added option for underlay opacity change

adjusted interface [removed invalid const]

mapview/2D/MV2DElementFloorUnderlay.h

@@ -20,6 +20,7 @@ private:
 	std::string tmpFile;
 	Floorplan::UnderlayImage* underlay;
 	BBox2 bbox;
+	float opacity = 0.5;
 
 	int selPoint = -1;
 
@@ -55,6 +56,9 @@ public:
 		selPoint = -1;	// clear selection
 	}
 
+	float getOpacity() const {return opacity;}
+	void setOpacity(const float o) {this->opacity = o;}
+
 	void paint(Painter& p) override {
 		(void) p;
 
@@ -101,9 +105,9 @@ public:
 			imgScaled = QImage();
 		}
 
-
-		float opacity = p.p->opacity();
-		p.p->setOpacity(0.50f);
+		// current opacity?
+		float _oldOpacity = p.p->opacity();
+		p.p->setOpacity(opacity);
 
 		// render downscaled image from cache? or use live-upscaling (faster, eats up less memory, ...)
 		if (imgScaled.width() > 0) {
@@ -113,7 +117,8 @@ public:
 			p.p->drawImage(QRectF(sx1, sy1-sh, sw, sh), img, QRectF(0,0,img.width(),img.height()));
 		}
 
-		p.p->setOpacity(opacity);
+		// reset
+		p.p->setOpacity(_oldOpacity);
 
 		// selected endpoint(s)?
 		if (hasFocus()) {

mapview/2D/tools/ToolSelector.h

@@ -282,6 +282,7 @@ private:
 
 		(void) m;
 
+		// currently: only accept keys when something is focused
 		if (focused) {
 
 			// pass it to the element which may consume this event