comparison layer/Layer.h @ 1547:e6362cf5ff1d

Pass a y-coord, optionally, to Layer::snapToFeatureFrame. This is necessary for BoxLayer which needs to coordinate its snaps with the box it is highlighting for editing. Then in BoxLayer, merge getPointToDrag and getLocalPoints into a single getLocalPoint and use this throughout.

      * is close, and leave it alone (returning false) otherwise.
      * SnapNeighbouring should always choose the same feature that
      * would be used in an editing operation through calls to
      * editStart etc.
      *
+     * If ycoord is non-negative, it contains the y coordinate at
+     * which the interaction that prompts this snap is taking place
+     * (e.g. of the mouse press used for a selection action). Layers
+     * that have objects at multiple different heights may choose to
+     * use this information. If the current action has no particular y
+     * coordinate associated with it, ycoord will be passed as -1.
+     *
      * Return true if a suitable feature was found and frame adjusted
      * accordingly.  Return false if no suitable feature was available
      * (and leave frame unmodified).  If returning true, also return
      * the resolution of the model in this layer in sample frames.
      */
     virtual bool snapToFeatureFrame(LayerGeometryProvider * /* v */,
                                     sv_frame_t & /* frame */,
                                     int &resolution,
-                                    SnapType /* snap */) const {
+                                    SnapType /* snap */,
+                                    int /* ycoord */) const {
         resolution = 1;
         return false;
     }
 
     /**