open selection panel modals on the panel

src/ui/MainWindow.cpp

@@ -7,6 +7,7 @@
 
 #include <QApplication>
 #include <QCloseEvent>
+#include <QDialog>
 #include <QDir>
 #include <QFile>
 #include <QInputDialog>
@@ -317,6 +318,9 @@ void MainWindow::openShipLayoutDialog(BuildingId shipyardId,
                             std::move(unlockedModuleIds),
                             m_gameWorldView->isDebugDrawEnabled(),
                             this);
+    // Opened from the panel's "Configure" button (REQ-MOD-UI-PREVIEW) or straight after
+    // a schematic change (REQ-MOD-UI-AUTO-DIALOG), so it opens on the panel either way.
+    placeOnSelectionPanel(dialog);
     if (dialog.exec() == QDialog::Accepted && dialog.getResult().has_value())
     {
         std::shared_ptr<SetShipLayoutCommand> command =
@@ -328,6 +332,45 @@ void MainWindow::openShipLayoutDialog(BuildingId shipyardId,
     }
 }
 
+void MainWindow::placeOnSelectionPanel(QDialog& dialog) const
+{
+    // The panel is up whenever one of these modals opens -- they are opened from its own
+    // controls, and it is shown whenever anything is selected (REQ-UI-EMPTY-SELECTION).
+    // Were it not, there would be no rectangle to center on and Qt's own centering on
+    // this window stands.
+    if (!m_selectionPanel->isVisible()) { return; }
+
+    // The dialog has never been shown, so it is still at its default size until its
+    // layout has run; centering it before that would use the wrong extent.
+    dialog.adjustSize();
+    const QSize dialogSize = dialog.size();
+
+    // The panel's live geometry, so a panel the player has dragged
+    // (REQ-UI-SELECTION-PANEL-DRAG) carries the modal with it.
+    const QRect panelRect(m_selectionPanel->mapToGlobal(QPoint(0, 0)),
+                          m_selectionPanel->size());
+    const QRect windowRect(mapToGlobal(QPoint(0, 0)), size());
+
+    QPoint topLeft(panelRect.center().x() - dialogSize.width() / 2,
+                   panelRect.center().y() - dialogSize.height() / 2);
+
+    // Pushed back inside the window, never resized to fit (REQ-UI-PANEL-MODAL). The far
+    // edge is clamped first and the near edge second, which is what aligns a dialog too
+    // large for the window with the window's top-left corner rather than pushing it off
+    // the opposite edge.
+    topLeft.setX(qMax(windowRect.left(),
+                      qMin(topLeft.x(), windowRect.right() - dialogSize.width() + 1)));
+    topLeft.setY(qMax(windowRect.top(),
+                      qMin(topLeft.y(), windowRect.bottom() - dialogSize.height() + 1)));
+
+    // Positions the dialog's frame, whose size is not known until it is first shown, so
+    // the result sits low by the title bar height against a true center -- measuring it
+    // would mean showing the dialog at the wrong place first. The move also marks the
+    // dialog as positioned, which is what stops QDialog from centering it on this window
+    // when it is shown.
+    dialog.move(topLeft);
+}
+
 void MainWindow::handleEvent(std::shared_ptr<const LayoutDialogRequestedEvent> event)
 {
     // A construction site has no Building yet; fall back to its site record so
@@ -385,6 +428,7 @@ void MainWindow::handleEvent(std::shared_ptr<const RecipeSelectionRequestedEvent
     bool autoOpenLayout = false;
     std::string chosenSchematic;
     RecipeSelectionDialog dialog(options, title, m_itemIcons.get(), this);
+    placeOnSelectionPanel(dialog);
     if (dialog.exec() == QDialog::Accepted && dialog.getChosenId().has_value())
     {
         std::shared_ptr<SetRecipeCommand> command = std::make_shared<SetRecipeCommand>();