LevelIndicator

Remarks

⚠ Not a ProgressBar with colours, and the difference is what the reading means rather than how it is drawn. A progress bar is about a job: it starts empty, only ever goes up, and being full is the good outcome. A level indicator is about a capacity — a disk, a battery, a budget, a memory pool — which goes both ways, never finishes, and where full may be exactly the thing you are worried about. Doc 49 § 7.1 ranks this sixth of the missing controls because ProgressBar was the only readout in the set and every panel wanting a capacity had to misuse it.

⚠ Which direction is bad is inferred from the order of the two thresholds whenever there are two. Warning = 0.7, Critical = 0.9 is a disk filling up and Warning = 0.3, Critical = 0.1 is a battery running down, with nothing else to set. See Level.

⚠ And stated by Direction when there is one line, because one line has no order. This type used to refuse any such property, arguing that a flag beside two numbers can contradict them and leave a control "silently wrong and looking configured". Both halves of that were wrong. A contradiction is not silent: a falling direction over a disk's rising pair reads Critical at every ordinary reading, which is the first thing anybody sees. What was silent was the case the refusal created — a battery with only Critical = 0.1 set had no way to say it falls, was inferred rising, and read critical at a full charge with nothing to show it was a guess (#1353). Inferred is still the default and still reads a lone line as a ceiling, so no existing indicator moves.

⚠ The level is a class rather than a colour. level-indicator.warning and .critical are what the theme selects on, exactly as .indeterminate is for a progress bar, so which hues mean "nearly full" stays a decision of the stylesheet and one palette answers for the whole interface. A Color4 property here would be a second palette that the theme cannot see.

Segmented and continuous are one control: Segments at zero draws a bar and above zero draws that many blocks of which the filled fraction is lit, which is what a signal strength or a rating is. Splitting them would be two controls with one arithmetic problem and two chances to round the boundary differently.

Fields and properties (15)

• protected override string TagName

  The element name this type answers to when a caller does not choose one.

• protected override bool AcceptsFocus
• protected override AccessibleRole NativeRole

  The role this kind of element has when nobody says otherwise.

• protected override string? NativeAccessibleValue
• public float Value
• public float Warning
• public float Critical
• public LevelDirection Direction
• public int Segments
• public LevelReading Level

  What the reading currently amounts to.

• public static readonly UiPropertyKey ValueProperty

  Identity for Value.

• public static readonly UiPropertyKey WarningProperty

  Identity for Warning.

• public static readonly UiPropertyKey CriticalProperty

  Identity for Critical.

• public static readonly UiPropertyKey DirectionProperty

  Identity for Direction.

• public static readonly UiPropertyKey SegmentsProperty

  Identity for Segments.

Methods (7)

• protected override void OnCreated()

  Builds whatever this element is made of, once, as it joins a document.

• protected override void OnDraw(DrawContext context)

  Draws whatever this element is, beyond what a stylesheet can describe.

• public void ClearValue()

  Unsets Value, so it takes its default or its ancestor's value again.

• public void ClearWarning()

  Unsets Warning, so it takes its default or its ancestor's value again.

• public void ClearCritical()

  Unsets Critical, so it takes its default or its ancestor's value again.

• public void ClearDirection()

  Unsets Direction, so it takes its default or its ancestor's value again.

• public void ClearSegments()

  Unsets Segments, so it takes its default or its ancestor's value again.

Used by (5)

• GalleryHelloUi
• GaugeTestsVixen.Ui.Controls.Tests
• LevelIndicatorImageTestsVixen.Graphics.Golden.Tests
• LevelIndicatorTestsVixen.Ui.Controls.Tests
• RangeFillEdgeTestsVixen.Ui.Controls.Tests