From 34ff7f1a7f7b04683087a544129937879cbf7b38 Mon Sep 17 00:00:00 2001
From: luxick <git@luxick.de>
Date: Thu, 15 Jan 2026 19:56:08 +0100
Subject: [PATCH] image zooming

---
 script.js | 427 ++++++++++++++++++++++++++++++++++--------------------
 style.css |   2 +
 2 files changed, 273 insertions(+), 156 deletions(-)

diff --git a/script.js b/script.js
index 4f12933..660120d 100644
--- a/script.js
+++ b/script.js
@@ -3,6 +3,267 @@
 (function () {
   'use strict';
 
+  // ============================================================
+  // Lightbox Module
+  // ============================================================
+  var Lightbox = (function () {
+    var lb = null;
+    var img = null;
+    var cap = null;
+    var items = [];
+    var index = 0;
+
+    // Zoom/pan state
+    var scale = 1;
+    var panX = 0;
+    var panY = 0;
+    var minScale = 1;
+    var maxScale = 5;
+    var isPanning = false;
+    var panStartX = 0;
+    var panStartY = 0;
+
+    // History state
+    var pushedHistory = false;
+    var closingFromPopstate = false;
+
+    function ensureElement() {
+      if (lb) return;
+
+      lb = document.createElement('div');
+      lb.className = 'luxtools-lightbox';
+      lb.setAttribute('role', 'dialog');
+      lb.setAttribute('aria-modal', 'true');
+      lb.setAttribute('aria-hidden', 'true');
+
+      lb.innerHTML =
+        '<div class="luxtools-lightbox-backdrop" data-luxtools-action="close"></div>' +
+        '<div class="luxtools-lightbox-stage">' +
+          '<button type="button" class="luxtools-lightbox-close" data-luxtools-action="close" aria-label="Close">×</button>' +
+          '<button type="button" class="luxtools-lightbox-zone luxtools-lightbox-zone-prev" data-luxtools-action="prev" aria-label="Previous"></button>' +
+          '<button type="button" class="luxtools-lightbox-zone luxtools-lightbox-zone-next" data-luxtools-action="next" aria-label="Next"></button>' +
+          '<div class="luxtools-lightbox-media">' +
+            '<img class="luxtools-lightbox-img" alt="" />' +
+          '</div>' +
+          '<div class="luxtools-lightbox-caption"></div>' +
+        '</div>';
+
+      document.body.appendChild(lb);
+      img = lb.querySelector('img.luxtools-lightbox-img');
+      cap = lb.querySelector('.luxtools-lightbox-caption');
+
+      lb.addEventListener('click', onClick);
+    }
+
+    function clampIndex(n) {
+      if (n < 0) return items.length - 1;
+      if (n >= items.length) return 0;
+      return n;
+    }
+
+    function applyTransform() {
+      if (scale <= 1 && panX === 0 && panY === 0) {
+        img.style.transform = '';
+      } else {
+        img.style.transform = 'scale(' + scale + ') translate(' + panX + 'px, ' + panY + 'px)';
+      }
+      img.style.cursor = scale > 1 ? 'grab' : '';
+    }
+
+    function resetZoom() {
+      scale = 1;
+      panX = 0;
+      panY = 0;
+      applyTransform();
+    }
+
+    function render() {
+      var it = items[index];
+      img.src = it.full;
+      img.setAttribute('data-luxtools-index', String(index));
+      if (cap) cap.textContent = (it.name || '').trim();
+      resetZoom();
+    }
+
+    function next() {
+      index = clampIndex(index + 1);
+      render();
+    }
+
+    function prev() {
+      index = clampIndex(index - 1);
+      render();
+    }
+
+    // Event handlers
+    function onWheel(e) {
+      e.preventDefault();
+      var delta = e.deltaY > 0 ? -0.15 : 0.15;
+      scale = Math.max(minScale, Math.min(maxScale, scale + delta));
+      if (scale <= 1) { panX = 0; panY = 0; }
+      applyTransform();
+    }
+
+    function onDblClick(e) {
+      e.preventDefault();
+      if (scale > 1) {
+        scale = 1;
+        panX = 0;
+        panY = 0;
+      } else {
+        scale = 2.5;
+      }
+      applyTransform();
+    }
+
+    function onMouseDown(e) {
+      if (scale > 1 && e.button === 0) {
+        isPanning = true;
+        panStartX = e.clientX - panX * scale;
+        panStartY = e.clientY - panY * scale;
+        img.style.cursor = 'grabbing';
+        e.preventDefault();
+      }
+    }
+
+    function onMouseMove(e) {
+      if (isPanning && scale > 1) {
+        panX = (e.clientX - panStartX) / scale;
+        panY = (e.clientY - panStartY) / scale;
+        applyTransform();
+        img.style.cursor = 'grabbing';
+      }
+    }
+
+    function onMouseUp() {
+      isPanning = false;
+      img.style.cursor = scale > 1 ? 'grab' : '';
+    }
+
+    function onKeyDown(e) {
+      if (!lb || !lb.classList.contains('is-open')) return;
+      var key = e.key || '';
+      if (key === 'Escape') {
+        e.preventDefault();
+        close();
+      } else if (key === 'ArrowRight') {
+        e.preventDefault();
+        next();
+      } else if (key === 'ArrowLeft') {
+        e.preventDefault();
+        prev();
+      }
+    }
+
+    function onPopState() {
+      if (!lb || !lb.classList.contains('is-open')) return;
+      closingFromPopstate = true;
+      try { close(); } finally { closingFromPopstate = false; }
+    }
+
+    function onClick(e) {
+      var t = e.target;
+      if (!t || !t.getAttribute) return;
+      var action = t.getAttribute('data-luxtools-action') || '';
+      if (action === 'close') { e.preventDefault(); close(); return; }
+      if (action === 'next') { e.preventDefault(); next(); return; }
+      if (action === 'prev') { e.preventDefault(); prev(); return; }
+
+      if (t.closest && t.closest('button.luxtools-lightbox-zone')) return;
+      if (t.closest && t.closest('img.luxtools-lightbox-img')) return;
+      e.preventDefault();
+      close();
+    }
+
+    function attachListeners() {
+      document.addEventListener('keydown', onKeyDown, true);
+      window.addEventListener('popstate', onPopState, true);
+      img.addEventListener('wheel', onWheel, { passive: false });
+      img.addEventListener('dblclick', onDblClick);
+      img.addEventListener('mousedown', onMouseDown);
+      document.addEventListener('mousemove', onMouseMove);
+      document.addEventListener('mouseup', onMouseUp);
+    }
+
+    function detachListeners() {
+      document.removeEventListener('keydown', onKeyDown, true);
+      window.removeEventListener('popstate', onPopState, true);
+      img.removeEventListener('wheel', onWheel);
+      img.removeEventListener('dblclick', onDblClick);
+      img.removeEventListener('mousedown', onMouseDown);
+      document.removeEventListener('mousemove', onMouseMove);
+      document.removeEventListener('mouseup', onMouseUp);
+    }
+
+    function open(galleryEl, startEl) {
+      var links = galleryEl.querySelectorAll('a.luxtools-gallery-item[data-luxtools-full]');
+      items = [];
+      links.forEach(function (a) {
+        var full = a.getAttribute('data-luxtools-full') || a.getAttribute('href') || '';
+        var name = a.getAttribute('data-luxtools-name') || a.getAttribute('title') || '';
+        if (!full) return;
+        items.push({ el: a, full: full, name: name });
+      });
+      if (!items.length) return;
+
+      index = 0;
+      for (var i = 0; i < items.length; i++) {
+        if (items[i].el === startEl) { index = i; break; }
+      }
+
+      ensureElement();
+      pushedHistory = false;
+      closingFromPopstate = false;
+
+      lb.classList.add('is-open');
+      lb.setAttribute('aria-hidden', 'false');
+      try { document.documentElement.classList.add('luxtools-noscroll'); } catch (e) {}
+      try { document.body.style.overflow = 'hidden'; } catch (e) {}
+
+      attachListeners();
+
+      try {
+        if (window.history && window.history.pushState) {
+          window.history.pushState({ luxtoolsLightbox: 1 }, '', window.location.href);
+          pushedHistory = true;
+        }
+      } catch (e) {}
+
+      render();
+    }
+
+    function close() {
+      if (!lb) return;
+
+      lb.classList.remove('is-open');
+      lb.setAttribute('aria-hidden', 'true');
+      try { document.documentElement.classList.remove('luxtools-noscroll'); } catch (e) {}
+      try { document.body.style.overflow = ''; } catch (e) {}
+      img.src = '';
+      resetZoom();
+
+      detachListeners();
+
+      if (pushedHistory && !closingFromPopstate) {
+        try {
+          if (window.history && window.history.state && window.history.state.luxtoolsLightbox === 1) {
+            window.history.back();
+          }
+        } catch (e) {}
+      }
+
+      items = [];
+    }
+
+    return {
+      open: open,
+      close: close
+    };
+  })();
+
+  // ============================================================
+  // Gallery Thumbnails
+  // ============================================================
   function initGalleryThumbs() {
     var imgs = document.querySelectorAll('div.luxtools-gallery img[data-thumb-src]');
     if (!imgs || !imgs.length) return;
@@ -43,161 +304,9 @@
     }
   }
 
-  function ensureLightbox() {
-    var existing = document.querySelector('.luxtools-lightbox');
-    if (existing) return existing;
-
-    var root = document.createElement('div');
-    root.className = 'luxtools-lightbox';
-    root.setAttribute('role', 'dialog');
-    root.setAttribute('aria-modal', 'true');
-    root.setAttribute('aria-hidden', 'true');
-
-    root.innerHTML =
-      '<div class="luxtools-lightbox-backdrop" data-luxtools-action="close"></div>' +
-      '<div class="luxtools-lightbox-stage">' +
-        '<button type="button" class="luxtools-lightbox-close" data-luxtools-action="close" aria-label="Close">×</button>' +
-        '<button type="button" class="luxtools-lightbox-zone luxtools-lightbox-zone-prev" data-luxtools-action="prev" aria-label="Previous"></button>' +
-        '<button type="button" class="luxtools-lightbox-zone luxtools-lightbox-zone-next" data-luxtools-action="next" aria-label="Next"></button>' +
-        '<div class="luxtools-lightbox-media">' +
-          '<img class="luxtools-lightbox-img" alt="" />' +
-        '</div>' +
-        '<div class="luxtools-lightbox-caption"></div>' +
-      '</div>';
-
-    document.body.appendChild(root);
-    return root;
-  }
-
-  function getGalleryItems(galleryEl) {
-    var links = galleryEl.querySelectorAll('a.luxtools-gallery-item[data-luxtools-full]');
-    var items = [];
-    links.forEach(function (a) {
-      var full = a.getAttribute('data-luxtools-full') || a.getAttribute('href') || '';
-      var name = a.getAttribute('data-luxtools-name') || a.getAttribute('title') || '';
-      if (!full) return;
-      items.push({ el: a, full: full, name: name });
-    });
-    return items;
-  }
-
-  function openLightboxFor(galleryEl, startEl) {
-    var items = getGalleryItems(galleryEl);
-    if (!items.length) return;
-
-    var index = 0;
-    for (var i = 0; i < items.length; i++) {
-      if (items[i].el === startEl) { index = i; break; }
-    }
-
-    var lb = ensureLightbox();
-    var img = lb.querySelector('img.luxtools-lightbox-img');
-    var cap = lb.querySelector('.luxtools-lightbox-caption');
-
-    var pushedHistory = false;
-    var closingFromPopstate = false;
-
-    function clamp(n) {
-      if (n < 0) return items.length - 1;
-      if (n >= items.length) return 0;
-      return n;
-    }
-
-    function render() {
-      var it = items[index];
-      img.src = it.full;
-      img.setAttribute('data-luxtools-index', String(index));
-      if (cap) cap.textContent = (it.name || '').trim();
-    }
-
-    function close() {
-      lb.classList.remove('is-open');
-      lb.setAttribute('aria-hidden', 'true');
-      try { document.documentElement.classList.remove('luxtools-noscroll'); } catch (e) {}
-      try { document.body.style.overflow = ''; } catch (e) {}
-      // Clear src to stop downloads on close.
-      img.src = '';
-      document.removeEventListener('keydown', onKeyDown, true);
-      window.removeEventListener('popstate', onPopState, true);
-
-      // If we opened by pushing a state, pop it when closing via UI.
-      if (pushedHistory && !closingFromPopstate) {
-        try {
-          if (window.history && window.history.state && window.history.state.luxtoolsLightbox === 1) {
-            window.history.back();
-          }
-        } catch (e) {
-          // ignore
-        }
-      }
-    }
-
-    function next() {
-      index = clamp(index + 1);
-      render();
-    }
-
-    function prev() {
-      index = clamp(index - 1);
-      render();
-    }
-
-    function onKeyDown(e) {
-      if (!lb.classList.contains('is-open')) return;
-      var key = e.key || '';
-      if (key === 'Escape') {
-        e.preventDefault();
-        close();
-      } else if (key === 'ArrowRight') {
-        e.preventDefault();
-        next();
-      } else if (key === 'ArrowLeft') {
-        e.preventDefault();
-        prev();
-      }
-    }
-
-    function onPopState() {
-      if (!lb.classList.contains('is-open')) return;
-      closingFromPopstate = true;
-      try { close(); } finally { closingFromPopstate = false; }
-    }
-
-    lb.onclick = function (e) {
-      var t = e.target;
-      if (!t || !t.getAttribute) return;
-      var action = t.getAttribute('data-luxtools-action') || '';
-      if (action === 'close') { e.preventDefault(); close(); return; }
-      if (action === 'next') { e.preventDefault(); next(); return; }
-      if (action === 'prev') { e.preventDefault(); prev(); return; }
-
-      // Click outside the image closes (but don't interfere with controls).
-      if (t.closest && t.closest('button.luxtools-lightbox-zone')) return;
-      if (t.closest && t.closest('img.luxtools-lightbox-img')) return;
-      e.preventDefault();
-      close();
-    };
-
-    // Open
-    lb.classList.add('is-open');
-    lb.setAttribute('aria-hidden', 'false');
-    try { document.documentElement.classList.add('luxtools-noscroll'); } catch (e) {}
-    try { document.body.style.overflow = 'hidden'; } catch (e) {}
-    document.addEventListener('keydown', onKeyDown, true);
-    window.addEventListener('popstate', onPopState, true);
-
-    // Allow closing via browser back button.
-    try {
-      if (window.history && window.history.pushState) {
-        window.history.pushState({ luxtoolsLightbox: 1 }, '', window.location.href);
-        pushedHistory = true;
-      }
-    } catch (e) {
-      // ignore
-    }
-    render();
-  }
-
+  // ============================================================
+  // Open Service (file:// links)
+  // ============================================================
   function getServiceUrl(el) {
     var url = el.getAttribute('data-service-url') || '';
     url = (url || '').trim();
@@ -444,6 +553,9 @@
     }, true);
   }
 
+  // ============================================================
+  // Click Handlers
+  // ============================================================
   function findOpenElement(target) {
     var el = target;
     while (el && el !== document) {
@@ -469,7 +581,7 @@
       var gallery = galleryItem.closest ? galleryItem.closest('div.luxtools-gallery[data-luxtools-gallery="1"]') : null;
       if (gallery) {
         event.preventDefault();
-        openLightboxFor(gallery, galleryItem);
+        Lightbox.open(gallery, galleryItem);
         return;
       }
     }
@@ -508,6 +620,9 @@
       });
   }
 
+  // ============================================================
+  // Initialize
+  // ============================================================
   document.addEventListener('click', onClick, false);
   document.addEventListener('DOMContentLoaded', initGalleryThumbs, false);
   document.addEventListener('DOMContentLoaded', initScratchpads, false);
diff --git a/style.css b/style.css
index 88592cd..e3f8d7b 100644
--- a/style.css
+++ b/style.css
@@ -291,6 +291,8 @@ html.luxtools-noscroll body {
      */
     max-width: calc(100vw - 1.6em);
     max-height: calc(100vh - 1.6em);
+    transform-origin: center center;
+    transition: transform 0.1s ease-out;
 }
 
 .luxtools-lightbox .luxtools-lightbox-caption {