tryst-segmented

An iOS/web-style segmented control for tryst, Crystal's Tcl/Tk binding — a rounded pill of mutually exclusive text options with a sliding highlight, in place of a row of ttk radio buttons. Built on Tryst::OwnerDrawnWidget and rendered through tryst-vector.

require "tryst"
require "tryst-segmented"

app = Tryst::App.new
control = Tryst::SegmentedControl.new(app, options: ["Day", "Week", "Month", "Year"], selected: "Week")
control.pack(padx: 16, pady: 8)

control.on_action { |value| puts "now on #{value}" }

app.show
app.mainloop

API

Constructor

• options — the segment labels, left to right. Must be non-empty and contain no duplicates.
• selected — starts on options.first if not given; must be one of options.
• accent — a #rrggbb hex string to override the theme's own accent color.
• disabled_dim — how much the accent/text dim when the whole control is disabled (0.0–1.0, default 0.45).
• height — the pill's height in logical pixels. Segment width comes from each label's own text, not from height — segments are never forced to equal width.

Instance methods

• #selected / #selected= — read or set the current selection. #selected= never fires #on_action.
• #on_action { |value| ... } — fires on every user-driven change (click, Left/Right), never for a programmatic #selected=.
• #disable_segment(option) / #enable_segment(option) / #segment_disabled?(option) — disable one segment without affecting the rest of the control. Independent of #disabled= (inherited, disables the whole control).

Interaction: click a segment, or Tab into the control and use Left/Right (clamped at either end, skipping any disabled segments).

There's no ui.segmented/DSL bind: — like Switch and ValueSlider, this lives at the App layer, not as a registered WidgetType (see CUSTOM_WIDGETS.md). Wire a Tryst::UI::Var manually:

control.on_action { |v| var.value = v }
var.on_change { |v| control.selected = v }

Requirements

Whatever tryst and tryst-vector need — Crystal >= 1.21.0, Tcl/Tk 8.6, and ThorVG >= 1.0 (see tryst-vector's own README).

Examples

crystal run examples/segmented_control_demo.cr

Tests

shards install
crystal spec                    # host
scripts/docker-test.sh          # Debian forky, same suite

scripts/docker-test.sh builds from this repo's own root; shards install inside the image fetches tryst and tryst-vector directly via their github: dependencies. It takes the same arguments crystal spec does, so a focused run works there too.