comparison base/ZoomConstraint.h @ 12:f67ddc287bc3

* Add ability to create empty layers for editing
* Add first basic editing capability (adding points to a time instant layer)
* Add various keyboard and mouse shortcuts for navigation &c
* Add ability to resize a selection by dragging its edges
* Add maximum zoom level

 /**
  * ZoomConstraint is a simple interface that describes a limitation on
  * the available zoom sizes for a view, for example based on cache
  * strategy or a (processing) window-size limitation.
  *
- * The default ZoomConstraint imposes no actual constraint.
+ * The default ZoomConstraint imposes no actual constraint except for
+ * a nominal maximum.
  */
 
 class ZoomConstraint
 {
 public:

      */
     virtual size_t getNearestBlockSize(size_t requestedBlockSize,
 				       RoundingDirection = RoundNearest)
 	const
     {
-	return requestedBlockSize;
+	if (requestedBlockSize > getMaxZoomLevel()) return getMaxZoomLevel();
+	else return requestedBlockSize;
     }
+
+    virtual size_t getMaxZoomLevel() const { return 262144; }
 };
 
 #endif