From a08b77a4547f63a50c1e0b30e932b24c4dd73c51 Mon Sep 17 00:00:00 2001
From: Alexander Bocken <alexander@bocken.org>
Date: Mon, 9 Feb 2026 08:48:05 +0100
Subject: [PATCH] extract PiP drag/snap/enlarge logic into shared createPip()
 utility

Both StickyImage and rosary page now use the same pip.svelte.ts factory
for mobile drag-to-corner, snap, and double-tap enlarge behavior.
---
 src/lib/components/StickyImage.svelte         | 138 ++-------------
 src/lib/js/pip.svelte.ts                      | 164 ++++++++++++++++++
 .../[rosary=rosaryLang]/+page.svelte          |  63 ++++++-
 3 files changed, 232 insertions(+), 133 deletions(-)
 create mode 100644 src/lib/js/pip.svelte.ts

diff --git a/src/lib/components/StickyImage.svelte b/src/lib/components/StickyImage.svelte
index 6638700b..b6fed7d7 100644
--- a/src/lib/components/StickyImage.svelte
+++ b/src/lib/components/StickyImage.svelte
@@ -1,5 +1,6 @@
 <script>
 	import { onMount } from 'svelte';
+	import { createPip } from '$lib/js/pip.svelte';
 
 	/**
 	 * @param {'layout' | 'overlay'} mode
@@ -10,17 +11,9 @@
 
 	let pipEl = $state(null);
 	let contentEl = $state(null);
-	let corner = $state('bottom-right');
-	let dragging = $state(false);
-	let enlarged = $state(false);
 	let inView = $state(false);
-	let dragOffset = { x: 0, y: 0 };
-	let dragPos = $state({ x: 0, y: 0 });
-	let dragMoved = false;
-	let lastTapTime = 0;
-	const MARGIN = 16;
-	const TAP_THRESHOLD = 10;
-	const DOUBLE_TAP_MS = 400;
+
+	const pip = createPip();
 
 	function isMobile() {
 		return !window.matchMedia('(min-width: 1024px)').matches;
@@ -31,121 +24,14 @@
 		return isMobile();
 	}
 
-	// Whether the image visibility is controlled by IntersectionObserver
-	function isObserverControlled() {
-		return mode === 'overlay';
-	}
-
-	function getCornerPos(c, el) {
-		const vw = window.innerWidth;
-		const vh = window.innerHeight;
-		const r = el.getBoundingClientRect();
-		return {
-			'top-left': { x: MARGIN, y: MARGIN },
-			'top-right': { x: vw - r.width - MARGIN, y: MARGIN },
-			'bottom-left': { x: MARGIN, y: vh - r.height - MARGIN },
-			'bottom-right': { x: vw - r.width - MARGIN, y: vh - r.height - MARGIN },
-		}[c];
-	}
-
-	function snapToCorner(el, c) {
-		const pos = getCornerPos(c, el);
-		corner = c;
-		dragPos = pos;
-		el.style.transition = 'transform 0.25s ease';
-		el.style.transform = `translate(${pos.x}px, ${pos.y}px)`;
-		el.addEventListener('transitionend', () => { el.style.transition = ''; }, { once: true });
-	}
-
-	function nearestCorner(x, y, el) {
-		const vw = window.innerWidth;
-		const vh = window.innerHeight;
-		const r = el.getBoundingClientRect();
-		const cx = x + r.width / 2;
-		const cy = y + r.height / 2;
-		const left = cx < vw / 2;
-		const top = cy < vh / 2;
-		return `${top ? 'top' : 'bottom'}-${left ? 'left' : 'right'}`;
-	}
-
-	function onPointerDown(e) {
-		if (!pipEl || !isPipActive()) return;
-		dragging = true;
-		dragMoved = false;
-		const r = pipEl.getBoundingClientRect();
-		dragOffset = { x: e.clientX - r.left, y: e.clientY - r.top };
-		pipEl.setPointerCapture(e.pointerId);
-		pipEl.style.transition = '';
-		e.preventDefault();
-	}
-
-	function onPointerMove(e) {
-		if (!dragging || !pipEl) return;
-		const x = e.clientX - dragOffset.x;
-		const y = e.clientY - dragOffset.y;
-		if (!dragMoved) {
-			const dx = Math.abs(x - dragPos.x);
-			const dy = Math.abs(y - dragPos.y);
-			if (dx > TAP_THRESHOLD || dy > TAP_THRESHOLD) dragMoved = true;
-		}
-		dragPos = { x, y };
-		pipEl.style.transform = `translate(${x}px, ${y}px)`;
-	}
-
-	function toggleEnlarged() {
-		if (!pipEl) return;
-		const rect = pipEl.getBoundingClientRect();
-		const vh = window.innerHeight / 100;
-		const currentH = enlarged ? 37.5 * vh : 25 * vh;
-		const targetH = enlarged ? 25 * vh : 37.5 * vh;
-		const ratio = targetH / currentH;
-
-		enlarged = !enlarged;
-
-		const newW = rect.width * ratio;
-		const newH = rect.height * ratio;
-		let newX = rect.left;
-		let newY = rect.top;
-		if (corner.includes('right')) newX = rect.right - newW;
-		if (corner.includes('bottom')) newY = rect.bottom - newH;
-
-		dragPos = { x: newX, y: newY };
-		pipEl.style.transition = 'transform 0.25s ease';
-		pipEl.style.transform = `translate(${newX}px, ${newY}px)`;
-		pipEl.addEventListener('transitionend', () => {
-			pipEl.style.transition = '';
-		}, { once: true });
-	}
-
-	function onPointerUp(e) {
-		if (!dragging || !pipEl) return;
-		dragging = false;
-
-		if (!dragMoved) {
-			const now = Date.now();
-			if (now - lastTapTime < DOUBLE_TAP_MS) {
-				lastTapTime = 0;
-				toggleEnlarged();
-				return;
-			}
-			lastTapTime = now;
-		}
-
-		const r = pipEl.getBoundingClientRect();
-		snapToCorner(pipEl, nearestCorner(r.left, r.top, pipEl));
-	}
-
 	function updateVisibility() {
 		if (!pipEl) return;
 		if (isPipActive()) {
 			// Mobile PiP mode
 			if (inView) {
-				const pos = getCornerPos(corner, pipEl);
-				dragPos = pos;
-				pipEl.style.transform = `translate(${pos.x}px, ${pos.y}px)`;
-				pipEl.style.opacity = '1';
+				pip.show(pipEl);
 			} else {
-				pipEl.style.opacity = '0';
+				pip.hide();
 			}
 		} else {
 			// Desktop (both modes): CSS handles everything
@@ -161,7 +47,11 @@
 
 	function onResize() {
 		if (!pipEl) return;
-		updateVisibility();
+		if (isPipActive() && inView) {
+			pip.reposition();
+		} else {
+			updateVisibility();
+		}
 	}
 
 	onMount(() => {
@@ -193,11 +83,11 @@
 	<!-- svelte-ignore a11y_no_static_element_interactions -->
 	<div
 		class="image-wrap"
-		class:enlarged
+		class:enlarged={pip.enlarged}
 		bind:this={pipEl}
-		onpointerdown={onPointerDown}
-		onpointermove={onPointerMove}
-		onpointerup={onPointerUp}
+		onpointerdown={pip.onpointerdown}
+		onpointermove={pip.onpointermove}
+		onpointerup={pip.onpointerup}
 	>
 		<img {src} {alt}>
 	</div>
diff --git a/src/lib/js/pip.svelte.ts b/src/lib/js/pip.svelte.ts
new file mode 100644
index 00000000..9906866a
--- /dev/null
+++ b/src/lib/js/pip.svelte.ts
@@ -0,0 +1,164 @@
+/**
+ * Shared PiP (Picture-in-Picture) drag/snap/enlarge composable.
+ * Extracts duplicated mobile PiP logic from StickyImage and rosary page.
+ */
+
+interface PipOptions {
+	margin?: number;
+	tapThreshold?: number;
+	doubleTapMs?: number;
+	initialCorner?: Corner;
+	smallHeight?: number;
+	largeHeight?: number;
+}
+
+type Corner = 'top-left' | 'top-right' | 'bottom-left' | 'bottom-right';
+
+export function createPip(opts: PipOptions = {}) {
+	const margin = opts.margin ?? 16;
+	const tapThreshold = opts.tapThreshold ?? 10;
+	const doubleTapMs = opts.doubleTapMs ?? 400;
+	const smallVh = opts.smallHeight ?? 25;
+	const largeVh = opts.largeHeight ?? 37.5;
+
+	let corner: Corner = $state(opts.initialCorner ?? 'bottom-right');
+	let dragging = $state(false);
+	let enlarged = $state(false);
+
+	let dragOffset = { x: 0, y: 0 };
+	let dragPos = { x: 0, y: 0 };
+	let dragMoved = false;
+	let lastTapTime = 0;
+	let el: HTMLElement | null = null;
+
+	function getCornerPos(c: Corner, target: HTMLElement) {
+		const vw = window.innerWidth;
+		const vh = window.innerHeight;
+		const r = target.getBoundingClientRect();
+		const positions: Record<Corner, { x: number; y: number }> = {
+			'top-left': { x: margin, y: margin },
+			'top-right': { x: vw - r.width - margin, y: margin },
+			'bottom-left': { x: margin, y: vh - r.height - margin },
+			'bottom-right': { x: vw - r.width - margin, y: vh - r.height - margin },
+		};
+		return positions[c];
+	}
+
+	function nearestCorner(x: number, y: number, target: HTMLElement): Corner {
+		const vw = window.innerWidth;
+		const vh = window.innerHeight;
+		const r = target.getBoundingClientRect();
+		const cx = x + r.width / 2;
+		const cy = y + r.height / 2;
+		const left = cx < vw / 2;
+		const top = cy < vh / 2;
+		return `${top ? 'top' : 'bottom'}-${left ? 'left' : 'right'}` as Corner;
+	}
+
+	function snapToCorner(target: HTMLElement, c: Corner) {
+		const pos = getCornerPos(c, target);
+		corner = c;
+		dragPos = pos;
+		target.style.transition = 'transform 0.25s ease';
+		target.style.transform = `translate(${pos.x}px, ${pos.y}px)`;
+		target.addEventListener('transitionend', () => { target.style.transition = ''; }, { once: true });
+	}
+
+	function toggleEnlarged() {
+		if (!el) return;
+		const rect = el.getBoundingClientRect();
+		const vh = window.innerHeight / 100;
+		const currentH = enlarged ? largeVh * vh : smallVh * vh;
+		const targetH = enlarged ? smallVh * vh : largeVh * vh;
+		const ratio = targetH / currentH;
+
+		enlarged = !enlarged;
+
+		const newW = rect.width * ratio;
+		const newH = rect.height * ratio;
+		let newX = rect.left;
+		let newY = rect.top;
+		if (corner.includes('right')) newX = rect.right - newW;
+		if (corner.includes('bottom')) newY = rect.bottom - newH;
+
+		dragPos = { x: newX, y: newY };
+		el.style.transition = 'transform 0.25s ease';
+		el.style.transform = `translate(${newX}px, ${newY}px)`;
+		el.addEventListener('transitionend', () => {
+			el!.style.transition = '';
+		}, { once: true });
+	}
+
+	function show(target: HTMLElement) {
+		el = target;
+		const pos = getCornerPos(corner, target);
+		dragPos = pos;
+		target.style.transform = `translate(${pos.x}px, ${pos.y}px)`;
+		target.style.opacity = '1';
+	}
+
+	function hide() {
+		if (el) el.style.opacity = '0';
+	}
+
+	function reposition() {
+		if (!el) return;
+		const pos = getCornerPos(corner, el);
+		dragPos = pos;
+		el.style.transform = `translate(${pos.x}px, ${pos.y}px)`;
+	}
+
+	function onpointerdown(e: PointerEvent) {
+		if (!el) return;
+		dragging = true;
+		dragMoved = false;
+		const r = el.getBoundingClientRect();
+		dragOffset = { x: e.clientX - r.left, y: e.clientY - r.top };
+		el.setPointerCapture(e.pointerId);
+		el.style.transition = '';
+		e.preventDefault();
+	}
+
+	function onpointermove(e: PointerEvent) {
+		if (!dragging || !el) return;
+		const x = e.clientX - dragOffset.x;
+		const y = e.clientY - dragOffset.y;
+		if (!dragMoved) {
+			const dx = Math.abs(x - dragPos.x);
+			const dy = Math.abs(y - dragPos.y);
+			if (dx > tapThreshold || dy > tapThreshold) dragMoved = true;
+		}
+		dragPos = { x, y };
+		el.style.transform = `translate(${x}px, ${y}px)`;
+	}
+
+	function onpointerup(_e: PointerEvent) {
+		if (!dragging || !el) return;
+		dragging = false;
+
+		if (!dragMoved) {
+			const now = Date.now();
+			if (now - lastTapTime < doubleTapMs) {
+				lastTapTime = 0;
+				toggleEnlarged();
+				return;
+			}
+			lastTapTime = now;
+		}
+
+		const r = el.getBoundingClientRect();
+		snapToCorner(el, nearestCorner(r.left, r.top, el));
+	}
+
+	return {
+		get corner() { return corner; },
+		get dragging() { return dragging; },
+		get enlarged() { return enlarged; },
+		show,
+		hide,
+		reposition,
+		onpointerdown,
+		onpointermove,
+		onpointerup
+	};
+}
diff --git a/src/routes/[faithLang=faithLang]/[rosary=rosaryLang]/+page.svelte b/src/routes/[faithLang=faithLang]/[rosary=rosaryLang]/+page.svelte
index 02e0c30f..dd02a0cd 100644
--- a/src/routes/[faithLang=faithLang]/[rosary=rosaryLang]/+page.svelte
+++ b/src/routes/[faithLang=faithLang]/[rosary=rosaryLang]/+page.svelte
@@ -1,6 +1,7 @@
 <script>
 import { onMount } from "svelte";
 import { createLanguageContext } from "$lib/contexts/languageContext.js";
+import { createPip } from "$lib/js/pip.svelte";
 import "$lib/css/christ.css";
 import "$lib/css/action_button.css";
 import Kreuzzeichen from "$lib/components/prayers/Kreuzzeichen.svelte";
@@ -352,6 +353,25 @@ function getMysteryImage(mystery, section) {
 }
 const mysteryPipSrc = $derived(getMysteryImage(selectedMystery, activeSection));
 
+// Mobile PiP drag/enlarge
+const pip = createPip();
+let rosaryPipEl = $state(null);
+let lastPipSrc = $state(null);
+
+function isMobilePip() {
+	return !window.matchMedia('(min-width: 900px)').matches;
+}
+
+$effect(() => {
+	if (mysteryPipSrc) lastPipSrc = mysteryPipSrc;
+	if (!rosaryPipEl || !isMobilePip()) return;
+	if (mysteryPipSrc) {
+		pip.show(rosaryPipEl);
+	} else {
+		pip.hide();
+	}
+});
+
 let mysteryImageContainer;
 let mysteryScrollRaf = null;
 
@@ -491,6 +511,14 @@ onMount(() => {
 	// Now allow saving to localStorage
 	hasLoadedFromStorage = true;
 
+	// PiP resize handler
+	const onPipResize = () => {
+		if (rosaryPipEl && isMobilePip() && mysteryPipSrc) {
+			pip.reposition();
+		}
+	};
+	window.addEventListener('resize', onPipResize);
+
 	let scrollLock = null; // Track which side initiated the scroll: 'prayer', 'svg', or 'click'
 	let scrollLockTimeout = null;
 
@@ -835,6 +863,7 @@ onMount(() => {
 		clearTimeout(scrollLockTimeout);
 		clearTimeout(svgScrollTimeout);
 		window.removeEventListener('scroll', handleWindowScroll);
+		window.removeEventListener('resize', onPipResize);
 		if (svgContainer) {
 			svgContainer.removeEventListener('scroll', handleSvgScroll);
 		}
@@ -1392,15 +1421,17 @@ h1 {
 /* Mobile PiP for mystery images */
 .mystery-pip {
 	position: fixed;
-	bottom: 16px;
-	right: 16px;
+	top: 0;
+	left: 0;
 	z-index: 10000;
-	pointer-events: none;
 	opacity: 0;
-	transition: opacity 0.3s ease;
+	touch-action: none;
+	cursor: grab;
+	user-select: none;
+	transition: opacity 0.25s ease;
 }
-.mystery-pip.visible {
-	opacity: 1;
+.mystery-pip:active {
+	cursor: grabbing;
 }
 .mystery-pip img {
 	height: 25vh;
@@ -1408,6 +1439,11 @@ h1 {
 	object-fit: contain;
 	border-radius: 6px;
 	box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
+	pointer-events: none;
+	transition: height 0.25s ease;
+}
+.mystery-pip.enlarged img {
+	height: 37.5vh;
 }
 @media (min-width: 900px) {
 	.mystery-pip {
@@ -1819,9 +1855,18 @@ h1 {
 
 	<!-- Mobile PiP for mystery images -->
 	{#if hasMysteryImages}
-		<div class="mystery-pip" class:visible={!!mysteryPipSrc}>
-			{#if mysteryPipSrc}
-				<img src={mysteryPipSrc} alt="">
+		<!-- svelte-ignore a11y_no_static_element_interactions -->
+		<div
+			class="mystery-pip"
+			class:visible={!!mysteryPipSrc}
+			class:enlarged={pip.enlarged}
+			bind:this={rosaryPipEl}
+			onpointerdown={pip.onpointerdown}
+			onpointermove={pip.onpointermove}
+			onpointerup={pip.onpointerup}
+		>
+			{#if lastPipSrc}
+				<img src={lastPipSrc} alt="">
 			{/if}
 		</div>
 	{/if}