AlignUtil

/*
    CASA Lib for ActionScript 3.0
    Copyright (c) 2011, Aaron Clinger & Contributors of CASA Lib
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*/
package org.casalib.util {
    import flash.display.DisplayObject;
    import flash.geom.Point;
    import flash.geom.Rectangle;
    import org.casalib.util.DisplayObjectUtil;
    
    
    /**
        Provides utility functions for aligning.
        
        @author Aaron Clinger
        @author Jon Adams
        @version 05/19/11
    */
    public class AlignUtil {
        public static const BOTTOM:String        = 'bottom';
        public static const BOTTOM_CENTER:String = 'bottomCenter';
        public static const BOTTOM_LEFT:String   = 'bottomLeft';
        public static const BOTTOM_RIGHT:String  = 'bottomRight';
        public static const CENTER:String        = 'center';
        public static const LEFT:String          = 'left';
        public static const MIDDLE:String        = 'middle';
        public static const MIDDLE_CENTER:String = 'middleCenter';
        public static const MIDDLE_LEFT:String   = 'middleLeft';
        public static const MIDDLE_RIGHT:String  = 'middleRight';
        public static const RIGHT:String         = 'right';
        public static const TOP:String           = 'top';
        public static const TOP_CENTER:String    = 'topCenter';
        public static const TOP_LEFT:String      = 'topLeft';
        public static const TOP_RIGHT:String     = 'topRight';
        
        
        /**
            Aligns a DisplayObject to the bounding Rectangle acording to the defined alignment.
            
            @param alignment: The alignment type/position.
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param outside: Align the DisplayObject to the outside of the bounds true, or the inside false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function align(alignment:String, displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false, targetCoordinateSpace:DisplayObject = null):void {
            const offsetPosition:Point = DisplayObjectUtil.getOffsetPosition(displayObject);
            
            switch (alignment) {
                case AlignUtil.TOP :
                case AlignUtil.MIDDLE :
                case AlignUtil.BOTTOM :
                    break;
                default :
                    displayObject.x = offsetPosition.x;
            }
            
            switch (alignment) {
                case AlignUtil.LEFT :
                case AlignUtil.CENTER :
                case AlignUtil.RIGHT :
                    break;
                default :
                    displayObject.y = offsetPosition.y;
            }
            
            const alignPosition:Point   = AlignUtil._getPosition(alignment, displayObject.width, displayObject.height, bounds, outside);
            const relPosition:Rectangle = displayObject.getBounds((targetCoordinateSpace == null) ? displayObject : targetCoordinateSpace);
            
            switch (alignment) {
                case AlignUtil.TOP :
                case AlignUtil.MIDDLE :
                case AlignUtil.BOTTOM :
                    break;
                default :
                    displayObject.x += alignPosition.x - relPosition.x;
                    
                    if (snapToPixel)
                        displayObject.x = Math.round(displayObject.x);
            }
            
            switch (alignment) {
                case AlignUtil.LEFT :
                case AlignUtil.CENTER :
                case AlignUtil.RIGHT :
                    break;
                default :
                    displayObject.y += alignPosition.y - relPosition.y;
                    
                    if (snapToPixel)
                        displayObject.y = Math.round(displayObject.y);
            }
        }
        
        /**
            Aligns a Rectangle to another Rectangle.
            
            @param align: The alignment type/position.
            @param rectangle: The Rectangle to align.
            @param bounds: The area in which to align the Rectangle.
            @param snapToPixel: Force the position to whole pixels true, or to let the Rectangle be positioned on sub-pixels false.
            @param outside: Align the Rectangle to the outside of the bounds true, or the inside false.
            @return A new aligned Rectangle.
        */
        public static function alignRectangle(alignment:String, rectangle:Rectangle, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false):Rectangle {
            const alignedRectangle:Rectangle = rectangle.clone();
            
            alignedRectangle.offsetPoint(AlignUtil._getPosition(alignment, rectangle.width, rectangle.height, bounds, outside));
            
            if (snapToPixel) {
                alignedRectangle.x = Math.round(alignedRectangle.x);
                alignedRectangle.y = Math.round(alignedRectangle.y);
            }
            
            return alignedRectangle;
        }
        
        /**
            Aligns a DisplayObject to the nearest Pixel.
            
            @param displayObject: The DisplayObject to align.
        */
        public static function alignToPixel(displayObject:DisplayObject):void {
            displayObject.x = Math.round(displayObject.x);
            displayObject.y = Math.round(displayObject.y);
        }
        
        /**
            Aligns a DisplayObject to the bottom of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param outside: Align the DisplayObject to the outside of the bounds true, or the inside false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignBottom(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.BOTTOM, displayObject, bounds, snapToPixel, outside, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the bottom left of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param outside: Align the DisplayObject to the outside of the bounds true, or the inside false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignBottomLeft(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.BOTTOM_LEFT, displayObject, bounds, snapToPixel, outside, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the bottom and horizontal center of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param outside: Align the DisplayObject to the outside of the bounds true, or the inside false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignBottomCenter(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.BOTTOM_CENTER, displayObject, bounds, snapToPixel, outside, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the bottom right of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param outside: Align the DisplayObject to the outside of the bounds true, or the inside false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignBottomRight(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.BOTTOM_RIGHT, displayObject, bounds, snapToPixel, outside, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the horizontal center of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignCenter(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.CENTER, displayObject, bounds, snapToPixel, false, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the left side of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param outside: Align the DisplayObject to the outside of the bounds true, or the inside false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignLeft(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.LEFT, displayObject, bounds, snapToPixel, outside, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the vertical middle of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignMiddle(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.MIDDLE, displayObject, bounds, snapToPixel, false, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the vertical middle and left side of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param outside: Align the DisplayObject to the outside of the bounds true, or the inside false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignMiddleLeft(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.MIDDLE_LEFT, displayObject, bounds, snapToPixel, outside, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the vertical middle and horizontal center of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignMiddleCenter(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.MIDDLE_CENTER, displayObject, bounds, snapToPixel, false, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the vertical middle and right side of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param outside: Align the DisplayObject to the outside of the bounds true, or the inside false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignMiddleRight(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.MIDDLE_RIGHT, displayObject, bounds, snapToPixel, outside, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the right side of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param outside: Align the DisplayObject to the outside of the bounds true, or the inside false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignRight(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.RIGHT, displayObject, bounds, snapToPixel, outside, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the top of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param outside: Align the DisplayObject to the outside of the bounds true, or the inside false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignTop(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.TOP, displayObject, bounds, snapToPixel, outside, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the top left of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param outside: Align the DisplayObject to the outside of the bounds true, or the inside false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignTopLeft(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.TOP_LEFT, displayObject, bounds, snapToPixel, outside, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the top side and horizontal center of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param outside: Align the DisplayObject to the outside of the bounds true, or the inside false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignTopCenter(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.TOP_CENTER, displayObject, bounds, snapToPixel, outside, targetCoordinateSpace);
        }
        
        /**
            Aligns a DisplayObject to the top right of the bounding Rectangle.
            
            @param displayObject: The DisplayObject to align.
            @param bounds: The area in which to align the DisplayObject.
            @param snapToPixel: Force the position to whole pixels true, or to let the DisplayObject be positioned on sub-pixels false.
            @param outside: Align the DisplayObject to the outside of the bounds true, or the inside false.
            @param targetCoordinateSpace: The display object that defines the coordinate system to use. Specify if the displayObject is not in the same scope as the desired coordinate space, or null to use the displayObject's coordinate space.
        */
        public static function alignTopRight(displayObject:DisplayObject, bounds:Rectangle, snapToPixel:Boolean = true, outside:Boolean = false, targetCoordinateSpace:DisplayObject = null):void {
            AlignUtil.align(AlignUtil.TOP_RIGHT, displayObject, bounds, snapToPixel, outside, targetCoordinateSpace);
        }
        
        protected static function _getPosition(alignment:String, targetWidth:uint, targetHeight:uint, bounds:Rectangle, outside:Boolean):Point {
            const position:Point = new Point();
            
            switch (alignment) {
                case AlignUtil.BOTTOM_LEFT :
                case AlignUtil.LEFT :
                case AlignUtil.MIDDLE_LEFT :
                case AlignUtil.TOP_LEFT :
                    position.x = outside ? bounds.x - targetWidth : bounds.x;
                    break;
                case AlignUtil.BOTTOM_CENTER :
                case AlignUtil.CENTER :
                case AlignUtil.MIDDLE_CENTER :
                case AlignUtil.TOP_CENTER :
                    position.x = (bounds.width - targetWidth) * 0.5 + bounds.x;
                    break;
                case AlignUtil.BOTTOM_RIGHT:
                case AlignUtil.MIDDLE_RIGHT:
                case AlignUtil.RIGHT:
                case AlignUtil.TOP_RIGHT:
                    position.x = outside ? bounds.right : bounds.right - targetWidth;
                    break;
            }
            
            switch (alignment) {
                case AlignUtil.TOP:
                case AlignUtil.TOP_CENTER:
                case AlignUtil.TOP_LEFT:
                case AlignUtil.TOP_RIGHT:
                    position.y = outside ? bounds.y - targetHeight : bounds.y;
                    break;
                case AlignUtil.MIDDLE :
                case AlignUtil.MIDDLE_CENTER :
                case AlignUtil.MIDDLE_LEFT :
                case AlignUtil.MIDDLE_RIGHT :
                    position.y = (bounds.height - targetHeight) * 0.5 + bounds.y;
                    break;
                case AlignUtil.BOTTOM:
                case AlignUtil.BOTTOM_CENTER:
                case AlignUtil.BOTTOM_LEFT:
                case AlignUtil.BOTTOM_RIGHT:
                    position.y = outside ? bounds.bottom : bounds.bottom - targetHeight;
                    break;
            }
            
            return position;
        }
    }
}