blinc_input

Polling-style input state for Blinc sketches and canvases.

Blinc's event model is callback-based — div().on_key_down(|e| …). Sketches and games typically want the polling shape: inside draw(), ask is_key_down(KeyCode::SPACE) or mouse_position(). blinc_input bridges the two.

Recommended wiring

Route events through blinc_canvas_kit if you're using it — both Sketch and CanvasKit already scope events to their canvas so you don't need to touch Div handles yourself:

// With `sketch(...)`:
use blinc_canvas_kit::prelude::*;   // includes SketchEvents
use blinc_input::InputState;
use blinc_core::events::KeyCode;

let input = InputState::new();
let i = input.clone();
let tree = sketch("demo", my_sketch).on_canvas_events(move |e| i.record(e));

// With `CanvasKit` (interactive node graphs, editors):
let mut kit = CanvasKit::new("main");
let i = input.clone();
kit.on_any_event(move |e| i.record(e));

Inside your draw loop, poll freely:

if input.is_key_down(KeyCode::SPACE)              { /* jump */ }
if input.is_mouse_just_pressed(MouseButton::Left) { /* fire */ }
let (mx, my) = input.mouse_position();
let (sx, sy) = input.scroll_delta();

input.frame_end();  // clear edge-triggered state for next frame

Bare Div escape hatch

If you're not using blinc_canvas_kit, attach the same bundle of handlers directly via the DivInputExt::capture_input helper:

use blinc_input::{DivInputExt, InputState};

let input = InputState::new();
let tree = div().w_full().h_full().capture_input(&input)
    .child(/* … */);

What's tracked

• Keys: held / just-pressed / just-released, with KeyCode from blinc_core::events.
• Mouse buttons: MouseButton::{Left, Middle, Right, Other(n)}, same held / just-pressed / just-released surface.
• Mouse position: (local_x, local_y) in the capturing Div's coordinate space.
• Scroll delta: accumulated per frame, cleared on frame_end.
• Modifiers: shift / ctrl / alt / meta snapshot from the most recent event.

See BACKLOG.md for planned additions — gamepad, virtual axis mapping, touch tracking, action-binding layer.

Event routing — what's reliable and what isn't

Built on top of Blinc's event router, so behavior inherits Blinc's rules:

• Pointer + scroll bubble through every ancestor of the hit / hovered element. capture_input(&root) reliably sees every pointer-down, pointer-up, pointer-move, and scroll — no caveat.
• Keys bubble leaf-to-root and stop at the first handler. Focus is set implicitly on pointer-down (the clicked node and its full ancestor chain become focused); clicking outside clears it. So:
  • In a sketch whose subtree has no child key handlers, keys reach capture_input after the first pointer-down anywhere inside.
  • If the subtree contains a widget that handles keys itself (text_input, code_editor, custom on_key_down on a child), that descendant absorbs the key and capture_input never sees it. Keep key-capturing widgets outside the region you want to drive with blinc_input, or read from them directly.

License

Apache-2.0.