first-commit

skills/html-ppt/assets/animations/fx/_util.js

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+/* html-ppt fx :: shared helpers */
+(function(){
+  window.HPX = window.HPX || {};
+  const U = window.HPX._u = {};
+
+  U.css = (el, name, fb) => {
+    const v = getComputedStyle(el).getPropertyValue(name).trim();
+    return v || fb;
+  };
+
+  U.accent = (el, fb) => U.css(el, '--accent', fb || '#7c5cff');
+  U.accent2 = (el, fb) => U.css(el, '--accent-2', fb || '#22d3ee');
+  U.text = (el, fb) => U.css(el, '--text-1', fb || '#eaeaf2');
+
+  U.palette = (el) => [
+    U.accent(el, '#7c5cff'),
+    U.accent2(el, '#22d3ee'),
+    U.css(el, '--ok', '#22c55e'),
+    U.css(el, '--warn', '#f59e0b'),
+    U.css(el, '--danger', '#ef4444'),
+  ];
+
+  U.canvas = (el) => {
+    if (getComputedStyle(el).position === 'static') el.style.position = 'relative';
+    const c = document.createElement('canvas');
+    c.style.cssText = 'position:absolute;inset:0;width:100%;height:100%;pointer-events:none;display:block;';
+    el.appendChild(c);
+    const ctx = c.getContext('2d');
+    let w = 0, h = 0, dpr = Math.max(1, Math.min(2, window.devicePixelRatio||1));
+    const fit = () => {
+      const r = el.getBoundingClientRect();
+      w = Math.max(1, r.width|0);
+      h = Math.max(1, r.height|0);
+      c.width = (w*dpr)|0;
+      c.height = (h*dpr)|0;
+      ctx.setTransform(dpr,0,0,dpr,0,0);
+    };
+    fit();
+    const ro = new ResizeObserver(fit);
+    ro.observe(el);
+    return {
+      c, ctx,
+      get w(){return w;}, get h(){return h;}, get dpr(){return dpr;},
+      destroy(){
+        try{ro.disconnect();}catch(e){}
+        if (c.parentNode) c.parentNode.removeChild(c);
+      }
+    };
+  };
+
+  U.loop = (fn) => {
+    let raf = 0, stopped = false, t0 = performance.now();
+    const tick = (t) => {
+      if (stopped) return;
+      fn((t - t0)/1000);
+      raf = requestAnimationFrame(tick);
+    };
+    raf = requestAnimationFrame(tick);
+    return () => { stopped = true; cancelAnimationFrame(raf); };
+  };
+
+  U.rand = (a,b) => a + Math.random()*(b-a);
+})();