source: trunk/src/org/expeditee/core/Anchoring.java@ 1513

package org.expeditee.core;

import org.expeditee.core.bounds.AxisAlignedBoxBounds;

/**
 * Class for anchoring the position of items within the frame. Anchoring is when
 * the position of the item is defined relative to the edge of the frame instead
 * of being defined in absolute coordinates. Can't be anchored to the left and
 * right edge at the same time, nor the top and bottom edge at the same time.
 * 
 * @author cts16
 */
public class Anchoring {
        
        private enum VerticalDirection { left, center, right }
        private enum HorizontalDirection { top, center, bottom }

        /**
         * The relative distance from the left, center or right edge (null means unanchored).
         */
        private Integer _xAnchor = null;
        /**
         * The relative distance from the top, center or bottom edge (null means unanchored).
         */
        private Integer _yAnchor = null;

        /** Whether the x-anchor is relative to the left or right edge. */
        private VerticalDirection verticalDirection = VerticalDirection.left;
        /** Whether the y-anchor is relative to the top or bottom edge. */
        private HorizontalDirection horizonalDirection = HorizontalDirection.top;

        public Anchoring() {
        }
        
        public void setXAnchor(Anchoring other) {
                if (other == null) {
                        return;
                }
                
                setXAnchor(other._xAnchor, other.verticalDirection);
        }

        public void setYAnchor(Anchoring other) {
                if (other == null)
                        return;

                setYAnchor(other._yAnchor, other.horizonalDirection);
        }

        public void setLeftAnchor(Integer offset) {
                setXAnchor(offset, VerticalDirection.left);
        }
        
        public void setCenterXAnchor(Integer offset) {
                setXAnchor(offset, VerticalDirection.center);
        }

        public void setRightAnchor(Integer offset) {
                setXAnchor(offset, VerticalDirection.right);
        }

        public void setTopAnchor(Integer offset) {
                setYAnchor(offset, HorizontalDirection.top);
        }
        
        public void setCenterYAnchor(Integer offset) {
                setYAnchor(offset, HorizontalDirection.center);
        }

        public void setBottomAnchor(Integer offset) {
                setYAnchor(offset, HorizontalDirection.bottom);
        }
        
        public void removeXAnchor() {
                setXAnchor(null, verticalDirection);
        }

        public void removeYAnchor() {
                setYAnchor(null, horizonalDirection);
        }

        public void removeAllAnchors() {
                removeXAnchor();
                removeYAnchor();
        }

        public Point getPositionInBox(AxisAlignedBoxBounds box) {
                Integer x = getXPositionInBox(box);
                Integer y = getYPositionInBox(box);

                if (x == null || y == null)
                        return null;

                return new Point(x, y);
        }

        public boolean isXAnchored() {
                return _xAnchor != null;
        }

        public boolean isYAnchored() {
                return _yAnchor != null;
        }

        public boolean isAnchored() {
                return isXAnchored() || isYAnchored();
        }
        
        public Integer getLeftAnchor() {
                return verticalDirection.equals(VerticalDirection.left) ? _xAnchor : null;
        }
        
        public Integer getCenterXAnchor() {
                return verticalDirection.equals(VerticalDirection.center) ? _xAnchor : null;
        }

        public Integer getRightAnchor() {
                return verticalDirection.equals(VerticalDirection.right) ? _xAnchor : null;
        }

        public Integer getTopAnchor() {
                return horizonalDirection.equals(HorizontalDirection.top) ? _yAnchor : null;
        }
        
        public Integer getCenterYAnchor() {
                return horizonalDirection.equals(HorizontalDirection.center) ? _yAnchor : null;
        }
        
        public Integer getBottomAnchor() {
                return horizonalDirection.equals(HorizontalDirection.bottom) ? _yAnchor : null;
        }
                        
        private void setXAnchor(Integer offset, VerticalDirection left) {
                _xAnchor = offset;
                verticalDirection = left;
        }

        private void setYAnchor(Integer offset, HorizontalDirection top) {
                _yAnchor = offset;
                horizonalDirection = top;
        }
        
        private Integer getXPositionInBox(AxisAlignedBoxBounds box) {
                if (box == null || _xAnchor == null)
                        return null;
                
                switch (verticalDirection) {
                case left:
                        return box.getMinX() + _xAnchor;
                case center:
                        return box.getCentreX() + _xAnchor;
                case right:
                        return box.getMaxX() - _xAnchor;
                default:
                        System.err.println("Anchoring::getXPositionInBox::VerticalDirection does not match available options.  Has the enum been updated without this function being updated?");
                        return null;
                }
        }
        
        private Integer getYPositionInBox(AxisAlignedBoxBounds box) {
                if (box == null || _yAnchor == null) {
                        return null;
                }
                
                switch (horizonalDirection) {
                case top:
                        return box.getMinY() + _yAnchor;
                case center:
                        return box.getCentreY() + _yAnchor;
                case bottom:
                        return box.getMaxY() - _yAnchor;
                default:
                        System.err.println("Anchoring::getYPositionInBox::HorizonalDirection does not match available options.  Has the enum been updated without this function being updated?");
                        return null;
                }
        }
}