feat(web): lecteur mobile — révéler le header au tap uniquement en vertical sur téléphone (scroll/wheel passifs ignorés) et piloter le zoom au pinch à deux doigts borné par les mêmes limites que les boutons, via nouveau module readerGestures (évolution #41)

apps/web/src/pages/ReaderPage.tsx

@@ -179,6 +179,7 @@ export function ReaderPage({ bookId }: { bookId: number }) {
       supportsZoom
         ? {
             zoom,
+            onZoomChange: (nextZoom) => changeZoom(nextZoom),
             onZoomOut: () => changeZoom((currentZoom) => currentZoom - READER_ZOOM_STEP),
             onZoomIn: () => changeZoom((currentZoom) => currentZoom + READER_ZOOM_STEP),
             onZoomReset: () => changeZoom(READER_ZOOM_DEFAULT)

apps/web/src/reader/ReaderShell.tsx

@@ -1,5 +1,5 @@
 import { ArrowLeft, ArrowRight, Maximize2, Minimize2 } from "lucide-react";
-import { useCallback, useEffect, useRef, useState, type ReactNode } from "react";
+import { useCallback, useEffect, useRef, useState, type PointerEvent as ReactPointerEvent, type ReactNode } from "react";
 import { ErrorRibbon } from "../components/ui";
 import { navigate } from "../router";
 import {
@@ -11,6 +11,7 @@ import {
   shouldHandleReaderNavigationKey,
   supportsElementFullscreen
 } from "./readerFullscreen";
+import { readerMovedBeyondTap, readerPinchZoom, readerPointDistance, type ReaderPoint } from "./readerGestures";
 import { readerZoomLabel, READER_ZOOM_DEFAULT, READER_ZOOM_MAX, READER_ZOOM_MIN } from "./readerLayout";
 import type { ReaderMode } from "./readerScroll";
 
@@ -24,6 +25,7 @@ export type ReaderControls = {
 
 export type ReaderZoomControls = {
   zoom: number;
+  onZoomChange: (zoom: number) => void;
   onZoomOut: () => void;
   onZoomIn: () => void;
   onZoomReset: () => void;
@@ -50,12 +52,19 @@ export function ReaderShell({ title, backHref, error, onRetry, controls, zoomCon
   const headerRef = useRef<HTMLElement>(null);
   const stageRef = useRef<HTMLElement>(null);
   const headerHideTimerRef = useRef<number | undefined>(undefined);
+  const tapStartRef = useRef<ReaderPoint | null>(null);
+  const activeTouchPointsRef = useRef(new Map<number, ReaderPoint>());
+  const pinchRef = useRef<{ distance: number; zoom: number } | null>(null);
   const [nativeFullscreen, setNativeFullscreen] = useState(false);
   const [fallbackFullscreen, setFallbackFullscreen] = useState(false);
   const [headerVisible, setHeaderVisible] = useState(true);
   const fullscreenActive = nativeFullscreen || fallbackFullscreen;
   const readerMode = modeControls?.mode ?? "horizontal";
 
+  const isMobileReaderViewport = useCallback(() => window.matchMedia("(max-width: 900px) and (pointer: coarse)").matches, []);
+
+  const shouldUseTapOnlyHeaderReveal = useCallback(() => readerMode === "vertical" && isMobileReaderViewport(), [isMobileReaderViewport, readerMode]);
+
   const clearHeaderHideTimer = useCallback(() => {
     if (headerHideTimerRef.current === undefined) return;
     window.clearTimeout(headerHideTimerRef.current);
@@ -83,6 +92,11 @@ export function ReaderShell({ title, backHref, error, onRetry, controls, zoomCon
     scheduleHeaderHide();
   }, [fullscreenActive, scheduleHeaderHide]);
 
+  const revealHeaderForPassiveGesture = useCallback(() => {
+    if (shouldUseTapOnlyHeaderReveal()) return;
+    revealHeader();
+  }, [revealHeader, shouldUseTapOnlyHeaderReveal]);
+
   const toggleFullscreen = useCallback(async () => {
     const readerElement = readerRef.current;
     if (!readerElement) return;
@@ -160,16 +174,99 @@ export function ReaderShell({ title, backHref, error, onRetry, controls, zoomCon
     return () => window.removeEventListener("keydown", handleKeyDown);
   }, [controls, fallbackFullscreen, modeControls?.mode, revealHeader]);
 
+  useEffect(() => {
+    const stage = stageRef.current;
+    if (!stage || !zoomControls) return;
+
+    const touchPoint = (touch: Touch): ReaderPoint => ({ x: touch.clientX, y: touch.clientY });
+    const startPinch = (event: TouchEvent) => {
+      if (!isMobileReaderViewport() || event.touches.length !== 2) {
+        pinchRef.current = null;
+        return;
+      }
+      const distance = readerPointDistance(touchPoint(event.touches[0]), touchPoint(event.touches[1]));
+      pinchRef.current = { distance, zoom: zoomControls.zoom };
+    };
+    const movePinch = (event: TouchEvent) => {
+      if (!pinchRef.current || event.touches.length !== 2) return;
+      event.preventDefault();
+      const distance = readerPointDistance(touchPoint(event.touches[0]), touchPoint(event.touches[1]));
+      zoomControls.onZoomChange(readerPinchZoom(pinchRef.current.zoom, pinchRef.current.distance, distance));
+    };
+    const endPinch = (event: TouchEvent) => {
+      if (event.touches.length < 2) pinchRef.current = null;
+    };
+
+    stage.addEventListener("touchstart", startPinch, { passive: true });
+    stage.addEventListener("touchmove", movePinch, { passive: false });
+    stage.addEventListener("touchend", endPinch);
+    stage.addEventListener("touchcancel", endPinch);
+    return () => {
+      stage.removeEventListener("touchstart", startPinch);
+      stage.removeEventListener("touchmove", movePinch);
+      stage.removeEventListener("touchend", endPinch);
+      stage.removeEventListener("touchcancel", endPinch);
+    };
+  }, [isMobileReaderViewport, zoomControls]);
+
+  const handleReaderPointerDown = useCallback(
+    (event: ReactPointerEvent<HTMLDivElement>) => {
+      if (!shouldUseTapOnlyHeaderReveal()) {
+        revealHeader();
+        return;
+      }
+      if (event.pointerType !== "touch" || !event.isPrimary || activeTouchPointsRef.current.size > 0) {
+        tapStartRef.current = null;
+        return;
+      }
+      activeTouchPointsRef.current.set(event.pointerId, { x: event.clientX, y: event.clientY });
+      tapStartRef.current = { x: event.clientX, y: event.clientY };
+    },
+    [revealHeader, shouldUseTapOnlyHeaderReveal]
+  );
+
+  const handleReaderPointerMove = useCallback(
+    (event: ReactPointerEvent<HTMLDivElement>) => {
+      if (!shouldUseTapOnlyHeaderReveal()) return;
+      const current = { x: event.clientX, y: event.clientY };
+      if (activeTouchPointsRef.current.has(event.pointerId)) activeTouchPointsRef.current.set(event.pointerId, current);
+      const tapStart = tapStartRef.current;
+      if (tapStart && readerMovedBeyondTap(tapStart, current)) tapStartRef.current = null;
+    },
+    [shouldUseTapOnlyHeaderReveal]
+  );
+
+  const handleReaderPointerUp = useCallback(
+    (event: ReactPointerEvent<HTMLDivElement>) => {
+      if (!shouldUseTapOnlyHeaderReveal()) return;
+      activeTouchPointsRef.current.delete(event.pointerId);
+      const tapStart = tapStartRef.current;
+      tapStartRef.current = null;
+      if (event.pointerType === "touch" && event.isPrimary && tapStart && !readerMovedBeyondTap(tapStart, { x: event.clientX, y: event.clientY })) {
+        revealHeader();
+      }
+    },
+    [revealHeader, shouldUseTapOnlyHeaderReveal]
+  );
+
+  const handleReaderPointerCancel = useCallback((event: ReactPointerEvent<HTMLDivElement>) => {
+    activeTouchPointsRef.current.delete(event.pointerId);
+    tapStartRef.current = null;
+  }, []);
+
   return (
     <div
       ref={readerRef}
       className={`reader-page reader-mode-${readerMode}${fallbackFullscreen ? " reader-fullscreen-fallback" : ""}${fullscreenActive ? " reader-fullscreen-active" : ""}${
         fullscreenActive && !headerVisible ? " reader-header-hidden" : ""
       }`}
-      onMouseMove={revealHeader}
-      onPointerDown={revealHeader}
-      onScrollCapture={revealHeader}
-      onWheel={revealHeader}
+      onMouseMove={revealHeaderForPassiveGesture}
+      onPointerDown={handleReaderPointerDown}
+      onPointerMove={handleReaderPointerMove}
+      onPointerUp={handleReaderPointerUp}
+      onPointerCancel={handleReaderPointerCancel}
+      onScrollCapture={revealHeaderForPassiveGesture}
+      onWheel={revealHeaderForPassiveGesture}
     >
       <header
         ref={headerRef}

apps/web/src/reader/readerGestures.ts

@@ -0,0 +1,19 @@
+import { clampReaderZoom } from "./readerLayout";
+
+export type ReaderPoint = {
+  x: number;
+  y: number;
+};
+
+export function readerPointDistance(first: ReaderPoint, second: ReaderPoint) {
+  return Math.hypot(first.x - second.x, first.y - second.y);
+}
+
+export function readerMovedBeyondTap(start: ReaderPoint, current: ReaderPoint, thresholdPx = 10) {
+  return readerPointDistance(start, current) > thresholdPx;
+}
+
+export function readerPinchZoom(startZoom: number, startDistance: number, currentDistance: number) {
+  if (startDistance <= 0 || currentDistance <= 0) return clampReaderZoom(startZoom);
+  return clampReaderZoom(startZoom * (currentDistance / startDistance));
+}

apps/web/src/reader/readerRuntime.test.ts

@@ -17,6 +17,7 @@ import {
 } from "./readerLayout";
 import { classifyPdfCanvas, pdfCanvasHasVisibleContent, pdfCanvasVisible, pdfRenderScale } from "./pdfRender";
 import { isElementFullscreen, isReaderHeaderActive, isReaderInteractiveTarget, readerArrowAction, readerNavigationAction, shouldHandleReaderArrowKey, supportsElementFullscreen } from "./readerFullscreen";
+import { readerMovedBeyondTap, readerPinchZoom, readerPointDistance } from "./readerGestures";
 import { configurePdfWorker, pdfWorkerSrc } from "./pdfWorker";
 import { isPageInRenderWindow, majorityVisiblePage, verticalRenderWindow } from "./readerScroll";
 import { readerErrorMessage } from "./ReaderError";
@@ -147,6 +148,15 @@ describe("reader runtime helpers", () => {
     expect(zoomReaderSize({ width: 800, height: 600 }, 200)).toEqual({ width: 1600, height: 1200 });
   });
 
+  it("maps mobile reader gestures without confusing tap, scroll and pinch", () => {
+    expect(readerPointDistance({ x: 0, y: 0 }, { x: 0, y: 120 })).toBe(120);
+    expect(readerMovedBeyondTap({ x: 20, y: 20 }, { x: 24, y: 27 })).toBe(false);
+    expect(readerMovedBeyondTap({ x: 20, y: 20 }, { x: 20, y: 42 })).toBe(true);
+    expect(readerPinchZoom(100, 100, 130)).toBe(125);
+    expect(readerPinchZoom(100, 100, 20)).toBe(50);
+    expect(readerPinchZoom(250, 100, 160)).toBe(300);
+  });
+
   it("ignores unusable reader viewport measurements", () => {
     expect(readableViewportSize({ width: 0, height: 833 })).toBeNull();
     expect(readableViewportSize({ width: 1, height: 1 })).toBeNull();
@@ -231,6 +241,17 @@ describe("reader runtime helpers", () => {
     expect(styles).toContain(".reader-mode-control select {\n    width: 100%;");
   });
 
+  it("keeps mobile vertical header reveal tied to tap instead of passive scroll", () => {
+    const source = readFileSync(new URL("./ReaderShell.tsx", import.meta.url), "utf8");
+
+    expect(source).toContain("shouldUseTapOnlyHeaderReveal");
+    expect(source).toContain("onScrollCapture={revealHeaderForPassiveGesture}");
+    expect(source).toContain("onWheel={revealHeaderForPassiveGesture}");
+    expect(source).toContain("onPointerUp={handleReaderPointerUp}");
+    expect(source).toContain("readerPinchZoom");
+    expect(source).toContain("zoomControls.onZoomChange");
+  });
+
   it("detects fullscreen support and active fullscreen element", () => {
     const fullscreenElement = { requestFullscreen: () => Promise.resolve() } as unknown as HTMLElement;
     const regularElement = {} as HTMLElement;