feat: own the message-pane zoom and persist it

Zoom was Chromium's, not the application's: the web view handled the
keys natively and never told anyone, so there was no value to save.
qtmaildir now owns it. Zoom in, out and reset are real actions, in the
View menu and rebindable through [keys], and the factor is persisted to
the UI state file. Ctrl+wheel over the body zooms and Ctrl+middle-click
resets, both filtered by ancestry from an application-level filter: the
events are delivered to an internal QQuickWidget the web view creates
lazily, so a filter on the view itself never sees them.

The factor is clamped to 0.5 - 3.0, and NaN, infinity, zero and negative
values fall back to 1.0, since a corrupt state file must not be able to
leave the pane unreadable with no visible way back.

Both risks the plan flagged turned out not to exist, verified by probe
rather than assumed. The application QAction wins over the web view's
native zoom key, so the tracked factor cannot diverge from what is on
screen. And the factor survives setHtml(), so the web view is the single
source of truth and needs no reapply per render.

A third finding is worth recording because it produced a wrong fix
first. A probe using QTest::keyClick() reported Ctrl++ as a dead
binding, and a test was written asserting that. Both were wrong: Ctrl++
is exactly what the '+' key emits on an Italian layout, confirmed
against the real keyboard, and it is the shipped default. Whether a
symbol needs Shift is a property of the layout, not of Qt, and
keyClick() reproduces neither. The test now only checks that every
default parses, and the comment in defaultBindings() says not to
re-derive this from synthetic input.

Ctrl+= is a second binding for reset, skipped when [keys] gives it to
something else.

Also fixes a pre-existing bug the new config key exposed. [general]
entries were read as "general/<key>", which matches nothing: QSettings'
INI backend treats a section literally named [general] as its own
fallback section and strips the prefix. notmuch_config had therefore
never worked. Both keys are now read without it; the file format is
unchanged.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/src/mainwindow.cpp b/src/mainwindow.cpp
index 081984d..c4955b6 100644
--- a/src/mainwindow.cpp
+++ b/src/mainwindow.cpp
@@ -105,6 +105,13 @@ void MainWindow::restoreUiState()
     if (!header.isEmpty()) {
         m_threadView->horizontalHeader()->restoreState(header);
     }
+
+    // The config value is the starting point for a profile that has never
+    // zoomed; once the user does, the state file is what they last had.
+    // clampZoom() rejects the garbage a hand-edited file can hold.
+    m_messageView->setZoomFactor(
+        state.value(QStringLiteral("message/zoom"), m_config.messageZoom())
+            .toDouble());
 }
 
 void MainWindow::saveUiState() const
@@ -116,6 +123,7 @@ void MainWindow::saveUiState() const
     state.setValue(QStringLiteral("window/splitter"), m_splitter->saveState());
     state.setValue(QStringLiteral("threadlist/header"),
                    m_threadView->horizontalHeader()->saveState());
+    state.setValue(QStringLiteral("message/zoom"), m_messageView->zoomFactor());
 }
 
 void MainWindow::closeEvent(QCloseEvent *event)
@@ -381,6 +389,32 @@ void MainWindow::registerActions()
               tr("Load remote images for the current thread"), [this]() {
         m_messageView->loadRemoteContent();
     });
+    addAction(QStringLiteral("zoom_in"), tr("Zoom &in"),
+              tr("Enlarge the message text"), [this]() {
+        m_messageView->zoomIn();
+    });
+    addAction(QStringLiteral("zoom_out"), tr("Zoom &out"),
+              tr("Shrink the message text"), [this]() {
+        m_messageView->zoomOut();
+    });
+    auto *zoomReset =
+        addAction(QStringLiteral("zoom_reset"), tr("&Actual size"),
+                  tr("Return the message text to its default size"), [this]() {
+        m_messageView->zoomReset();
+    });
+
+    // Ctrl+= alongside the configured binding: '=' reads as "back to normal",
+    // and on a layout where '+' is Shift+'=' it is the unshifted key next to
+    // zoom in. Appended rather than assigned, so a [keys] override of
+    // zoom_reset keeps working and simply gains this as a second way in.
+    // A user who bound Ctrl+= to something else in [keys] keeps their binding.
+    const QKeySequence altReset(QStringLiteral("Ctrl+="));
+    if (m_keyMap.actionFor(altReset).isEmpty()) {
+        QList<QKeySequence> shortcuts = zoomReset->shortcuts();
+        shortcuts.append(altReset);
+        zoomReset->setShortcuts(shortcuts);
+    }
+
     addAction(QStringLiteral("undo"), tr("&Undo"),
               tr("Undo the last tag change"), [this]() {
         if (m_undoStack.canUndo())
@@ -428,6 +462,10 @@ void MainWindow::buildMenus()
     viewMenu->addSeparator();
     viewMenu->addAction(m_actions.value(QStringLiteral("toggle_html")));
     viewMenu->addAction(m_actions.value(QStringLiteral("load_remote")));
+    viewMenu->addSeparator();
+    viewMenu->addAction(m_actions.value(QStringLiteral("zoom_in")));
+    viewMenu->addAction(m_actions.value(QStringLiteral("zoom_out")));
+    viewMenu->addAction(m_actions.value(QStringLiteral("zoom_reset")));
 
     auto *helpMenu = menuBar()->addMenu(tr("&Help"));
     auto *shortcuts = helpMenu->addAction(tr("&Keyboard shortcuts"));