Markdown: Add option for hiding preview

Make it possible to hide the preview, by having a toggle button for
"Show Preview" and "Show Editor", and ensure that at least one is always
on and they are in the order as the views themselves. Disable the "Swap
Views" button if only one is shown.

Change-Id: I0ec1e06c2a8ec94e34bf52eae45ba009fd8cd1b5
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: André Hartmann <aha_1980@gmx.de>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

1 files changed, 50 insertions, 20 deletions

diff --git a/src/plugins/texteditor/markdowneditor.cpp b/src/plugins/texteditor/markdowneditor.cpp
index b6993dacd5..afdda1bfb4 100644
--- a/src/plugins/texteditor/markdowneditor.cpp
+++ b/src/plugins/texteditor/markdowneditor.cpp
@@ -65,46 +65,76 @@ public:
         setContext(Core::Context(MARKDOWNVIEWER_ID));
         setWidget(&m_widget);
 
+        auto togglePreviewVisible = new QToolButton;
+        togglePreviewVisible->setText(Tr::tr("Show Preview"));
+        togglePreviewVisible->setCheckable(true);
+        togglePreviewVisible->setChecked(true);
+
         auto toggleEditorVisible = new QToolButton;
-        toggleEditorVisible->setText(Tr::tr("Hide Editor"));
+        toggleEditorVisible->setText(Tr::tr("Show Editor"));
         toggleEditorVisible->setCheckable(true);
         toggleEditorVisible->setChecked(true);
 
         auto swapViews = new QToolButton;
         swapViews->setText(Tr::tr("Swap Views"));
 
-        auto layout = new QHBoxLayout(&m_toolbar);
-        layout->setSpacing(0);
-        layout->setContentsMargins(0, 0, 0, 0);
-        layout->addStretch();
-        layout->addWidget(toggleEditorVisible);
-        layout->addWidget(swapViews);
+        auto toolbarLayout = new QHBoxLayout(&m_toolbar);
+        toolbarLayout->setSpacing(0);
+        toolbarLayout->setContentsMargins(0, 0, 0, 0);
+        toolbarLayout->addStretch();
+        if (textEditorRight) {
+            toolbarLayout->addWidget(togglePreviewVisible);
+            toolbarLayout->addWidget(toggleEditorVisible);
+        } else {
+            toolbarLayout->addWidget(toggleEditorVisible);
+            toolbarLayout->addWidget(togglePreviewVisible);
+        }
+        toolbarLayout->addWidget(swapViews);
 
         connect(m_document.data(), &TextDocument::mimeTypeChanged,
                 m_document.data(), &TextDocument::changed);
 
+        const auto viewToggled =
+            [swapViews](QWidget *view, bool visible, QWidget *otherView, QToolButton *otherButton) {
+                if (view->isVisible() == visible)
+                    return;
+                view->setVisible(visible);
+                if (visible) {
+                    view->setFocus();
+                } else if (otherView->isVisible()) {
+                    otherView->setFocus();
+                } else {
+                    // make sure at least one view is visible
+                    otherButton->toggle();
+                }
+                swapViews->setEnabled(view->isVisible() && otherView->isVisible());
+            };
+
         connect(toggleEditorVisible,
                 &QToolButton::toggled,
-                m_textEditorWidget,
-                [this, browser, toggleEditorVisible](bool editorVisible) {
-                    if (m_textEditorWidget->isVisible() == editorVisible)
-                        return;
-                    m_textEditorWidget->setVisible(editorVisible);
-                    if (editorVisible)
-                        m_textEditorWidget->setFocus();
-                    else
-                        browser->setFocus();
-
-                    toggleEditorVisible->setText(editorVisible ? Tr::tr("Hide Editor")
-                                                               : Tr::tr("Show Editor"));
+                this,
+                [this, browser, togglePreviewVisible, viewToggled](bool visible) {
+                    viewToggled(m_textEditorWidget, visible, browser, togglePreviewVisible);
+                });
+        connect(togglePreviewVisible,
+                &QToolButton::toggled,
+                this,
+                [this, browser, toggleEditorVisible, viewToggled](bool visible) {
+                    viewToggled(browser, visible, m_textEditorWidget, toggleEditorVisible);
                 });
 
-        connect(swapViews, &QToolButton::clicked, m_textEditorWidget, [this] {
+        connect(swapViews, &QToolButton::clicked, m_textEditorWidget, [this, toolbarLayout] {
             QTC_ASSERT(m_widget.count() > 1, return);
+            // switch views
             auto placeholder = std::make_unique<QWidget>();
             auto second = m_widget.replaceWidget(1, placeholder.get());
             auto first = m_widget.replaceWidget(0, second);
             m_widget.replaceWidget(1, first);
+            // switch buttons
+            const int rightIndex = toolbarLayout->count() - 2;
+            QLayoutItem *right = toolbarLayout->takeAt(rightIndex);
+            toolbarLayout->insertItem(rightIndex - 1, right);
+            // save settings
             Utils::QtcSettings *s = Core::ICore::settings();
             s->setValueWithDefault(MARKDOWNVIEWER_TEXTEDITOR_RIGHT,
                                    !s->value(MARKDOWNVIEWER_TEXTEDITOR_RIGHT,