Route canvas keyboard claims through text and gesture boundaries

src/lib/canvas-bindings/index.ts

@@ -10,3 +10,5 @@ export type * from './compat-types.ts';
 
 export {createSelectorStore} from './selectors.ts';
 export type {ExternalSource} from './selectors.ts';
+export {routeCanvasKey} from './input-router.ts';
+export type {CanvasKeyInput,InputClaim,KeyHandler} from './input-router.ts';

src/lib/canvas-bindings/input-router.ts

@@ -0,0 +1,11 @@
+/** Host normalizes DOM/native input; only the winning layer consumes an event. */
+export type CanvasKeyInput={readonly key:string;readonly composing?:boolean;readonly textEditing?:boolean;readonly overlay?:boolean;readonly defaultPrevented?:boolean;readonly ctrl?:boolean;readonly meta?:boolean;readonly alt?:boolean;readonly shift?:boolean};
+export type InputClaim='text'|'overlay'|'gesture'|'tool'|'shortcut'|'unclaimed';
+export type KeyHandler=(input:CanvasKeyInput)=>boolean;
+export function routeCanvasKey(input:CanvasKeyInput,handlers:{gesture?:KeyHandler;tool?:KeyHandler;shortcut?:KeyHandler}):InputClaim{
+ if(input.defaultPrevented)return 'unclaimed';
+ if(input.composing||input.textEditing)return 'text';
+ if(input.overlay)return 'overlay';
+ for(const layer of ['gesture','tool','shortcut'] as const)if(handlers[layer]?.(input))return layer;
+ return 'unclaimed';
+}