Export JPEG and Canvas Size take the app's colour picker; a panel opens over a modal sheet (13.4a)

src/UI/ColorPickerSheet+Dialog.cpp

@@ -0,0 +1,37 @@
+#include "UI/ColorPickerSheet+Dialog.h"
+#include <QHideEvent>
+
+// The brush's swatch: 34 by 18, a white ring.
+DialogColorSwatch::DialogColorSwatch(const QString &title, std::function<PaletteColor()> colour, std::function<void(const PaletteColor &)> change,
+                                     EditorSession &session, QWidget *parent)
+    : SwatchButton(colour, 4, 1, 1, parent), m_session(session)
+{
+    setFixedSize(34, 18);
+    setAccessibleName(title);
+    connect(this, &QAbstractButton::clicked, this, [this, title, colour, change, &session] {
+        session.openDialogColorPicker(title, colour(), [this, change](const PaletteColor &picked) {
+            change(picked);
+            update();
+        });
+    });
+    connect(&session, &EditorSession::changed, this, [this, &session] {
+        const std::optional<PaletteColor> now = session.colorPicker() ? std::optional(session.colorPicker()->color()) : std::nullopt;
+        if (now == m_seen)
+            return;
+        m_seen = now;
+        session.previewDialogColor();
+    });
+}
+
+void DialogColorSwatch::hideEvent(QHideEvent *event)
+{
+    if (!event->spontaneous())
+        closePicker(m_session);
+    SwatchButton::hideEvent(event);
+}
+
+void DialogColorSwatch::closePicker(EditorSession &session)
+{
+    if (session.pickingForDialog())
+        session.closeColorPicker(true);
+}