、值文本和线的方向。没有时，它是一个按钮，在你提供时带有展开状态。
• 即使看不见，它也是焦点顺序中的一个停靠点。键盘焦点一到就连同焦点环立即显现，所以用键盘的人总能看到焦点在哪里。
• 轴向的方向键请求一步，Shift 加方向键以及 Page Up 和 Page Down 请求一大步，Home 和 End 请求最小和最大的大小。Enter 和 Space 激活它。其他所有按键都交给你。
• 按下不会取得焦点，也不会选中文字，所以拖动手柄时字段仍保留插入符。拖动会跟随指针越过窗口的边缘。
• 不拖动而按下就会激活，所以你提供的每个大小都能用一次点击或轻点到达。
• 放大文字时它保持原来的大小：它是边上的标记，不是文字。
• 在强制颜色模式下，线使用按钮文字颜色，被指向或按下时使用高亮颜色，禁用时使用禁用文字颜色。
• 在从右到左的布局中，圆弧的结束一侧的角在左边，斜向光标随之转向，左方向键指向结束边，inline 向左为正。

需要你做的事

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• 提供 label。没有它，手柄仍会绘制并工作，调试构建会报告这一点。
• 用人们熟悉的单位，保持 value、min、max 和 valueText 为最新。
• 用一个不需要拖动的大小来响应 activate。对无法拖动的人来说，只有拖动是不够的。
• 拖动期间，不要让所调整之物中的 iframe 获取指针（pointer-events: none），否则指针经过它时拖动会中断。
• 确认在你允许的每个大小下内容都仍然可用。