topical media & game development
lib-flex-book-com-rubenswieringa-geom-Geom.ax
lib-flex-book-com-rubenswieringa-geom-Geom.ax
(swf
)
[ flash
]
flex
package com.rubenswieringa.geom {
import flash.geom.*;
import flash.display.Graphics;
import com.rubenswieringa.utils.*;
import com.rubenswieringa.drawing.*;
All-static class providing functionality for making basic geometric calculations.
@author Ruben Swieringa
ruben.swieringa@gmail.com
www.rubenswieringa.com
www.rubenswieringa.com/blog
@version 1.0.0
edit 9b*
* This class is a slightly stripped-down version of the original @ax-lib-flex-book-com-rubenswieringa-geom-Geom class (the unfinished methods isClockwise() and trim() have been removed)
Before modifying and/or redistributing this class, please contact Ruben Swieringa (ruben.swieringa@gmail.com).
View code documentation at:
http://www.rubenswieringa.com/code/as3/flex/@file/docs/
*
public class @ax-lib-flex-book-com-rubenswieringa-geom-Geom {
String representation for top.
public static const TOP:String = "top";
String representation for left.
public static const LEFT:String = "left";
String representation for bottom.
public static const BOTTOM:String = "bottom";
String representation for right.
public static const RIGHT:String = "right";
String representation for top-left.
public static const TL:String = "topleft";
String representation for bottom-left.
public static const BL:String = "bottomleft";
String representation for bottom-right.
public static const BR:String = "bottomright";
String representation for top-right.
public static const TR:String = "topright";
@see @ax-lib-flex-book-com-rubenswieringa-geom-Geom#getHVLineIntersection()
@private
protected static const HORIZONTAL:String = "h";
@see @ax-lib-flex-book-com-rubenswieringa-geom-Geom#getHVLineIntersection()
@private
protected static const VERTICAL:String = "v";
Constructor.
@private
public function @ax-lib-flex-book-com-rubenswieringa-geom-Geom ():void {}
Calculates angle (in radians) between two Points.
@param point1 Point
@param point2 Point
@return Number
public static function getAngle (point1:Point, point2:Point):Number {
return Math.atan2(point2.y-point1.y, point2.x-point1.x);
}
Takes a value and transforms it from degrees into radians.
@param radians An angle in radians.
@return The angle in degrees.
@see @ax-lib-flex-book-com-rubenswieringa-geom-Geom#radians()
public static function degrees (radians:Number):Number {
return radians * 180 / Math.PI;
}
Takes a value and transforms it from radians into degrees.
@param degrees An angle in degrees.
@return The angle in radians.
@see @ax-lib-flex-book-com-rubenswieringa-geom-Geom#degrees()
public static function radians (degrees:Number):Number {
return Math.PI / 180 * degrees;
}
Calculates the position of Point #2, which is positioned on a certain amount of pixels (radius parameter) from Point #1 (point parameter) at a certain angle (angle parameter).
@param point Point #1.
@param angle The angle (in radians) that Point #2 makes with Point #1.
@param radius The distances between Point #1 and Point #2.
@return Point #2.
public static function getPointFromAngle (point:Point, angle:Number, radius:Number):Point {
var x:Number = point.x + radius * Math.cos(angle);
var y:Number = point.y + radius * Math.sin(angle);
return new Point(x, y);
}
Indicates whether or not a Point is in a certain corner of a Rectangle.
@param rect Rectangle who's area to inspect.
@param point Point of which to find out whether or not it is in the specified corner of rect.
@param corner Either @ax-lib-flex-book-com-rubenswieringa-geom-Geom.TL, @ax-lib-flex-book-com-rubenswieringa-geom-Geom.TR, @ax-lib-flex-book-com-rubenswieringa-geom-Geom.BR, or @ax-lib-flex-book-com-rubenswieringa-geom-Geom.BL.
@param triangular If true, the Rectangle is imaginary split in half diagonally before the calculations are conducted. If false, the method will use Rectangle corners instead of triangular ones.
@see @ax-lib-flex-book-com-rubenswieringa-geom-Geom#TL
@see @ax-lib-flex-book-com-rubenswieringa-geom-Geom#TR
@see @ax-lib-flex-book-com-rubenswieringa-geom-Geom#BR
@see @ax-lib-flex-book-com-rubenswieringa-geom-Geom#BL
@return true if point is in the specified corner of rect.
public static function isPointInCorner (rect:Rectangle,
point:Point,
corner:String,
triangular:Boolean=true):Boolean {
// if the value of the corner parameter is invalid, return false:
if (corner != @ax-lib-flex-book-com-rubenswieringa-geom-Geom.BL &&
corner != @ax-lib-flex-book-com-rubenswieringa-geom-Geom.BR &&
corner != @ax-lib-flex-book-com-rubenswieringa-geom-Geom.TL &&
corner != @ax-lib-flex-book-com-rubenswieringa-geom-Geom.TR){
return false;
}
// if the Rectangle does not contain Point at all, return false:
if (!rect.containsPoint(point)){
return false;
}
// find out whether or not the provided corner of Rectangle contains Point:
if (triangular){
var value:Boolean;
var relativeMouse:Point = new Point(point.x-rect.x, point.y-rect.y);
// if we're working with an imaginary seperation-line going from top-right to bottom-left:
if (relativeMouse.y*(rect.width/rect.height) > relativeMouse.x){
if (corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.BL) value = true;
if (corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.TR) value = false;
}else{
if (corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.BL) value = false;
if (corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.TR) value = true;
}
// if we're working with an imaginary seperation-line going from top-left to bottom-right:
if (rect.width-(relativeMouse.y*(rect.width/rect.height)) > relativeMouse.x){
if (corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.TL) value = true;
if (corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.BR) value = false;
}else{
if (corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.TL) value = false;
if (corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.BR) value = true;
}
// return value:
return value;
}else{
// create inner Rectangle describing the value of the corner parameter provided:
var innerRect:Rectangle = rect.clone();
if (corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.TR || corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.BR) innerRect.left = rect.x + rect.width/2;
if (corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.TL || corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.BL) innerRect.width = rect.width/2;
if (corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.TR || corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.TL) innerRect.height = rect.height/2;
if (corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.BR || corner == @ax-lib-flex-book-com-rubenswieringa-geom-Geom.BR) innerRect.top = rect.y + rect.height/2;
// return value:
return innerRect.containsPoint(point);
}
}
Returns an Array of Points indicating where a Line intersects with a Rectangle.
This method loops through all sides (Lines) of a Rectangle and stores intersections in the returned Array.
Note that instead of looking up (for instance) the bottom intersection by using 2 as an index value om the returned Array, you can also use the BOTTOM constant of the SuperRectangle class. Needless to say, the same goes for the TOP, RIGHT, and LEFT constants of the SuperRectangle class.
@param line A Line instance.
@param rect A Rectangle instance.
@param includeNull When set to true non-intersections values (when the getHVLineIntersection method returns null) are also inserted into the returned Array. This might come in handy when you want to find out where an intersection from the Array occured, the first value in the Array (0) is actually the returned intersection with the top side of the Rectangle, the second (1) is the intersection with the right side of the Rectangle, and so forth. This parameter defaults to false.
@see @ax-lib-flex-book-com-rubenswieringa-geom-Geom#getHLineIntersection()
@see @ax-lib-flex-book-com-rubenswieringa-geom-Geom#getVLineIntersection()
@see Line
@see SuperRectangle
@see SuperRectangle#TOP
@see SuperRectangle#RIGHT
@see SuperRectangle#BOTTOM
@see SuperRectangle#LEFT
@return Array
public static function getRectIntersections (line:Line,
rect:Rectangle,
includeNull:Boolean=false):Array {
var intersections:Array = [];
var lines:Array = SuperRectangle.createSuperRectangle(rect).getLines();
var intersection:Point;
for (var i:int=0; i<lines.length; i++){
intersection = Line.getIntersection(line, lines[i]);
if (intersection != null || includeNull){
intersections.push(intersection);
}
}
return intersections;
}
Indicates whether or not two Points are in such a position on a SuperRectangle its border that they need extra inbetween Points to describe the inbetween path from one to another along the SuperRectangle its border. This method is typically used by the trim method.
@see @ax-lib-flex-book-com-rubenswieringa-geom-Geom#trim()
@private
protected static function needsCorners (point1:Object, point2:Object, rect:SuperRectangle):Boolean {
if (point1.isOriginal != point2.isOriginal){
var one:Object = (point1.isOriginal) ? point2 : point1;
var two:Object = (point2.isOriginal) ? point2 : point1;
if (!one.parent.a.equals(two.point) && !one.parent.b.equals(two.point)){
return true;
}
}
if (!point1.isOriginal && !point2.isOriginal){
if (!point1.parent.equals(point2.parent)){
if (rect.isOnSide(point1.point) != rect.isOnSide(point2.point)){
return true;
}
if (rect.isOnSide(point1.point) == rect.isOnSide(point2.point)){
switch (rect.isOnSide(point1.point)){
case SuperRectangle.NONE :
return true;
case SuperRectangle.TOP :
if (point2.point.x < point1.point.x) return true;
case SuperRectangle.RIGHT :
if (point2.point.y < point1.point.y) return true;
case SuperRectangle.BOTTOM :
if (point2.point.x > point1.point.x) return true;
case SuperRectangle.LEFT :
if (point2.point.y > point1.point.y) return true;
}
}
}
}
return false;
}
Returns the Array index of the Point that is the nearest to a given coordinate.
@param area An Array consisting of Points.
@param point Point for which to look up the nearest coordinate.
@return Index of the nearest Point. Returns -1 if no Point instance was found in the provided Array.
public static function getNearest (area:Array, point:Point):int {
var nearest:int = -1;
for (var i:int=0; i<area.length; i++){
if (area[i] == null || !(area[i] is Point)){
continue;
}
if (nearest == -1 || Point.distance(area[i], point) < Point.distance(area[nearest], point)){
nearest = i;
}
}
return nearest;
}
Returns the coordinates of a star shape.
@param radius The radius of the outer corners of the star.
@param center Center of the star.
@param rotation Rotation (radians) of the star.
@param points Amount of points (outer corners) that the star has. Defaults to 5.
@returns Array of Points.
public static function star (radius:Number,
center:Point,
rotation:Number=0,
points:uint=5):Array {
var area:Array = [];
var angle:Number = (Math.PI*2) / (points*2);
rotation -= Math.PI/2;
for (var i:int=0; i<points; i++){
area.push(@ax-lib-flex-book-com-rubenswieringa-geom-Geom.getPointFromAngle(center, rotation+angle*(i*2), radius));
area.push(@ax-lib-flex-book-com-rubenswieringa-geom-Geom.getPointFromAngle(center, rotation+angle*(i*2+1), radius/2));
}
return area;
}
}
}
(C) Æliens
18/6/2009
You may not copy or print any of this material without explicit permission of the author or the publisher.
In case of other copyright issues, contact the author.
