v0.2.1

A long document in the editor lays out only what the window shows, syntax colours in a text field follow its edits, an incremental syntax document, and a scrollbar thumb 2px off its edge.

New

• syntax::document::Document holds a source parsed across edits. edit takes the replaced byte range, where the new text ends and the whole text now, reparses from the old tree and answers the byte ranges whose spans may have changed; spans and spans_in answer what syntax::highlight would paint. Document::new answers None for a wasm grammar and for a language with an injections query.
• ui::input::Edit is one replacement in a field's text, as start, old_end and new_end byte offsets. Edit::between gives the smallest edit between two texts and Edit::map carries a byte range through one.
• ui::scroll::Overlay::margin sets the gap between the pane's edge and a scrollbar thumb, across the axis. It defaults to 2px, and the 10px track under the thumb keeps its width at any margin.
• Theme::EDGE (12) is the distance from a column's edge to the glyph of the control at the end of a row. ui::widgets::ICON_GLYPH is the icon button's glyph size and ICON_EDGE_PAD the padding that sets an icon button's glyph EDGE from its container's edge.
• markdown::Editing::keep names blocks, or source lines for render_source, to build wherever they are, and Editing::scroll is the scroll container a document sits in.

Changed

• With layouts given, markdown::render_with and render_source build only the blocks, or source lines, within half a screen of the part of the window the document shows, plus the caret's, the selection anchor's and those in keep. The rest are placed at their last measured height or a guess from their length, BlockLayouts answers only for what was built, and heights above the first block showing that come out different move Editing::scroll by the difference.
• markdown::Editing has keep and scroll fields; a struct literal without ..Default::default() has to name them.
• FieldEvent::Changed carries the Edit the field applied, and TextField moves its syntax spans through each edit rather than leaving them where they were until set_spans.
• Overlay::channel is gone; Overlay::margin places the thumb. A scrollbar thumb sits 2px from the pane's edge rather than 7px.
• markdown::Block, BlockKind, Text, MarkSpan, Mark, Form, QuoteKind and Align derive Hash.
• Editor::select on an editor without focus builds and reveals the selected block, keeping the reveal until the caret is in view.
• Built on bezel-gpui 0.3.13.

Fixed

• Scrolling a long document in the editor costs time in proportion to the window rather than the document: 1000 sections scroll at about 1 ms a frame, down from 33 ms.
• Text and icons over a translucent background no longer carry a dark rim along their edges on macOS; bezel-gpui 0.3.13 blends the destination alpha with one minus the source alpha.
• Syntax colours in a TextField stay on their characters between an edit and the recolour that follows it.