Class SnapToGeometry

  • All Implemented Interfaces:
    org.eclipse.draw2d.PositionConstants

    public class SnapToGeometry
    extends SnapToHelper
    A temporary helper used to perform snapping to existing elements. This helper can be used in conjunction with the DragEditPartsTracker when dragging editparts within a graphical viewer. Snapping is based on the existing children of a container. When snapping a rectangle, the edges of the rectangle will snap to edges of other rectangles generated from the children of the given container. Similarly, the centers and middles of rectangles will snap to each other.

    If the snap request is being made during a Move, Reparent or Resize, then the figures of the participants of that request will not be used for snapping. If the request is a Clone, then the figures for the parts being cloned will be used as possible snap locations.

    This helper does not keep up with changes made to the container editpart. Clients should instantiate a new helper each time one is requested and not hold on to instances of the helper.

    Since:
    3.0
    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      protected static class  SnapToGeometry.Entry
      A vertical or horizontal snapping point. since 3.0
    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected SnapToGeometry.Entry[] cols
      The vertical columnd being snapped to.
      protected GraphicalEditPart container
      The container editpart providing the coordinates and the children to which snapping occurs.
      static java.lang.String KEY_EAST_ANCHOR
      The key used to identify the East anchor point in the extended data of a request.
      static java.lang.String KEY_NORTH_ANCHOR
      The key used to identify the North anchor point in the extended data of a request.
      static java.lang.String KEY_SOUTH_ANCHOR
      The key used to identify the South anchor point in the extended data of a request.
      static java.lang.String KEY_WEST_ANCHOR
      The key used to identify the West anchor point in the extended data of a request.
      static java.lang.String PROPERTY_SNAP_ENABLED
      A property indicating whether this helper should be used.
      protected SnapToGeometry.Entry[] rows
      The horizontal rows being snapped to.
      protected static double THRESHOLD
      The sensitivity of the snapping.
      • Fields inherited from interface org.eclipse.draw2d.PositionConstants

        ALWAYS_LEFT, ALWAYS_RIGHT, BOTTOM, CENTER, EAST, EAST_WEST, HORIZONTAL, LEFT, LEFT_CENTER_RIGHT, MIDDLE, NONE, NORTH, NORTH_EAST, NORTH_SOUTH, NORTH_WEST, NSEW, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TOP_MIDDLE_BOTTOM, VERTICAL, WEST
    • Constructor Summary

      Constructors 
      Constructor Description
      SnapToGeometry​(GraphicalEditPart container)
      Constructs a helper that will use the given part as its basis for snapping.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      protected java.util.List generateSnapPartsList​(java.util.List exclusions)
      Generates a list of parts which should be snapped to.
      protected double getCorrectionFor​(SnapToGeometry.Entry[] entries, java.util.Map extendedData, boolean vert, double near, double far)
      Returns the correction value for the given entries and sides.
      protected double getCorrectionFor​(SnapToGeometry.Entry[] entries, java.util.Map extendedData, boolean vert, double value, int side)
      Returns the correction value between +/- getThreshold(), or the #getThreshold () if no corrections were found.
      protected org.eclipse.draw2d.geometry.Rectangle getFigureBounds​(GraphicalEditPart part)
      Returns the rectangular contribution for the given editpart.
      protected double getThreshold()
      Get the sensitivity of the snapping.
      protected void populateRowsAndCols​(java.util.List parts)
      Updates the cached row and column Entries using the provided parts.
      protected void setThreshold​(double newThreshold)
      Set the sensitivity of the snapping.
      int snapRectangle​(Request request, int snapOrientation, org.eclipse.draw2d.geometry.PrecisionRectangle baseRect, org.eclipse.draw2d.geometry.PrecisionRectangle result)
      Applies a snap correction to a Rectangle based on a given Rectangle.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • PROPERTY_SNAP_ENABLED

        public static final java.lang.String PROPERTY_SNAP_ENABLED
        A property indicating whether this helper should be used. The value should be an instance of Boolean. Currently, this class does not check to see if the viewer property is set to true.
        See Also:
        EditPartViewer.setProperty(String, Object), Constant Field Values
      • KEY_NORTH_ANCHOR

        public static final java.lang.String KEY_NORTH_ANCHOR
        The key used to identify the North anchor point in the extended data of a request. The north anchor may be set to an Integer value indicating where the snapping is occurring. This is used for feedback purposes.
        See Also:
        Constant Field Values
      • KEY_SOUTH_ANCHOR

        public static final java.lang.String KEY_SOUTH_ANCHOR
        The key used to identify the South anchor point in the extended data of a request. The south anchor may be set to an Integer value indicating where the snapping is occurring. This is used for feedback purposes.
        See Also:
        Constant Field Values
      • KEY_WEST_ANCHOR

        public static final java.lang.String KEY_WEST_ANCHOR
        The key used to identify the West anchor point in the extended data of a request. The west anchor may be set to an Integer value indicating where the snapping is occurring. This is used for feedback purposes.
        See Also:
        Constant Field Values
      • KEY_EAST_ANCHOR

        public static final java.lang.String KEY_EAST_ANCHOR
        The key used to identify the East anchor point in the extended data of a request. The east anchor may be set to an Integer value indicating where the snapping is occurring. This is used for feedback purposes.
        See Also:
        Constant Field Values
      • THRESHOLD

        protected static final double THRESHOLD
        The sensitivity of the snapping. Corrections greater than this value will not occur.
        See Also:
        Constant Field Values
      • container

        protected GraphicalEditPart container
        The container editpart providing the coordinates and the children to which snapping occurs.
    • Constructor Detail

      • SnapToGeometry

        public SnapToGeometry​(GraphicalEditPart container)
        Constructs a helper that will use the given part as its basis for snapping. The part's contents pane will provide the coordinate system and its children determine the existing elements.
        Parameters:
        container - the container editpart
        Since:
        3.0
    • Method Detail

      • getThreshold

        protected double getThreshold()
        Get the sensitivity of the snapping. Corrections greater than this value will not occur.
        Returns:
        the snapping threshold
        Since:
        3.4
      • setThreshold

        protected void setThreshold​(double newThreshold)
        Set the sensitivity of the snapping.
        Parameters:
        newThreshold - the new snapping threshold
        Since:
        3.4
        See Also:
        getThreshold()
      • generateSnapPartsList

        protected java.util.List generateSnapPartsList​(java.util.List exclusions)
        Generates a list of parts which should be snapped to. The list is the original children, minus the given exclusions, minus and children whose figures are not visible.
        Parameters:
        exclusions - the children to exclude
        Returns:
        a list of parts which should be snapped to
        Since:
        3.0
      • getCorrectionFor

        protected double getCorrectionFor​(SnapToGeometry.Entry[] entries,
                                          java.util.Map extendedData,
                                          boolean vert,
                                          double near,
                                          double far)
        Returns the correction value for the given entries and sides. During a move, the left, right, or center is free to snap to a location.
        Parameters:
        entries - the entries
        extendedData - the requests extended data
        vert - true if the correction is vertical
        near - the left/top side of the rectangle
        far - the right/bottom side of the rectangle
        Returns:
        the correction amount or #getThreshold () if no correction was made
      • getCorrectionFor

        protected double getCorrectionFor​(SnapToGeometry.Entry[] entries,
                                          java.util.Map extendedData,
                                          boolean vert,
                                          double value,
                                          int side)
        Returns the correction value between +/- getThreshold(), or the #getThreshold () if no corrections were found.
        Parameters:
        entries - the entries
        extendedData - the map for setting values
        vert - true if vertical
        value - the value being corrected
        side - which sides should be considered
        Returns:
        the correction or #getThreshold () if no correction was made
      • getFigureBounds

        protected org.eclipse.draw2d.geometry.Rectangle getFigureBounds​(GraphicalEditPart part)
        Returns the rectangular contribution for the given editpart. This is the rectangle with which snapping is performed.
        Parameters:
        part - the child
        Returns:
        the rectangular guide for that part
        Since:
        3.0
      • populateRowsAndCols

        protected void populateRowsAndCols​(java.util.List parts)
        Updates the cached row and column Entries using the provided parts.
        Parameters:
        parts - a List of EditParts
        Since:
        3.0
      • snapRectangle

        public int snapRectangle​(Request request,
                                 int snapOrientation,
                                 org.eclipse.draw2d.geometry.PrecisionRectangle baseRect,
                                 org.eclipse.draw2d.geometry.PrecisionRectangle result)
        Description copied from class: SnapToHelper
        Applies a snap correction to a Rectangle based on a given Rectangle. The provided baseRect will be used as a reference for snapping. The types of snapping to be performed are indicated by the snapOrientation parameter. The correction is applied to the result field.

        The baseRect is not modified. The correction is applied to the result. The request's extended data may contain additional information about the snapping which was performed.

        All coordinate information received and returned by this method should be in absolute coordinates.

        Specified by:
        snapRectangle in class SnapToHelper
        Parameters:
        request - the request or null
        snapOrientation - the input snap locations
        baseRect - the input rectangle
        result - the correction is applied to this rectangle
        Returns:
        the remaining snap locations
        See Also:
        SnapToHelper.snapRectangle(Request, int, PrecisionRectangle, PrecisionRectangle)