decoration: add NON_SOLID flag for shadow

fixes #3841

src/render/decorations/CHyprDropShadowDecoration.cpp

@@ -26,6 +26,10 @@ void CHyprDropShadowDecoration::onPositioningReply(const SDecorationPositioningR
     updateWindow(m_pWindow);
 }
 
+uint64_t CHyprDropShadowDecoration::getDecorationFlags() {
+    return DECORATION_NON_SOLID;
+}
+
 void CHyprDropShadowDecoration::damageEntire() {
     static auto* const PSHADOWS = &g_pConfigManager->getConfigValuePtr("decoration:drop_shadow")->intValue;
 

src/render/decorations/CHyprDropShadowDecoration.hpp

@@ -21,6 +21,8 @@ class CHyprDropShadowDecoration : public IHyprWindowDecoration {
 
     virtual eDecorationLayer           getDecorationLayer();
 
+    virtual uint64_t                   getDecorationFlags();
+
   private:
     SWindowDecorationExtents m_seExtents;
     SWindowDecorationExtents m_seReportedExtents;

src/render/decorations/DecorationPositioner.cpp

@@ -168,8 +168,11 @@ void CDecorationPositioner::onWindowUpdate(CWindow* pWindow) {
         const bool LEFT    = wd->positioningInfo.edges & DECORATION_EDGE_LEFT;
         const bool RIGHT   = wd->positioningInfo.edges & DECORATION_EDGE_RIGHT;
         const int  EDGESNO = TOP + BOTTOM + LEFT + RIGHT;
+        const bool SOLID   = !(wd->pDecoration->getDecorationFlags() & DECORATION_NON_SOLID);
 
         if (wd->positioningInfo.policy == DECORATION_POSITION_ABSOLUTE) {
+
+            if (SOLID) {
                 if (LEFT)
                     stickyOffsetXL += wd->positioningInfo.desiredExtents.topLeft.x;
                 if (RIGHT)
@@ -178,6 +181,7 @@ void CDecorationPositioner::onWindowUpdate(CWindow* pWindow) {
                     stickyOffsetYT += wd->positioningInfo.desiredExtents.topLeft.y;
                 if (BOTTOM)
                     stickyOffsetYB += wd->positioningInfo.desiredExtents.bottomRight.y;
+            }
 
             wd->lastReply = {};
             wd->pDecoration->onPositioningReply({});
@@ -210,22 +214,26 @@ void CDecorationPositioner::onWindowUpdate(CWindow* pWindow) {
                 pos.x -= desiredSize;
                 size = {desiredSize, wb.size().y};
 
+                if (SOLID)
                     stickyOffsetXL += desiredSize;
             } else if (RIGHT) {
                 pos  = wb.pos() + Vector2D{wb.size().x, 0} - EDGEPOINT + Vector2D{stickyOffsetXR, 0};
                 size = {desiredSize, wb.size().y};
 
+                if (SOLID)
                     stickyOffsetXR += desiredSize;
             } else if (TOP) {
                 pos = wb.pos() - EDGEPOINT - Vector2D{0, stickyOffsetYT};
                 pos.y -= desiredSize;
                 size = {wb.size().x, desiredSize};
 
+                if (SOLID)
                     stickyOffsetYT += desiredSize;
             } else {
                 pos  = wb.pos() + Vector2D{0, wb.size().y} - EDGEPOINT - Vector2D{0, stickyOffsetYB};
                 size = {wb.size().x, desiredSize};
 
+                if (SOLID)
                     stickyOffsetYB += desiredSize;
             }
 

src/render/decorations/DecorationPositioner.hpp

@@ -9,12 +9,14 @@
 class CWindow;
 class IHyprWindowDecoration;
 
-enum eDecorationPositioningPolicy {
+enum eDecorationPositioningPolicy
-    DECORATION_POSITION_ABSOLUTE = 0, /* Decoration does not interfere with anything else */
+{
+    DECORATION_POSITION_ABSOLUTE = 0, /* Decoration wants absolute positioning */
     DECORATION_POSITION_STICKY,       /* Decoration is stuck to some edge of a window */
 };
 
-enum eDecorationEdges {
+enum eDecorationEdges
+{
     DECORATION_EDGE_TOP    = 1 << 0,
     DECORATION_EDGE_BOTTOM = 1 << 1,
     DECORATION_EDGE_LEFT   = 1 << 2,

src/render/decorations/IHyprWindowDecoration.hpp

@@ -24,6 +24,7 @@ enum eDecorationFlags
 {
     DECORATION_ALLOWS_MOUSE_INPUT  = 1 << 0, /* this decoration accepts mouse input */
     DECORATION_PART_OF_MAIN_WINDOW = 1 << 1, /* this decoration is a *seamless* part of the main window, so stuff like shadows will include it */
+    DECORATION_NON_SOLID           = 1 << 2, /* this decoration is not solid. Other decorations should draw on top of it. Example: shadow */
 };
 
 class CWindow;