flutter_syntax_highlight 0.4.0

Dart-only syntax highlighting in two layers: a pure-Dart tokenizer underneath and a thin widget on top. The tokens rejoin into the exact input, byte for byte.

Changelog

0.4.0

On Android, the horizontal scrollbar of SyntaxText can now be dragged. Before this, touch users there had no way to scroll sideways: dragging over the text selects it, and the scrollbar was hidden and ignored drags.

• On Android, the horizontal scrollbar is always shown and draggable, unless your app's ScrollbarThemeData sets thumbVisibility or interactive. A value you set wins, even false. The vertical scrollbar is unchanged, and other platforms are unchanged.
• Because the bar is now interactive on Android, tapping along it also pages the code sideways. Flutter's scrollbar cannot allow dragging without that.
• With scrollable: true, the horizontal scrollbar is now drawn at the bottom of the widget on every platform, instead of after the last line of code.
• Both scrollbars now sit at the edges of the widget, and ignore the screen's insets (MediaQuery padding). Before this, a widget in the middle of a phone screen drew its horizontal bar over the last line of code, raised by the bottom inset, and the vertical bar's track was shortened by the top and bottom insets. Keeping the widget out of the system areas is your app's job, for example with SafeArea. Text selection still sees the insets.
• On desktop, with scrollable: true, the vertical scrollbar is no longer drawn twice. Material adds its own scrollbar to vertical scroll views on desktop, and it tracked the same position as the widget's. The widget now turns that one off for its vertical view only, and keeps the rest of your app's ScrollBehavior.
• A palette with a background no longer replaces your app's scrollbar theme. It sets only the thumb color, and keeps the rest of your ScrollbarThemeData.

0.3.0

SyntaxText now glides on a mouse wheel instead of jumping a notch at a time.

Breaking: the SDK floor is now Flutter 3.32 / Dart 3.8 (was 3.27 / 3.6). The wheel motion comes from flutter_smooth_wheel_scroll, which needs that floor. On Flutter 3.27–3.31, stay on 0.2.0.

• A wheel notch animates to its target with a spring, and notches during the motion add to the target. It never passes the start or end of the code. Shift+wheel moves sideways the same way, and a wheel turned over the scrollbar glides too, because the scrollbar shares the view's controller.
• Dragging, dragging the scrollbar, the keyboard and the trackpad move exactly as before.
• wheelMotion picks the motion: WheelMotion.spring (the default), .curve or .lerp, or null to move at once. It applies to both axes, and changing it keeps the scroll position.
• WheelMotion is exported from this package, so you do not need to depend on flutter_smooth_wheel_scroll yourself to pass one.
• How far a notch travels is app-wide and not set here — use SmoothWheelBinding from flutter_smooth_wheel_scroll in your main().
• The example gained a wheel demo: a code block longer and wider than the window, with a picker for the motion.

0.2.0

The palette derived from your ColorScheme now borrows your app's accent, in two places, diluted. Nothing else changed; the tokenizer is untouched.

• string (and escape, which follows its literal) is pulled from onSurfaceVariant towards tertiary; function, which had no style at all, is pulled from onSurface towards primary. number and punctuation stay where they were, so the literals gain a distinction between them.
• It still introduces no hue of its own — every colour is a neutral role from your scheme or a neutral role mixed with one of your scheme's accents, and a monochrome scheme still yields a monochrome palette.
• How far to pull was measured over the whole hue circle in both brightnesses, against two scales this palette already contained. See docs/adr/0003-the-derived-default-borrows-the-app-s-accent-diluted.md.
• The example gained a seed picker, so the derivation is visible rather than merely claimed.

Named presets are unchanged. If you pass one, or your own SyntaxPalette, nothing about this release affects you.

0.1.0

First release.

Tokenizer

• tokenizeDart(String source) returns a List<DartToken> whose texts concatenate back to the input, byte for byte. Tokens are cut at recorded offsets and never rebuilt, so CRLF and letter case survive unchanged.
• The file imports nothing — not Flutter, not dart:* — and a test fails if that ever stops being true.
• Eight kinds, every one decidable by scanning characters left to right: plain, comment, keyword, string, number, punctuation, escape, function. Distinctions that need a parser are deliberately absent; the reasoning is in docs/adr/0001-token-kinds-are-lexical-only.md.
• The inside of ${...} is scanned recursively with the same rules as the outside, so a string nested in an interpolation comes back out as a string. Nested block comments, raw strings, triple-quoted strings, and unterminated strings and interpolations are each handled, the last two by stopping at the end of the line.

Widget

• SyntaxText(source, {palette, copyable, scrollable, fontFamily, fontFamilyFallback, fontSize, height, padding, copyTooltip, copiedTooltip}) draws selectable, copyable code. It takes a string, not an asset key, so it has no loading state.
• Horizontal scrolling is always owned by the widget — code does not wrap. scrollable governs the vertical axis only.
• SyntaxPalette holds one optional TextStyle per kind plus an optional background. SyntaxPalette.fromColorScheme derives the default from the consumer's ColorScheme without introducing a hue of its own, and paints no background, so it is right in light and dark with nothing to configure.
• Ten named presets — solarizedDark, solarizedLight, oneDark, oneLight, monokai, gruvboxDark, gruvboxLight, tokyoNight, tokyoNightLight, cobalt2 — each an excerpt of an MIT-licensed upstream theme, carrying the background its colours were chosen against. Provenance, pinned commit by pinned commit, is in NOTICES.