implement visual feedback for copy building settings with shift + click gesture

src/ui/GameWorldView.cpp

@@ -271,6 +271,20 @@ void GameWorldView::onFrame()
         m_activeBeams = std::move(live);
     }
 
+    // Expire copy/paste flashes. Lifetime is wall-clock (the frame delta), so the
+    // flash plays for a fixed real duration regardless of game speed, including
+    // while the game is paused (REQ-BLD-COPY-CONFIG-FEEDBACK).
+    if (!m_copyConfigFlashes.empty())
+    {
+        std::vector<CopyConfigFlash> live;
+        for (CopyConfigFlash flash : m_copyConfigFlashes)
+        {
+            flash.remainingMs -= elapsed;
+            if (flash.remainingMs > 0) { live.push_back(flash); }
+        }
+        m_copyConfigFlashes = std::move(live);
+    }
+
     // Apply held scroll
     {
         // Pan speed depends on where the view is centered (REQ-UI-SCROLL-SPEED).
@@ -384,6 +398,7 @@ void GameWorldView::paintGL()
 
     drawTiles(painter);
     drawBuildings(painter);
+    drawCopyConfigFeedback(painter);
     drawStations(painter);
     drawBeltItems(painter);
     drawScrap(painter);
@@ -998,6 +1013,29 @@ void GameWorldView::drawBuildings(QPainter& painter)
     drawSelectionHighlights(painter);
 }
 
+std::optional<QRectF> GameWorldView::footprintWidgetRect(BuildingId id) const
+{
+    std::optional<QPoint> anchor;
+    std::optional<QSize>  footprint;
+
+    if (const Building* b = m_sim->buildings().findBuilding(id))
+    {
+        anchor    = b->anchor;
+        footprint = b->footprint;
+    }
+    else if (const ConstructionSite* s = m_sim->buildings().findSite(id))
+    {
+        anchor    = s->anchor;
+        footprint = s->footprint;
+    }
+    if (!anchor.has_value() || !footprint.has_value()) { return std::nullopt; }
+
+    const QPointF tl = tileToWidget(*anchor);
+    return QRectF(tl.x(), tl.y(),
+        footprint->width()  * static_cast<qreal>(tilePx()),
+        footprint->height() * static_cast<qreal>(tilePx()));
+}
+
 void GameWorldView::drawSelectionHighlights(QPainter& painter)
 {
     painter.setPen(QPen(m_visuals->overlays.selectedOutline, 2));
@@ -1005,26 +1043,47 @@ void GameWorldView::drawSelectionHighlights(QPainter& painter)
 
     for (BuildingId selId : m_selectedBuildingIds)
     {
-        std::optional<QPoint> anchor;
-        std::optional<QSize>  footprint;
+        const std::optional<QRectF> rect = footprintWidgetRect(selId);
+        if (!rect.has_value()) { continue; }
+        // Outline sits 1px outside the footprint (into adjacent tiles).
+        painter.drawRect(rect->adjusted(-1, -1, 1, 1));
+    }
+}
 
-        if (const Building* b = m_sim->buildings().findBuilding(selId))
-        {
-            anchor    = b->anchor;
-            footprint = b->footprint;
-        }
-        else if (const ConstructionSite* s = m_sim->buildings().findSite(selId))
-        {
-            anchor    = s->anchor;
-            footprint = s->footprint;
-        }
-        if (!anchor.has_value() || !footprint.has_value()) { continue; }
+void GameWorldView::drawCopyConfigFeedback(QPainter& painter)
+{
+    const QColor color = m_visuals->overlays.copyConfig;
 
-        const QPointF tl = tileToWidget(*anchor);
-        const QRectF  bboxRect(tl.x(), tl.y(),
-            footprint->width()  * static_cast<qreal>(tilePx()),
-            footprint->height() * static_cast<qreal>(tilePx()));
-        painter.drawRect(bboxRect.adjusted(-1, -1, 1, 1));
+    // Eligible-target tint: while a configuration is cached, every same-type
+    // building and site (the source included) is a valid paste target and is
+    // washed in the copy-settings color (REQ-BLD-COPY-CONFIG-FEEDBACK).
+    if (m_copiedConfig.has_value())
+    {
+        painter.setPen(Qt::NoPen);
+        painter.setBrush(color);
+        const BuildingType type = m_copiedConfig->type;
+        for (const Building& b : m_sim->buildings().allBuildings())
+        {
+            if (b.type != type) { continue; }
+            const std::optional<QRectF> rect = footprintWidgetRect(b.id);
+            if (rect.has_value()) { painter.drawRect(*rect); }
+        }
+        for (const ConstructionSite& s : m_sim->buildings().allSites())
+        {
+            if (s.type != type) { continue; }
+            const std::optional<QRectF> rect = footprintWidgetRect(s.id);
+            if (rect.has_value()) { painter.drawRect(*rect); }
+        }
+    }
+
+    // Copy / paste flashes: a brief outline in the same color, drawn like the
+    // selection outline (REQ-BLD-COPY-CONFIG-FEEDBACK).
+    painter.setPen(QPen(color, 2));
+    painter.setBrush(Qt::NoBrush);
+    for (const CopyConfigFlash& flash : m_copyConfigFlashes)
+    {
+        const std::optional<QRectF> rect = footprintWidgetRect(flash.id);
+        if (rect.has_value()) { painter.drawRect(rect->adjusted(-1, -1, 1, 1)); }
     }
 }
 
@@ -1905,6 +1964,7 @@ void GameWorldView::copyConfigFrom(BuildingId id)
     if (!config->recipeId.has_value() && !config->isSplitter) { return; }
 
     m_copiedConfig = config;
+    m_copyConfigFlashes.push_back({ id, kCopyFlashDurationMs });
 }
 
 void GameWorldView::pasteConfigTo(BuildingId id)
@@ -1914,6 +1974,9 @@ void GameWorldView::pasteConfigTo(BuildingId id)
     const std::optional<BuildingConfig> target = readBuildingConfig(*m_sim, id);
     if (!target.has_value() || target->type != m_copiedConfig->type) { return; }
 
+    // The paste applies below; flash the target to confirm (REQ-BLD-COPY-CONFIG-FEEDBACK).
+    m_copyConfigFlashes.push_back({ id, kCopyFlashDurationMs });
+
     const BuildingConfig& source = *m_copiedConfig;
 
     // The cached settings were valid on a same-type source building, so they are
@@ -2041,6 +2104,7 @@ void GameWorldView::resetForNewGame()
         std::make_shared<DemolishModeChangedEvent>(false));
     m_selectedBuildingIds.clear();
     m_copiedConfig     = std::nullopt;
+    m_copyConfigFlashes.clear();
     m_boxSelecting     = false;
     m_scrollXTiles     = 0.0f;
     m_scrollLeft       = false;