ddd

client/input/drag.js

@@ -0,0 +1,73 @@
+(function(root,factory){
+  const api=factory(root.BendFrameScheduler);
+  if(typeof module==='object'&&module.exports)module.exports=factory(require('./frame-scheduler.js'));
+  root.BendDragScheduler=api;
+})(typeof globalThis!=='undefined'?globalThis:this,function(FrameScheduler){
+  'use strict';
+
+  const STATES=Object.freeze(['idle','armed','running','draining','settling','cancelled']);
+
+  function createDragScheduler(options={}){
+    if(!FrameScheduler?.createFrameScheduler)throw new TypeError('BendFrameScheduler is required');
+    if(typeof options.onFrame!=='function')throw new TypeError('Drag onFrame callback is required');
+    const maxSamples=Math.max(2,Number(options.maxSamples)||12);
+    const trim=typeof options.trim==='function'?options.trim:samples=>samples.splice(0,Math.max(0,samples.length-maxSamples));
+    let state='idle',pointerId=null,latest=null,logical=[],revision=0,visualRevision=0,logicalRevision=0;
+    const frame=FrameScheduler.createFrameScheduler({
+      interval:options.interval,
+      tolerance:options.tolerance,
+      watchdogDelay:options.watchdogDelay,
+      requestFrame:options.requestFrame,
+      cancelFrame:options.cancelFrame,
+      setDelay:options.setDelay,
+      clearDelay:options.clearDelay,
+      now:options.now,
+      onWatchdog:options.onWatchdog,
+      commit:(_signal,timestamp)=>options.onFrame(api,timestamp)
+    });
+    const assertState=next=>{if(!STATES.includes(next))throw new TypeError(`Unknown drag state: ${next}`);state=next};
+    const clearData=()=>{pointerId=null;latest=null;logical.length=0;revision=0;visualRevision=0;logicalRevision=0};
+    const arm=id=>{
+      if(id==null)throw new TypeError('Drag pointerId is required');
+      frame.cancel({resetCadence:true});clearData();pointerId=id;assertState('armed');return api;
+    };
+    const push=(sample,{schedule=true}={})=>{
+      if(!sample||sample.pointerId==null)return false;
+      if(state==='idle'||state==='cancelled'||state==='settling')arm(sample.pointerId);
+      if(sample.pointerId!==pointerId||state==='draining')return false;
+      latest=sample;logical.push(sample);trim(logical,maxSamples);revision++;
+      if(state==='armed')assertState('running');
+      if(schedule)frame.push(revision);
+      return revision;
+    };
+    const requestFrame=()=>{if(latest&&state!=='idle'&&state!=='cancelled')frame.push(revision)};
+    const beginDrain=sample=>{
+      if(sample)push(sample,{schedule:false});
+      if(state==='idle'||state==='cancelled')return false;
+      frame.cancel();assertState('draining');return true;
+    };
+    const beginSettling=()=>{if(state==='draining'||state==='running'||state==='armed')assertState('settling');frame.cancel();return state==='settling'};
+    const settle=()=>{frame.cancel({resetCadence:true});clearData();assertState('idle')};
+    const cancel=()=>{frame.cancel({resetCadence:true});clearData();assertState('cancelled')};
+    const takeLogical=max=>{
+      const count=Math.max(0,Math.min(logical.length,Number(max)||1));
+      return logical.splice(0,count);
+    };
+    const drainLogical=()=>logical.splice(0);
+    const markVisual=()=>{visualRevision=revision};
+    const markLogical=()=>{if(!logical.length)logicalRevision=revision};
+    const inspect=()=>Object.freeze({
+      state,pointerId,latest,logicalCount:logical.length,revision,visualRevision,logicalRevision,
+      freshVisual:visualRevision!==revision,freshLogical:logicalRevision!==revision
+    });
+    const api=Object.freeze({
+      arm,push,requestFrame,beginDrain,beginSettling,settle,cancel,takeLogical,drainLogical,
+      latest:()=>latest,
+      hasLogical:()=>logical.length>0,
+      markVisual,markLogical,inspect
+    });
+    return api;
+  }
+
+  return Object.freeze({STATES,createDragScheduler});
+});