마우스 오버 후 1초가 지나면 이미지 미리보기 팝업창 실행

src/renderer/handlers/hover-preview.js

@@ -0,0 +1,73 @@
+const DELAY = 1000;
+
+let _el      = null;
+let _imgEl   = null;
+let _timer   = null;
+let _visible = false;
+
+export function init() {
+  _el = document.createElement('div');
+  _el.className = 'hover-preview';
+
+  _imgEl = document.createElement('img');
+  _el.appendChild(_imgEl);
+  document.body.appendChild(_el);
+}
+
+export function setupCard(card) {
+  card.addEventListener('mouseenter', _onEnter);
+  card.addEventListener('mouseleave', _onLeave);
+}
+
+function _onEnter() {
+  const card = this;
+  clearTimeout(_timer);
+  _timer = setTimeout(() => {
+    const thumb = card.querySelector('img.card-thumb');
+    if (!thumb) return;
+    _imgEl.src = thumb.src;
+    _visible = true;
+    _show(card);
+  }, DELAY);
+}
+
+function _onLeave() {
+  clearTimeout(_timer);
+  _timer   = null;
+  _visible = false;
+  _el.style.display     = 'none';
+  _el.style.visibility  = 'hidden';
+}
+
+function _show(card) {
+  // 위치 계산 전 화면 밖에 렌더링해서 실제 크기를 측정
+  _el.style.display    = 'block';
+  _el.style.visibility = 'hidden';
+  _el.style.left = '0px';
+  _el.style.top  = '0px';
+
+  requestAnimationFrame(() => {
+    if (!_visible) return;
+
+    const popup    = _el.getBoundingClientRect();
+    const cardRect = card.getBoundingClientRect();
+    const vw = window.innerWidth;
+    const vh = window.innerHeight;
+    const gap = 16;
+
+    // 가로: 카드 오른쪽 우선, 공간 부족 시 왼쪽
+    let left = cardRect.right + gap;
+    if (left + popup.width > vw - 8) {
+      left = cardRect.left - popup.width - gap;
+    }
+    left = Math.max(8, Math.min(left, vw - popup.width - 8));
+
+    // 세로: 카드와 중앙 정렬, 화면 경계 클램프
+    let top = cardRect.top + (cardRect.height - popup.height) / 2;
+    top = Math.max(8, Math.min(top, vh - popup.height - 8));
+
+    _el.style.left       = left + 'px';
+    _el.style.top        = top  + 'px';
+    _el.style.visibility = 'visible';
+  });
+}

src/renderer/renderer.js

@@ -1,7 +1,8 @@
-import { state }     from './state.js';
-import * as pinchZoom from './handlers/pinch-zoom.js';
-import * as selection  from './handlers/selection.js';
-import * as dragDrop   from './handlers/drag-drop.js';
+import { state }        from './state.js';
+import * as pinchZoom   from './handlers/pinch-zoom.js';
+import * as selection    from './handlers/selection.js';
+import * as dragDrop     from './handlers/drag-drop.js';
+import * as hoverPreview from './handlers/hover-preview.js';
 
 // ── DOM ──────────────────────────────────────────────
 const grid          = document.getElementById('grid');
@@ -38,6 +39,7 @@ const callbacks = {
 pinchZoom.init({ gridContainer, thumbSizeHint });
 selection.init({ gridContainer, rubberBand, grid, state, callbacks });
 dragDrop.init({ grid, gridContainer, dragGhostEl, state, callbacks });
+hoverPreview.init();
 
 // ── 버튼 이벤트 ──────────────────────────────────
 inputPrefix.addEventListener('input', updatePreview);
@@ -146,6 +148,7 @@ function createCard(file, idx, dataUrl) {
   card.appendChild(body);
 
   dragDrop.setupCard(card);
+  hoverPreview.setupCard(card);
   card.addEventListener('click', selection.onCardClick);
 
   return card;

src/renderer/style.css

@@ -269,6 +269,29 @@ body {
 @keyframes spin { to { transform: rotate(360deg); } }
 #loading p { color: var(--text); font-size: 14px; }
 
+/* ── 호버 이미지 팝업 ── */
+.hover-preview {
+  position: fixed;
+  display: none;
+  visibility: hidden;
+  z-index: 8000;
+  pointer-events: none;
+  background: #0d0d1a;
+  border: 1px solid var(--border);
+  border-radius: 12px;
+  padding: 8px;
+  box-shadow: 0 20px 60px rgba(0,0,0,0.85), 0 0 0 1px rgba(124,106,247,0.15);
+}
+.hover-preview img {
+  display: block;
+  max-width: 840px;
+  max-height: 840px;
+  width: auto;
+  height: auto;
+  border-radius: 6px;
+  object-fit: contain;
+}
+
 /* ── 토스트 ── */
 #toast {
   position: fixed; bottom: 40px; left: 50%;